Bone turnover alterations across the menopausal transition in south-eastern Chinese women [corrected]

Association of follicle-stimulating hormone with bone turnover markers and bone mineral density in Chinese women across the menopausal transition

BACKGROUND

Elevated follicle-stimulating hormone (FSH) is associated with an increased risk of postmenopausal osteoporosis. This study investigated the association of serum FSH with bone turnover markers (BTMs) and bone mineral density (BMD) in healthy women undergoing menopausal transition.

METHODS

A total of 487 healthy women (age 35-65 years, 50 ± 8.5 years) were enrolled in this study. Serum FSH, BTMs, and BMD at lumbar spine and total hip were measured in these subjects.

RESULTS

Follicle-stimulating hormone was positively correlated with various BTMs (r = 0.339-0.583, all p < 0.001) and negatively correlated with lumbar spine and total hip BMD (r = -0.629 and -0.514, all p < 0.001). After adjusting for age and body mass index, the partial correlation coefficients of FSH with BTMs and BMD remained significant. Estimating from the regression equation, for every 10 IU/L increase in serum FSH, BTMs increased by 0.38-3.6 units, and BMD decreased by 0.03-0.05 g/cm2 , respectively. Multiple linear regression analysis showed that FSH was a positive factor for serum bone-specific alkaline phosphatase, osteocalcin, and N-telopeptide of collagen type 1 (β = 0.188-0.403, all p < 0.001), and a negative factor for lumbar spine BMD and serum C-telopeptide of collagen type 1 (β = -0.629 and -0.183, all p < 0.001).

CONCLUSIONS

This study suggests that serum FSH levels are an independent risk factor for BTMs and BMD in menopause-transitioning women, particularly for serum BAP and lumbar spine BMD.

FSH may mediate the association between HbA1c and bone turnover markers in postmenopausal women with type 2 diabetes

INTRODUCTION

Recent studies in postmenopausal women have found associations of follicle-stimulating hormone (FSH) levels with both glucose metabolism and bone turnover. The objective of the study was to investigate whether FSH may contribute to suppressed bone turnover markers (BTMs) in postmenopausal women with type 2 diabetes (T2D).

MATERIALS AND METHODS

888 postmenopausal women with T2D, 352 nondiabetes (prediabetes plus normoglycemia) were included from the METAL study. HbA1c, sex hormones, 25-hydroxy vitamin D (25(OH)D), serum procollagen type I N-terminal propeptide (P1NP), and β-C-terminal telopeptide (β-CTX) were measured.

RESULTS

P1NP and β-CTX decreased in postmenopausal T2D women compared with nondiabetes controls (both p < 0.001). The major factors responsible for the changes in P1NP were HbA1c (β = - 0.050, p < 0.001), 25(OH)D (β = - 0.003, p = 0.006), FSH (β = 0.001, p = 0.044) and metformin (β = - 0.109, p < 0.001), for β-CTX were HbA1c (β = - 0.049, p < 0.001), body mass index (BMI) (β = - 0.011, p = 0.005), 25(OH)D (β = - 0.003, p = 0.003), FSH (β = 0.002, p = 0.022) and metformin (β = - 0.091, p = 0.001) in postmenopausal T2D women based on multivariate regression analysis. With the increase in HbA1c, FSH decreased significantly (p for trend < 0.001). Mediation analysis demonstrated that FSH partly mediated the suppression of LnP1NP and Lnβ-CTX by HbA1c (β = - 0.009 and - 0.010, respectively), and Lnβ-CTX by BMI (β = - 0.015) when multiple confounders were considered (all p < 0.05).

CONCLUSION

HbA1c was the crucial determinant contributing to the suppression of BTMs. FSH might play a novel mediation role in BTM suppression due to HbA1c or BMI.

Variation of urinary and serum bone turnover marker reference values among pre and postmenopausal women in Asia: a systematic review

PURPOSE

Bone turnover markers (BTMs) are not widely used in clinical decision-making partly due to the wide variation of the reference values. This paper describes the geographical variation in BTMs reported from Asian countries.

METHOD

A systematic search was conducted using the PubMed, EMBASE, and Ovid. We searched for BTMs or individual BTMs in Asia or different countries in the Asian region. Original research which published BTM values were included while reviews, comments, and meta-analyses were excluded.

RESULTS

Of 650 articles, 23 fulfilled the selection criteria and were considered for this study. Among premenopausal women, mean intact OC ranged from 3.35 in Japan to 7.38 ng/mL (55%) in Thailand while it ranged between 3.35 and 5.8 ng/mL (42%) within Japan. Mean BALP varied from 15.9 in India to 41.2 U/L (61%) in Japan whereas in India, it ranged between 15.9 and 53.7 U/L (70%). Mean sP1NP ranged from 29.5 in Japan to 38.02 ng/mL in China (22%) whereas sCTX varied from 0.26 in Thailand to 0.099 ng/mL (62%) in Japan. Among postmenopausal women, mean total OC ranged from 10.02 in India to 29.8 ng/mL (66%) in Japan and intact OC ranged between 2.69 and 9.49 ng/mL (72%) within China. Mean BALP ranged from 20.9 in Japan to 60.28 U/L (65%) in China, and within China, it ranged from 28.2 to 60.28 U/L (53%). Mean sP1NP ranged from 40.11 in China to 56.4 ng/mL (29%) in Japan whereas it ranged within China from 40.11 to 53.76 ng/mL (25%). Mean sCTX varied from 0.25 to 0.433 ng/mL (42%) between the same countries respectively while within China, it varied from 0.25 to 0.395 ng/mL (37%). Urinary BTMs showed a lesser variation.

