Menstrual irregularity and bone mass in premenopausal women: cross-sectional associations with testosterone and SHBG

Sex differences in the association between stroke risk factors and pre-clinical predictors of stroke in the childhood determinants of Adult Health study

BACKGROUND AND AIMS

It is unclear why blood pressure (BP), metabolic markers and smoking increase stroke incidence in women more than men. We examined these associations with carotid artery structure and function in a prospective cohort study.

METHODS

Participants in the Australian Childhood Determinants of Adult Health study at ages 26-36 years (2004-06) were followed-up at 39-49 years (2014-19). Baseline risk factors included smoking, fasting glucose, insulin, systolic and diastolic BP. Carotid artery plaques, intima-media thickness [IMT], lumen diameter and carotid distensibility [CD] were assessed at follow up. Log binomial and linear regression with risk factor × sex interactions predicted carotid measures. Sex-stratified models adjusting for confounders were fitted when significant interactions were identified.

RESULTS

Among 779 participants (50% women), there were significant risk factor × sex interactions with baseline smoking, systolic BP and glucose associated with carotid measures in women only. Current smoking was associated with incidence of plaques (RRunadjusted 1.97 95% CI 1.4, 3.39), which reduced when adjusted for sociodemographics, depression, and diet (RRadjusted 1.82 95% CI 0.90, 3.66). Greater systolic BP was associated with lower CD adjusted for sociodemographics (βadjusted -0.166 95% CI -0.233, -0.098) and hypertension with greater lumen diameter (βunadjusted 0.131 95% CI 0.037, 0.225), which decreased when adjusted for sociodemographics, body composition and insulin (βadjusted 0.063 95% CI -0.052, 0.178). Greater glucose (βunadjusted -0.212 95% CI -0.397, -0.028) was associated with lower CD, which decreased when adjusted for sociodemographics, BP, depression and polycystic ovary syndrome (βadjusted -0.023 95% CI -0.249, 0.201).

CONCLUSIONS

Smoking, SBP and glucose affect carotid structure and function more in women than men with some of this risk due to co-occurring risk factors.

Association of Sex Hormones and Sex Hormone-Binding Globulin Levels With Bone Mineral Density in Adolescents Aged 12-19 Years

BACKGROUND

Sex hormones are recognized to play a significant role in increasing bone mineral density (BMD) and promoting bone maturation during adolescence. The purpose of our study was to use a database with large population data to evaluate the association of BMD with sex hormones (including testosterone and estradiol) and sex hormone-binding globulin (SHBG) in adolescent boys and girls aged 12-19 years.

METHODS

The data for our study were taken from the National Health and Nutrition Examination Survey 2013-2016, and we used weighted multiple linear regression models to assess the relationship between testosterone, estradiol, and SHBG and total BMD. We use weighted generalized additive models and smooth curve fitting to discover underlying nonlinear relationships.

RESULTS

A total of 1648 teenagers (853 boys, 795 girls) were selected for the final analysis. In boys, testosterone and estradiol levels were positively associated with total BMD, whereas SHBG levels were negatively associated with total BMD after adjusting for covariates [P < 0.05; 95% confidence interval (CI)]. In addition, there was a point between estradiol and total BMD, after which the positive correlation between estradiol and total BMD was relatively insignificant in boys. In girls, there was a positive association between estradiol and total BMD (P < 0.05; 95% CI), but there was no significant association between the testosterone (β 0.0004; 95% CI -0.0001 to 0.0008) or SHBG (β -0.0001; 95% CI -0.0002 to 0.0001) levels and total BMD. We also found an inverted U-shaped association between testosterone and total BMD with the inflection point at 25.4 ng/dL of testosterone.

CONCLUSIONS

We found differences in the association of sex hormones with total BMD in boys and girls. Based on our findings, an appropriate increase in serum testosterone levels may be beneficial for skeletal development in girls because of the inverted U-shaped relationship (with the inflection point at 25.4 ng/dL of testosterone), and a high testosterone level might be detrimental to BMD. Furthermore, keeping estradiol levels below a certain level in boys (24.3 pg/mL) may be considered.

Association between serum estradiol level, sex hormone binding globulin level, and bone mineral density in middle-aged postmenopausal women

Background

Changes in sex hormones are thought to play an important role in bone health in postmenopausal women. Our aim in this study was to evaluate the association between levels of estradiol (E2), which is the most potent endogenous estrogen, and sex hormone binding globulin (SHBG) and bone mineral density (BMD) among postmenopausal women, 40–59 years of age.

Methods

Using data from the National Health and Nutrition Examination Survey 2013–2016, we performed weighted multivariable linear regression models to evaluate the associations between serum levels of E2 and SHBG and lumbar BMD. A weighted generalized additive model and smooth curve fitting were used to address potential nonlinearity.

