Bone density of normal women in relation to endogenous and exogenous oestrogens

The influence of premenopausal hormones on severity of climacteric symptoms and use of HRT

OBJECTIVES

There is wide variation in the severity of climacteric symptoms and we hypothesized that this could be a reflection of premenopausal hormone levels.

METHODS

As part of a long-term cohort study of endocrine risk factors for breast cancer, blood had been collected between 1986 and 1990 from 1882 premenopausal women aged >or=35 years. Questionnaires on menopausal symptom severity were sent to 1,843 surviving women in 2001, of whom 1,434 replied. Estradiol, progesterone and testosterone levels were measured by radioimmunoassay in 680 women who reported a natural menopause and completed the symptom severity section in full.

RESULTS

Symptom severity fell with rising premenopausal estradiol levels and women with higher premenopausal testosterone levels had more severe vasomotor symptoms. Over 70% of women with above-median severity of symptoms had used hormone replacement therapy (HRT). Those with higher testosterone levels were less likely to take HRT.

CONCLUSIONS

Premenopausal hormone levels may predict risk of severe menopausal symptoms, which in turn influences use of HRT. Paradoxically, a high testosterone level was associated with more vasomotor symptoms but reduced use of HRT. Those at greatest risk of climacteric symptoms may be at lower risk of breast cancer because of premenopausal reduced estrogen exposure.

The impact of the Occupation of Guernsey 1940-1945 on breast cancer risk factors and incidence

To examine the impact of the German Occupation of Guernsey (1940-1945) on breast cancer risk factors and incidence. Under study were 1019 women who stayed, or whose mothers had stayed, in Guernsey, and 1358 women evacuated or born to evacuated mothers. Amongst those born 1926-1934 who remained in Guernsey, the secular trend of earlier menarche disappeared: menarche was delayed by 12 months for those born in 1930. By March 2006, 97 breast cancers had been diagnosed, 37 in the occupied group. Unusually, higher age at menarche appeared to be associated with increased risk of breast cancer (>or=14 years vs. <or=13 years: HR = 1.52, 95% CI = 0.80-2.92). Separate analyses by birth cohort revealed a non-significantly higher incidence in the subgroup born from 1926 to 1934 (HR = 1.30, 95% CI = 0.62-2.76). Delay in menarche among women remaining in Guernsey during the Occupation, rather than being protective, was associated with an increased risk of breast cancer.

Endogenous sex steroids and bone mineral density in healthy Greek postmenopausal women

The aim of this study was to assess the association of endogenous sex steroids with bone mineral density (BMD) in healthy postmenopausal women not on hormone therapy. A total of 884 postmenopausal women aged 42-71 years were studied in a cross-sectional design. Parameters assessed were follicle-stimulating hormone, luteinizing hormone, estradiol, total testosterone, sex hormone-binding globulin, free estrogen index (FEI), free androgen index (FAI), Delta4-androstendione (Delta4A), dehydroepiandrosterone sulfate (DHEAS), bone alkaline posphatase, and bone mineral density at the lumbar spine (L-BMD) and femoral neck (N-BMD). Estradiol and FEI associated positively with both L-BMD and N-BMD (r = 0.21-0.47, P < 0.01). These associations remained significant after adjustment for age, years since menopause, and body mass index. FAI correlated positively with both L-BMD and N-BMD (r = 0.18 and 0.33, respectively; P < 0.01). At the multivariate analysis, however, FAI remained the significant determinant only for N-BMD. Delta4A associated positively with N-BMD (r = 0.27, P = 0.001), whereas DHEAS showed no association with BMD at either site. Thus, endogenous steroids are significant determinants of postmenopausal BMD. Endogenous estradiol may be more important for lumbar spine BMD, whereas endogenous androgens are associated mainly with femoral neck BMD.

Hormone dependency of breast tumours developing in the Guernsey Cohort study

The aim of this study was to determine whether endogenous estradiol levels in postmenopausal women helped determine the estrogen receptor status of subsequent breast cancers. Within the Guernsey Cohort study of 6127 women, 140 have been diagnosed with breast cancer of whom 59 had estradiol assays performed and ER status available. Estradiol levels in serum and urine were measured by radioimmunoassay and ER status of tumours by immunohistochemistry. Of the individuals in the highest tertile of serum estradiol 35% had ER+ve tumours compared with 27% in the lowest tertile. In terms of 16hydroxyestrone excretion the proportions ER+ve tumours were 22% in the lowest tertile and 38% in the highest tertile. This suggests that endogenous estrogen levels do impact on the phenotype of subsequent breast cancer.

