In recent years, much publicity has been directed to the fraudulent claims in anti-abortion rhetoric that abortion increases a woman's risk of developing breast cancer. This never actually amounted to more than a tenuous suggestion that there might be an association of slightly increased risk of breast cancer with delaying first pregnancy until the late twenties (possibly implicating abstinence no less than abortion?). Anti-abortion propagandists jumped on this and twisted and distorted what meager suggestions there were into a big scare campaign. There are simply no reputable scientific studies that support this. Furthermore, they are not considered warranted by organizations including the American Cancer Society, National Cancer Institute, National Breast Cancer Coalition, World Health Organization, Center for Reproductive Law and Policy, Alan Guttmacher Institute, Planned Parenthood Federation of America, and others. Impervious to reality and truth, however, anti-abortion propagandists make the preposterous claim that these groups are conspiring in a "pro-abortion cover up" of the "abortion-breast cancer link."
Even if it were true, the best even the anti-abortion propagandists could come up with was a possible, highly questionable increase that was tiny when the statistical results were truthfully examined - sort of like doubling your chance of winning the lottery if you buy two tickets instead of only one. Although one's chances of winning the jackpot actually are thereby doubled, which sounds like a lot when stated in that way, the likelihood is still minute. That's hardly a reasonable argument for banning or restricting abortion or for even regarding breast cancer as a risk factor in abortion. Some studies suggest that just one alcohol-containing drink a day, or even less (maybe even wine consumed in the sacrament of Communion, or even the wine for the multitudes Jesus is storied to have miraculously produced from water?), might carry a similar or even greater increased risk of breast cancer than that claimed for abortion, but, as far as I know, no knowledgeable, honest, and sane person is seriously calling for prohibition of alcohol as a public health measure to reduce the incidence of breast cancer.
It is widely accepted that carrying a pregnancy to term before age 30 helps to protect women against breast cancer. Women who terminate their pregnancies forgo this slight protective effect, but that does not mean abortion itself increases the risk of cancer. The main studies that implicate abortion as a risk factor were conducted by asking women with breast cancer about their medical histories. Researchers then compared the answers of those subjects to those of similar women who had not developed cancer. There was a small correlation between abortion and cancer, and it was especially noted among women who had ended pregnancies as teenagers. However, researchers of the American Cancer Society and other highly reputable cancer research bodies rightly contend that such studies are not reliable because women who have developed cancer are far more likely to report every detail of their histories than women who are healthy, especially when it involves admitting to strangers conducting surveys something as controversial and private as having had an abortion in the past. They put more stock in studies such as a 1997 review from Denmark, which looked at the medical charts of every woman in the country born over several decades. Every abortion and case of cancer in Denmark is required by law to be reported to a national registry. Scouring those databanks, researchers found no correlation between abortions and breast tumors.
Skeptics also point out that even the studies implicating abortion as a risk factor show it is no more significant than other documented but rarely fretted about ones, such as living in an urban area, being tall, or having an advanced education, as well as the very minor consumption of alcoholic beverages mentioned above. Abortion rights advocates' position is that it is not only unnecessary but also irresponsible to raise the issue with patients. It just adds unnecessary stress and anguish at a very stressful time in their lives, and can even lead to a lifelong dread of cancer.
I would have no objection at all to advising teenagers of a risk of breast cancer associated with abortion if it were known to be true and if I thought it would accomplish anything but possibly unnecessarily creating a lifelong and possibly debilitating fear of cancer - in fact I would insist that they be warned of any real risk.
Furthermore, if this alleged breast cancer risk were real and due to delaying pregnancy beyond the teenage years as they claim, would this not mean that they should also be warned against abstinence or against delaying pregnancy and childbirth much beyond puberty?
Background It has been hypothesized that an interrupted pregnancy might increase a woman's risk of breast cancer because breast cells could proliferate without the later protective effect of differentiation.
Methods We established a population-based cohort with information on parity and vital status consisting of all Danish women born from April 1, 1935, through March 31, 1978. Through linkage with the National Registry of Induced Abortions, information on the number and dates of induced abortions among those women was combined with information on the gestational age of each aborted fetus. All new cases of breast cancer were identified through linkage with the Danish Cancer Registry.
Results In the cohort of 1.5 million women (28.5 million person-years), we identified 370,715 induced abortions among 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for known risk factors, induced abortion was not associated with an increased risk of breast cancer (relative risk, 1.00; 95 percent confidence interval, 0.94 to 1.06). No increases in risk were found in subgroups defined according to age at abortion, parity, time since abortion, or age at diagnosis of breast cancer. The relative risk of breast cancer increased with increasing gestational age of the fetus at the time of the most recent induced abortion: <7 weeks, 0.81 (95 percent confidence interval, 0.58 to 1.13); >12 weeks, 1.38 (1.00 to 1.90) (reference category, 9 to 10 weeks).
ConclusionsInduced abortions have no overall effect on the risk of breast cancer.
A full-term pregnancy increases a woman's short-term risk of breast cancer, possibly as a result of the growth-enhancing properties of pregnancy-induced estrogen secretion. By contrast, such a pregnancy decreases the long-term risk of breast cancer, perhaps by inducing terminal differentiation of the susceptible mammary cells.1, 2, 3, 4, 5 Studies in animals suggest that the potential for terminal differentiation of breast cells is lower for a pregnancy terminated by abortion than for a full-term pregnancy. On this basis Russo and Russo3 have proposed that a full-term pregnancy allows complete differentiation of breast cells, thereby protecting against cancer, whereas an abortion forestalls the late protective effect of differentiation, thereby increasing the risk of breast cancer.
Epidemiologic studies of the association between abortion and the subsequent risk of breast cancer have yielded inconsistent results, with estimates of risk ranging from moderately elevated to significantly lowered.6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 In a recent case–control study, Daling et al. found evidence of an elevated risk in women who had an induced abortion between 9 and 12 weeks' gestation, but this finding was based on a very limited number of women.7 In the present study, we took advantage of Denmark's mandatory reporting of all induced abortions, together with the week of gestation, to evaluate the hypothesis of Russo and Russo.3
MethodsBefore initiating this study, we obtained permission from Denmark's National Scientific Ethics Committee and Data Protection Board. For this investigation we linked data from the Civil Registration System (CRS) with data from the National Registry for Induced Abortions and the Danish Cancer Registry. Since April 1, 1968, the CRS has assigned a unique identification number to all Danish residents, which permits information from different registries to be linked. The CRS also keeps updated files on the dates of live births and documents demographic variables such as emigration and deaths.
