Clinical review: DHEA replacement for postmenopausal women

CONTEXT

It has been proposed that because dehydroepiandrosterone (DHEA) and its sulfate, DHEAS, are important precursors for estrogen and androgen production, treatment with DHEA is a physiologically based strategy for the alleviation of hormone deficiency symptoms in postmenopausal women. We have summarized the physiology of DHEA in women and reviewed the findings from randomized controlled trials (RCT) of the effects of DHEA therapy in postmenopausal women with normal adrenal function.

EVIDENCE ACQUISITION

We reviewed the medical literature for key papers investigating DHEA physiology and RCT of the use of DHEA in postmenopausal women through November 2010. The focus was on sexual function, well-being, metabolic parameters, and cognition as study endpoints.

EVIDENCE SYNTHESIS

Although cross-sectional studies have indicated a link between low DHEA levels and impaired sexual function, well-being, and cognitive performance in postmenopausal women, placebo-controlled RCT do not show benefits of oral DHEA for any of these outcomes or favorable effects on lipids and carbohydrate metabolism.

CONCLUSIONS

Taken together, findings from this review of the published literature of studies do not support the use of DHEA in postmenopausal women at this time.

Placental characteristics as a proxy measure of serum hormone and protein levels during pregnancy with a male fetus

OBJECTIVE

In utero exposure to steroid hormones may be related to risk of some cancers such as testicular germ cell tumors (TGCT). To determine whether placental characteristics are good surrogate measures of maternal biomarker levels, we evaluated the correlations in mothers of sons at higher (whites, n = 150) and lower (blacks, n = 150) risk of TGCT. Associations with birth weight were also examined.

METHODS

All mothers, participants in the Collaborative Perinatal Project, were primigravidas who gave birth to male singletons. Associations between placental weight and placental thickness and third-trimester biomarker levels were evaluated using linear regression. Partial correlation coefficients for placental characteristics and birth weight were also estimated.

RESULTS

Placental weight was positively correlated with alpha-fetoprotein (AFP), sex hormone-binding globulin (SHBG), testosterone, estradiol and estriol in whites, and AFP and estriol in blacks. Placental thickness was not associated with any biomarker. After adjustment for placental weight, birth weight was not correlated with any biomarker.

CONCLUSIONS

In these data, placental weight was modestly correlated with third-trimester biomarker level; however, it appeared to be a better surrogate for third-trimester biomarker level than birth weight. Placental thickness had limited utility as a surrogate measure for biomarker levels.

Pharmacokinetics, tolerability and cycle control of three transdermal contraceptive delivery systems containing different doses of ethinylestradiol and levonorgestrel

BACKGROUND

The only available contraceptive patch, Ortho Evra®, delivers a relatively high dose of estrogen.

MATERIALS AND METHODS

Three transdermal contraceptive delivery systems (TCDS) containing low doses of ethinylestradiol (EE) and levonorgestrel (LNG) were evaluated in two open-label randomized trials. In a phase 1, two-period, cross-over trial, AG200-12.5 and AG200LE were compared with a 150 μg LNG/30 μg EE oral contraceptive (OC) (Levlen®) in 39 women. In a phase 2, parallel-group, multicenter, three-cycle study, AG200LE, AG200-12.5 and a higher-dose formulation, AG200-15, were evaluated in 123 women.

RESULTS

In Study 1, mean steady-state plasma concentrations (Css, pg/mL) for the TCDS were 17 pg/mL to 26 pg/mL for EE and 1117 pg/mL to 1505 pg/mL for LNG (for AG200LE and AG200-12.5 respectively). Maximum concentration (Cmax) and Css for both analytes were significantly lower than for Levlen. In both studies, the Css levels for EE and LNG in all groups were within the ranges reported for low-dose OCs. Cycle control for AG200-15, assessed by breakthrough bleeding and spotting episodes as well as number of days of unscheduled bleeding and/or spotting, was similar to that reported for low-dose OCs. Most adverse events were considered mild to moderate in intensity. The incidence of patches falling off was <2%.

CONCLUSIONS

All three patches exhibited excellent safety and wearability profiles while maintaining plasma drug levels required for ovulation suppression and adequate cycle control. A slight increase in the EE dose in AG200-15 still places this TCDS within the range of low-dose OCs, with EE exposure much lower than reported for Ortho Evra. AG200-15 was selected for further testing in phase 3 studies.

