Androgens, insulin-like growth factor-I (IGF-I), and carrier proteins (SHBG, IGFBP-3) in postmenopause

Association of Acculturation and Hispanic/Latino Background with Endogenous Sex and Thyroid-Related Hormones Among Middle-Aged and Older Hispanic/Latino Adults: the HCHS/SOL Study

BACKGROUND

Hormones are linked to cardiometabolic diseases and may be impacted by acculturation though multiple mechanisms. We evaluated associations of Hispanic/Latino background and acculturation with levels of sex- and thyroid-related hormones and the potential mediating effect of adiposity, lifestyle factors, and sleep apnea syndrome on these associations.

METHODS

We studied 1789 adults, aged 45-74, from a sub-cohort of the Hispanic Community Health Survey/Study of Latinos. Peri/pre-menopausal women and individuals on medications related to hormones were excluded. Our study assessed eleven sex- and thyroid-related hormones, Hispanic/Latino background, and five acculturation measures. Associations were assessed using multivariable linear and logistic regression adjusted for survey design and confounding variables. We explored potential mediation using a path analysis.

RESULTS

In postmenopausal women, acculturation score-MESA was associated with decreased thyroid-stimulating hormone (β = - 0.13;95%CI = - 0.22, - 0.03) while age at immigration greater than the median (vs US-born) was associated with decreased (β = - 14.6; 95%CI = - 28.2, - 0.99) triiodothyronine (T3). In men, language acculturation and acculturation score-MESA were associated with increased estradiol and sex hormone-binding globulin (SHBG) while age at immigration greater and lesser than the median (vs US-born) was associated with decreased SHBG. Hispanic/Latino background (Mexicans as reference) were selectively associated with sex- and thyroid-related hormone levels in both sexes. Current smoking and sleep apnea syndrome partially mediated the association of Cuban and Puerto Rican heritage (vs Mexican) with T3 levels in men and postmenopausal women, respectively.

CONCLUSION

Selected acculturation measures were associated with thyroid-related hormones in postmenopausal women and sex-related hormones in men. Understanding the mechanisms involved in the relationship of acculturation and Hispanic/Latino background with hormones warrants additional investigation.

Perfluoroalkyl substances and sex hormones in postmenopausal women: NHANES 2013-2016

BACKGROUND

Although an alteration in sex hormones has been linked to perfluoroalkyl substances (PFAS) in premenopausal women and girls, whether such associations exist in postmenopausal women remains uncertain.

OBJECTS

To examine the associations between serum PFAS concentrations and sex hormone levels in postmenopausal women.

METHODS

Data from the National Health and Nutrition Examination Survey (NHANES) 2013-2016 waves were used. A total of 706 postmenopausal women with information on serum PFAS [perfluorohexane sulfonic acid (PFHxS), pefluorodecanoic acid (PFDA); perfluorononanoic acid (PFNA); linear perfluorooctanoate (n-PFOA); linear perfluorooctane sulfonate (n-PFOS); monomethyl branched isomers of PFOS (Sm-PFOS)], sex hormones indicators [e.g., total testosterone (TT), estradiol (E₂) and sex hormone binding globulin (SHBG)] as well as selected covariates were included. An indicator of circulating free testosterone (FT), and ratio of TT to E₂ (TT/E₂) were generated. Multiple linear regression accounting for the primary sampling unit, strata, and environmental sampling weights of PFAS was used for association analyses. Effect modification by obesity and type of menopause was explored via stratified analyses as well as the testing of interaction terms. Principal component analysis (PCA) and Bayesian kernel machine regression (BKMR) were conducted to assess these relationships in a multiple PFAS exposure setting.

RESULTS

After adjusting for potential confounders, total perfluorooctanoate (TPFOA: n-PFOA + Sb-PFOA) and total perfluorooctane sulfonate (TPFOS: n-PFOS + Sm-PFOS), and their linear and branched isomers were positively associated with two androgen indicators (i.e., TT and FT). PCA results revealed that the principal component (PC) composed of n-PFOA was positively associated with ln (TT) [β = 0.09, 95% confidential interval (CI): 0.02, 0.16; per ln-ng/mL increase in exposure], and ln (FT) (β = 0.12, 95% CI: 0.05, 0.2) in overweight/obese [body mass index (BMI) ≥ 25 kg/m²] women, but not in those with BMI < 25 kg/m². Additionally, among overweight/obese women, PFHxS was positively associated with androgens and negatively with ln (SHBG) (β = -0.06, 95% CI: -0.12, -0.01). The PC composed of Sm-PFOS, n-PFOS, and PFHxS was positively associated with ln (TT) levels among overweight/obese women. Results from BKMR also confirmed the findings on n-PFOA and PFHxS.