The reporting of induced abortions to the National Board of Health has been mandatory since 1939. In 1973, the legal right to an induced abortion through 12 weeks' gestation was established for women with residence in Denmark. Induced abortions after week 12 were permitted under medical or other circumstances, such as rape, that could greatly interfere with the proper care of the newborn child. Since 1973, information on all induced abortions, including the date of the procedure and the week of gestation at the time, has been computerized in the national registry of induced abortions.25 The induced abortions included in this analysis (those occurring between 1973 and 1992) were performed almost exclusively by surgical removal.
The Danish Cancer Registry contains information on all cases of cancer diagnosed in the country since 1943. It receives reports from clinicians, pathologists, clinics, radiotherapy units, and hospitals. 26
SubjectsA research data base comprising all Danish women born between April 1, 1935, and March 31, 1978, and including information on any live-born children, was established on the basis of information from the CRS. The individually identifiable CRS numbers were used to form a link with the national registry of induced abortions, which supplied information on the date of any induced abortion and the gestational age of the aborted fetus. Subjects' CRS numbers were subsequently linked with the Danish Cancer Registry to identify the subjects with a diagnosis of invasive breast cancer.
Statistical AnalysisFollow-up for breast cancer for all the women began on April 1, 1968, or on their 12th birthday, whichever came later. The period at risk continued until a diagnosis of breast cancer, death, emigration, loss to follow-up, or December 31, 1992 (at which date the cancer registry was considered complete) — whichever occurred first. The possible effect of the duration of the pregnancies that ultimately ended in induced abortions was investigated in a log-linear Poisson regression model.27 The numbers of person-years at risk were calculated for groups defined according to the week of gestation for induced abortions that took place at less than 7, 7 to 8, 9 to 10, 11 to 12, 13 to 14, 15 to 18, and more than 18 weeks' gestation. Women with more than one induced abortion were, in the period between the first and second abortion, considered at risk according to the week of gestation at the time of the first induced abortion; between the second and third abortions they were considered at risk according to the week of gestation at the time of the second induced abortion; and so on.
Adjustment was made for attained age in one-year intervals and for the calendar period in which the abortion occurred (1968–1972, 1973–1977, 1978–1982, 1983–1987, and 1988–1992), parity (0, 1, 2, 3, 4, 5, 6, and >7), and age at delivery of a first child (12 to 19, 20 to 24, 25 to 29, 30 to 34, and >34 years). In an exploratory analysis we also categorized the women according to calendar period and age at first delivery in one-year intervals, but this had no effect on the results — a finding that argues against residual confounding. For simplicity, the attained age of a woman is denoted as her "age at the time of diagnosis of breast cancer." "Calendar period" and "calendar period at time of diagnosis of breast cancer" are used synonymously. Tests for trend were performed with gestational age treated as a continuous variable and the mean gestational age used as the value for each group. Rate ratios for the incidence of breast cancer were estimated with the use of the SAS procedures software package PROC GENMOD.28 These rate ratios are referred to as relative risks in this article.
ResultsOverall, 1,529,512 women were included in the cohort. Of these, 280,965 (18.4 percent) had a total of 370,715 induced abortions, distributed as follows: 215,902 women (76.8 percent) each had one induced abortion; 47,906 women (17.1 percent) each had two; and 17,157 women (6.1 percent) each had three or more. The distribution of the number of induced abortions according to gestational age was as follows: less than 7 weeks, 3.1 percent; 7 to 8 weeks, 37.1 percent; 9 to 10 weeks, 41.8 percent; 11 to 12 weeks, 15.7 percent; more than 12 weeks, 2.3 percent. Women without a history of induced abortion accounted for 25,850,000 person-years of follow-up. In this group, there were 8908 cases of breast cancer. In comparison, among women with a history of induced abortion, accounting for 2,697,000 person-years of follow-up, there were 1338 cases of breast cancer.
Overall, the risk of breast cancer in women with a history of induced abortion was not different from that in women without such a history, after potential confounding by age, parity, age at delivery of a first child, and calendar period was taken into account (relative risk, 1.00; 95 percent confidence interval, 0.94 to 1.06).
Table 1 presents the association between variables related to abortion history and the risk of breast cancer. We calculated both the relative risk adjusted for age, parity, calendar period, and age at first delivery and the further adjusted multivariate relative risk (adjusted also for the other variables shown in the table). The adjustment had little or no effect on any of the risk estimates. Age at the time of the induced abortion did not significantly influence the overall risk, but there was a tendency toward a higher risk of breast cancer among women in the lowest age category — between 12 and 19 years of age (relative risk, 1.29; 95 percent confidence interval, 0.80 to 2.08). Neither the number of induced abortions nor whether or not the woman had given birth to a live infant (i.e., whether the induced abortion occurred in a nulliparous woman or either before or after a live birth) significantly influenced the risk of breast cancer. We also examined the time interval between the induced abortion and the diagnosis of breast cancer but found no indication of a differential effect (<1 year, relative risk = 0.97; 1 to 4 years, relative risk = 0.99; >5 years, relative risk = 1 [reference category]) (Table 1).
Table 1. Adjusted Relative Risk of Breast Cancer in Women with a History of Induced Abortion.
There was no effect of induced abortion on the risk of breast cancer after adjustment for the ages of the women at the time of the diagnosis of breast cancer (12 to 34 years, relative risk = 0.95 [95 percent confidence interval, 0.78 to 1.14]; 35 to 39 years, relative risk = 0.99 [0.87 to 1.14]; 40 to 44 years, relative risk = 1.01 [0.91 to 1.12]; 45 to 49 years, relative risk = 1 [reference category]; >50 years, relative risk = 1.03 [0.88 to 1.21]; P for trend = 0.97). Also, neither the calendar period at the time of diagnosis of breast cancer (P = 0.17) nor the calendar period at the time of induced abortion (P = 0.83) modified the relation between induced abortion and the risk of breast cancer.
With each one-week increase in the gestational age of the fetus, however, there was a 3 percent increase in the risk of breast cancer. The relative risk increased from 0.81 (95 percent confidence interval, 0.58 to 1.13) among women whose most recent induced abortion was at less than 7 weeks of gestation to 1.38 (95 percent confidence interval, 1.00 to 1.90) among women whose most recent abortion was at more than 12 weeks of gestation. We acknowledge the small number of cases in the group with abortions later than 12 weeks, but we evaluated this period further and found the following relative risks: weeks 13 to 14, 1.13 (95 percent confidence interval, 0.51 to 2.53); weeks 15 to 18, 1.23 (0.76 to 2.00); weeks >18, 1.89 (1.11 to 3.22) (P for trend = 0.016, Table 1).