Brain levels of sex steroid hormones in men and women during normal aging and in Alzheimer's disease

We examined the relationships between normal aging, Alzheimer's disease (AD), and brain levels of sex steroid hormones in men and women. In postmortem brain tissue from neuropathologically normal, postmenopausal women, we found no age-related changes in brain levels of either androgens or estrogens. In comparing women with and without AD at different ages, brain levels of estrogens and androgens were lower in AD cases aged 80 years and older but not significantly different in the 60-79 year age range. In male brains, we observed that normal aging was associated with significant decreases in androgens but not estrogens. Further, in men aged 60-79 years, brain levels of testosterone but not estrogens were lower in cases with mild neuropathological changes as well as those with advanced AD neuropathology. In male cases over age 80, brain levels hormones did not significantly vary by neuropathological status. To begin investigating the relationships between hormone levels and indices of AD neuropathology, we measured brain levels of soluble β-amyloid (Aβ). In male cases with mild neuropathological changes, we found an inverse relationship between brain levels of testosterone and soluble Aβ. Collectively, these findings demonstrate sex-specific relationships between normal, age-related depletion of androgens and estrogens in men and women, which may be relevant to development of AD.

Effect of tamoxifen or anastrozole on steroid sulfatase activity and serum androgen concentrations in postmenopausal women with breast cancer

BACKGROUND

In postmenopausal women estrogens can be formed by the aromatase pathway, which gives rise to estrone, and the steroid sulfatase (STS) route which can result in the formation of estrogens and androstenediol, a steroid with potent estrogenic properties. Aromatase inhibitors, such as anastrozole, are now in clinical use whereas STS inhibitors, such as STX64, are still undergoing clinical evaluation. STX64 was recently shown to block STS activity and reduce serum androstenediol concentrations in postmenopausal women with breast cancer. In contrast, little is known about the effects of aromatase inhibitors or anti-estrogens on STS activity or serum androgen levels.

PATIENTS AND METHODS

Study 1: Blood was collected from ten postmenopausal women with breast cancer before and after two-week treatment with anastrozole and serum concentrations of androstenediol and other androgens and estrogens were assessed. Study 2: Blood samples were collected from 15 breast cancer patients before and after four-week treatment with anastrozole and 10 patients before and after four-week treatment with tamoxifen. Blood was used to assess STS activity in peripheral blood lymphocytes (PBLs) and serum dehydroepiandrosterone sulfate and dehydroepiandrosterone levels.

RESULTS

Neither anastrozole nor tamoxifen had any significant effect on STS activity as measured in PBLs. Anastrozole did not affect serum androstenediol concentrations.

CONCLUSION

Anastrozole and tamoxifen did not inhibit STS activity and serum androstenediol concentrations were not reduced by aromatase inhibition. As androstenediol has estrogenic properties, it is possible that the combination of an aromatase inhibitor and STS inhibitor may give a therapeutic advantage over the use of either agent alone.

Associations between polymorphisms in glucuronidation and sulfation enzymes and sex steroid concentrations in premenopausal women in the United States

Glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGT) and sulfation, catalyzed by sulfotransferases (SULT), are pathways through which sex steroids are metabolized to less active compounds. These enzymes are highly polymorphic and genetic variants frequently result in higher or lower activity. The phenotypic effects of these polymorphisms on circulating sex steroids in premenopausal women have not yet been investigated. One hundred and seventy women aged 40-45 years had a blood sample drawn during the follicular phase of the menstrual cycle for sex steroid measures and to obtain genomic DNA. Urine was collected for 2-hydroxy (OH) estrone (E(1)) and 16α-OH E(1) measures. Generalized linear regression models were used to assess associations between sex steroids and polymorphisms in the UGT1A and UGT2B families, SULT1A1, and SULT1E1. Women with the UGT1A1(TA7/TA7) genotype had 25% lower mean estradiol (E(2)) concentrations compared to the wildtype (TA6/TA6) (p=0.02). Similar associations were observed between SULT1A1(R213/H213) and E(1) (13% lower mean E(1) concentration vs. wildtype; p-value=0.02) and UGT2B4(E458/E458) and dehydroepiandrosterone (DHEA) (20% lower mean DHEA vs. wildtype; p-value=0.03). The SULT1E1(A/C) and the UGT1A1(TA7)-UGT1A3(R11) haplotypes were associated with reduced estrogen concentrations. Further study of UGT and SULT polymorphisms and circulating sex steroid measures in larger populations of premenopausal women is warranted.