CONCLUSIONS

Our study indicates that n-PFOA and PFHxS were positively associated with levels of several androgen indicators in postmenopausal women, particularly among overweight/obese ones. Given the higher risk of cardiometabolic diseases associated with elevated levels of androgens in postmenopausal women, future studies are needed to explore the potential underlying mechanisms.

Sex hormones and stroke: Beyond estrogens

Stroke risk and poor stroke outcomes in postmenopausal women have usually beeen attributed to decreased levels of estrogen. However, two lines of evidence suggest that this hormone may not be solely responsible for elevated stroke risk in this population. First, the increased risk for CVD and stroke occurs much earlier than menopause at a time when estrogen levels are not yet reduced. Second, estrogen therapy has not successfully reduced stroke risk in all studies. Other sex hormones may therefore also contribute to stroke risk. Prior to menopause, levels of the gonadotrophin Follicle Stimulating Hormone (FSH) are elevated while levels of the gonadal peptide inhibin are lowered, indicating an overall decrease in ovarian reserve. Similarly, reduced estrogen levels at menopause significantly increase the ratio of androgens to estrogens. In view of the evidence that androgens may be unfavorable for CVD and stroke, this elevated ratio of testosterone to estrogen may also contribute to the postmenopause-associated stroke risk. This review synthesizes evidence from different clinical populations including natural menopause, surgical menopause, women on chemotherapy, and preclinical stroke models to dissect the role of ovarian hormones and stroke risk and outcomes.

Bioavailable Testosterone Linearly Declines Over A Wide Age Spectrum in Men and Women From The Baltimore Longitudinal Study of Aging

BACKGROUND

Age-related changes in testosterone levels in older persons and especially in women have not been fully explored. The objective of this study was to describe age-related trajectories of total testosterone (TT), ammonium sulfate precipitation-measured bioavailable testosterone (mBT), and sex hormone-binding glycoprotein (SHBG) in men and women from the Baltimore Longitudinal Study of Aging, with special focus on the oldest adults.

METHODS

Participants included 788 White men and women aged 30-96 years with excellent representation of old and oldest old, who reported not taking medications known to interfere with testosterone. Longitudinal data were included when available. TT, mBT, and SHBG were assayed. Age-related trajectories of mBT were compared with those obtained using calculated bioavailable testosterone (cBT). Generalized least square models were performed to describe age-related trajectories of TT, mBT, and SHBG in men and women.

RESULTS

mBT linearly declines over the life span and even at older ages in both sexes. In men, TT remains quite stable until the age of 70 years and then declines at older ages, whereas in women TT progressively declines in premenopausal years and slightly increases at older ages. Differences in age-related trajectories between total and bioavailable testosterone are only partially explained by age changes in SHBG, whose levels increases at accelerated rates in old persons. Noteworthy, although mBT and cBT highly correlated with one another, mBT is a much stronger correlate of chronological age than cBT.

CONCLUSION

In both men and women, mBT linearly declines over the life span and even at old ages. Its relationship with age-related phenotypes should be further investigated.

Hormonal therapy of intrinsic aging

Intrinsic skin aging represents the biological clock of the skin cells per se and reflects the reduction processes that are common in internal organs. The reduced secretion of the pituitary, adrenal glands, and the gonads contributes to characteristic aging-associated body and skin phenotypes as well as behavior patterns. Our knowledge of whether there is a direct or indirect connection between hormonal deficiency and skin aging still remains limited. In females, serum levels of 17β-estradiol, dehydroepiandrosterone, progesterone, growth hormone (GH), and its downstream hormone insulin-like growth factor I (IGF-I) are significantly decreased with increasing age. In males, serum levels of GH and IGF-I decrease significantly, whereas it can decrease in late age in a part of the population. Hormones have been shown to influence skin morphology and functions, skin permeability, wound healing, sebaceous lipogenesis, and the metabolism of skin cells. Prevention of skin aging by estrogen/progesterone replacement therapy is effective if administered early after menopause and influences intrinsically aged skin only. Vitamin D substitution and antioxidant treatment may also be beneficial. Replacement therapy with androgens, GH, IGF-I, progesterone, melatonin, cortisol, and thyroid hormones still remains controversial.

