Reproductive history in relation to plasma hormone levels in healthy post-menopausal women

Associations of reproductive factors with postmenopausal follicle stimulating hormone

Purpose

Recent studies have suggested that higher postmenopausal follicle stimulating hormone (FSH) may be associated with lower risk of diabetes. However, relatively little is known about postmenopausal FSH levels, including the level of variation between women and whether reproductive factors are associated with this variation.

Methods

We assessed the relationship of multiple reproductive factors with FSH levels among 588 postmenopausal women in the Kuopio Ischaemic Heart Disease Risk Factor Study. Participants were aged 53 to 73 years and not using hormone therapy at study enrollment (1998–2001) when reproductive factors were assessed and FSH was measured.

Results

After adjustment for age, menopause timing, sex steroid levels, adiposity and behavioral factors, we observed numbers of pregnancies and age at first birth were each inversely associated with FSH levels. For example, women with ≥ 3 births and an age at first birth ≥ 25 years had mean FSH levels that were 7.8 IU/L lower than those of women with 1–2 births and an age at first birth ≤ 24 years (P = 0.003). Number of miscarriages was inversely associated with FSH levels (-2.7 IU/L per miscarriage; P = 0.02). Women reporting 4 or more years of past hormone therapy use had significantly higher mean FSH levels than women who had never used hormone therapy (P for trend = 0.006).

Conclusion

Multiple reproductive factors were associated with postmenopausal FSH, independent of estradiol, adiposity and other confounders. These findings warrant replication and further exploration of potential underlying mechanism.

Age at natural menopause and risk of type 2 diabetes: a prospective cohort study

AIMS/HYPOTHESIS

In this study, we aimed to examine the association between age at natural menopause and risk of type 2 diabetes, and to assess whether this association is independent of potential mediators.

METHODS

We included 3639 postmenopausal women from the prospective, population-based Rotterdam Study. Age at natural menopause was self-reported retrospectively and was treated as a continuous variable and in categories (premature, <40 years; early, 40-44 years; normal, 45-55 years; and late menopause, >55 years [reference]). Type 2 diabetes events were diagnosed on the basis of medical records and glucose measurements from Rotterdam Study visits. HRs and 95% CIs were calculated using Cox proportional hazards models, adjusted for confounding factors; in another model, they were additionally adjusted for potential mediators, including obesity, C-reactive protein, glucose and insulin, as well as for levels of total oestradiol and androgens.

RESULTS

During a median follow-up of 9.2 years, we identified 348 individuals with incident type 2 diabetes. After adjustment for confounders, HRs for type 2 diabetes were 3.7 (95% CI 1.8, 7.5), 2.4 (95% CI 1.3, 4.3) and 1.60 (95% CI 1.0, 2.8) for women with premature, early and normal menopause, respectively, relative to those with late menopause (p _trend <0.001). The HR for type 2 diabetes per 1 year older at menopause was 0.96 (95% CI 0.94, 0.98). Further adjustment for BMI, glycaemic traits, metabolic risk factors, C-reactive protein, endogenous sex hormone levels or shared genetic factors did not affect this association.

CONCLUSIONS/INTERPRETATION

Early onset of natural menopause is an independent marker for type 2 diabetes in postmenopausal women.

The association of reproductive and lifestyle factors with a score of multiple endogenous hormones

INTRODUCTION

We recently reported that high levels of multiple sex and growth hormones were associated with increased postmenopausal breast cancer risk. Limited research has explored the relationship between reproductive, anthropometric, and lifestyle factors and levels of multiple hormones simultaneously.

METHODS

This cross-sectional analysis included 738 postmenopausal Nurses' Health Study participants who were controls in a breast cancer nested case-control study and had measured levels of estrone, estradiol, estrone sulfate, testosterone, androstenedione, dehydroepiandrosterone sulfate, prolactin, and sex hormone binding globulin (SHBG). A score was created by summing the number of hormones a woman had above (below for SHBG) each hormone's age-adjusted geometric mean. The association between lifestyle, anthropometric, and reproductive exposures and the score was assessed using generalized linear models.

RESULTS

The hormone score ranged from 0 to 8 with a mean of 4.0 (standard deviation = 2.2). Body mass index (BMI) and alcohol consumption at blood draw were positively associated with the hormone score: a 5 unit increase in BMI was associated with a 0.79 (95%CI: 0.63, 0.95) unit increase in the score (p < 0.0001) and each 15 g/day increase in alcohol consumption was associated with a 0.41 (95%CI: 0.18, 0.63) unit increase in the score (p = 0.0004). Family history of breast cancer, age at menarche, and physical activity were not associated with the score.