Results

A total of 608 postmenopausal women were included in the analysis. The serum E2 level was positively associated with lumbar BMD, after adjusting for other covariates (β 0.65; 95% confidence interval (CI) 0.38–0.93). An inverted U-shaped association between the serum E2 level and lumbar BMD was further identified, with the point of inflection at an E2 level of 70 pg/mL. There was no significant association between the SHBG level and lumbar BMD (β 0.01; 95% CI − 0.30 to 0.31). However, the association between these two variables was U-shaped, with the point of inflection at an SHBG level of 65 nmol/L.

Conclusions

Based on our findings, it may be beneficial to appropriately increase serum E2 levels to promote bone health in postmenopausal women with low estrogen levels. Considering the inverted U-shaped association, an excessive E2 level may be harmful to BMD. In addition, increasing the SHBG level to within the normal range (65–144 nmol/L) may be considered.

Genetically Predicted Sex Hormone-Binding Globulin and Bone Mineral Density: A Mendelian Randomization Study

Previous observational studies have identified various risk factors associated with the development of osteoporosis, including sex hormone-binding globulin (SHBG). The aim of this study was to determine the potential causal effects of circulating SHBG concentrations on bone mineral density (BMD). Two-sample Mendelian randomization (MR) approach was applied in analyses. From summary-level data of genome-wide association studies (GWAS), we selected 11 single-nucleotide polymorphisms (SNPs) associated with SHBG levels as instrumental variable, and used summary statistics for BMD at forearm (FA) (n = 8143), femoral neck (FN) (n = 32,735), lumbar spine (LS) (n = 28,498) and heel (HL) (n = 394,929), and total-body BMD of different age-stages (15 or less, 15-30, 30-45, 45-60, 60 or more years old) (n = 67,358). Inverse causal associations was observed between SHBG levels and FA BMD (Effect = - 0.26; 95% CI - 0.49 to - 0.04; P = 0.022), HL eBMD (Effect = - 0.09; 95% CI - 0.12 to - 0.06; P = 3.19 × 10^-9), and total-body BMD in people aged 45-60 years (Effect = - 0.16; 95% CI - 0.31 to - 2.4 × 10^-3; P = 0.047) and over 60 years (Effect = - 0.19; 95% CI - 0.33 to - 0.05; P = 0.006). Our study demonstrates that circulating SHBG concentrations are inversely associated with FA and HL eBMD, and total-body BMD in people aged over 45 years, suggesting that the role of SHBG in the development of osteoporosis might be affected by chronological age of patients and skeletal sites.

Polycystic Ovary Syndrome, Oligomenorrhea, and Risk of Ovarian Cancer Histotypes: Evidence from the Ovarian Cancer Association Consortium

Background: Polycystic ovary syndrome (PCOS), and one of its distinguishing characteristics, oligomenorrhea, have both been associated with ovarian cancer risk in some but not all studies. However, these associations have been rarely examined by ovarian cancer histotypes, which may explain the lack of clear associations reported in previous studies.Methods: We analyzed data from 14 case-control studies including 16,594 women with invasive ovarian cancer (n = 13,719) or borderline ovarian disease (n = 2,875) and 17,718 controls. Adjusted study-specific ORs were calculated using logistic regression and combined using random-effects meta-analysis. Pooled histotype-specific ORs were calculated using polytomous logistic regression.Results: Women reporting menstrual cycle length >35 days had decreased risk of invasive ovarian cancer compared with women reporting cycle length ≤35 days [OR = 0.70; 95% confidence interval (CI) = 0.58-0.84]. Decreased risk of invasive ovarian cancer was also observed among women who reported irregular menstrual cycles compared with women with regular cycles (OR = 0.83; 95% CI = 0.76-0.89). No significant association was observed between self-reported PCOS and invasive ovarian cancer risk (OR = 0.87; 95% CI = 0.65-1.15). There was a decreased risk of all individual invasive histotypes for women with menstrual cycle length >35 days, but no association with serous borderline tumors (Pheterogeneity = 0.006). Similarly, we observed decreased risks of most invasive histotypes among women with irregular cycles, but an increased risk of borderline serous and mucinous tumors (Pheterogeneity < 0.0001).Conclusions: Our results suggest that menstrual cycle characteristics influence ovarian cancer risk differentially based on histotype.Impact: These results highlight the importance of examining ovarian cancer risk factors associations by histologic subtype. Cancer Epidemiol Biomarkers Prev; 27(2); 174-82. ©2017 AACR.

