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Background: The relationship between the levels of gonadotropic hormones and bone metabolism-related cytokines in Chinese women is unclear. We investigated the relationship between FSH and LH and OPG, leptin, TGF-beta1, and TGF-beta2 in Chinese women., Methods: A cross-sectional study of 694 Chinese women, aged 20 to 82y was conducted. Levels of serum FSH, LH, OPG, leptin, TGF-beta1, and TGF-beta2 were determined., Results: In premenopausal females, serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels seemly showed no correlation with the cytokine levels. In perimenopausal females, serum FSH and LH levels showed significant positive correlation with osteoprotegerin (OPG) and transforming growth factor-beta2 (TGF-beta2) levels (r=0.286 to 0.405, all P=0.000), whereas they showed negative correlation with TGF-beta1 levels (r=-0.413 and -0.354, all P=0.000). In postmenopausal females, FSH and LH levels showed positive correlation with OPG levels (r=0.247 and 0.241, all P=0.000), negative correlation with leptin and TGF-beta1 levels (r=-0.234 to -0.319, all P=0.000), and no correlation with TGF-beta2 levels. Multiple linear regression stepwise analysis revealed the following results. In premenopausal females, 2.0% and 1.5% of the changes in LH could be explained by OPG and leptin, respectively, while 1.9% of the changes in OPG could be explained by LH. In perimenopausal females, the determinants of OPG and TGF-beta1 on FSH were 10.9% and 17.0%, respectively, and the determinants of OPG, TGF-beta1 and TGF-beta2 on LH were 4.5%, 4.9% and 16.4%, respectively. The determinants of FSH and LH on OPG were 14.5% and 2.5%, respectively. The determinant of FSH on TGF-beta1 was 4.5%, while the determinant of LH on TGF-beta2 was 16.4%. In postmenopausal females, the determinants of leptin and OPG on FSH were 10.2% and 2.8%, respectively, and the determinants of OPG and TGF-beta1 on LH were 5.8% and 2.3%, respectively. The determinant of FSH on OPG, leptin and TGF-beta1 were 6.1%, 3.4% and 9.2%., Conclusions: These results indicate that age-related gonadotropic hormone levels are associated with changes in OPG, TGF-beta1, TGF-beta2 and leptin, and change with menopausal status., (Copyright 2010 Elsevier B.V. All rights reserved.)

Background: Adiponectin and leptin, as the main circulating peptides secreted by adipose tissue, are potential contributors to bone metabolism. However, their association with bone mineral density (BMD) is unknown. We investigated whether these serum adipocytokines concentrations are associated with BMD and bone turnover markers., Methods: Serum adiponectin, leptin concentrations, bone turnover biochemical markers, and BMD were determined in 265 premenopausal and 336 postmenopausal Chinese women., Results: In postmenopausal Chinese women, the multiple linear stepwise regression analysis showed that year since menopause, lean mass, estradiol, and adiponectin, but not fat mass, leptin, were independent predictors of BMD in postmenopausal Chinese women. However, in premenopausal Chinese women, adiponectin was not the predictor of BMD. The significant positive correlations between adiponectin and bone-specific alkaline phosphatase (BAP), bone cross-linked N-telopeptides of type I collagen (NTX) were found only in postmenopausal women. Serum BAP, and NTX, but not adiponectin, decreased in response to alendronate therapy., Conclusions: Adiponectin was an independent predictor of BMD, and positively correlated with bone turnover biochemical markers in postmenopausal Chinese women, but not premenopausal women. It suggested that adiponectin may exert a negative effect on bone mass by promoting excessive bone resorption associated with bone loss. However, these effects may be mediated by menopausal status., (Copyright 2010 Elsevier B.V. All rights reserved.)