CONCLUSIONS

Reproductive breast cancer risk factors were not associated with elevated levels of multiple endogenous hormones, whereas anthropometric and lifestyle factors, particularly BMI and alcohol consumption, tended to be associated with higher levels of multiple hormones.

Benign breast and gynecologic conditions, reproductive and hormonal factors, and risk of thyroid cancer

The higher incidence of thyroid cancer in women compared with men suggests an influence of sex steroid hormones in the etiology of this malignancy. We investigated a comprehensive set of potential indicators of lifetime sex steroid hormone exposure in relation to thyroid cancer risk. Using data from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, which enrolled 70,047 women, 50 to 78 years old, we prospectively examined associations of self-reported history of benign breast and gynecologic conditions, reproductive factors, and exogenous sex hormone use with thyroid cancer risk. Multivariable-adjusted HRs and 95% confidence intervals (CI) were calculated in models using age as the time metric. During follow-up (median, 11 years), 127 women were diagnosed with first primary thyroid cancer. Older age at natural menopause (≥55 vs. <50 years; HR, 2.24; 95% CI, 1.20-4.18), greater estimated lifetime number of ovulatory cycles (≥490 vs. <415 cycles; HR, 2.40; 95% CI, 1.33-4.30), greater number of live births (≥5 vs. 1-2; HR, 1.72; 95% CI, 1.05-2.82), and history of uterine fibroids (HR, 1.72; 95% CI, 1.18-2.50) were associated with an increased risk of thyroid cancer. Earlier age at menarche, greater number of reproductive years, history of a tubal ligation, and history of ovarian cysts were nonsignificantly associated with increased thyroid cancer risk. No associations were observed for oral contraceptive use, menopausal hormone therapy, or history of benign breast disease or endometriosis. In general, we found that factors reflecting a greater length of exposure to endogenous hormones, particularly during the reproductive years, were associated with risk of postmenopausal thyroid cancer.

Diets and hormonal levels in postmenopausal women with or without breast cancer

The role of diet in breast cancer (BC) risk is unclear. Fiber could reduce BC risk, through the enterohepatic circulation of estrogens. We examined the relationship between diet and sex hormones in postmenopausal women with or without BC. Thirty-one postmenopausal women (10 omnivores, 11 vegetarians, and 10 BC omnivores) were recruited. Dietary records (5 days) and hormone levels (3 days) were evaluated on 4 occasions over 1 yr. Vegetarians showed a lower fat/fiber ratio, a higher intake of total and cereal fiber (g/d)/body weight (kg), a significantly lower level of plasma estrone-sulfate, estradiol, free-estradiol, free-testosterone, and ring D oxygenated estrogens, and a significantly higher level of sex-hormone-binding-globulin than BC subjects. Fiber was consumed in slightly larger amounts by omnivores than by BC subjects. Omnivores had significantly lower plasma testosterone and estrone-sulfate but higher sex-hormone-binding-globulin than BC subjects. No difference was found for the urinary 16-oxygenated estrogens. However, the 2-MeO-E1/2-OH-E1 ratio was significantly lower in omnivores than in BC group. This ratio is positively associated with the fat/fiber ratio. In conclusion, testosterone may contribute to causing alterations in the levels of catechol estrogens and 16-oxygenated estrogens. The fat/fiber ratio appears to be useful in evaluating dietary effects on estrogen metabolism.

Circulating sex hormones and breast cancer risk factors in postmenopausal women: reanalysis of 13 studies

Background:

Breast cancer risk for postmenopausal women is positively associated with circulating concentrations of oestrogens and androgens, but the determinants of these hormones are not well understood.

Methods:

Cross-sectional analyses of breast cancer risk factors and circulating hormone concentrations in more than 6000 postmenopausal women controls in 13 prospective studies.