A 12-month moderate-intensity exercise intervention does not alter serum prolactin concentrations

INTRODUCTION

Many studies have investigated the immediate impact of physical activity on prolactin concentrations; however, it is currently unclear what impact exercise may have on prolactin concentrations in the long-term, particularly among women. Understanding the role of exercise on prolactin is important because epidemiologic studies have reported increased risks of breast cancer in association with high prolactin concentrations. We investigated whether exercise alters serum prolactin concentrations at two time points within a one-year exercise intervention.

METHODS

Out of 96 women aged 40-75 years, 47 were randomized to a 12-month regimen of moderate-intensity physical activity and 49 were randomized to the control group. Participants in the exercise group (exercisers) took part in exercise at gym facilities 3 times per week and 3 times per week on their own. Serum prolactin was collected from participants at baseline, 3 and 12 months. Using generalized linear models, we compared the percent change in prolactin concentrations from baseline to the two follow-up time points in the exercisers versus the control group.

RESULTS

While we observed the suggestion of differences in the change in serum prolactin concentrations in some subgroups, overall there was no difference in the change in prolactin concentrations between exercisers and controls at 3 months (p=0.57) or 12 months (p=0.42).

CONCLUSION

Our study does not support the hypothesis that long-term exercise influences serum prolactin concentrations.

A prospective evaluation of C-reactive protein levels and colorectal adenoma development

BACKGROUND

Inflammation is hypothesized to play a role in colorectal tumorigenesis. Circulating levels of C-reactive protein (CRP), a serologic marker of the inflammatory response, have been positively associated with colorectal cancer development in some studies; however, there are limited data on the relation of CRP with colorectal adenomas, established precursors of colorectal cancer.

METHODS

A nested case-control investigation of CRP levels and incident colorectal adenoma was conducted in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a randomized trial of 154,942 individuals designed to test the efficacy of flexible sigmoidoscopy on colorectal cancer mortality when performed once, and then repeated 3 to 5 years later. Serum CRP levels were measured in baseline blood specimens from participants who were free of polyps in the left-sided colorectum at the baseline screening procedure, but who were found at the subsequent screen to have at least one colorectal adenoma (n=356), and in a set of polyp-free, frequency-matched controls (n=396).

RESULTS

In a multivariable logistic regression model that included established colorectal adenoma risk factors, a 1-unit increase in log CRP level was associated with a 15% reduction in risk of developing colorectal adenoma (OR=0.85, 95% CI, 0.75-0.98, Ptrend=0.01). This association did not differ according to body size, smoking behavior, gender, use of nonsteroidal antiinflammatory drugs, or adenoma location.

CONCLUSIONS

High circulating CRP levels may be protective against colorectal adenoma development.

IMPACT

Though at contrast with mechanistic data on inflammation and colorectal tumorigenesis, this finding is not inconsistent with prior results on CRP and colorectal adenoma and warrants further investigation.

Carbamazepine coadministration with an oral contraceptive: effects on steroid pharmacokinetics, ovulation, and bleeding

PURPOSE

Antiepileptic drugs (AEDs) are widely used in reproductive-age women. The AED carbamazepine (CBZ) induces the hepatic cytochrome P450 system, thereby accelerating hormone metabolism. We sought to assess the pharmacodynamic effects of CBZ on breakthrough bleeding and ovulation during oral contraceptive (OC) use.

METHODS

A double-blind, randomized, crossover study of healthy women ages 18-35 years. Participants took an OC containing 20 μg ethinyl estradiol (EE) and 100 μg levonorgestrel (LNG) for 4 months. Concurrently, participants took 600 mg CBZ or a matching placebo for 2 months each, administered in random order. During the second month of CBZ or placebo, we measured EE and LNG levels 12 times over 24 h, ovarian follicular diameters with eight biweekly vaginal ultrasounds, weekly progesterone levels, and bleeding (using a diary).