DiscussionOur study of a population-based cohort uncovered no overall increased risk of breast cancer among women with a history of induced abortion. This result is very much in line with the results of previous retrospective cohort studies,9,10,15,16 two of which actually suggested a decreased risk.10,15 However, all previously published retrospective cohort studies lack detailed information on the week of gestation at the time of abortion. The results of case–control studies have been inconsistent,6,7,8,11,12,13,14,17,18,19, 20,21,22,23,24 but several groups have reported an increased risk of breast cancer among women with a history of induced abortion.7,8,13,21,22,23,24
A recent meta-analysis found an overall increased risk of breast cancer among women with a history of induced abortion of 1.3 (95 percent confidence interval, 1.2 to 1.4).24 The authors concluded that "such a broad base of statistical agreement rules out any reasonable possibility that the association is the result of bias or any other confounding variable." However, since almost all 23 studies included in the analysis were case–control studies, it is not unreasonable to assume that many of them were inherently biased, making the pooled conclusions biased as well. Furthermore, the authors based their results on a crude analysis of published odds ratios and relative risks with no attempt to incorporate the original raw data into a more sophisticated statistical analysis.
Almost inevitably, case–control studies arouse concern about the potential problem of differential misclassification. Even after its legalization, abortion remains a sensitive issue. It is possible that women with breast cancer might be more willing to report induced abortions than healthy women. A Swedish study that compared registry information with interview data regarding induced abortion attributed an increase in the risk of breast cancer of between 16 and 50 percent to differential misclassification in interview data. 7,29 The problem of misclassification based on reporting led Newcomb et al. to conclude that studies that do not rely on interviews with case and control subjects are necessary to resolve whether there is a link between induced abortion and breast cancer.8 In our study, all the information on dates and the number of induced abortions, reproductive history, and cancer diagnosis was obtained from national registries, which are compiled through a system of mandatory reporting for the entire population. Follow-up included complete information on death and emigration and was performed through computerized linkage of registry information by means of individually identifiable registration numbers. These measures, we believe, allowed us to avoid some of the major methodologic problems of previous studies.
A limitation of our research data base was that information on induced abortions has been computerized only since 1973. Therefore, we might have obtained an incomplete history of induced abortions for some of the oldest women in the cohort. However, we found that the risk of breast cancer among women with a history of induced abortion was no different from that among women without such a history, nor did we find that the number of induced abortions influenced the risk of breast cancer. Therefore, it is unlikely that missing information about abortions before 1973 affected the results of our analysis.
Induced abortion had no overall effect on the risk of breast cancer, but we found a statistically significant increase in risk among women with a history of second-trimester abortion. The fact that such an increase did not affect the overall result clearly indicates that it is based on small numbers and therefore requires cautious interpretation. The increased risk among women who had had second-trimester abortions finds biologic support in experiments in rats and is in line with the hypothesis of Russo and Russo.3
We were concerned that women whose breast cancer was diagnosed during pregnancy might have been advised to have induced abortions, a situation that would not be equally distributed according to the week of gestation at the time of the abortion. Since the time at risk was calculated only up to the diagnosis of breast cancer, only late abortions that were misclassified as occurring before the diagnosis of cancer could represent a problem. However, a stratified analysis of the risk of breast cancer according to the length of time since an induced abortion showed no differential risk and, in particular, no increased risk within the first year after abortion. Abortions induced at gestational ages of more than 12 weeks were performed primarily for medical or social reasons. The women who had such abortions could have had a relatively high risk of breast cancer, but we could not identify any medical condition associated with both a high risk and late induced abortion. Women with drinking problems might delay the interruption of their unwanted pregnancies, but the association between alcohol and breast cancer is weak and inconsistent.30
We cannot explain why a very early induced abortion was associated with a slight, although insignificant, decrease in risk. Nulliparous women with a history of induced abortion did not differ from parous women in their risk of breast cancer. Among nulliparous women, the possible effects of lactation and later births are irrelevant. We are therefore confident that neither of these variables had any confounding effect on our overall result.
Supported by grants from the Danish Cancer Society, the Danish National Research Foundation, and the U.S. Department of Defense (DAMD17-96-1-6321). Dr. Melbye is a Medical Research Council professor and is supported by the Danish Medical Research Council.
Source InformationFrom the Department of Epidemiology Research, Danish Epidemiology Science Center, Statens Serum Institut (M.M., J.W., M.F., T.W., P.K.A.), the Danish Cancer Registry (J.H.O.), and the National Board of Health (K.H.-L.) — all in Copenhagen, Denmark. The views expressed in this paper do not necessarily reflect the position or the policy of the U.S. government.
Address reprint requests to Dr. Melbye at the Department of Epidemiology Research, Danish Epidemiology Science Center, Statens Serum Institut, 5 Artillerivej, DK-2300 Copenhagen S, Denmark.
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Early studies of breast cancer raised substantial concern regarding risk associated with induced abortion and miscarriage. Literature reviews suggest that study findings depend heavily on the comparison group and that the use of parous women as a reference group for nulliparous women may artificially inflate risk. To examine the individual effects of induced abortion and miscarriage on breast cancer risk of parous and nulliparous women, 744 patients 40 years of age and diagnosed from 1983-1988 were matched by parity, age, and race with controls living in the same neighborhood in Los Angeles County. In-person interviews were conducted to obtain a detailed reproductive history. Risk estimates were obtained by conditional logistic regression using nulligravid women as the reference group for nulliparous women with a history of incomplete pregnancy and parous women with no incomplete pregnancies as the reference group for parous women with a history of incomplete pregnancy. Breast cancer risk of parous women was unrelated to a history of miscarriage or induced abortion. Breast cancer risk was reduced among nulliparous women with a history of induced abortion relative to nulligravid women, although the risk estimate was imprecise. Risk declined as the number of induced abortions increased (P = 0.04). Our results do not support the hypothesis that induced abortion or miscarriage increase the breast cancer risk of young women.
The aim of this study is to prospectively assess pregnancy hormone levels as correlates of subsequent development of pre-eclampsia, a condition that has been shown to be inversely associated with breast cancer risk in the offspring. A cohort of 260 Caucasian women in Boston, Massachusetts, was followed through pregnancy. Maternal blood was collected at the 16th and 27th weeks of gestation, and 18 women were diagnosed with pre-eclampsia after blood collection. Information on sociodemographic variables and risk factors of pre-eclampsia was collected through an interviewer-administered questionnaire and review of medical records. At the 16th week, there was a nonsignificant positive association between progesterone levels and pre-eclampsia [relative risk (RR) = 1.63, 95% confidence interval (CI), 0.97-2.74, per 1 SD increase]. By the 27th week, the association between progesterone and pre-eclampsia was strengthened (RR = 2.65, 95% CI, 1.46-4.81, per SD), and sex hormone-binding globulin levels were somewhat inversely related to pre-eclampsia (RR = 0.61, 95% CI, 0.31-1.20, per SD). No difference was found with respect to prolactin, estradiol, and estriol levels. Our findings indicate that progesterone may have a role in the late manifestation of pre-eclampsia pathology but are also compatible with the hypothesis that increases in progesterone represent an early compensatory mechanism.
