Years Of Oral Contraceptive Use Research Articles

Differences in risk factors for epithelial ovarian cancer by histologic type. Results of a case-control study.

A case-control study of associations between dietary and reproductive factors and cancer of the ovary was conducted during 1989-1992 in metropolitan Toronto and nearby areas of southern Ontario, Canada. In total, 450 women aged 35-79 years with histologically verified new primary epithelial ovarian cancers were interviewed concerning their reproductive history and dietary practices. Over the same time period, 564 randomly selected population controls, frequency-matched to the cases according to three 15-year age groups, were also interviewed. Continuous unconditional logistic regression methods were used for analysis. It was found that childbearing and use of oral contraceptives were associated with significant decreasing trends in the risk of epithelial ovarian cancer of all principal histologic types except mucinous tumors. For each full-term pregnancy, the odds ratio was 0.76 (95% confidence interval (CI) 0.69-0.85) for nonmucinous tumors and 1.03 (95% CI 0.88-1.21) for mucinous tumors; for each year of oral contraceptive use, the odds ratio was 0.89 (95% CI 0.85-0.93) for nonmucinous tumors and 0.98 (95% CI 0.93-1.04) for mucinous tumors (p = 0.00051 and p = 0.0040, respectively, for the difference in odds ratios between mucinous and nonmucinous tumors). Saturated fat intake also appeared to convey greater increased risk for women with mucinous tumors than for women with neoplasms of other histologic types (p = 0.029). Among women with nonmucinous tumors, increasing trends in risk of invasive serous cancer (p = 0.018), and particularly endometrioid cancer (p = 0.0041), were seen with use of noncontraceptive estrogens. Otherwise, borderline-malignant neoplasms seemed to have a similar spectrum of risk factor associations as invasive cancers. On the basis of this study and a number of others, the authors suggest that mucinous ovarian tumors may be etiologically unrelated to other types of epithelial tumors, and thus should be considered separately in studies of ovarian cancer.

Carotenoids, vitamin A, and estrogen receptor status in breast cancer.

Among patients with breast cancer, tumors that contain estrogen receptors (ER) are associated with improved survival and better response to hormone therapy than those not expressing these receptors. The purpose of these case comparison studies was to examine the relationship between carotenoids, vitamin A, and the tumor ER status in women at diagnosis of primary breast cancer. The focus of the first study was the relationship between dietary intake and ER status, and the focus of the second study was the relationship between ER status and the plasma carotenoid, retinol, and tocopherol concentrations. We evaluated tumor ER status and self-reported dietary intake in 142 women and plasma concentrations of carotenoids, retinol, and tocopherols in 149 women, at diagnosis of breast cancer, before any medical or surgical treatment. In the first study the overall odds of ER-positive status were increased in relation to number of mammograms in the past five years, number of breast-fed babies, dietary carotenoid intake, and more frequent intake of yellow and green vegetables. Overall odds of ER-positive status were decreased in relation to years of oral contraceptive use and preformed vitamin A intake. In the second study older women, women with higher plasma lutein concentration, and women not using beta-carotene supplements were more likely to be ER positive, when data were adjusted for body mass index and factors that may influence breast cancer risk or hormonal status. Significant independent relationships between plasma retinol or tocopherol concentrations and ER status were not observed. The strong and independent relationships between carotenoid intake, plasma lutein concentration, and ER status may relate to observations linking a carotenoid-rich diet with improved prognosis after diagnosis of breast cancer.

Hormones and breast cancer.