KEY FINDINGS

We enrolled 25 women; 10 completed the study. Five women discontinued because of reversible CBZ side effects. Mean area under the curve (AUC) measurements were lower during CBZ use compared to placebo for EE (1,778 vs. 986 pg*h/ml, p < 0.001) and LNG (24.8 vs. 13.8 pg*h/ml, p = 0.04). Ovulation occurred in 5 of 10 CBZ cycles compared to 1 of 10 placebo cycles (p = 0.06). Three or more days of breakthrough bleeding occurred during 8 of the 10 CBZ cycles compared to 2 of the 10 placebo cycles (p = 0.07).

SIGNIFICANCE

A commonly used dose of CBZ decreased levels of contraceptive steroids, increased breakthrough bleeding, and permitted ovulation during use of a low-dose OC. Women treated with CBZ are not adequately protected from pregnancy by low-dose OCs.

Prospective case-control study of premenopausal serum estradiol and testosterone levels and breast cancer risk

INTRODUCTION

Breast cancer is frequently a hormonally dependent cancer, and associations of circulating estrogens and androgens with subsequent breast cancer risk are well established in postmenopausal women. Associations of serum estrogens and androgens with breast cancer risk in premenopausal women are less well studied. The objective of this study was to determine whether estradiol and testosterone levels in serum collected before menopause are associated with subsequent breast cancer risk.

METHODS

We conducted a prospective case-control study of 266 participants who were registered in the Columbia, Missouri, Serum Bank and not using exogenous hormones at the time of blood collection. Each of 98 in situ or invasive breast cancer cases with prediagnostic serum collected before menopause was matched to two controls by age, date, menstrual cycle day, and time of day of blood collection. Estradiol and testosterone concentrations were quantified by using specific radioimmunoassays, and sex hormone-binding globulin (SHBG) was quantified with a chemiluminescent immunoassay to allow calculation of the non-SHBG bound hormone fractions. Data were analyzed by using conditional logistic regression. All tests of statistical significance were two-sided.

RESULTS

Serum testosterone was strongly and significantly associated with breast cancer risk. The relative odds (OR) for increasing quartiles of total testosterone were 1.0, 2.1 (95% confidence interval (CI) 0.9 to 4.8), 1.5 (95% CI, 0.6 to 3.4), and 3.3 (95% CI, 1.5 to 7.5, P(trend) = 0.006). Comparable ORs for the non-SHBG bound fraction of testosterone that is bioavailable were 1.0, 1.7 (95% CI, 0.7 to 4.2), 1.7 (95% CI, 0.7 to 4.0), and 4.2 (95% CI, 1.6 to 10.9, P(trend) = 0.002). Total and non-SHBG-bound estradiol were not associated with breast cancer, but extreme variation in levels across the menstrual cycle coupled with relatively small numbers, particularly for analyses stratified by cycle phase, limited the power to detect associations.

CONCLUSIONS

Results suggest that premenopausal women with elevated serum testosterone levels are at an increased risk of breast cancer.

DHEA-S levels and cardiovascular disease mortality in postmenopausal women: results from the National Institutes of Health--National Heart, Lung, and Blood Institute (NHLBI)-sponsored Women's Ischemia Syndrome Evaluation (WISE)

CONTEXT

Dehydroepiandrosterone sulfate (DHEA-S), a major circulating sex steroid prohormone, declines with age. Low levels have been associated with increased cardiovascular disease (CVD) risk and all-cause mortality, although these results have not been consistently replicated, particularly in women.

OBJECTIVE

Our objective was to examine the association of circulating DHEA-S levels, CVD, and mortality risk among postmenopausal women with suspected myocardial ischemia.

DESIGN

In the Women's Ischemia Syndrome Evaluation, 270 postmenopausal women underwent coronary angiography and blood hormone levels for suspected ischemia and were followed annually. The primary outcome of interest was CVD mortality; secondary analyses included all-cause mortality and nonfatal CVD events (myocardial infarction, stroke, and congestive heart failure) and angiographic obstructive coronary artery disease (CAD).

RESULTS

Women in the lowest DHEA-S tertile had higher CVD mortality (17% 6-yr mortality rate vs. 8%; log-rank P = 0.011), and all-cause mortality (21 vs. 10%; P = 0.011) compared with women with higher DHEA-S levels. The increased CVD mortality risk [hazard ratio (HR) = 2.55; 95% confidence interval (CI) = 1.19-5.45] remained unchanged after adjustment for multiple CVD risk factors (HR = 2.43; 95% CI = 1.06-5.56) but became nonsignificant when further adjusting for the presence or severity of angiographic obstructive CAD (HR = 1.99; 95% CI = 0.87-4.59). Results were similar for all-cause mortality. Lower DHEA-S levels were only marginally but not independently associated with obstructive CAD.