Results:

Concentrations of all hormones were lower in older than younger women, with the largest difference for dehydroepiandrosterone sulphate (DHEAS), whereas sex hormone-binding globulin (SHBG) was higher in the older women. Androgens were lower in women with bilateral ovariectomy than in naturally postmenopausal women, with the largest difference for free testosterone. All hormones were higher in obese than lean women, with the largest difference for free oestradiol, whereas SHBG was lower in obese women. Smokers of 15+ cigarettes per day had higher levels of all hormones than non-smokers, with the largest difference for testosterone. Drinkers of 20+ g alcohol per day had higher levels of all hormones, but lower SHBG, than non-drinkers, with the largest difference for DHEAS. Hormone concentrations were not strongly related to age at menarche, parity, age at first full-term pregnancy or family history of breast cancer.

Conclusion:

Sex hormone concentrations were strongly associated with several established or suspected risk factors for breast cancer, and may mediate the effects of these factors on breast cancer risk.

Postmenopausal vaginal atrophy correlates with decreased estradiol and body mass index and does not depend on the time since menopause

OBJECTIVE

To evaluate the relationship between morphologic cell characteristics in Papanicolaou (Pap) smears and serum estradiol, body mass index (BMI) and the time elapsed since menopause. Study design. In 92 women Pap smears were grouped into atrophic and mature cell patterns and compared with estradiol, BMI and the time since menopause.

RESULTS

Forty-one patients with mature cell pattern were on average 7.1 years from menopause and 51 patients with atrophic pattern 8.2 years, but this difference was not significant. Estradiol in patients with mature cell pattern was significantly higher (52.1 +/- 48.5 pmol/l) than in patients with atrophic pattern (25.6 +/- 40.0 pmol/l). Similarly, BMI was significantly higher (27.9 +/- 4.2 kg/m(2)) in patients with mature cell pattern than in patients with atrophic pattern (25.7 +/- 3.8 kg/m(2)). There was no significant correlation between the time since menopause and estradiol among patients with mature and atrophic cell pattern. The same was true for the correlation between the time from menopause and BMI in patients with mature and atrophic pattern.

CONCLUSIONS

Estradiol and BMI are associated with vaginal cell maturation and atrophy in postmenopausal women. Vaginal cell atrophy does not depend on the time since menopause.

Variation in breast cancer hormone receptor and HER2 levels by etiologic factors: a population-based analysis

Evidence suggests that breast cancer hormone receptor status varies by etiologic factors, but studies have been inconsistent. In a population-based case-control study in Poland that included 2,386 cases and 2,502 controls, we assessed ER-alpha and PR status of tumors based on clinical records according to etiologic exposure data collected via interview. For 842 cancers, we evaluated ER-alpha, ER-beta, PR and HER2 levels by semiquantitative microscopic scoring of immunostained tissue microarrays and a quantitative immunofluorescence method, automated quantitative analysis (AQUAtrade mark). We related marker levels in tumors to etiologic factors, using standard regression models and novel statistical methods, permitting adjustment for both correlated tumor features and exposures. Results obtained with different assays were generally consistent. Receptor levels varied most significantly with body mass index (BMI), a factor that was inversely related to risk among premenopausal women and directly related to risk among postmenopausal women with larger tumors. After adjustment for correlated markers, exposures and pathologic characteristics, PR and HER2 AQUA levels were inversely related to BMI among premenopausal women (p-trend = 0.01, both comparisons), whereas among postmenopausal women, PR levels were associated directly with BMI (p-trend = 0.002). Among postmenopausal women, analyses demonstrated that BMI was related to an interaction of PR and HER2: odds ratio (OR) = 0.86 (95% CI = 0.69-1.07) for low PR and HER2 expression vs. OR = 1.78 (95% CI = 1.25-2.55) for high expression (p-heterogeneity = 0.001). PR and HER2 levels in breast cancer vary by BMI, suggesting a heterogeneous etiology for tumors related to these markers.

Endometrial cancer risk in estrogen users after switching to estrogen-progestin therapy

OBJECTIVE

It is unknown whether postmenopausal unopposed estrogen users are better off, in terms of endometrial cancer risk, switching to a combined estrogen-progestin regimen or stopping hormone use altogether.

METHODS

We analyzed data from a series of three population-based case-control studies in western Washington state during 1985-1999, comparing proportions of "switchers" and "stoppers" in cases and controls. We also assessed whether the risk of endometrial cancer in either group of former unopposed estrogen users returned to that of never users.