The exact nature of the association between hormones and the development of breast cancer remains uncertain. Studies of endogenous hormone levels and breast cancer suggest a possible role of estrogens and androgens in the cause of breast cancer. Numerous studies have been conducted to assess the risk of breast cancer among women exposed to exogenous hormones. Several studies of women who have used oral contraceptives have shown a twofold increase in risk for the onset of breast cancer at an early age associated with 10 years of oral contraceptive use. One of the largest studies, the Cancer and Steroid Hormone Study, found no association between breast cancer and oral contraceptive use for women up to the age of 54. A meta-analysis combining the results of 31 published studies of the association between hormone replacement therapy and breast cancer revealed no increased risk of breast cancer associated with ever-use (risk ratio [RR], 1.02; 95% confidence interval [CI], 0.93-1.12). Use of oral contraceptives for more than 10 years was associated with a small increased risk (RR, 1.23; 95% CI, 1.08-1.40), but few studies have examined very long term use. A recent study of pregnancy and breast cancer outcome found no adverse influence of pregnancy shortly before or after diagnosis of breast cancer on prognosis. The results of a wide range of studies should be considered when weighing the benefits and risks of hormone use among women at increased risk of breast cancer or with a history of breast cancer.

Oral contraceptive use and breast cancer risk among African-American women.

Recent epidemiologic studies, most of them in predominantly White populations, have suggested that long duration of oral contraceptive (OC) use may increase the risk of breast cancer at young ages. We assessed the relationship of OC use to the risk of breast cancer in African-American women aged 25 to 59 years, using interview data from a multipurpose hospital-based case-control study. Five hundred and twenty-four cases hospitalized for invasive breast cancer were compared with 1,021 controls with nonmalignant conditions unrelated to OC use. Relative risks (RR) and 95 percent confidence intervals (CI) were estimated relative to a reference category of use for less than 12 months; potential confounders were controlled by multiple logistic regression analysis. Among women under age 45, three or more years of OC use was associated with an increased risk of breast cancer: the RR estimate was 2.8 (CI = 1.5-5.0) for three to four years of use, and declined to 1.5 (CI = 08.3.0) for 10 or more years of use. Recency and timing of use did not explain the observed association. Among women aged 45 to 59, OC use was associated with little or no increase in risk: the RR estimate for three or more years of use was 1.3 (CI = 0.7-2.4). The findings add to the evidence from studies of White women and a recent study of Black women which have suggested an increased risk of breast cancer at young ages for moderate or long duration use of OCs.

Pregnancy and lifestyle study: the long-term use of the contraceptive pill and the risk of age-related miscarriage.

Maternal ageing is a very important factor in aneuploidy. It is associated with an increased risk of a liveborn trisomy, especially Down's syndrome, and with a dramatic increase in trisomic conceptions, the majority of which miscarry. A total of 585 volunteer couples who were planning pregnancies participated in a prospective study of reproduction. The couples answered extensive questionnaires and early pregnancy tests (day 28) were conducted each month. The number of years of contraceptive pill use was correlated with pregnancy outcome. Lowered rates of miscarriage were found with increased years of pill use. The cut-off point for this positive effect appeared to be 9 years. Use of oral contraceptives for > or = 9 years was associated with a spontaneous abortion rate of 11.3%, which is about half the rate (23%) which was found in couples who had not used the pill. However, the effect of pill taking was correlated with female age, and when age was examined as an independent factor, the reduction in miscarriage was only statistically significant in women > 30 years old, where the rate of abortion reduced from 28 to 7%. Because age-related aneuploidy in humans probably occurs as a direct or an indirect result of follicle depletion, it is proposed that the long-term use of the oral contraceptive pill protects against abortion due to aneuploidy by preserving the number of follicles.

Does Low-Dose Combination Oral Contraceptive Use Affect Uterine Size or Menstrual Flow in Premenopausal Women With Leiomyomas?

To assess whether low-dose oral contraceptive (OC) use affects uterine size or menstrual flow in women with leiomyomas. Eighty-seven premenopausal women with leiomyomas were enrolled in a 1-year study. Fifty-five women took low-dose monophasic OCs, and 32 took no OCs or other hormonally active medications. Uterine size was assessed by bimanual and sonographic examinations before and after the study. Duration of menstrual flow and hematocrit were also assessed. Fifty (91%) of 55 women completed 1 year of OC use. There was no significant difference in mean uterine size determined by bimanual examination or in uterine volume measured by sonography after 12 months of OC use. Likewise, there were no significant changes in these indices among the 32 women who did not take OCs. The mean duration of menstrual flow decreased significantly, from 5.8 to 4.4 days (P < .01), in the group of women taking OCs. The mean hematocrit increased significantly, from 35.8 to 37.8% (P = .014), in this group. In contrast, the women who did not take OCs had no significant changes in these indices. In most women with leiomyomas, low-dose OC use provides the noncontraceptive benefit of a reduction in the duration of menstrual flow, with resultant improvement in hematocrit, without increasing uterine size.