Human endometrium expresses TGF-ß and TGF-ß receptors where they regulate several endometrial biological activities implicated in embryo implantation, irregular bleeding, endometriosis, and cancer. In the present study, we determined the expression of Smads, intracellular signals that mediate TGF-ß receptors signals from the cell surface to the nucleus, in the endometrium as well as isolated endometrial epithelial (EEC) and stromal (ESC) cells. We also determined whether TGF-ß regulates the expression Smads and activates Smad3 in these cells and endometrial surface epithelial cell line (HES). Using semiquantitative RT-PCR, Western blot analysis, and immunohistochemistry, we found that endometrium, EEC, ESC, and HES express Smad3, -4, and -7 mRNA and protein and contain phosphorylated Smad3 (pSmad3). Smads and pSmad3 were localized in the epithelial and stromal cells with cytoplasmic/nuclear localization. TGF-ß in a dose- and time-dependent manner increased the expression of Smads mRNA and protein, the rate of pSmad3 activation, and Smad3 translocation into the nucleus in ESC and HES. The effect of TGF-ß on pSmad3 induction was, in part, abrogated by the pretreatment of HES and ESC with TGF-ß type II receptor antisense oligonucleotides. We conclude that human endometrium expresses the necessary components of Smad signaling pathway, whose expression and induction in endometrial epithelial and stromal cells are regulated by TGF-ß.
This work was supported in part by NIH Grant HD37432. This work was presented in part at the 49th Annual Meeting of the Society for Gynecological Investigation, Los Angeles, California, March 2002.
ST. PAUL, Minn. (AP) - Abortion politics led the state Health Department to publish unreliable information about a link between abortions and breast cancer, state health workers wrote in e-mails obtained by the Star Tribune of Minneapolis.
Government e-mails obtained under the state's open records laws reveal that a division director and others questioned an assertion on the department's Web site and in a pamphlet that having an abortion may increase the risk of breast cancer.
The statement, posted in late September, was viewed inside the Health Department as a disservice to citizens and damaging to the department's credibility, according to e-mails circulated in the department in October.
Critics of the department's position on abortion and breast cancer say the statement is designed to frighten women considering abortion.
The e-mails also show that Gov. Tim Pawlenty's office had a role in approving the language on breast cancer risk as well as another controversial statement on fetal pain.
Health Commissioner Dianne Mandernach in an interview defended the Web site and pamphlet and said Pawlenty, who opposes abortion, did not direct her to adopt the language. The decision on the wording was decided by both of them, she said.
Mary Manning, the department's director of health promotion and chronic diseases, which includes breast cancer, complained in one e-mail that the agency had taken an "untenable" scientific position.
Mandernach said in the interview that there are conflicting studies about the cancer risk. "We are not taking an inaccurate scientific position," she said.
Manning circulated a memo to her division's staff members in October, saying they should tell anyone who asks that having an abortion does not increase a woman's risk for breast cancer.
The e-mail cited findings of the National Cancer Institute. A panel of 100 breast cancer experts reviewed all the research and concluded last spring that some small, flawed studies published before the mid-1990s had found a link to breast cancer, but larger, more reliable studies showed no connection.
Manning told staff members that if anyone questioned the discrepancy between the institute and the Health Department's published position, he or she should be referred to higher-ups.
Manning did not return a telephone call from The Associated Press on Monday.
In October, the division's staff had became ``paralyzed,'' Manning said in an e-mail. Some feared that they would be fired for saying there is no increased cancer risk from abortion, she wrote in an e-mail.
As a result, Manning got permission from Mandernach to send the memo to the division staff.
The e-mails also reveal that an aide in Pawlenty's office communicated with the Health Department over the language on breast cancer risk and fetal pain.
According to the e-mails, Mandernach resisted a later effort by the governor's office to write part of her response to newspaper editorials that were critical of the abortion statements.
In an e-mail to Bob Schroeder, the governor's then-deputy chief of staff, Mandernach wrote that she had serious concerns about his suggested response.
"There are statements included that cause all loss of credibility for me with the Medical community. ... I hate to be a fly in the ointment, but I feel very strongly about this," she wrote in the Oct. 23 e-mail.
Schroeder later told Mandernach to use her best judgment in her response to the newspaper.
The abortion Web site and the pamphlet were developed by the Health Department to comply with a new state law. It requires the department to publish information about abortion risks and alternatives to ending a pregnancy.
The site was launched in July. Initially, it mentioned older studies that identified a breast cancer risk, but said the institute report and "newer studies have consistently shown no risk." On the question of fetal pain, the Web site said, "Experts are undecided about when the unborn child perceives pain. Research in this area is ongoing."
However, a department researcher had sent Mandernach a long e-mail summarizing the scientific research studies on fetal pain. Scientists know little about fetal pain, she said, but the consensus is that it starts at 26 weeks, not 20. That's the point when the fetus' brain develops the neural connections associated with pain, she said.
In late September, new language was posted, which said: "Findings from some studies suggest there is an increased risk of breast cancer among women who had an abortion, while findings from other studies suggest there is no increased risk."
Dr. Steven Miles, a professor of medicine at the University of Minnesota's Center for Bioethics, said of the abortion-cancer link: "Every medical association that has looked at this says the matter is closed. There is no relationship here."
On fetal pain, the Web site and pamphlet now say: "Some experts have concluded the unborn child feels physical pain after 20 weeks gestation."
Both Pawlenty and Minnesota Citizens Concerned for Life, an advocacy group that opposes abortion, were consulted, Mandernach said. Abortion rights advocates and those who provide abortion were not consulted, she said, nor did they initiate any feedback on their own.
Sarah Stoesz, chief executive officer of Planned Parenthood of Minnesota and South Dakota, said the information is manipulative.
Scott Fischbach, MCCL's executive director, said he believes the language on breast cancer risk and fetal pain is complete and accurate.