Baseline bone mineral density of the total lumbar spine may predict for chemotherapy-induced ovarian failure

Age at treatment and the total cumulative dose of cyclophosphamide are established predictors of chemotherapy-induced ovarian failure in premenopausal women with breast cancer. In a prospective trial of 49 women receiving adjuvant chemotherapy, we sought to identify whether other factors including family history of osteoporosis, lifestyle factors, reproductive hormones, bone turnover markers, or bone mineral density (BMD) of the hip or total spine measured before (baseline) and 6 months after chemotherapy increased the risk of ovarian failure. Univariate logistic regression analyses were used to identify the variables related to the risk of ovarian failure, and a multivariate logistic regression model was used to find the best of predictors of ovarian failure among the variables. In the multivariate model a higher total spine BMD at baseline (OR=6.0, p=0.02, 95% CI 1.4-27.3), and a 10% change in estradiol (E2) from baseline to six months (OR=0.80, p=0.02, 95% CI 0.67-0.97) were predictive of ovarian failure adjusted for age. In particular, as total spine BMD at baseline increases by 0.1 g/cm2 the odds of developing chemotherapy-induced ovarian failure increases by 6-fold. The multivariate model provides a good fit to the data (GOF p-value=0.8852), and provides excellent discrimination between those women who will and will not develop ovarian failure (Area under ROC=0.9487). If confirmed in larger data sets, using baseline spinal BMD to identify women who are at higher risk of developing ovarian failure independent of their age would be of value.

Osteopenia and osteoporosis in women with breast cancer

Osteopenia and osteoporosis are prevalent in women. Epidemiologic studies show that the risk of breast cancer is greater in postmenopausal women with higher bone mineral density (BMD). Standard treatments for breast cancer such as adjuvant chemotherapy or hormonal therapy can increase bone loss, and hence may increase the risk of osteoporosis. Premenopausal women treated with standard adjuvant chemotherapy frequently develop permanent ovarian failure, or early menopause. Ovarian failure is associated with accelerated bone loss, and bisphosphonates may mitigate this bone loss in women treated with adjuvant chemotherapy. Tamoxifen preserves BMD in postmenopausal women; however, in premenopausal women tamoxifen may increase bone loss. Anastrazole, an aromatase inhibitor, is approved for adjuvant treatment of postmenopausal women with early-stage, estrogen receptor-positive breast cancer. With a follow-up duration of less than 5 years, anastrazole-treated women experience increased fractures relative to those treated with tamoxifen. The management of osteopenia and osteoporosis in women with breast cancer generally does not differ from women without breast cancer. Adequate dietary calcium and vitamin D intake, encouraging weight-bearing exercise, and counseling about the relationship between smoking and alcohol and bone loss are all prudent recommendations for overall health and may lessen bone loss and the risk of subsequent osteoporosis. BMD should be measured in women with chemotherapy-induced ovarian failure, and in those on aromatase inhibitors. Bisphosphonates reduce the bone loss associated with chemotherapy-induced ovarian failure, and clinical trials evaluating third-generation bisphosphonates in women with chemotherapy-induced ovarian failure are underway. As many women with breast cancer will be long-term survivors, increasing recognition of maintaining skeletal health is important.

Breast cancer prevention: present and future

Increased risk of breast cancer may result from modifiable factors such as endogenous hormone levels, obesity, HRT, and non-lactation, or non-modifiable factors such as genetic susceptibility or increasing age. Those factors that are easiest to modify may have a limited impact on the totality of breast cancer. The Gail model, based on known factors may be useful for estimating life-time risk in some individuals. Tamoxifen prevention still remains contentious. In the NSABP-P1 study, there was a 49% reduction in risk of breast cancer in women given tamoxifen but in the Italian and Royal Marsden trials, no effect on breast cancer incidence was detected, possibly because of the different case-mix in these studies. Raloxifene, tested in the MORE trial reduced the incidence of breast cancer by 65%. The effect was restricted to ER positive tumours: no reduction in ER negative cancers was seen. Life-style factors such as diet, obesity, exercise, and age of first full term pregnancy and number of pregnancies have a mild to moderate impact on risk and so may have little effect on the incidence of breast cancer. Reduction of alcohol intake could lead to a modest reduction in the risk of breast cancer but possibly adversely affect other diseases. So far, studies of retinoids have not shown a benefit in terms of breast cancer risk reduction. Fat reduction and GnRH analogues reduce mammographic density but have not yet been shown to affect risk.

Serum estradiol and sex hormone-binding globulin and the risk of hip fracture in elderly women: the EPIDOS study

It has been suggested that low serum 17beta-estradiol (E2) and sex hormone-binding globulin (SHBG) may predict hip fracture in postmenopausal women. We have investigated the predictive value of serum E2 and SHBG concentrations and urinary deoxypyridinoline (D-Pyr) and type I collagen breakdown products (CTX) in a large prospective cohort of 7,598 healthy elderly ambulatory women (EPIDOS study), aged 75 years or more. We performed a nested case control study, by matching 212 patients with incident hip fracture with 636 controls. Mean follow-up was 3.3 years (maximum, 4.9 years). Women having serum E2 below the limit of detection (3 pg/ml), that is, 2% of the population, were not at higher risk, with a relative hazard (RH) of 1.59 (95% CI = 0.45-5.55). Women having serum E2 below 5, 6, 7, or 8 pg/ml, in the lowest quartile, or below the median had no increased risk of hip fracture. In contrast, women having serum E2 in the highest quartile (i.e., > or = 10 pg/ml) were protected, with an RH of 0.66 (0.44-0.98) that did not remain significant after adjustment for weight (RH = 0.71 [0.47-1.06]). High serum SHBG values with different cut-offs tended to be associated with an increased risk of hip fracture. Women in the highest quartile had an RH of 2.5 (1.37-4.61), compared with those in the lowest quartile, that decreased markedly after adjustment for body weight (1.61 [0.99 -2.62]). The highest quartile of the ratio E2/SHBG, which is an index of free E2, was associated with a lower hip fracture risk (RH = 0.6 [0.4-0.91]) that was no longer significant after adjustment for weight. In contrast, urinary D-Pyr and CTX, when elevated above the upper limit of premenopausal values, were predictive of hip fracture, with an RH of 2.07 (1.49-2.9) and 1.67 (1.19-2.32), respectively, even after adjustment for body weight, serum E2, and SHBG. We conclude that in healthy elderly French women over 75 years of age, serum E2 and E2/SHBG in the highest quartile are associated with a lower risk of hip fracture and that this association is explained by a higher body weight. In addition, serum levels of E2 and SHBG do not account for the increased risk of hip fracture associated with high levels of bone resorption markers.