Dietary fat intake and risk of epithelial ovarian cancer.

Evidence exists that dietary fat may be a contributory factor in the development of hormone-related cancers such as ovarian cancer. Previous studies have demonstrated significantly higher circulating-estrogen levels among nonvegetarian women than among vegetarian women; the increase correlated directly with consumption of saturated fat. However, the contribution that dietary fat plays in the development of hormone-related cancers remains unresolved. Our purpose was to evaluate whether saturated fat intake increases the risk of ovarian cancer development. Population-based sampling was used to acquire cases and controls over a 3-year period from the study area, which included the highly populated region surrounding the western end of Lake Ontario, Canada. From the Ontario Cancer Registry, all histologically confirmed, primary malignant or borderline malignant epithelial ovarian tumors first diagnosed from November 1989 through October 1992 among study-area residents aged 35-79 years were determined. In total, 631 eligible case subjects were identified, of whom 450 (71.3%) were interviewed concerning reproduction and diet; 564 randomly selected population control subjects were similarly interviewed. From the quantitative diet-history information, average daily intakes of macronutrients and micronutrients were calculated. Unconditional continuous logistic regression methods were used for analysis, with adjustment for age at interview, number of full-term pregnancies, years of oral contraceptive use, and total daily caloric intake. Saturated fat consumption was associated with increasing risk of ovarian cancer (odds ratio [OR] = 1.20 for each 10 g/day of intake; 95% confidence interval [CI] = 1.03-1.40; one-sided P = .0082). No relationship was seen with intake of unsaturated fats. Egg consumption also appeared related to increased risk (OR = 1.42 for each 100 mg of egg cholesterol per day; 95% CI = 1.18-1.72; two-sided P = .0002), though this association may have resulted from disease-related changes in the dietary practices of case subjects prior to diagnosis. Consumption of vegetable fiber (but not fruit or cereal fiber) was associated with decreased risk (OR = 0.63 for each 10 g/day; 95% CI = 0.49-0.80; two-sided P = .0001). All three nutrients (saturated fat, egg cholesterol, and vegetable fiber) remained statistically significant when included in the same regression model. Diet may contribute to risk of ovarian cancer development. If confirmed in further studies, this association may allow women to appreciably lower their risk of ovarian cancer through dietary modifications: reducing the intake of saturated fats and eating more vegetables.

Oral contraceptives and risk of breast cancer in women aged 20-54 years

Summary Although the use of oral contraceptives (OCs) is not generally associated with increased risk of breast cancer, higher risks have been reported for some subgroups of users. We have carried out a population-based case-control study in the Netherlands to assess the effect of timing and duration of OC use on the risk of breast cancer developing at various ages. 918 women with breast cancer (20-54 years at diagnosis) were pair-matched by age with controls randomly selected from municipal registries. Information on OC use obtained from women and their prescribers was combined according to standard decision rules. Overall, long-term use of OCs (≥12 years) had an associated relative risk (RR) of 1 3 (95% Cl 0·9-1 9; test for trend in risk with months of use p = 0·03). This positive trend was found in both the youngest ( < 36 years; p=0 08) and the oldest (46-54 years, p=0·004) age groups, but not in women aged 36-45 years. The RR of developing breast cancer before age 36 was 2·1 (1·0-4·5) for 4 or more years of OC use compared with shorter use. In women younger than 36, risk increased for longer OC use before age 20 (1 44 per year, p=0·04). Recent use (previous 3 years) was associated with increased risk in women of 46-54 (RR 1 9 [0·9-4·1], p=0·02). We conclude that 4 or more years of OC use, especially if partly before age 20, is associated with an increased risk of breast cancer developing at an early age. There is limited evidence that the excess risk disappears as the cohort of young OC users ages, but this issue needs confirmation.