You may be interested to know that there is yet another excellent study that shows no increased risk of breast cancer after induced abortion. The study was based on about 100,000 women aged 40-65 who were members of the health insurance plan for teachers in France. Abortion history and many other variables were measured in 1990-91, and the participants were followed for about 9 years. The relative risk of developing breast cancer during the 9 years was .91 (95% confidence interval .82-.99). One could conclude that abortion is protective, but I wouldn't go that far and neither did the authors. Spontaneous abortion was also unrelated to subsequent breast cancer.
X. Paoletti, F. Clavel-Chapelon and the E3N group INSERM, Induced and spontaneous abortion and breast cancer risk: Results from the E3N cohort study, International J. of Cancer: 106, 270-276 (2003).
The effect of environmental/lifestyle factors on breast cancer risk may be modified by
genetic predisposition.
In a population-based case-control-family study performed in Germany including 706 cases by age 50 years, 1381 population, and 252 sister controls, we investigated main effects for environmental/lifestyle factors and genetic susceptibility and gene–environment interaction (G x E). Different surrogate measures for genetic predisposition using pedigree information were used: first-degree family history of breast or ovarian cancer; and gene carrier probability using a genetic model based on rare dominant genes. Possible G x E interaction was studied by (1) logistic regression using cases and population controls including an interaction term; (2) comparing results using sister controls and population controls; (3) case-only analysis with logistic regression and (4) a mixture logistic model.
ResultsFamilial predisposition showed the strongest main effect and the estimated gene carrier
probability gave the best fit. High parity and longer duration of breastfeeding reduced breast cancer risk
significantly, a history of abortions increased risk and age at menarche showed no significant effect. We
found significant G x E interaction between parity and genetic susceptibility using different surrogate
measures. In women most likely to have a high genetic susceptibility, high parity was less protective. Later
age at menarche was protective in women with a positive family history. No evidence for G x E interaction
was found for breastfeeding and abortion.
Conclusions
These findings corroborate results from other studies and provide further evidence that the magnitude of protection from parity is reduced in women most likely to have a genetic risk in spite of the limitations of using surrogate genetic measures.
Keywords Gene carrier probability, mixture logistic model, case-only design, population and sibling controls.Accepted 20 May 2003
Am J Epidemiol 2003; 158:798-806.
© 2003 by Johns Hopkins Bloomberg School of Public Health
1 Pennsylvania State University College of Medicine, Hershey, PA.
2 Meharry Medical College, Nashville, TN.
3 Current address: United States Military Cancer Institute, Walter Reed Army Medical Center, Washington, DC.
In this case-control study, the authors aimed to examine whether use of an electric bedding device increased breast cancer risk in African-American women. Cases were 304 African-American patients diagnosed with breast cancer during 1995-1998 who were aged 20-64 years and lived in one of three Tennessee counties. Controls were 305 African-American women without breast cancer who were selected through random digit dialing and frequency-matched to cases by age and county. Information on the use of an electric blanket or heated water bed and other risk factors was collected through telephone interviews. Breast cancer risk associated with use of an electric bedding device increased with the number of years of use, the number of seasons of use, and the length of time of use during sleep. When women who used an electric bedding device for more than 6 months per year (and therefore were more likely to have used a heated water bed, which generates lower magnetic fields) were excluded, the corresponding dose-response relations were more striking. Similar trends in dose response were shown in both premenopausal and postmenopausal women and for both estrogen receptor-positive and estrogen receptor-negative tumors. The use of electric bedding devices may increase breast cancer risk in African-American women aged 20-4 years. Such an association might not vary substantially by menopausal status or estrogen receptor status.
Key Words: bedding and linens; blacks; breast neoplasms; case-control studies; electromagnetic fields; women
Abbreviations: CI, confidence interval; EMF(s), electromagnetic field(s); ER, estrogen receptor; SES, socioeconomic status.
Am J Epidemiol, 2003; 157:185-194.
© 2003 by Johns Hopkins Bloomberg School of Public Health
This case-control study was associated with a regional register of ectopic pregnancy between 1993 and 2000 in France. It included 803 cases of ectopic pregnancy and 1,683 deliveries and was powerful enough to investigate all ectopic pregnancy risk factors. The main risk factors were infectious history (adjusted attributable risk = 0.33; adjusted odds ratio for previous pelvic infectious disease = 3.4, 95% percent confidence interval (CI): 2.4, 5.0) and smoking (adjusted attributable risk = 0.35; adjusted odds ratio = 3.9, 95% CI: 2.6, 5.9 for >20 cigarettes/day vs. women who had never smoked). The other risk factors were age (associated per se with a risk of ectopic pregnancy), prior spontaneous abortions, history of infertility, and previous use of an intrauterine device. Prior medical induced abortion was associated with a risk of ectopic pregnancy (adjusted odds ratio= 2.8, 95% CI: 1.1, 7.2); no such association was observed for surgical abortion (adjusted odds ratio = 1.1, 95% CI: 0.8, 1.6). The total attributable risk of all the factors investigated was 0.76. As close associations were found between ectopic pregnancy and infertility and between ectopic pregnancy and spontaneous abortion, further research into ectopic pregnancy should focus on risk factors common to these conditions. In terms of public health, increasing awareness of the effects of smoking may be useful for ectopic pregnancy prevention.
Key Words: abortion, induced; case-control studies; infertility, female; pregnancy, ectopic;
registries; risk factors; sexually transmitted diseases; tobacco
Abbreviation: CI, confidence interval.
J.
Clin. Invest. 112:973-977 (2003). doi:10.1172/JCI200319993.
©2003 by the American Society for Clinical Investigation.
Women have traditionally been underrepresented in clinical trials. In order to translate recent advances in our understanding of the molecular and physiological bases of sex differences into new therapeutics and health practices, sound sex-specific clinical data are imperative. Since the founding of the Office of Research on Women's Health within the Office of the Director at the NIH in 1990, inequities in federally funded biomedical research, diagnosis, and treatment of diseases affecting women in the U.S. have been reviewed. Discussed herein is the evolution of gender-related research innovations, primarily within the last decade, and strategies and challenges involved in the success of this recent development.
Medicine is the one discipline in American scientific endeavor in which reforms regarding the role of women as both researchers and research subjects have been institutionalized at the highest level. Adequately addressing women's health issues did not require new technical breakthroughs or simply more female doctors, though the latter helped facilitate change. Nor was women's greater equality in biomedical research a result of the presumed self-correcting mechanisms of objective science. As former director of the NIH, from 1991 to 1993, Bernadine Healy remarked, "research alone cannot correct the disparities, inequities, or insensitivities of the health care system" 1. Reforming certain aspects of how medical research is conducted with respect to the females required new judgments of social worth and a new political will. Even though much has been achieved in addressing issues important to women's health, critics call for continued innovation in medical theories and practices in this field.