Effects of polymorphisms of the sex hormone-binding globulin (SHBG) gene on free estradiol and bone mineral density

BACKGROUND

Polymorphisms of the sex hormone-binding globulin (SHBG) gene are associated with differences in SHBG levels, influencing the risk for breast cancer and polycystic ovarian syndrome, but no association has been reported for osteoporosis in postmenopausal women.

OBJECTIVE

To determine the effect of G to A substitution in the 5'UTR (rs1799941) and the Asp356Asn (rs6259) polymorphisms of the SHBG gene on bone mineral density (BMD).

METHODS

This is a cross-sectional study in a university-based research center from May, 2002 to December, 2007. A total of two hundred and thirteen healthy postmenopausal Caucasian women > or = 1 year from last menstrual period participated to this study. Serum estradiol by ultrasensitive radioimmnunoassay, serum sex hormone-binding globulin by immunoradiometric assay, and urinary NTx by enzyme-linked immunoassay were measured. BMD measurements were performed by dual energy X-ray absorptiometry and genotyping by Pyrosequencing.

RESULTS

There were no significant differences in SHBG levels associated with either rs1799941 or rs6259. Using a p value of <0.00625 for significance, we found that subjects with the A allele (GA+AA) for the rs1799941, had a trend for lower free estradiol index (FEI) compared to the GG genotype (p=0.04). They also had significantly lower BMD at the intertrochanter (p=0.003) and trend for lower BMD at the total hip (p=0.02). There was no significant difference in FEI levels between the genotypes for the rs6259 polymorphism, but women with the Asn allele (Asp/Asn+Asn/Asn), had significantly lower BMD in the total femur (p=0.004) and intertrochanter (0.002) compared to those with the Asp/Asp genotype.

CONCLUSIONS

Our data suggest that polymorphisms of the SHBG gene are associated with significant differences in BMD at the proximal femur sites. Thus, genetic variations in the SHBG gene may influence BMD at the hip in postmenopausal women.

Hormonal changes during menopause

Ovarian senescence occurs gradually during the fourth and fifth decades of life, leading to menopause at an average age of about 51 years. This senescence results in a changing hormonal milieu, with decreases in the levels of estrogens and androgens. Similar changes may be induced by surgical menopause (bilateral oophorectomy) or ovarian failure resulting from cancer treatment. The declining levels of estrogens and androgens affect many tissues of the body and can produce a variety of signs and symptoms, including vasomotor symptoms, decreased bone density, changes in mood and energy, loss of pubic hair and changes in the genital tissues, and effects on sexual function. Accurate measurement of testosterone levels in postmenopausal women requires methods that are validated in the lower ranges of testosterone level observed in this population.

Sex hormone binding globulin levels across the adult lifespan in women--the role of body mass index and fasting insulin

SHBG is a major carrier of androgens. In men, SHBG levels increase with age, while in women data are scant. There is evidence that body mass index (BMI) and fasting insulin influence SHBG concentration. Since low SHBG levels are predictors of insulin resistance and diabetes, understanding the relationship of SHBG with age, insulin, and BMI is important to gain insight into the role of SHBG as a cardiovascular risk factor in women. Differences in SHBG across adult life span and their relationship with insulin and BMI were evaluated in a representative cohort of 616 Italian women free of diabetes and not on hormone replacement therapy enrolled in the InCHIANTI Study. The relationship of SHBG with age, BMI, and fasting insulin levels was analyzed using linear regression and by loess smoother. Serum SHBG levels showed a U-shaped trajectory with age, declining from the 2nd to the 6th decade of life and increasing after the 6th decade (p<0.0001). Age-related trends for BMI and fasting insulin mirrored the trend observed for SHBG. After adjusting for fasting insulin, the relationship between log (SHBG) and age square was attenuated (beta coefficient from 0.00044 to 0.00039) and was further reduced after adjustment for BMI (from 0.00039 to 0.00028). SHBG levels show an age-related U-shaped trajectory. These changes mirror the age-related changes in BMI and fasting insulin, suggesting that BMI and insulin negatively influence SHBG concentration.

