An independent positive relationship between the serum total osteocalcin level and fat-free mass in healthy premenopausal women.

CONTEXT: It is widely reported that osteocalcin is negatively associated with fat mass. However, there are few reports describing its correlation with fat-free mass, particularly in women. OBJECTIVES: The objective of the current study was to investigate the possible relationship between osteocalcin and fat-free mass in healthy, nonobese women. DESIGN AND SETTING: This study was performed in a tertiary university teaching hospital. SUBJECTS: A total of 504 healthy women aged 20-75 years were enrolled. MAIN OUTCOME MEASURES: Body composition was measured using a bioelectronics impedance analyzer. The serum concentrations of total osteocalcin, estradiol, leptin, osteoprotegerin, the receptor activator of nuclear factor-κB ligand, IGF-I, fasting plasma glucose, and urinary N-terminal telopeptide of type I collagen were tested. The bone mineral densities (BMDs) at the lumbar spine and proximal femoral neck were measured by dual-energy X-ray absorptiometry. RESULTS: The serum total osteocalcin level had a significant positive association with fat-free mass (r = 0.168, P = .007) after adjusting for age, fat mass, menopausal status, estradiol, fasting glucose, leptin, osteoprotegerin, receptor activator of nuclear factor-κB ligand, IGF-I, N-terminal telopeptide of type I collagen, BMDs, and waist and hip circumference. Analysis in pre- and postmenopausal women demonstrated that this association was only present in premenopausal women (r = 0.190, P = .005). The multiple stepwise regression analysis revealed that hip circumference, femoral neck-BMD, fat mass, leptin, osteocalcin, and age are the contributors to the changes in fat-free mass in premenopausal women (adjusted R(2) = 0.521, P < .001). CONCLUSION: The serum level of total osteocalcin was positively associated with fat-free mass independent of age, fat mass, leptin, and other confounders in premenopausal women.

The effects of bisphenol A (BPA) exposure on fat mass and serum leptin concentrations have no impact on bone mineral densities in non-obese premenopausal women.

OBJECTIVES: Bisphenol A (BPA) exposure may promote obesity, but its effect on bone mineral density (BMD) has not been reported in humans. We aimed to examine the relationships between BPA exposure, body composition, serum estradiol, leptin, osteocalcin levels and BMDs in healthy premenopausal women. DESIGN AND METHODS: In this cross-sectional study, a total of 246 healthy premenopausal women aged 20 years and older with regular menstrual cycles were investigated. Body mass index (BMI), fat mass, fat-free mass and BMDs were measured by DXA. Serum estradiol, leptin, osteocalcin, urinary BPA and NTx levels were also tested. RESULTS: Urinary BPA levels were positively associated with fat mass (r=0.193, p=0.006) and leptin (r=0.236, p=0.001) but not with fat-free mass after adjusting for age and BMI. BPA was not associated with serum estradiol levels, BMDs, or bone resorption marker NTx and bone formation parameter osteocalcin, either. A multivariate stepwise regression analysis confirmed that serum leptin levels were positively influenced by fat mass (ß=0.746, p<0.001) and BPA (ß=0.127, p=0.01) but negatively correlated with fat-free mass (ß=-0.196, p<0.001). However, the changes of BMDs at the lumbar spine (ß=0.298, p<0.001) and femoral neck (ß=0.305, p<0.001) were primarily explained by fat-free mass, and were irrelevant of the fat mass, leptin or BPA exposure. CONCLUSIONS: Although BPA exposure is related with increased amount of fat mass and elevated serum leptin levels, it has neutral effect on BMDs in premenopausal women, possibly due to the exclusive role of fat-free mass, which is unrelated to BPA in determining BMDs.

Interactions of osteoporosis candidate genes for age at menarche, age at natural menopause, and maximal height in Han Chinese women.