Gender-biased medicineThe 1980s saw the great awakening of mainstream medicine to issues of womens' health. Researchers, both male and female, began to shower infamy upon several large and influential studies that omitted women as subjects of medical research. These most notably included (a) the Physicians' Health Study of the effects of aspirin on cardiovascular disease, in which 22,071 men and 0 women physicians were enrolled 2; (b) the Multiple Risk Factor Intervention Trial (MRFIT), a randomized trial conducted from 1973 to 1982 to evaluate correlations among blood pressure, smoking, cholesterol, and coronary heart disease in 12,866 men and 0 women 3; and (c) the National Institute on Aging's Baltimore Longitudinal Study of Aging, extending from 1958 to 1975 4, which excluded female subjects, despite the fact that women constitute two-thirds of the population over age 65. Perhaps most surprising is that the first study of the role of estrogen in preventing heart disease was conducted solely on men, as it was considered a possible treatment 5.
Women's health issues have not been entirely ignored. The well-known Framingham Heart Study, initiated in 1948, has long stood as the benchmark epidemiological study on cardiovascular health and included slightly more women than men 6. The Nurses' Health Study I and II, established in 1976 and 1989, respectively, followed large numbers of registered female nurses, initially to study the long-term use of oral contraceptives,and has been used over the years to look at other health issues, such as the correlation between low-dose aspirin administration and risk of heart attack in women. Unlike the Physicians' Health Study, the Nurses' Health Study was an observational investigation, not a more costly, randomized clinical trial 7. Like the study of male physicians, the study of female nurses evaluated predominantly white, health-conscious populations.
Is what's good for the gander good for the goose?Until 1988, clinical trials of new drugs by the U.S. Food and Drug Administration (FDA) were routinely conducted predominantly on men 8, even though women consume approximately 80% of pharmaceuticals in the US. The results of male-only clinical trials have led to the development of diagnoses, preventive measures, and treatments that are commonly extrapolated to women, yet the reverse is rare. In 1992, a survey by the US General Accounting Office, the body responsible for the audit, evaluation, and investigation of Congressional policy and funding decisions, found that less than half of publicly available prescription drugs had been analyzed for sex-related response differences 9. A consequence of extrapolating the results of male-only clinical data to female consumers is that women were (and still are) typically prescribed dosages devised for men's average weights and metabolisms. For example, it is now known that acetaminophen, an ingredient in many pain relievers, is eliminated by the female body at approximately 60% the rate of elimination documented in men 10.
The administration of drugs to women at dosages designed for men can place women at risk for overdose. Furthermore, while little is known about the effects of aspirin on heart disease in women, postmenopausal women, like men, have been encouraged to take aspirin daily. The effects of other widely used drugs, such as Valium, were never tested in randomized clinical trials with female subjects, although 2 million women per year consume this drug to control conditions such as anxiety, epilepsy, muscle spasms, and alcohol addiction.
Investigators have defended their choice of males as research subjects on the grounds that men are cheaper and easier to study. The estrous cycle is viewed as a methodological complication during analysis that increases research costs because many more control groups are required. Researchers have also feared that the inclusion of women of childbearing age in clinical trials might endanger fetuses. FDA guidelines restricting research on women of childbearing potential were first implemented in 1977 in reaction to the birth defects resulting from thalidomide and diethylstilbestrol administrated during pregnancy, and the FDA only revised these guidelines to include this population of women in early-phase clinical trials in 1993. These protective restrictions, however, can support the portrayal of women as "walking wombs," unable or unwilling to control their fertility. These guidelines also overlooked the pharmacologic needs of many pregnant women, three-quarters of whom require drug therapy during pregnancy and currently use prescription or over-the-counter drugs for chronic conditions such as diabetes or depression 11.
The net effect of gender bias in medical research is that women are at risk for adverse drug reactions and may suffer unnecessarily and die. Such adverse reactions occur approximately twice as often in women as in men. For example, some antithrombotic agents used to break up blood clots immediately after a heart attack, while beneficial to many men, may cause significant bleeding problems in women 12.
Commonly prescribed drugs used to treat high blood pressure tend to lower men's mortality from heart attack but have been shown to increase cardiac-related deaths among women 12.
Emerging evidence also suggests that the effects of antidepressants can vary over the course of the menstrual cycle. Subsequently, drug dosage may be too high at some points during estrous and too low at others. Besides that, drugs developed for men and untested on women may be dangerous for women, drugs that are potentially beneficial to women may be eliminated in early phases of clinical testing when the test group does not include women and no benefits are manifest in male subjects 13. Concomitantly, while women tend to be undertreated in many areas of medicine, they are also at risk for overtreatment in the area of reproduction, such as unnecessary cesarean sections and hysterectomies 14.
Much has now been made in the US of the need to depart from the "usual male model," where testing is routinely done on males, and from the "usual white model," where test subjects are of white European origins, in medical research and health 15, 16.
Researchers are now wary of developing a "usual female model," where females are assumed to conform to a unitary category of sex, and racial and ethnic differences remain unanalyized. Whereas the women's health movement of the 1970s sought to solidify sisterhood through the commonalities of female childbirth experiences, there is now an emphasis on the differing health needs of different racial and ethnic groups of women. Only very limited conclusions can be drawn about a patient's disease from her biological sex. This is revealed in the variation of disease morbidity and mortality in different ethnic populations. African-American women are, for example, more at risk for stroke, heart attack, and hypertension than European-American women. While African-American women have a lower incidence of breast cancer than European-American women, they die more often as a result. Hispanic women's rates of cervical cancer are twice as high as those of non-Hispanic white women. In addition, non-Hispanic white women have higher rates of osteoporosis than Hispanic or African-American women; however, because osteoporosis is considered a white disease in the US, African-American and Hispanic women may not be properly screened and educated about it 17.
The feminist sea changeBeginning in the late 1980s and 1990s, feminist calls for reform in federally funded biomedical research in the US were taken up by the federal government. The 1990s saw what could only be called a revolution in biomedicine for women in the US. In September 1990, the US federal government founded the Office of Research on Women's Health within the Office of the Director at the NIH. This office has two primary missions: to develop opportunities for and to support women's recruitment and reentry into, and advancement in, biomedical professions, and to ensure that research conducted and supported by the NIH adequately addresses diseases, disorders, and conditions that affect women. In 1991, the federal government announced the establishment of the Women's Health Initiative, a major 15-year research program coordinated among 40 clinical centers nationwide, in conjunction with the Department of Health and Human Services, the NIH, and the National Heart, Lung, and Blood Institute, to which $625 million was budgeted toward the study of the most common causes of death, disability, and poor quality of life in postmenopausal women. Between 1990 and 1994, Congress enacted no fewer than 25 pieces of legislation to support advancements in the understanding and management of the health of American women. The most important of these was the NIH Revitalization Act of 1993 18.