CONCLUSIONS

Among postmenopausal women with coronary risk factors undergoing coronary angiography for suspected myocardial ischemia, lower DHEA-S levels were linked with higher CVD mortality and all-cause mortality. Our study provides valuable feasibility data useful for future investigations and possible mechanistic pathways.

Sex differences in β-amyloid accumulation in 3xTg-AD mice: role of neonatal sex steroid hormone exposure

The risk of Alzheimer's disease (AD) is higher in women than in men, a sex difference that likely results from the effects of sex steroid hormones. To investigate this relationship, we first compared progression of β-amyloid (Aβ) pathology in male and female triple transgenic (3xTg-AD) mice. We found that female 3xTg-AD mice exhibit significantly greater Aβ burden and larger behavioral deficits than age-matched males. Next, we evaluated how the organizational effects of sex steroid hormones during postnatal development may affect adult vulnerability to Aβ pathology. We observed that male 3xTg-AD mice demasculinized during early development exhibit significantly increased Aβ accumulation in adulthood. In contrast, female mice defeminized during early development exhibit a more male-like pattern of Aβ pathology in adulthood. Taken together, these results demonstrate significant sex differences in pathology in 3xTg-AD mice and suggest that these differences may be mediated by organizational actions of sex steroid hormones during development.

Correlation of serum androgens with anthropometric and metabolic indices in healthy, nonobese postmenopausal women

OBJECTIVE

The role of testosterone in the regulation of metabolic and physiological function in men is well defined, but its role in women remains enigmatic. Thus, the present study sought to assess the contribution of endogenous circulating androgens to the regulation of metabolic function, body morphometry, and physical function in normal naturally postmenopausal women.

METHODS

Using a cross-sectional design, we measured serum androgens in a cohort of 29 naturally postmenopausal women and correlated the results with metabolic, morphometric, and functional outcome parameters. These included insulin sensitivity, whole-body fat and lean body mass, visceral/abdominal fat areasm and aerobic capacity.

RESULTS

Higher serum testosterone levels were related to greater maximal aerobic capacity and reduced adiposity. Additionally, higher serum dihydrotestosterone, dehydroepiandrosterone sulfate, androstenedione, and androstenetriol glucuronidate levels were correlated to greater insulin sensitivity.

CONCLUSION

In naturally postmenopausal women, endogenous androgens may play a role in the maintenance of beneficial patterns of metabolic, morphometric, and functional parameters.

The relationship of menopausal status and rapid menopausal transition with carotid intima-media thickness progression in women: a report from the Los Angeles Atherosclerosis Study

CONTEXT

The onset of menopause has been associated with an increase in cardiovascular risk factors. However, little information is available about the rapidity of the menopausal transition and its relationship to the development of preclinical cardiovascular disease (CVD).

OBJECTIVE

Our objective was to assess whether the rate of carotid intima-media thickness (cIMT) progression over time differs according to 1) menopausal status and 2) rapidity of the menopausal transition.

DESIGN

We evaluated 203 community-based women aged 45-60 yr without previously diagnosed CVD who underwent three repeated measurements of cIMT as a measure of preclinical CVD over 3 yr. Menopausal status was ascertained at each visit based on menstrual cycle parameters and reproductive hormone profiles. Of these, 21 remained premenopausal, 51 transitioned, and 131 were postmenopausal throughout the observation period.

RESULTS

Age-adjusted cIMT progression rates were similar among premenopausal, transitioning, and postmenopausal women. In the 51 transitioning women, age was not related to rate of cIMT progression. However, the rapidity of menopausal transition was related to cIMT progression: women transitioning from pre- to postmenopause within the 3-yr period had a higher rate of cIMT progression compared with women with a slower transition. Statistical adjustments for the significant covariates of systolic blood pressure, body mass index, race, cigarette smoking, or hormone therapy use did not alter the findings.