"The Estimated Effect of Oral Contraceptive Use on the Cumulative Risk of Epithelial Ovarian Cancer."

This study sought to determine the effect of oral contraceptive (OC) use on the cumulative incidence of epithelial ovarian cancer from ages 20 to 40 20 to 50m and 20 to 55 years among 4 groups of women: positive family history negative family history parous and nulliparous. Cancer and Steroid Hormone Study data were combined with data from the Surveillance Epidemiology and End Results Network to provide estimates of the age-specific incidence rates of epithelial ovarian cancer among never-users of OCs in the 4 specified groups of women. These rates provided the basis for calculating cumulative incidences. The rates in women using OCs were estimated from meta-analysis of the epidemiologic literature using regression equations expressing the log-relative rate of epithelial ovarian cancer as a function of duration of use and recency. In all 4 groups the cumulative number of epithelial ovarian cancer cases estimated to occur per 100000 OC users compared to never-users decreased with increasing duration of OC use. The authors results suggest that 5 years of OC use by nulliparous women can reduce their ovarian cancer risk to the level seen in parous women who never use OCs and that 10 years of OC use by women with a positive family history can reduce their risk to a level below that for women whose family history is negative and who never use OCs. These data represent the first published estimates of the effect of OC use on the cumulative incidence of epithelial ovarian cancer by family history and by parity. The demonstrated substantial noncontraceptive benefit from OCs justifies their judicious use as a potentially powerful resource for primary prevention in women at high risk of ovarian cancer. (authors)

Menopausal hormone usage and breast cancer in Saskatchewan: a record-linkage cohort study.

The association between the occurrence of carcinoma of the breast and previous usage of menopausal estrogens, progestins, and oral contraceptives is examined in a record-linkage study using the Saskatchewan Health Prescription-Drug-Plan Database. Saskatchewan Health is a governmental agency that funds publicly insured health care for essentially all residents of the province. For this study, all women aged 43-49 years in 1976 resident in Saskatchewan were identified from the Saskatchewan Health master registration file. These women were linked by registration beneficiary number to the Drug-Plan Database for the period from January 1976 to June 1987 and to the Provincial Cancer Registry Database for the period from March 1960 to December 1990. The fact and date of death or emigration from the province were obtained through the annual updates of the health plan. Of the 33,003 women initially in the cohort, 213 had a breast cancer diagnosed before 1976 and were omitted from this analysis. Between 1976 and 1990, 742 new primary breast cancer cases occurred. Women taking estrogens unopposed by progestins had an elevated risk of breast cancer, the risk increasing by 7% (relative risk = 1.072, 95% confidence interval 1.02-1.13; p = 0.008) for each 252 tablets used (approximately 1 year of use). Usage of estrogens opposed by progestins showed no association with risk (p = 0.48). Women taking oral contraceptives during this follow-up period also had a higher risk, increasing by 14% (relative risk = 1.144, 95% confidence interval 1.05-1.24; p = 0.002) for every 252 tablets used. These 1-year risk elevations are small but become appreciable at longer durations. For example, at 5 years of unopposed estrogen use, the relative risk is 1.42; for 5 years of oral contraceptive use, it is 1.96.