RESULTS

After multivariate adjustment using unconditional logistic regression, women who switched to a combined regimen with a progestin added for at least ten days/month (37 cases, 47 controls) had half the risk of endometrial cancer of women who stopped hormone use altogether (86 cases, 78 controls) (adjusted odds ratio = 0.5, 95% confidence interval: 0.3-1.1). Most subgroups of former users, whether they switched or stopped, had some increased risk of endometrial cancer compared to never users.

CONCLUSIONS

Results from this study suggest that unopposed estrogen users may reduce their risk of endometrial cancer more by switching to a combined regimen with progestin added for at least ten days/month than by stopping hormone use altogether.

Associations between reproductive and menstrual factors and postmenopausal androgen concentrations

BACKGROUND

Reproductive and menstrual characteristics, as well as high circulating estrogen and androgen concentrations, are associated with the risk of breast and ovarian cancer in postmenopausal women. To explore possible etiological relationships between menstrual and reproductive characteristics and cancer risk, we examined associations between menstrual and reproductive factors and serum concentrations of total testosterone, free testosterone, androstenedione, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEA-S).

METHODS

This study was conducted in 167 postmenopausal women, using data from the pre-randomization visit of an exercise clinical trial. Participants were sedentary, overweight/ obese, and not on hormone therapy.

RESULTS

DHEA-S concentrations were 42% higher, total testosterone concentrations were 35% lower, and free testosterone concentrations were 23% lower in women with both ovaries removed compared with those with both remaining (p = 0.01, p = 0.01, and p = 0.03, respectively). Women who had used herbal therapy in the past had, on average, 25% higher concentrations of total and free testosterone than women who had never used these herbal therapies (p = 0.03 and p = 0.004, respectively). No other significant associations were detected.

CONCLUSIONS

Overall, this study does not support the hypothesis that reproductive or menstrual factors, with the exception of oophorectomy status, are associated with postmenopausal androgen concentrations.

Lactation reduces prolactin levels in reproductively experienced female rats

Long-term alterations in prolactin (PRL) secretion following reproductive experience have been demonstrated in both women and female rats. In the rat, these changes include decreased PRL secretion in response to a dopamine antagonist challenge following ovariectomy, decreased post-coital diurnal and nocturnal prolactin surges in multigravid versus primigravid females, as well as decreased suckling-induced prolactin release in multiparous versus primiparous females. To date, there have been no studies examining PRL secretion following reproductive experience in cycling female rats. Studies in women, however, have demonstrated a reduction in basal PRL secretion during the menstrual cycle. The purpose of the present work was to determine whether similar changes occur in the rat during the estrous cycle and to what extent lactation is involved in these effects. In addition to examining PRL, potential parity-induced changes in estradiol secretion were also studied. The findings revealed a significant decrease in PRL levels during the afternoon of proestrus, which was only observed in primiparous females that had lactated. Significant differences in estradiol secretion were not detected following reproductive experience. Thus, a reduction in the PRL surge on the afternoon of proestrus is a consequence of reproductive experience that requires both pregnancy and lactation.

Associations between Reproductive and Menstrual Factors and Postmenopausal Sex Hormone Concentrations

Reproductive and menstrual characteristics, as well as high circulating estrogen concentrations, are associated with risk of hormone-related cancers in postmenopausal women. To explore possible etiologic relationships between menstrual/reproductive characteristics and risk of hormone-related cancers, we examined associations between menstrual/reproductive factors and serum concentrations of free estradiol, total estradiol, estrone, sex hormone binding globulin (SHBG), and follicle stimulating hormone (FSH). This study was conducted in 173 postmenopausal women using data from the prerandomization visit of an exercise clinical trial. Participants were sedentary, overweight/obese, and not on hormone therapy. Women ≥20 years past menopause had 23% lower total estradiol and 30% lower free estradiol concentrations than women within 4 years of menopause (P for trend = 0.04 and 0.02, respectively). Nulliparous women had 19% higher FSH concentrations than parous women (P = 0.02). Among parous women, parity was positively associated with SHBG and negatively associated with free estradiol concentrations. Women with ≥4 children had 20% lower free estradiol and 38% higher SHBG concentrations compared with women with one birth (P for trend = 0.02 and 0.01, respectively). Total number of months spent breast-feeding was modestly and inversely associated with serum FSH concentrations (P for trend = 0.07). Our results suggest that menstrual/reproductive characteristics may be associated with postmenopausal hormone concentrations; verification of these results in other studies may elucidate how these variables influence risk of hormone-related cancers.