CONCLUSIONS

Among healthy women undergoing repeated cIMT measurement, a more rapid menopausal transition was associated with a higher rate of preclinical CVD progression measured by cIMT. Further work is needed to explore potential mechanisms of this effect.

Advantages and challenges of mass spectrometry assays for steroid hormones

Although steroid hormones have been measured, primarily in urine, by gas chromatography-mass spectrometry (GC-MS) assays for many years, in the past decade both clinical and research laboratories have dramatically increased usage of liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for measuring circulating levels of steroid hormones. Because of their high validity and throughput, mass spectrometry (MS) assays have replaced conventional radioimmunoassays (RIAs) and direct immunoassays for steroid hormones in larger reference laboratories, and they are touted to become the "gold standard" for steroid hormone quantitation. These advances in MS assays present several major challenges, which include the affordability of smaller laboratories to purchase MS instruments and pay for related operating costs; improving assay sensitivity, especially for measuring low estradiol levels in postmenopausal women and women treated with aromatase inhibitors; developing assays for quantitating profiles of steroid hormone metabolites in serum and tissues; standardizing steroid MS assays; and obtaining reliable reference intervals. The present review discusses the advantages of MS assays over conventional RIAs and direct immunoassays in steroid hormone measurements, and points out some of the important challenges facing the rapid increase in usage of MS assays.

Associations between markers of inflammation and physiological and pharmacological levels of circulating sex hormones in postmenopausal women

OBJECTIVE

Hormone therapy has been shown to reduce markers of vascular inflammation in . C-reactive protein (CRP), a marker of generalized inflammation, is raised by oral estradiol therapy (ET). It is not known how sex hormone concentrations relate to the markers of inflammation in postmenopausal women taking or not taking hormone therapy.

METHODS

This observational study includes postmenopausal women participating in the Estrogen in the Prevention of Atherosclerosis Trial. Multiple measures of serum sex hormone and sex hormone-binding globulin(SHBG) levels from 107 postmenopausal women taking oral ET and 109 taking placebo for 2 years were correlated with markers of inflammation over the same time period using generalized estimating equations.

RESULTS

Levels of soluble intercellular adhesion molecule-1 were significantly inversely associated with estrone(P = 0.05), total and free estradiol (P = 0.008 and 0.02, respectively), and SHBG (P = 0.03) only among oral ET users. Serum homocysteine levels were also inversely associated with estrone (P = 0.001) and total and free estradiol (P = 0.0006 and 0.0009, respectively) in ET-treated women only. No such associations were observed among women taking placebo. CRP was positively associated with estrogens and SHBG among women taking oral ET but inversely associated with SHBG among the placebo group.

CONCLUSIONS

The inverse associations of estrogens with soluble intercellular adhesion molecule-1 and homocysteine support an anti-inflammatory property of estrogen, which was observed only at pharmacological levels in postmenopausal women. The positive associations between estrogens and CRP in the ET-treated women can be explained by the first-pass hepatic effect rather than a proinflammatory response.

Androgens, growth factors, and risk of prostate cancer: the Multiethnic Cohort

BACKGROUND

Androgens and growth factors are thought to be associated with prostate cancer risk, although past research has produced mixed results.

METHODS

We conducted a nested case-control study of biomarkers of prostate cancer risk within the Multiethnic Cohort. We compared prediagnostic levels of testosterone, dihydrotestosterone (DHT), sex hormone-binding globulin (SHBG), 3alpha-androstanediol glucuronide (3alpha-diol G), insulin-like growth factor I (IGF-I), IGF-II, IGF-binding protein 1 (IGFBP-1), and IGFBP-3 in serum from 467 incident prostate cancer cases and 934 cancer-free controls. Controls were matched to the cases on geographic site (HI, LA), ethnicity, age at specimen collection (+/-1 year), date (+/-1 month) and time of day (+/-2 hr) of sample collection, and fasting status (<6, 6-7, 8-9, >10 hr). Multivariate conditional logistic regression models were used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Serum concentrations of testosterone, DHT, SHBG, 3alpha-diol G, IGF-I, IGF-II, IGFBP-1, and IGFBP-3 were not associated with risk of prostate cancer. Tests for trend of quartiles of serum concentrations also did not show any association. Results were relatively unchanged for men with advanced prostate cancer and their matched controls. However, the follow-up period was relatively short (mean of 1.9 years). Analysis by ethnic group showed an increased risk for Latino men in the second (OR = 3.67, 95% CI: 1.63-8.24) and third (OR = 2.96, 95% CI: 1.19-7.40) tertiles of IGF-I serum levels compared with the first tertile.