Oral Contraceptives and Breast Cancer

Changes in endogenous hormones at various times in life (e.g., early menarche, birth of the 1st child at an advanced maternal age, and late menopause) increase the changes of developing breast cancer. It is reasonable then to expect oral contraceptive (OC) use to increase the risk of breast cancer. It is difficult, however, to prove OC exposure has this effect due to changed OC use patterns plus OCs consist of many different hormones at various doses and compositions. Yet, OC use in the past (even more than 15 years of OC use) had not increased the risk of breast cancer in women of all combined age groups. 3 research groups have identified a small increase in overall risk in low risk women, but unidentified sources of bias or confounding could account for this increased risk. Some recent studies indicate an increased risk of breast cancer with duration of OC use, but the risk depends somewhat on dose of either the estrogen or the progestin. Nonetheless, these findings were weak and inconclusive. Other research shows long-term OC use increases the risk of breast cancer in just young women (under 45 years old). Future epidemiologic studies thus need to address increased breast cancer risk in women under 45 years old who used OCs for a long time. They need to look at whether the risk is due to early use and continues into older age or to longterm use at any time in just young women. Some studies should include women with and without various biological markers of susceptibility. Other studies should measure blood levels of estrogens and progestins in women using the same OCs. BAsed on the information now available, it would be unwise for physicians to warn women against using the highly effective OCs because they do prevent unwanted pregnancy and are protective against ovarian and endometrial cancer.

Oral Contraceptive Use and the Occurrence of Gallstone Disease - A Case-Control Study

Background. We evaluated the hypothesized transient effect of oral contraceptive use on the occurrence of gallstone disease in a case–control study. Methods. The study comprised 82 acute cases, and 249 general population controls, 28 elective cases, and 106 radiodiagnosis controls. Risk-period-specific rate ratios were estimated by logistic regression analysis. Results. During the first 5 years after any year of oral contraceptive use (0- to 5-year risk period) the rate ratio was 1.6 (90% confidence interval, 0.83–2.95), and for the 6-to 10- and 11- to 20-year risk periods, 1.2 (0.67–2.13) and 1.1 (0.69–1.65), respectively. Further evaluation showed substantial confounding by other risk factors. After these were controlled for, the rate ratios were 1.1, 1.8, and 1.0 for the respective risk periods. When oral contraceptive use had been started recently (within 5 years before diagnosis) the rate ratio was 4.8 (0.79–29.7); recent oral contraceptive use was not associated with gallstone disease if preceded by 6 or more years of oral contraceptive use (rate ratio 0.8 (0.15–4.55)). Conclusions. The results are consistent with a transient effect of oral contraceptive use that does not accumulate beyond 10 years of use. However, the substantial confounding effect in our study raises the question whether the present and previously reported estimates of the effect may be biased by confounding.

Medical aspects of oral contraceptive discontinuation.

Oral contraceptive (OC) compliance is adversely affected by three medical factors: side effects, poor cycle control, and patients' fears of serious diseases. Most physicians recognize these factors but fail to understand their true impact on continuation rates. In one study, half of current OC users who changed brands and half of former OC users cited unwanted side effects as their reason for discontinuation. Moreover, a substantial number of women discontinue OCs without consulting their physicians. Among the so-called nuisance side effects cited by patients, the most prominent are bleeding irregularities. In new patients just beginning OC therapy, bleeding irregularities such as breakthrough bleeding and amenorrhea can lead to a very high discontinuation rate; as many as 50% of new users discontinue OCs before the end of the first year because of such side effects. OC discontinuation rates among other patient populations vary. The problem has not been studied extensively, but existing data show the problem is a large one. One study involving 550 women of various ages and years of OC use confirmed that cycle control problems led many women to discontinue OC use--often resulting in an unplanned pregnancy. Six percent of the women in this study discontinued OC use because of poor cycle control, and 23% of this group experienced subsequent unwanted pregnancies. In contrast, clinical tolerance with the new progestins such as gestodene is good; in one study 86% of patients had normal bleeding patterns. The principal consequences of poor cycle control are loss of confidence in the OC and the physician, increased anxiety, disruption of sexual relations, additional physician calls and visits, pregnancy tests, discontinuation, and noncompliance. The perception that European women have regarding the pill is that it is a reliable method that does not interfere with sexual activities. However, doubts about the safety of OCs influence compliance with the method. While concerns regarding blood clots have diminished, the fear of cancer is still a concern for many women. The androgenic side effects of weight gain, acne,and breast tenderness are particularly troubling for adolescents, who are sensitive to changes in body image. In one recent study, 20% to 25% of women stopped taking OCs because of weight gain or acne, and another 25% stopped because of fear of cancer. The medical component of improving compliance is the physician's choice of OC. Formulations with low, effective doses of hormones and the fewest side effects should be selected. Cycle control and the side-effect profile are improved with the new progestins.(ABSTRACT TRUNCATED AT 400 WORDS)