OBJECTIVE: Age at menarche (AAM), age at natural menopause (ANM), and maximal height are closely related to bone mineral densities and osteoporosis. It is still unclear whether osteoporosis susceptibility genes are also associated with AAM, ANM, and maximal height in Chinese women. METHODS: In this relatively large cross-sectional sample of 722 Han Chinese postmenopausal women, 22 single nucleotide polymorphisms (SNPs) within 12 osteoporosis candidate genes that were identified from genome-wide association studies and replicated in our previous study were studied. The effects of a single gene on the AAM, ANM, and maximal height were investigated by linear regression analysis, whereas the gene-gene interactions were determined by a generalized multifactor dimensionality reduction method. RESULTS: It was revealed that the major histocompatibility complex (MHC) gene (rs3130340) was associated with ANM even after Bonferroni correction (P = 0.001). A significant gene-gene interaction for ANM involving rs3130340 in MHC, rs1038304 and rs4870044 in estrogen receptor-α gene (ESR1), and a significant three-SNP interaction model (SNP rs2273061 in jagged1, SNP rs6929137 in ESR1, and SNP rs2306033 in low-density lipoprotein receptor-related protein 4) for maximal height were identified. No single or combined effect of tested SNPs on AAM was discovered. CONCLUSIONS: Our study indicates that osteoporosis susceptibility SNPs, such as ESR1 (rs1038304, rs4870044, rs6929137), MHC (rs3130340), low-density lipoprotein receptor-related protein 4 (rs2306033), and jagged1 (rs2273061), might independently and/or in an interactive manner influence ANM and maximal height. All the SNPs tested had no association with AAM.

IGF-1 as an early marker for low bone mass or osteoporosis in premenopausal and postmenopausal women.

To find out which of the following parameters-serum levels of insulin-like growth factor 1 (IGF-1), osteoprotegerin (OPG), leptin, osteocalcin (OC), and urinary excretion of N-terminal telopeptide of type I collagen (NTx), can be used as an early marker for osteopenia/osteoporosis in women diagnosed by dual-energy X-ray absorptiometry (DXA), 282 premenopausal and 222 postmenopausal women aged 20-75 years were investigated by the measurement of bone mineral densities (BMDs) at lumbar spine (LS) and femoral neck (FN) by DXA, together with serum concentrations of IGF-1, OPG, leptin, OC, and urinary NTx. The characteristics of the earliest marker(s) were tested with the receiver operating characteristic (ROC) analysis. The area under the curve (AUC), sensitivity, and specificity parameters were determined. It was revealed that serum levels of IGF-1 and leptin changed the earliest, with both markers significantly decreasing (P < 0.0001) or increasing (P = 0.020), respectively, at age 30. However, in ROC analysis, IGF-1 was the only early parameter that had the capacity to differentiate the low bone mass/osteoporosis women from the normal ones (P < 0.0001). If the serum level of IGF-1 at 1.5 SD below its peak was adopted as a cutoff point, it could identify women with low bone mass/osteoporosis with a sensitivity of 73% and specificity of 67%. In the premenopausal women subgroup analysis, the low bone mass women (30/282, 10.6%) were older (38.2 +/- 1.7 vs. 34.5 +/- 0.5 years; P = 0.026), with lower serum levels of IGF-1 (215.1 +/- 22.4 vs. 278.8 +/- 9.4 ng/ml; P = 0.02) and less lean mass (33.1 +/- 0.6 vs. 34.8 +/- 0.2 kg; P = 0.010) than the normal ones. After controlling for age, the serum level of IGF-1 had a weak, but still significant, positive correlation with lean mass (r = 0.17, P < 0.001). In conclusion, measurement of serum IGF-1 in young women may help in the early identification of those at risk for developing low bone mass and osteoporosis.

The influence of Lys3Asn polymorphism in the osteoprotegerin gene on bone mineral density in Chinese postmenopausal women.