CONCLUSIONS

The suggested increased risk for IGF-I in Latino men merits further study, with greater statistical power.

Pharmacokinetics of a combined oral contraceptive in obese and normal-weight women

BACKGROUND

This study was conducted to compare oral contraceptive (OC) pharmacokinetics (PK) in normal-weight [body mass index (BMI) 19.0-24.9] and obese (BMI 30.0-39.9) women.

STUDY DESIGN

During the third week of the third cycle of OC use, we admitted 15 normal-weight and 15 obese women for collection of 12 venous specimens over 24 h. Using radioimmunoassay techniques, we measured levels of ethinyl estradiol (EE) and levonorgestrel (LNG). During the same cycle, women underwent twice-weekly sonography to assess ovarian follicular development and blood draws to measure endogenous estradiol (E2) and progesterone levels.

RESULTS

Obese women had a lower area under the curve (AUC; 1077.2 vs. 1413.7 pg*h/mL) and lower maximum values (85.7 vs. 129.5 pg/mL) for EE than normal-weight women (p=.04 and <0.01, respectively); EE trough levels were similar between BMI groups. The similar, but smaller, differences in their LNG levels for AUC and maximum values (C(max)) were not statistically significant. While peak values differed somewhat, the LNG trough levels were similar for obese and normal-weight women (2.6 and 2.5 ng/mL, respectively). Women with greater EE AUC had smaller follicular diameters (p=.05) and lower E2 levels (p=.04). While follicular diameters tended to be larger among obese women, these differences were not statistically significant.

CONCLUSION

OC hormone peak levels are lower among obese women compared to normal-weight women, but their trough levels are similar. In this small study, the observed PK differences did not translate into more ovarian follicular activity among obese OC users.

Adolescent diet and subsequent serum hormones, breast density, and bone mineral density in young women: results of the Dietary Intervention Study in Children follow-up study

BACKGROUND

Adolescent diet is hypothesized to influence breast cancer risk. We evaluated the long-term effects of an intervention to lower fat intake among adolescent girls on biomarkers that are related to breast cancer risk in adults.

METHODS

A follow-up study was conducted on 230 girls who participated in the Dietary Intervention Study in Children (DISC), in which healthy, prepubertal, 8 to 10 year olds were randomly assigned to usual care or to a behavioral intervention that promoted a reduced fat diet. Participants were 25 to 29 years old at follow-up visits. All tests of statistical significance are two-sided.

RESULTS

In analyses that did not take account of diet at the time of the follow-up visit, the only statistically significant treatment group difference was higher bone mineral content in intervention group participants compared with usual care group participants; their mean bone mineral contents were 2,444 and 2,377 g, respectively. After adjustment for current diet, the intervention group also had statistically significantly higher bone mineral density and luteal phase serum estradiol concentrations. Serum progesterone concentrations and breast density did not differ by treatment group in unadjusted or adjusted analyses.

CONCLUSIONS

Results do not support the hypothesis that consumption of a lower fat diet during adolescence reduces breast cancer risk via effects on subsequent serum estradiol and progesterone levels, breast density, or bone mineral density. It remains unclear, however, if the results are specific to the DISC intervention or are more broadly applicable.

IMPACT

Modest reductions in fat intake during adolescence are unlikely to lower later breast cancer risk via long-term effects on the biomarkers measured.

Effect of statins on estrogen and androgen levels in postmenopausal women treated with estradiol

OBJECTIVE

A considerable number of postmenopausal women who receive estrogen therapy are also treated for hypercholesterolemia with cholesterol-lowering statins. Statins and steroid hormones can compete for the same steroid-metabolizing enzymes. We investigated whether long-term administration of statins had an effect on serum estrogen and androgen levels in postmenopausal women receiving and not receiving oral estrogen therapy.

METHODS

A subgroup analysis from the Estrogen in the Prevention of Atherosclerosis Trial, a randomized, double-blind, placebo-controlled trial, was performed. A total of 222 women were randomized to receive either placebo or 1 mg of oral micronized 17β-estradiol daily for 2 years. In both the placebo and treatment groups, participants with low density lipoprotein cholesterol levels >160 mg/dl were treated with statins. Blood samples were obtained at baseline and every 6 months during the trial. Serum levels of dehydroepiandrosterone, androstenedione, testosterone, estrone and 17β-estradiol were measured by radioimmunoassay.