The Influence of Lactose Consumption on the Association of Oral Contraceptive Use and Ovarian Cancer Risk

The authors investigated the joint effects of diet and oral contraceptive use on ovarian cancer risk in 194 white women aged 65 years or less with epithelial ovarian cancer and 193 age- and residence-matched controls in Boston between 1984 and 1987 by using in-person interviews and self-administered food frequency questionnaires. Use of oral contraceptives for 3 months or more was associated with a modest protective effect for ovarian cancer (odds ratio (OR) = 0.7, 95 percent confidence interval (CI) 0.5-1.1). In women who consumed 11 g or less per day of lactose, use of oral contraceptives for 3 months or more was associated with a nonsignificant increased risk (OR = 1.6, 95 percent CI 0.8-3.2). In women who consumed more than 11 g per day of lactose, use of oral contraceptives for 3 months or more was associated with a substantially decreased risk of ovarian cancer (OR = 0.3, 95 percent CI 0.1-0.7). Within this group, the strongest association occurred with more than 4 years of total oral contraceptive use (OR = 0.2, 95 percent CI 0.1-0.6) and in those who had more than 2 years of oral contraceptive use after age 30 years (OR = 0.1, 95 percent CI 0.03-0.4). These results suggest that, with respect to ovarian cancer, lactose users may be the most likely to benefit from oral contraceptive use and that the benefit may be strongest when oral contraceptive use occurs after age 30 years.

Combined progestin and estrogen (oral), and other forms of hormonal contraception

This review examines controversies concerning serious side effects of oral contraceptives. Current concerns about the pill are with either relatively small excess risks or with very long-term effects, which need not be small. The main outstanding questions are the effects on cardiovascular disease of lowering doses and the effects on breast cancer of oral contraceptive use at a young age. In the end, the possible effects on breast cancer incidence cause the most concern. It is argued that most epidemiologic studies are too small to reliably detect effects among particular subgroups and it is possibly too soon to know what the long-term effects of using oral contraceptives while young on breast cancer actually are. However, complacency is contraindicated.

Oral contraceptives and breast cancer: A case-control study with hospital and community controls

Several recent reports have noted an increase risk of breast cancer associated with the use of oral contraceptives (OCs) among various subgroups of young women. These reports spurred us to analyze data from a case-control study in North Carolina of 158 breast cancer patients, 326 hospital controls, and 1140 community controls less than 60 years of age. A logistic regression model was used to calculate odds ratios and 95% confidence intervals and to control for potential confounders. No association between ever-use of OCs and the risk of breast cancer was found for cases compared with either control group. No increased risk was observed for OC use before age 25 or before first full-term pregnancy, or in relation to duration of use, recency of use, or time since first use. Analysis of the subgroup of women less than 45 years of age also showed no relationship between OC use and breast cancer risk. However, an elevated risk of breast cancer was observed among nulliparous women with 5 or more years of OC use in comparisons with hospital controls (odds ratio 7.8) and community controls (odds ratio 2.3). This analysis was based on small numbers of subjects and the 95% confidence intervals touched or overlapped with 1. An unexpected association between duration of OC use and breast cancer risk was found among older premenopausal women in comparisons of cases with both control groups. For these women, a trend was evident in the odds ratio by duration of OC use, and the comparison between cases and community controls was statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral contraceptives and the risk of endometrial cancer