Menstrual cycle characteristics and steroid hormone, prolactin, and growth factor levels in premenopausal women

PURPOSE

Menstrual cycle characteristics are markers of endocrine milieu. However, associations between age at menarche and adulthood sex steroid hormone levels have been inconsistent, and data on menstrual characteristics and non-sex steroid hormones are sparse.

METHODS

We assessed the relations of menstrual characteristics with premenopausal plasma sex steroid hormones, sex hormone binding globulin (SHBG), prolactin, and growth factors among 2,745 premenopausal women (age 32-52) from the Nurses' Health Study II. Geometric means and tests for trend were calculated using multivariable general linear models.

RESULTS

Early age at menarche was associated with higher premenopausal early-follicular free estradiol (percent difference < 12 vs. > 13 years = 11%), early-follicular estrone (7%), luteal estrone (7%), and free testosterone (8%) (all p trend < 0.05). Short menstrual cycle length at age 18-22 was associated with higher early-follicular total (< 26 vs. > 39 days = 18%) and free estradiol (16%), early-follicular estrone (9%), SHBG (7%), lower luteal free estradiol (- 14%), total (- 6%), and free testosterone (- 15%) (all p trend < 0.05). Short adult menstrual length was associated with higher early-follicular total estradiol (< 26 vs. > 31 days = 14%), SHBG (10%), lower luteal estrone (- 8%), progesterone (- 9%), total (- 11%) and free testosterone (- 25%), and androstenedione (- 14%) (all p trend < 0.05). Irregularity of menses at 18-22 was associated with lower early-follicular total (irregular vs. very regular = - 14%) and free estradiol (- 14%), and early-follicular estrone (- 8%) (All p trend < 0.05). Irregularity of adult menstrual cycle was associated with lower luteal total estradiol (irregular vs. very regular = - 8%), SHBG (- 3%), higher total (8%), and free testosterone (11%) (all p trend < 0.05).

CONCLUSIONS

Early-life and adulthood menstrual characteristics are moderately associated with mid-to-late reproductive year's hormone concentrations. These relations of menstrual characteristics with endogenous hormone levels could partially account for associations between menstrual characteristics and reproductive cancers or other chronic diseases.

Effect of sex-hormone levels, sex, body mass index and other host factors on human craniofacial bone regeneration with bioactive tricalcium phosphate grafts

Little is known regarding the associations between sex-hormone levels, sex, body mass index (BMI), age, other host factors and biomaterial stimulated bone regeneration in the human craniofacial skeleton. The aim of this study was to elucidate the associations between these factors and bone formation after sinus floor augmentation procedures (SFA) utilizing a bioactive tricalcium phosphate (TCP) bone grafting material. We conducted a prospective study in a human population in which 60 male and 60 female participants underwent SFA and dental implant placement using a staged approach. BMI as well as levels of serum estradiol (E2), total testosterone (TT), and the free androgen index (FAI) were measured by radioimmunoassay and electrochemoluminescent-immunoassay. At implant placement, 6 months after SFA, bone biopsy specimens were harvested for hard tissue histology, the amount of bone formation was evaluated by histomorphometry and immunohistochemical analysis of osteogenic marker expression. The Wilcoxon rank-sum U test, Spearman correlations and linear regression analysis were used to explore the association between bone formation and BMI, hormonal and other host factors. BMI and log E2 were significantly positively associated with bone formation in male individuals (p < 0.05). Histomorphometry revealed trends toward greater bone formation and osteogenic marker expression with non-smokers compared to smokers. In male patients, higher E2 levels and higher BMI enhanced TCP stimulated craniofacial i.e. intramembranous bone repair.

Long and irregular menstrual cycles, polycystic ovary syndrome, and ovarian cancer risk in a population-based case-control study

Long and irregular menstrual cycles, a hallmark of polycystic ovary syndrome (PCOS), have been associated with higher androgen and lower sex hormone binding globulin levels and this altered hormonal environment may increase the risk of specific histologic subtypes of ovarian cancer. We investigated whether menstrual cycle characteristics and self-reported PCOS were associated with ovarian cancer risk among 2,041 women with epithelial ovarian cancer and 2,100 controls in the New England Case-Control Study (1992-2008). Menstrual cycle irregularity, menstrual cycle length, and PCOS were collected through in-person interview. Unconditional logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (95% CIs) for ovarian cancer risk overall, and polytomous logistic regression to evaluate whether risk differed between histologic subtypes. Overall, we observed no elevation in ovarian cancer risk for women who reported periods that were never regular or for those reporting a menstrual cycle length of >35 days with ORs of 0.87 (95% CI = 0.69-1.10) and 0.83 (95% CI = 0.44-1.54), respectively. We observed no overall association between self-reported PCOS and ovarian cancer (OR = 0.97; 95% CI = 0.61-1.56). However, we observed significant differences in the association with menstrual cycle irregularity and risk of ovarian cancer subtypes (p_{heterogeneity}  = 0.03) as well as by BMI and OC use (p_interaction  < 0.01). Most notable, menstrual cycle irregularity was associated with a decreased risk of high grade serous tumors but an increased risk of serous borderline tumors among women who had never used OCs and those who were overweight. Future research in a large collaborative consortium may help clarify these associations.