RESULTS

Among 86 placebo- and 90 estradiol-treated subjects with baseline and on-trial hormone measurements, no significant differences were observed between the statin-free and statin-treated groups in mean changes from baseline to on-trial levels in any of the androgens or estrogens, whether or not the postmenopausal women were treated with estrogen.

CONCLUSION

The results suggest that estrogen therapy and statins can be used simultaneously with no deleterious effects on circulating hormone levels.

Abstract 2827: Adolescent diet and serum hormones, breast density and bone mineral density in young adults: findings from the Dietary Intervention in Children (DISC) Follow-Up Study

Background: Adolescent diet is hypothesized to influence breast cancer risk, and we previously showed that an intervention to lower fat intake during adolescence was associated with lower serum estrogens and progesterone. We have now evaluated the long-term effects of this intervention on serum hormones, breast density and bone mineral density (BMD), biomarkers that are positively related to breast cancer risk in adults. Methods: We conducted a follow-up study of 230 girls who participated in 1988-1997 in the Dietary Intervention Study in Children (DISC), in which healthy, prepubertal 8-10 year olds with elevated low-density lipoprotein cholesterol were randomly assigned to usual care or to a behavioral intervention that promoted a reduced-fat diet. Follow-up visits were conducted in 2006-2008, when participants were 25-29 years old. Serum estradiol and progesterone were measured by radioimmunoassays, breast density was measured by magnetic resonance imaging, and whole body bone mineral content (BMC) and BMD were measured by dual x-ray absorptiometry (DXA). Analyses were performed using linear mixed models. All tests of statistical significance are two-sided. Results: In analyses that did not take account of current diet at the time of the follow-up visit, the only statistically significant (p=.04) treatment group difference was higher whole body BMC in the intervention group compared to the usual care group; their mean BMCs were 2,444g (95% confidence interval (CI)=2,391-2,496g) and 2,378g (95% CI=2,325-2,431g), respectively. After adjustment for current dietary intakes of fat and fiber, intervention group participants’ mean BMD was 1.19g/cm2 (95% CI=1.17-1.21g/cm2), which was statistically significantly (p=.01) higher compared to usual care group participants mean BMD of 1.16g/cm2 (95% CI=1.14-1.18g/cm2). Furthermore, mean luteal phase serum estradiol concentrations were statistically significantly (p=.02) higher in intervention group participants compared to usual care group participants after adjustment for current diet; their mean concentrations were 142pg/mL (95% CI=115-174pg/mL) and 97pg/mL (95% CI=76-122pg/mL), respectively. Serum progesterone concentrations and breast density did not differ by treatment group in unadjusted or adjusted analyses. Conclusion: Results do not support the hypothesis that consumption of a lower fat diet during adolescence reduces later breast cancer risk via effects on serum estradiol and progesterone, breast density or BMD.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2827.

Limitations of direct immunoassays for measuring circulating estradiol levels in postmenopausal women and men in epidemiologic studies

Serum estradiol (E(2)) serves as an important diagnostic marker in a variety of clinical conditions. In epidemiologic studies, E(2) is commonly used to define the etiologic role of estrogen in hormone-related cancers and chronic conditions. Having an accurate and reliable E(2) assay is of critical importance in these studies, especially when measuring the very low E(2) levels (<30 pg/mL) common in postmenopausal women and men, and for discerning the relatively small (usually <20%) case-control differences in E(2) levels. Because E(2) is metabolized to >100 metabolites in the body, some of which cross-react with E(2) antibodies, direct RIAs without purification steps lack specificity for E(2) and can substantially overestimate E(2) levels. Although direct E(2) RIAs using commercial kits are simpler, less time consuming, and less expensive and require less sample volume than conventional RIAs with preceding purification steps, their lack of sensitivity and specificity makes them invalid for measuring circulating E(2) levels in epidemiologic studies of postmenopausal women or men. Instead, we recommend the use of a well-validated RIA with purification steps to improve sensitivity and specificity and to help achieve the necessary accuracy and reliability needed for epidemiologic studies.