The relationship between the use of combination oral contraceptives (OCs) and the risk of endometrial cancer was assessed in a case-control study conducted in the Swiss Canton of Vaud between 1 January 1988 and 31 July 1990. Subjects included 122 women aged 75 or less with histologically confirmed endometrial cancer, and 309 control women in hospital for acute conditions unrelated to OC use. Overall, 14 percent of cases and 27 percent of controls had ever used OCs, corresponding to a multivariate relative risk (RR) of 0.5 (95 percent confidence interval [CI]: 0.3, 0.8). The risk of endometrial cancer was found to be related inversely to duration of OC use: RR = 1.0 for less than two years of OC use; 0.5 for two to five years; and 0.3 (95 percent CI: 0.1, 0.7) for more than five years. The protection appeared greater within 20 years since last use, and the RR rose to 0.8 after 20 or more years since last use; numbers are too small, however, for reliable inference from these subanalyses. No significant interaction or modifying effect was observed with other major factors related to endometrial cancer, including parity, body mass index, estrogen replacement therapy, and cigarette smoking. While this study provides further evidence for the protective effect of OCs against risk of endometrial cancer, the relationship requires continued evaluation to assess the long-term implications and public health impact of OC use.

Oral contraceptives and breast cancer

Among women in general the risk of breast cancer through 59 years of age does not appear to be affected appreciably by the use of oral contraceptives. Nonetheless, concern continues to be expressed about the effects of early age at first use, long-term duration of use, formulation, and a variety of other factors thought to influence breast cancer risk in the presence of oral contraception. A number of recent studies restricted to young women suggest that long-term use may increase the risk of disease occurring very early, but the present lack of consistent findings in well-conducted epidemiologic studies prevents any certain conclusion with regard to cause-and-effect. However, if an increased risk were indeed present, the most plausible interpretation is that long-term oral contraception promotes earlier clinical manifestation of breast cancer in some women while having no net impact on their lifetime risk of the disease.

Carbohydrate metabolic studies during twelve months of treatment with a low-dose combination oral contraceptive

Carbohydrate metabolism was evaluated in twenty healthy women volunteers using a low-dose combination oral contraceptive (OC) containing 30 μg of ethinyl estradiol and 500 μg of dl-norgestrel by measurement of serum glucose and insulin levels during 3-hour oral glucose tolerance test (OGTT) before and after 3, 6 and 12 months of medication. There were no significant differences in body weight or blood pressure between pretreatment and posttreatment. Fasting serum glucose levels were slightly reduced, though not significantly, during all periods of treatment. But serum glucose levels were increased at 1, 2 and 3 hours in association with high insulin responses during OGTT in all periods of OC therapy, indicating mild to moderate insulin resistance. These data suggest that the low-dose combination OC used in the study exerts alterations on carbohydrate metabolism in women during one year of OC use.

Cancer of the Breast and Reproductive Tract in Relation to Use of Oral Contraceptives

Effects of oral contraception on cancers of the female breast and reproductive tract are critically reviewed from human studies reported since 1980. The cumulative risk of breast cancer through 59 years of age appears to bear no relationship to oral contraceptive (OC) use whatsoever. Studies restricted to women under age 45, however, raise concern about a possible adverse effect from OC use before a first-term pregnancy. A duration-related protective effect against endometrial cancer occurs from use of combined OCs. The risk is reduced by about 40% with 2 years of use, and by about 60% with 4 or more years of oral contraception. Oral contraception in excess of 3 years protects against ovarian cancer. Four years of use confers a 50% reduction in risk and 7 or more years of use confers a 60%-80% reduction in ovarian cancer risk. Studies of cervical dysplasia and carcinoma in situ suggest elevated risks with 2 or more years of OC use, although results are difficult to interpret in view of numerous factors that might distort the findings. The risk of invasive cervical cancer appear to be unaffected by up to 5 years of oral contraception. Beyond this, there is evidence suggesting an elevated risk which approaches a 2-fold increase at 10 years of use. Cancers of the vagina and fallopian tube are extremely rare. Their risks have yet to be characterized in relation to oral contraception.