Maternal preeclampsia and bone mineral density of the adult offspring

OBJECTIVE

Preterm birth at very low birthweight (<1500 g) is associated with cardiometabolic risk factors and reduced bone mineral density in the adult offspring. Preeclampsia is a frequent cause of preterm birth and is also associated with cardiometabolic risk factors in the offspring. Whether it is associated with bone mineral density is not known.

STUDY DESIGN

We evaluated skeletal health in participants of the Helsinki Study of Very Low Birthweight Adults: 144 born at very low birthweight and 139 born at term. From the very low birthweight and term offspring a respective 32 and 11 were born from pregnancy complicated by preeclampsia. We measured bone mineral density at age 18.5 to 27.1 years by dual X-ray absorptiometry.

RESULTS

Very low birthweight adults exposed to maternal preeclampsia had higher lumbar spine Z score (mean -0.44, compared with -1.07 in very low birthweight unexposed adults, P = .002), femoral neck Z score (-0.05 vs -0.53, P = .003) and whole body bone mineral density Z score (-0.14 vs -0.72, P = .001). Corresponding Z scores for those born at term were -0.02 (preeclampsia) and -0.45 (no preeclampsia) for lumbar spine (P = .2), 0.78 and 0.08 for femoral neck (P = .02) and 0.02 and -0.31 for whole body bone mineral density Z score (P = .08). The results survived adjustment for offspring current height, body mass index, leisure time physical activity, socioeconomic position, smoking, and maternal smoking during pregnancy, and maternal prepregnancy body mass index.

CONCLUSION

Young adults exposed to maternal preeclampsia have higher bone mineral density than those not exposed. This difference is seen among those born at very low birthweight and seems also to be present among those born at term.

Defining hyperandrogenaemia according to the free androgen index in Chinese women: a cross-sectional study

OBJECTIVE(S)

To determine the normative cut-off value for the free androgen index (FAI) among reproductive-age women in China.

DESIGN

Cross-sectional, population-based study.

SETTING

A multistage systematic cluster random sampling among 16 communities from two rural and two city regions.

PATIENT(S)

A total of 1526 women were randomly selected from a representative sample of 3009 women aged 20-45 years from the general population of southern China. Among these women, 444 subjects without known factors affecting androgen levels were selected as the reference group.

INTERVENTION(S)

Subjects underwent physical examination, blood tests of hormone and metabolic profiles, and ultrasound evaluations. MEASUREMENT OF THE MAIN OUTCOMES: The FAI was calculated according to the following equation: FAI = 100 × total testosterone (nmol/l)/sex hormone-binding globulin (nmol/l). The normative cut-off value of the FAI was computed based on the 5th-95th percentiles and K-means cluster analysis (K = 2).

RESULTS

A reference range of 0·7-6·4 of the FAI was indicated by the 5th and 95th percentiles. K-means cluster analysis identified 6·1 as the cut-off value for the FAI in the total population, which was close to the upper limit determined by the 95th percentile. Hyperandrogenic women present with elevated risk factors for metabolic disorders. The mean FAI values decreased with age among the total population, as evaluated by either K-means clustering or a percentile analysis. The FAI value was negatively correlated with age (r = -0·185, P < 0·0001) and positively correlated with body mass index after adjustment for age (r = 0·250, P < 0·0001).

CONCLUSION

A reference range of 0·7-6·4 FAI was indicated by the 5th and 95th percentiles among the reference group, which excluded the subjects with factors known to affect androgen levels; 6·1 was identified by the K-means cluster analysis as the cut-off value of the FAI for the general population. Hyperandrogenic women present with higher risks for metabolic disorders.

The mutual dependence between bone and gonads

It has long been known that sex steroid hormones regulate bone mass accrual. This observation raises the testable hypothesis that bone may in turn regulate the synthesis and secretion of sex steroid hormones in one or both genders. This hypothesis is comprised within a more general hypothesis that bone mass, energy metabolism, and reproduction are regulated coordinately. The identification of osteocalcin as an osteoblast-specific secreted molecule allows us to address this question in molecular terms. This review details how the regulation of male fertility by osteocalcin was unraveled, and how osteocalcin signaling in Leydig cells of the testis occurs. It also discusses the implication of this novel mode of regulation of testosterone synthesis observed in males but not in females.