The therapeutic potential of phytoestrogens

Phytoestrogens, such as the soya isoflavones genistein and daidzein, are currently being extensively investigated through both molecular, preclinical and clinical studies to determine their potential health benefits. Phytoestrogens may protect against chronic diseases such as hormone-dependent cancer (e.g., breast and prostate cancer), cardiovascular disease and osteoporosis. Investigations of phytoestrogen metabolism and bioavailability are also of great relevance. Conversion by gut microflora of daizein to its isoflavan metabolite equol, which is a more potent oestrogen and anti-oxidant, occurs only in some individuals (about 35% of subjects tested are equol excretors). This has considerable implications for daidzein bioavailability and also for cancer risk. Oxidative damage has been implicated in the development of heart disease and cancer and soya phytoestrogens have been reported to decrease plasma F(2)-isoprostane concentrations (biomarker for in vivo lipid peroxidation) and increase low density lipoprotein oxidation resistance. This anti-oxidant action of phytoestrogens could potentially contribute to their therapeutic efficacy. The findings from the current ongoing studies are all likely to contribute to determining the potential use of phytoestrogens as therapeutic agents.

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

OBJECTIVES

We sought to examine the relationship between reproductive history and measures of selected gonadotrophins and steroid hormones among post-menopausal women. Previous studies have suggested that there is a negative correlation between parity and post-menopausal serum estrogens, which may be a mechanism by which pregnancies protect women from the development of breast cancer.

METHODS

We analyzed women who experienced a natural menopause within the Healthy Women Study cohort both 1 and 8 years after menopause. Lifetime reproductive history was obtained and blood was assayed for estrone, estradiol, androstenedione, testosterone, follicle stimulating hormone (FSH), and luteinizing hormone (LH) at 1 year post-menopause and for many of these steroid hormones at 8 years post-menopause. Also at 8 years post-menopause, a hip bone mineral density measure was obtained.

RESULTS

Age at menopause related to a modest increase in estrone at 1 year but a decrease in estrone and estradiol at eight years. Adjustment for body mass index (BMI), oral contraceptive use, alcohol use, cigarette smoking, and education had little impact on these findings. There were no other internally consistent relationships between reproductive variables and steroid hormones or hip-bone mineral density.

CONCLUSIONS

These observations do not support the hypothesis that parity acts to diminish endogenous levels of post-menopausal estrogens.

Endogenous sex steroids and bone mineral density in older women and men: the Rancho Bernardo Study

This study examines the associations between endogenous sex steroids and bone mineral density (BMD), using data from a geographically defined cohort in Rancho Bernardo, California. Participants were community-dwelling women and men aged 50-89 years who took part in a study of endogenous sex steroid measurement between 1984-1987 and who had BMD measured in 1988-1991. Those taking corticosteroids or estrogen at the time of sex steroid determination were excluded. The main study outcomes were BMD of the ultradistal radius, midshaft radius, lumbar spine, and total hip by sex steroid level, adjusted for age, body mass index, cigarette smoking, alcohol consumption, leisure exercise, use of thiazides, thyroid hormones, and former estrogen use (women only). At the time of the hormone measurements, the mean age of the 457 women was 72.1 years and that of the 534 men was 68.6 years. A statistically significant positive relation was seen between bioavailable estradiol and BMD at all sites in women and men. Total estradiol was significantly associated with BMD at all sites in women and at all but the ultradistal radius in men. Estrone had a global effect on BMD in women and was not measured in men. Higher bioavailable (but not total) testosterone levels were associated with higher BMD of the ultradistal radius, spine, and hip in men and the ultradistal radius in women. Dehydroepiandrosterone was positively associated with BMD of the midradius, spine, and hip in women and was not associated with BMD at any site in men. Of the sex steroids tested, bioavailable estrogen was most strongly associated with BMD in both women and men. We conclude that endogenous sex steroid levels are significantly related to bone density in older women and men. Individual variation in age-related bone loss may be partially accounted for by alterations in sex steroid levels with aging. Further study to elucidate safe environmental and medical methods to maintain optimal sex steroid levels in old age is needed.