The objective was to identify single nucleotide polymorphisms (SNPs) in exons of the osteoprotegerin gene and to analyze the relationship between the SNPs and bone mineral density in postmenopausal women. We used polymerase chain reaction (PCR) and direct sequencing methods to identify SNPs and genotypes in 205 postmenopausal women. BMD at the lumbar spine (L2-4) and femoral neck (FN) were measured by dual-energy X-ray absorptiometry (DEXA). Serum osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappaB ligand (RANKL) and urinary N-telopeptide of type I collagen (NTx) were also measured. In exon 1 of the OPG gene, we found the Lys3Asn SNP. In 205 postmenopausal women, the Asn-allele frequency was 26.0%, and the distribution of Lys3Asn genotypes was Lys-Lys 56.6%, Lys-Asn 34.6% and Asn-Asn 8.8%, respectively. BMD at the lumbar spine (L2-4) of the Asn-Asn genotype was significantly higher (9.5-12.6%) than Lys-Asn and Lys-Lys genotypes (P=0.012), with evidence for an allele dose effect (P=0.008). Results remained similar after adjustment for age and body mass index. The Lys3Asn polymorphism of the OPG gene alone accounted for 7.7% of the variance of the L2-4 BMD in a multiple regression model. Logistic regression analysis revealed that the OPG genotype Lys-Lys had a 2.7 times (95% CI: 0.83-9.11) greater risk for osteopenia/osteoporosis than the Asn-Asn genotype. The Lys3Asn polymorphism in the OPG gene is associated with L2-4 BMD in postmenopausal women. The Lys-allele is associated with lower BMD and an increased risk for osteoporosis.

[Study of the impact of candidate genes on bone mineral density in postmenopausal women].

OBJECTIVE: To investigate the impact of multiple candidate genes on bone mineral density in postmenopausal women. METHODS: Bone mineral density (BMD) at lumbar spine and femoral neck were measured by dual-energy X-ray absorptiometry (DEXA) in 205 postmenopausal women. Polymerase chain reaction (PCR) and direct sequencing technique were used to identify osteoprotegerin gene polymorphism. Parathyroid hormone, calcitonin receptor, osteocalcin and leptin receptor genes were evaluated through PCR and restriction fragment length polymorphism. Leptin gene was genotyped by PCR and agarose electrophoresis. RESULTS: One G-1181C single nucleotide polymorphism was found in the first exon of the osteoprotegerin gene. After adjustment for age and body mass index, women who were with the CC genotype of osteoprotegerin gene or the bb genotype of parathyroid hormone gene had the highest BMD value at the lumbar spine, which was (1.042 +/- 0.142) g/cm(2) and (1.196 +/- 0.133) g/cm(2), respectively. No association was found among calcitonin receptor, osteocalcin, leptin and leptin receptor genes with BMD in postmenopausal women. Multivariate regression analysis found that the osteoprotegerin, parathyroid hormone and osteocalcin genes associated with the variance of BMD at the lumbar spine, and the parathyroid gene associated with the variance of BMD at the femoral neck. CONCLUSIONS: There is some association between osteoprotegerin, parathyroid hormone genes and BMD in postmenopausal women. However, no relationship has been found among calcitonin receptor, osteocalcin, leptin and leptin receptor genes with BMD in postmenopausal women. The osteoprotegerin gene may be the useful genetic marker for osteopenia in postmenopausal women.

[The relationship between body composition measured with bioelectric impedance analysis and bone mass in female].

OBJECTIVE: To investigate the effect of fat mass and fat-free mass on bone mineral density (BMD) in pre- and postmenopausal women. METHODS: 282 premenopausal women with regular menstruation and 205 postmenopausal women were enrolled in this study. BMD at lumbar spine (L(2 - 4)) and femoral neck (FN) were measured with dual-energy X-ray absorptiometry (DEXA). Fat mass and fat-free mass were measured with bioelectric impedance analysis (BIA). Height, weight, waist and hip circumference were recorded. Body mass index (BMI) and waist hip ratio (WHR) were calculated. RESULTS: Fat mass and fat-free mass were significantly positively correlated with L(2 - 4) and FN BMD in both pre- and postmenopausal women (P < 0.01). Multiple regression analysis showed that in premenopausal women, fat-free mass and age were significant determinants of L(2 - 4) BMD (R(2) = 0.077, P = 0.000), while fat-free mass, age and BMI were significant determinants of FN BMD (R(2) = 0.130, P = 0.000). In postmenopausal women, fat mass and age were significant determinants of BMD at L(2 - 4) and FN (R(2) were 0.153 and 0.184 respectively, P = 0.000). CONCLUSIONS: Fat mass and fat-free mass have different effects on BMD in pre- and postmenopausal women. Fat-free mass is a significant determinant of BMD in premenopausal women, while fat mass contributes most to BMD in postmenopausal women.