Background: Transforming growth factor-beta 1 (TGF-beta1), TGF-beta2, osteoprotegerin (OPG), and leptin are important cytokines in the regulation of bone remodeling. We investigated the relationship of TGF-beta1 and TGF-beta2 concentrations with those of OPG and leptin in Chinese females., Methods: The serum concentrations of TGF-beta1, TGF-beta2, OPG, and leptin were measured by ELISA in 459 healthy Chinese females aged 25-80 y., Results: The mean values (+/-SD) of the serum concentrations of TGF-beta1, TGF-beta2, OPG, and leptin in Chinese females were 29.7+/-1.69 microg/l, 13.7+/-3.86 microg/l, 3.81+/-1.96 pmol/l, and 10.5+/-2.01 microg/l, respectively. Further, the serum TGF-beta1 concentrations of postmenopausal women were significantly lower than those of perimenopausal and premenopausal women (24.3+/-1.59 vs 33.4+/-1.69 and 37.6+/-1.64, respectively), while the TGF-beta2 concentrations of postmenopausal women were significantly higher than those of perimenopausal and premenopausal women (14.6+/-3.91 vs 13.5+/-3.93 and 11.7+/-2.68, respectively). The serum TGF-beta1 concentration was found to be significantly negatively correlated with age (r=-0.335, P=0.000) and the TGF-beta2 concentration, to be significantly positively correlated with age (r=0.230, P=0.000). The TGF-beta1 concentration was found to be significantly negatively correlated with both TGF-beta2 (r=-0.261, P=0.000) and OPG (r=-0.313, P=0.000) concentrations; a significantly positive correlation was found between the TGF-beta1 and leptin concentrations (r=0.164, P=0.000) and between TGF-beta2 and OPG concentrations (r=0.432, P=0.000)., Conclusion: These results provide age-related reference values of TGF-beta1 and TGF-beta2 in Chinese adult women, and reveal the relationships between these cytokines.

Background: Osteoprotegerin (OPG) and leptin are important cellular factors in the regulation of bone remodeling. We investigated the serum OPG and leptin in Chinese women., Methods: The serum OPG and leptin in 690 Chinese women aged 20-81 y were measured by an ELISA. The values of OPG and leptin in women of other races were acquired from previous reports on the same., Results: The geometric mean values (+/- SD) of the serum OPG and leptin in Chinese women were 3.42+/-1.91 pmol/l and 10.5+/-1.99 microg/l, respectively. Further, the serum OPG (4.39+/-1.85 vs 2.74+/-1.81) and leptin (11.4+/-2.21 vs 9.68+/-1.81) in postmenopausal women were significantly higher than in premenopausal women. The serum OPG in middle-aged Chinese women was significantly higher than that in middle-aged Austrian and Icelandic women; however, this is quite contrary to the results obtained in the case of old-aged women. The values of serum leptin in Chinese women were significantly lower than those in white, black, and Mexican American women., Conclusions: These results provide reliable reference values for OPG and leptin in Chinese adult women. The serum of OPG and leptin differ with ethnicity.

Background: Serum leptin concentration is associated with age, fat and bone mineral density (BMD), and there are ethnic differences in physique and BMD values. The relationship between serum leptin concentration and BMD in Chinese women is presently unknown. We examined the relationship of serum leptin concentration with age, body weight, BMI and BMD in mainland Chinese women., Methods: Serum leptin concentration in a population of 676 Chinese females, aged 20-80 years (45.4+/-14.8 years, mean+/-S.D.), was measured using an enzyme-linked immunosorbent assay (ELISA). BMD values were measured by dual-energy X-ray absorptiometry (DXA) at a number of sites: the posteroanterior lumbar spine (PA, L1-L4), lateral lumbar spine (Lat, L2-L4), hip (including the femoral neck (FN) and total hip (T-hip)), and forearm (one-third region (RU1/3) and total region (RUT)). The relationship between changes in serum leptin concentration with age, body weight, height, body mass index (BMI) and BMD values at six sites were analyzed using 10 different regression models, and the models giving the best fit were selected., Results: The cubic regression model best described the changes in serum leptin concentration with age (R(2)=0.048, p<0.001) and body weight (R(2)=0.352, p<0.001), while the quadratic regression model was best for serum leptin concentration changes with BMI (R(2)=0.410, p<0.001); serum leptin concentration was not correlated with height. Serum leptin concentration was significantly higher in postmenopausal than premenopausal women (p<0.001). Serum leptin concentration was correlated with Lat BMD (R(2)=0.012, p<0.018), FN BMD (R(2)=0.006, p<0.041) and T-hip BMD (R(2)=0.013, p<0.004) in the whole population. In premenopausal women, leptin was positively associated with BMD except for Lat (R(2)=0.029-0.055, p<0.008); in postmenopausal women, leptin was also positively associated with AP, FN, T-hip BMD (R(2)=0.026-0.042, p<0.007). However, after adjusting for BMI not for body weight, there was no association between serum leptin concentration and age. Meanwhile, after adjustment for age, body weight and BMI, there was no association between serum leptin concentration and BMD values in premenopausal and postmenopausal women., Conclusions: Age-related changes in serum leptin concentration is dependent on BMI, but not a direct determinant of BMD in Chinese females.