CONCLUSION

A wide inter-country and intra-country variation of serum BTMs was observed among pre and postmenopausal women in Asia. Differences in selection criteria of subjects and those inherited to analytical methods may have contributed to these differences.

The effects of exposure to lead, cadmium and mercury on follicle-stimulating hormone levels in men and postmenopausal women: data from the Second Korean National Environmental Health Survey (2012-2014)

Background

Follicle-stimulating hormone (FSH), a gonadotropin secreted by the pituitary gland, is a representative secondary sex hormone and an important indicator of reproductive function. The effects of heavy metals such as lead, cadmium, and mercury on humans have been studied, but reports on their effects on sex hormone levels are lacking. Therefore, we investigated the relationship between heavy metal exposure and FSH levels in Korean men and postmenopausal women.

Methods

A total of 4,689 adults (2,763 men and 1,926 postmenopausal women aged 50 years or over) who participated in the Second Korean National Environmental Health Survey (2012–2014) were included. We compared differences in serum FSH levels by demographic characteristics using the t-test and analysis of variance. Multiple linear regression analysis was used to determine the relationship between the blood levels of lead and mercury and the urine cadmium level, and serum FSH levels.

Results

On multiple linear regression analysis, lead exposure was positively associated with serum FSH concentrations in postmenopausal women (β = 2.929, p = 0.019). However, we found no significant association between serum FSH concentration and blood lead and mercury levels, or urine cadmium level, in men.

Conclusions

This study suggests that lead exposure can affect the FSH level in postmenopausal women. Further studies are needed to evaluate the effects of low-dose long-term exposure to heavy metals on sex hormones.

FSH Beyond Fertility

The traditional view of follicle-stimulating hormone (FSH) as a reproductive hormone is changing. It has been shown that FSH receptors (FSHRs) are expressed in various extra-gonadal tissues and mediate the biological effects of FSH at those sites. Molecular, animal, epidemiologic, and clinical data suggest that elevated serum FSH may play a significant role in the evolution of bone loss and obesity, as well as contributing to cardiovascular and cancer risk. This review summarizes recent data on FSH action beyond reproduction.

Association of bone turnover markers with glucose metabolism in Chinese population

The association between type 2 diabetes (T2DM) and bone metabolism has been discussed previously but is controversial. In this study we aimed to evaluate the association of bone turnover markers with glucose metabolism in Chinese population, in which 919 males and 4171 postmenopausal females in a region of Shanghai were recruited. Anthropometric and biochemical traits related to glucose and bone metabolism were analyzed. Participants were classified according to their glucose tolerance as normal glucose tolerance (NGT), impaired glucose regulation (IGR) or T2DM. Males and females were analyzed separately, and then associations between bone turnover markers (BTMs) and glucose metabolism were evaluated. The results showed that in females, the serum levels of N-terminal osteocalcin (N-MID), N-terminal procollagen of type I collagen (PINP) and β-cross-linked C-telopeptide of type I collagen (β-CTX) were significantly decreased in the T2DM group compared to the NGT group (P<0.01). When age, body mass index, serum lipids, fat percentage, visceral fat area, subcutaneous fat area, anti-diabetic medicines, PINP, N-MID and β-CTX were included in one logistic model, N-MID (OR [95% CI]: 0.954 [0.932; 0.976]; P=0.0001) was significantly associated with T2DM in females. In females, N-MID was associated with insulin sensitivity and HOMA-β. PINP was significantly associated with HOMA-β, GUTT-ISI, Stumvoll first-phase insulin secretion index (STU-1) and Stumvoll second-phase insulin secretion index (STU-2), but β-CTX was associated only with HOMA-β (β±SE: 0.1331±0.0311; P=1.95×10^-5) and GUTT-ISI (β±SE: 0.0727±0.0229; P=0.0015). In males, N-MID was significantly correlated with HOMA-β (β±SE: 0.3439±0.0633; P=7.75×10^-8), GUTT-ISI (β±SE: 0.1601±0.0531; P=0.0027) and STU-1 (β±SE: 0.2529±0.1033; P=0.0146). Significant associations were also detected between β-CTX and HOMA-β (β±SE: 0.2736±0.0812; P=0.0009). This study reveals that BTMs are highly associated with T2DM, insulin sensitivity and beta cell function in both Chinese males and postmenopausal females.

Associations of blood lead levels with reproductive hormone levels in men and postmenopausal women: Results from the SPECT-China Study

We examined whether blood lead levels (BLLs) were associated with reproductive hormone levels in a cross-sectional study using data from the SPECT-China study. We selected 2286 men and 1571 postmenopausal women without hormone replacement therapy. BLLs, blood cadmium, total testosterone (TT), oestradiol (E2), luteinizing hormone (LH), follicle stimulating hormone (FSH) and sex hormone binding globulin(SHBG) levels were measured. The results showed that median values (interquartile range) of BLLs were 44.00 μg/L (29.00–62.30) for men and 41.00 μg/L (27.00–59.81) for postmenopausal women. In linear regression, after adjusting for age, current smoking status, body mass index, systolic blood pressure, diabetes and blood cadmium level, TT (P for trend = 0.001) and SHBG (P for trend < 0.001) levels were still positively associated with BLLs in men. Meanwhile, significant positive associations were found for BLLs with SHBG (P for trend = 0.002), FSH (P for trend = 0.001) and LH (P for trend = 0.026) levels in postmenopausal women. Additionally, the association between BLL and SHBG was modified by dysglycaemia (P for interaction = 0.03) in postmenopausal women. In conclusion, BLLs were associated with reproductive hormone levels in the general population of Chinese men and postmenopausal women, which may have important implications for human health. Concerted efforts to reduce adult lead exposure are warranted.