[The relationships between changes of serum osteoprotegerin, nuclear factor-kappa B ligand receptor activator, and age, menopause, bone biochemical markers and bone mineral densities in women aged 20 - 75].

OBJECTIVE: To investigate the relationships between the serum levels of osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B ligand (RANKL) with age, menopause, bone biochemical markers and bone mineral densities (BMDs) in pre- and postmenopausal women and to determine the contributing factors for serum OPG and RANKL. METHODS: 504 pre- and postmenopausal women aged between 20 and 75 years were enrolled in this study. BMDs at lumbar spine and proximal femur were measured with dual-energy X-ray absorption meter. The serum osteocalcin (BGP), OPG, RANKL and urinary type I collagen (NTx) were also tested. RESULTS: Age was positively related with serum OPG (r = 0.442, P < 0.001) and was negatively in association with serum RANKL (r = -0.263, P < 0.001). Postmenopausal women showed higher levels of serum OPG [(107.6 +/- 3.0) ng/L], while their serum concentrations of RANKL [(4.7 +/- 0.4) ng/L] and RANKL/OPG ratios (0.045 +/- 0.004) were significantly lower than those of premenopausal women [(72.0 +/- 1.8) ng/L, (5.8 +/- 0.3) ng/L and 0.099 +/- 0.008]. Neither serum OPG nor RANKL or RANKL/OPG was in association with BMDs at lumbar spine or proximal femur after adjustment of age, years-since-menopause (YSM) and body mass index. Serum OPG was positively related with urinary NTx/creatinine. Serum RANKL was negatively related with serum BGP. Serum OPG, RANKL and RANKL/OPG showed no differences among normal, osteopenic and osteoporotic postmenopausal women. In multiple regression analysis, YSM, age and bone markers were the independent contributors to OPG-RANKL system. CONCLUSIONS: The elevation of serum OPG along with age might be a compensatary mechanism against the accelerated bone resorption, while the decreased level of serum RANKL might be helpful for restoring the reduced bone formation in postmenopausal women. YSM, age, together with bone tune-over markers were the main factors affecting serum concentrations of OPG and RANKL.

Relationship between body composition and bone mineral density in healthy young and premenopausal Chinese women.

This study investigated the relative contribution of fat mass and lean mass to bone mineral density (BMD) in young and premenopausal healthy Chinese women. The study was performed in 282 young and premenopausal healthy women with regular menstrual cycles. The BMD at lumbar spine (L2-L4), total hip and total body, together with fat mass and lean mass were assessed by dual-energy X-ray absorptiometry (DXA); body height, weight, waist and hip circumference were also measured, and body mass index (BMI) and waist-hip ratio were calculated. Fat mass was a major determinant for BMI, BMI and lean mass were positively related to L2-L4, total hip and total body bone density ( P<0.001 for all), lean mass was the only independent factor contributing to BMD at L2-L4 (standardized coefficient beta=0.282, P<0.001), total hip (beta=0.336, P<0.001) and total body (beta=0.361, P<0.001) in multiple stepwise regression analysis. The correlation between BMI and BMD was improved after adjustment for fat mass, while decreased or even lost when lean mass was adjusted. These data suggested that in the Chinese population, lean mass is an important factor determining BMD in young and premenopausal women.

[Relationship between body composition and bone mineral density in healthy premenopausal women].

OBJECTIVE: To investigate the relative contribution of fat mass and lean mass on bone mineral density (BMD) in premenopausal healthy women. METHODS: The BMD at lumbar spine, proximal femur and total body, together with fat mass and lean mass was determined by dual-energy X-ray absorptiometry (DEXA), the body height, weight, waist, and hip circumference were also measured, and body mass index (BMI) and waist-hip ratio were calculated in 282 premenopausal women. RESULTS: Fat mass was a major determinant for BMI, BMI and lean mass were positively related with L2-4, proximal femur and total body BMD (P = 0.000 for all), and lean mass were the only independent factor contributing to L2-4 (standardized coefficient beta = 0.282, P = 0.000), proximal femur (beta = 0.336, P = 0.000) and total body BMD (beta = 0.361, P = 0.000) in stepwise regression analysis. The relationship between BMI and BMD was further improved after controlling fat mass, while decreased or even lost when controlling lean mass. CONCLUSIONS: Lean mass was an important factor determining BMD in premenopausal women.