Also significant was the publication of the NIH Guidelines on the Inclusion of Women and Minorities as Subjects in Clinical Research 19. The act reinforced existing NIH policies, with a number of major differences (see Reform of investigation without representation) 20, ranging from requiring that females and minorities be adequately represented in clinical trials to establishing new federal regulations for mammography 21, 22. In 1994, the FDA also created an Office of Women's Health, which oversees correction of gender disparities in drug research and administration policies 23.
Taxation without representationMuch of the impetus for the women's health movement came from the feminist idea that women should get their fair share of research dollars, both as researchers and as research subjects. Attention was drawn to the failure to include women in publically funded research. Quite appropriately, many people supported the idea that since women pay taxes that contribute to federally funded health research, they deserve to derive benefit from that research. Simply taking women seriously as researchers and including them as research subjects in areas other than reproduction - a base-line liberal approach - has had a tremendous impact on medicine. The reforms have been simple in their conception - inquiry should include female subjects - but dramatic in their realization: the right of females to be included in basic medical research is now secured by federal law.
Beyond the liberal approach to gender equity in biomedical research, which emphasizes equal attention to the health needs of men and women, a reconceptualizing of sex-related differences in the human body has been crucial to advances in women's health 24. When the General Accounting Office reviewed NIH policies in 1989, there was still no uniform definition of research specific to women's health. Medical researchers had long assumed that the phrase "women's health" referred to reproductive health - involving attention to birthing, contraception, abortion, breast and uterine cancer, premenstrual syndrome, and other maladies distinctively female. Definitions of women's health now treat the whole array of women's distinctive biology. Florence Haseltine, founder of the Society for Advancement of Women's Health Research and a powerhouse for reform at the NIH, has identified this shift from reproductive health to more general female health issues as being crucial for ongoing reforms in women's health research. 25.
The NIH now defines women's health research as the study of diseases unique to women (such as breast cancer), or diseases with a higher prevalence in women than in men (such as osteoporosis), or diseases that present differently in women than in men (such as heart disease). Working from this conceptual base, the Women's Health Initiative has focused attention on the prevention of osteoporosis in addition to the leading causes of death in women: cardiovascular disease and breast and colon cancer. The NIH Office of Research on Women's Health has also funded understudied areas of research, including women's occupational health, sex-related differences in autoimmune diseases, and female urologic health.
Critics of the Women's Health InitiativeNot everyone, of course, agrees that women's health requires special attention. Critics deny that it has been improper to leave women out of randomized clinical trials, such as the MRFIT studies. According to this view, since men die from heart disease at earlier ages than women, they are an appropriate group for study 26.
The Women's Health Initiative currently receives approximately 6% of the NIH annual budget, and critics charge that the funds earmarked for the study of female-specific disorders is excessive. They argue that 13% of the NIH annual budget is already devoted to health issues directly related to women, while only 6.5% of the budget contributes to the study of diseases unique to men. Their trump card is that the life expectancy of an American female, at 78.6 years, substantially outstrips that of the American male, at 71.8 years, suggesting that women are currently well cared for.
Other critics deny that feminism has now adequately addressed women's health in medical research and charge that the Women's Health Initiative and the poorly funded Office of Research on Women's Health are merely efforts to diffuse the explosive politics surrounding federal funding of women's health research 12.
What is equal or fair in this instance? Is the solution to equalize spending on men's and women's health research? One could argue that research that uses the male body as the norm serves men better even when fewer dollars are spent on male-specific diseases. One might also argue that the greater role of women in human reproduction warrants more research on female reproductive health. But surely the goal of US biomedical research is to study both men and women of various classes, races, and backgrounds to maximize their long-term health and well-being.
A call for broader reform: beyond the biomedical modelFeminist reform within the NIH has been critical in improving health care for women. But some feminists suggest that it may not be enough simply to include women in clinical studies already in progress or to take into account their distinctive physiology. Study populations can be reconfigured and women's diseases can be given research priority within existing medical practices, they claim, without dramatically improving women's health. These feminists contrast the dominant "biomedical" model of research with a "community" or "social" model of the investigation and evaluation of women's health. They challenge approaches that focus narrowly on disease management and biochemical processes in organ systems, cells, or genes 27. Broad social models that seek to ground health in the community do not ignore genetic or biological aspects of health — certainly the genetic components of Tay-Sachs disease, sickle-cell anemia, cystic fibrosis, and ß-thalassemia require study. Nor do advocates of the community or social models deny the importance of personal lifestyle (attention to nutrition, exercise, relaxation, and restraint from smoking and drug abuse). They do, however, see as equally important an understanding of how health and disease are affected by an individual's daily life, access to medical care, economic standing, and relation to his or her community. Advocates of relating health and disease to broader social factors see health as embedded in communities, not restricted to individual bodies.
What brought about change at the NIH?It is commonly assumed that increasing the number of female physicians is sufficient to bring about change in medical theories and practices with respect to women 28. Increasing the number of women in the medical profession is, of course, important. The NIH Office of Research on Women's Health has rightly set women's recruitment and reentry into, and retention in, biomedical careers as one of its goals. But to see this as the decisive factor in promoting better health care for women oversimplifies and depoliticizes a complex cultural process. It is not just women but feminists — both men and women — inside and outside the medical field who have driven reform in medical research policies. The changes discussed here in the study and practice of medicine in the US have resulted from a multidimensional process of social change that has included (a) a broadly based women's movement; (b) fundamental changes in attitudes toward women; (c) the collaboration of men opposed to the apparent inequality in research policies; (d) the institutionalization of academic research on women and gender in universities; (e) strong congressional lobbies on emotional issues such as breast cancer research; (f) a reasonably strong economy; and (g) action by Congress to legislate gender equality in health research. The same forces and changes that successfully increased the number of women in the medical profession have also facilitated a change in attitudes and policies regarding the conduct of research relating to women's health. The reform of gender-related medical research may now serve as a model for correcting gender bias in other sciences. Most importantly, including an analysis of significant sexual differences in biomedical research has facilitated the development of reliable databases upon which physicians and other health professionals can base informed clinical decisions and health recommendations for both women and men.
Sidebar 1, http://www.jci.org/content/vol112/issue7/images/data/973/DC1/JCI0319993sb1.jpgConflict of interest: The author has declared that no conflict of interest exists.