Care of Women in Menopause: Sexual Function, Dysfunction and Therapeutic Modalities

Introduction: The physiological changes that occur in menopause alter sexual function and affect well-being. Hormonal changes contribute significantly to reduced sexual function in older women and sexual dysfunction may well be amenable to treatment with exogenous hormones or other agents. Materials and Methods: Relevant clinical studies were identified by a computerised literature search. The collated data were presented to fellow gynaecologists for review, analysis of results and discussion in a series of meetings dedicated to finding the best evidence in menopause management. The evidence was assessed and used to prepare guidelines around the management of women who are affected by sexual dysfunction in menopause. Results: Hormone therapy benefits many women who have dyspareunia related to vaginal atrophy, reduced libido and decreased satisfaction, particularly if these symptoms adversely affect their quality of life. Alternative agents such as tibolone and sildenafil citrate can be useful adjuncts. Conclusions: It is increasingly important to recognise postmenopausal sexual dysfunction. Treatment of this syndrome must be individualised to the specific complaints of each woman. Hormones and other agents are relevant treatment options for properly-selected women. Key words: Androgen, Dyspareunia, Oestrogen, Postmenopause, Sex disorders

Early postoperative changes in testosterone, dehydroepiandrosterone sulfate, and sex hormone-binding globulin after hysterectomy with or without concomitant oophorectomy

OBJECTIVE

To investigate the cross-sectional associations of hysterectomy and oophorectomy status, chronological age, and body mass index with early postoperative plasma levels of total and free T, DHEAS, and sex hormone-binding globulin (SHBG).

DESIGN

A cross-sectional study.

SETTING

University hospital.

PATIENT(S)

Ninety-two women age 35-47 years who were scheduled for hysterectomy and/or oophorectomy, advocated for benign gynecological pathologies.

INTERVENTION(S)

Ninety-two eligible premenopausal women underwent hysterectomy and/or oophorectomy, with plasma T, DHEAS, and SHBG levels assayed before surgery and during the postoperative period.

MAIN OUTCOME MEASURE(S)

Effects of time x operation and age x operation interactions between oophorectomized and nonoophorectomized groups and within-subject main effect of time on plasma androgen levels.

RESULT(S)

Of 92 women, hysterectomy alone was performed in only 49 (53.3%) cases. Oophorectomy, either unilateral or bilateral, was performed in 35.8% of cases. Age x within-group interactions exhibited an important difference (P=.03) in total T levels. The time x between- and within-group interaction effects on plasma DHEAS levels of postoperative day 7, compared with day 1, were statistically significant (P<.001). The effect of time x group interaction was remarkable, in terms of SHBG levels during the postoperative period. Age x oophorectomy interaction exhibited a statistically significant change of decline in DHEAS levels on postoperative day 7 (P=.05).

CONCLUSION(S)

The present study demonstrated a time and operation effect decline in plasma DHEAS levels. In contrast, the time x operation interaction on SHBG levels exhibited an increase toward postoperative day 7.

Androgen levels in adult females: changes with age, menopause, and oophorectomy

CONTEXT

Changes in androgen levels across the adult female life span and the effects of natural menopause and oophorectomy have not been clearly established.

OBJECTIVE

The objective of this study was to document the effects of age on androgen levels in healthy women and to explore the effects of natural and surgical menopause.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study was conducted of 1423 non-healthcare-seeking women, aged 18-75 yr, randomly recruited from the community over 15 months.

MAIN OUTCOME MEASURES

Serum levels by age of total testosterone (T), calculated free T, dehydroepiandrosterone sulfate, and androstenedione in a reference group of women free of confounding factors. Women in the reference group had no usage of exogenous steroid therapy; no history of tubal ligation, hysterectomy, or bilateral oophorectomy; and no hyperprolactinemia or polycystic ovarian syndrome. The effects of natural and surgical menopause on sex steroid levels were also examined.

RESULTS

In the reference population (n = 595), total T, calculated free T, dehydroepiandrosterone sulfate, and androstenedione declined steeply with age (P < 0.001), with the decline of each being greater in the earlier than the later decades. Examination of serum androgen levels by year in women aged 45-54 yr showed no independent effect of menopausal status on androgen levels. In women aged 55 yr or older, those who reported bilateral oophorectomy and were not on exogenous steroids had significantly lower total T and free T levels than women 55 yr or older in the reference group.

CONCLUSIONS

We report that serum androgen levels decline steeply in the early reproductive years and do not vary because a consequence of natural menopause and that the postmenopausal ovary appears to be an ongoing site of testosterone production. These significant variations in androgens with age must be taken into account when normal ranges are reported and in studies of the role of androgens in women.