Nonstandard abbreviations used: Multiple Risk Factor Intervention Trial (MRFIT); Food and Drug Administration (FDA).
ReferencesHaving an abortion does not increase a woman's risk of developing breast cancer, researchers have found. A study of just under 4,000 women by doctors at Sweden's Karolinska Institute found no link between terminations and the disease. Some studies have suggested abortions could increase the risk of cancer, but many experts say the evidence is weak.
Last week three MPs sent out their own survey to UK doctors in a bid to examine the potential link. There is no proven link between abortion and the risk of breast cancer. Christine Fogg, Breast Cancer Care Researchers identified 1,759 women who had given birth between 1973 and 1991 and then gone on to develop breast cancer by comparing data from the Swedish Medical Birth Register and the Swedish Cancer Register. They then looked at the same number of cases from the birth register who had not gone on to develop cancer. All had been asked if they had previously had any abortions while receiving maternity care. Researchers found 383 of those who went on to develop breast cancer and 473 of those who did not had had at least one abortion, suggesting terminating a pregnancy was not linked with an increased risk of breast cancer. In fact, women who had had at least one abortion had a reduced risk of breast cancer compared to those who had none.
Dr Gunnar Larfors, who led the research, said: "We have looked at some 4,000 journals from maternity centres in which women have responded to standardised questions about abortions, among other things, and have not found any correlation between abortions and increased risk of breast cancer. "In fact, aborted pregnancies had some preventive effect in our study." It has been known for some time that pregnancy had a preventive effect against breast cancer, although it is not yet clear why this is the case. Mr Larfors said abortion was still a taboo subject, so if women on the street were asked, they might be unlikely to admit that had had one. But he said a woman who had suffered from breast cancer was asked about previous abortions would probably answer truthfully. He added: "This can skew the results to make it seem as if breast cancer is tied to abortion. "In our study all women had answered the same question before developing breast cancer."
Breast cancer campaigners urged women not to be unduly worried. Christine Fogg, joint chief executive of Breast Cancer Care, said: "Current research has consistently failed to show any link between induced or spontaneous abortions and breast cancer risk." She said "scare stories" which claimed to show a link increased the anxiety of many women. "We want to reassure women that there is no proven link between abortion and the risk of breast cancer and that age remains the strongest risk factor for breast cancer."
Following the concerns raised last week, Professor Joel Brind, from City University of New York, who claims his findings suggest a link between abortion and breast cancer after being invited by pro-life campaigners Life, is to speak to MPs on Wednesday.
Story from BBC NEWS: http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/3431817.stmIn response to those who have taken issue with CMAJ over publication of the article by David Reardon and associates,1 I would like to point out that in medical ethics the concept of informed consent is of paramount importance. Regardless of one's opinions about the abortion issue, educating patients about the benefits and risks of an intervention is integral to good medicine. Thus, physicians should be willing to inform their patients of the risks associated with abortion. Aside from the usual risks associated with a surgical procedure, these include increased risks of psychiatric illness,1 future preterm birth 2 and breast cancer. 3 , 4
I commend CMAJ for refusing to allow politics to trump the scientific progress of women's health care.
Shauna C. Hollingshead, Medical Student University of Alberta Edmonton, Alta. Canadian Physicians for Life.
ReferencesThe recent publication of a study on psychiatric admission rates among low-income women after abortion and childbirth 1 has elicited a barrage of letters to CMAJ of a pitch that we do not frequently encounter (page 101). 2 We are chided for publishing flawed research and told that we should be ashamed of publishing the "opinions" of self-evidently biased researchers. We are accused of doing a disservice to women, medicine and the Journal, of failing to conduct proper peer review, and of not adequately scrutinizing the credentials of the authors.
The abortion debate is so highly charged that a state of respectful listening on either side is almost impossible to achieve. This debate is conducted publicly in religious, ideological and political terms: forms of discourse in which detachment is rare. But we do seem to have the idea in medicine that science offers us a more dispassionate means of analysis. To consider abortion as a health issue, indeed as a medical "procedure," is to remove it from metaphysical and moral argument and to place it in a pragmatic realm where one deals in terms such as safety, equity of access, outcomes and risk-benefit ratios, and where the prevailing ethical discourse, when it is evoked, uses secular words like autonomy and patient choice.
Hence, perhaps the thing that is most offensive to some of our correspondents is the apparent co-opting of the medical view by persons they believe to be unqualified — or disqualified. The attack in our letters column is largely an ad hominem objection to the authors' ideological biases and credentials. There are two questions here: first, does ideological bias necessarily taint research? Second, are those who publish research responsible for its ultimate uses?
The answer to the first must be that opinion can of course cloud analysis. In light of the passion surrounding the subject of abortion we subjected this paper to especially cautious review and revision. We also recognized that research in this field is difficult to execute. Randomized trials are out of the question, and so one must rely on observational data, with all the difficulties of controlling for confounding variables. But the hypothesis that abortion (or childbirth) might have a psychological impact is not unreasonable, and to desist from posing a question because one may obtain an unwanted answer is hardly scientific. If we disqualified these researchers from presenting their data, we could never hear from authors with pro-choice views, either.
The phrase used by Deborah Stone3 in her classic text on public policy — "No number is innocent" — might be read as saying that every statistical analysis is guilty of serving one political agenda or another. A softer interpretation is that quantitative analysis is always subject to contextual influences. Biases and expectations, pre-existing knowledge and methodologic habits all influence what kinds of hypotheses are tested and how. Ultimately, our measurements are delimited by what can be measured, and by what we choose to measure. Feminist critiques have frequently pointed out the failure of mainstream health research to "count women in," whether in randomized controlled trials or in economic analyses of health reforms.4 When researchers do attempt to amass quantitative evidence in women's health the ideological stakes are high: evidence is trailing rather far behind politics. Thus, the values of self-care and patient empowerment exemplified by breast self-examination gave rise to a similar outcry against unwanted results published in this journal.5, 6,7
But if it is true that more explicit research into women's health issues will point the way to better care, better outcomes and more equity in access, we cannot toss out data any time we don't like their implications. Nor can we leap from a single observational study to public policy. We must allow the gradual and honest accumulation of further evidence to confirm or contradict what we think we know.
Which brings us to the second question: Should we deny the publication of a study because it might be applied by one or the other side of a factionalized debate? It strikes us that the results of the study by Reardon and colleagues are neutral: they could be "used" to further the argument that abortion is undesirable; or to support arguments for better post-abortion counselling and support. We cannot second-guess such interpretations without unfairly imposing our own values on the research we choose to publish. — CMAJ
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