[Association of calcitonin receptor gene polymorphism with bone mineral density in Shanghai women].

OBJECTIVE: To investigate the association of calcitonin receptor (CTR) gene polymorphism with bone mineral density (BMD) in premenopausal and postmenopausal women. METHODS: CTR genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 184 premenopausal women and 199 postmenopausal women in Shanghai area. BMD at lumbar spine (L2-4) and femoral neck (FN) were measured by dual-energy X-ray absorptiometry (DEXA). RESULTS: The distribution of CTR genotypes in 383 Shanghai women were CC genotype 83.8%, TC genotype 14.6%, TT genotype 1.6%, respectively. BMD at FN of CC genotype was significantly higher than TC and TT genotypes (P < 0.01) in postmenopausal women. But there was no difference in BMD of different CTR genotypes in premenopausal women. Multiple regression analysis showed that CTR genotypes were associated with FN BMD in postmenopausal women (P < 0.05). CONCLUSIONS: The polymorphism of CTR gene was associated with BMD in postmenopausal women.

[A study of the degrees of insulin resistance and first-phase insulin secretion of beta-cells in metabolic syndrome patients with different glucose tolerance].

OBJECTIVE: To explore the insulin resistance and first-phase insulin secretion of beta-cells in normal persons, obese persons with normal glucose tolerance, obese persons with impaired glucose tolerance (IGT) and obese persons with type 2 diabetes (T2DM). METHODS: 75 g oral glucose tolerance test (OGTT) and Bergman's minimal model method of frequently sampled intravenous glucose tolerance test (FSIGTT) with reduced sample number (n = 12) were performed on a total of 151 subjects, 29 normal controls (control group), 44 obese persons with normal glucose tolerance (obesity group), 36 obese persons with IGT (IGT group), and 42 T2DMT patients (T2DM group) to determine the acute insulin response to glucose (AIRg), insulin sensitivity index (S(I)), and glucose effectiveness (S(G)). The disposition index (DI, AIRg X S(I)) was calculated to determine whether AIRg was adequate to compensate for insulin resistance. RESULTS: The S(I) value of the control group was significantly higher than those of the obesity, IGT, and T2DM groups (all P < 0.01), without significant difference among the latter three groups. The S(G) value of the control group was not significantly different from that of the obesity group, but significantly higher than those of the IGT and T2DM groups (both P < 0.01), without significant difference any 2 groups from the latter two groups. The AIRg of the normal group was similar to that of the IGT group (2.61 mU x L(-1) x min(-1) +/- 0.13 mU.L(-1) x min(-1) vs 2.56 mU x L(-1) x min(-1) +/- 0.25 mU x L(-1) x min(-1)), and significantly lower than that of the obesity group (3.02 mU x L(-1) x min(-1) +/- 0.27 mU x L(-1) x min(-1), P < 0.01) and higher than that of the T2DM group (1.54 mU x L(-1) x min(-1) +/- 0.55 mU x L(-1) x min(-1), P < 0.01). The value of DI was gradually decreased from the sequence of the groups of control, obesity, IGT, and T2DM (3.16 +/- 0.31, 2.65 +/- 0.50, 1.67 +/- 0.54), with significant differences between any two groups (all P < 0.01). Multiple regression analyses with S(I) and AIRg as dependent variables showed that S(I) was negatively correlated with BMI, 2 h glucose level in OGTT, 2 h insulin, triglyceride, and cholesterol (r(2) = 0.589, P < 0.001), and AIRg was positively correlated with BMI, S(G), fasting insulin, and 2 h insulin level and negatively correlated with 2 h glucose, and age (r(2) = 0.515, P < 0.001). CONCLUSION: Obese patients with different glucose tolerance have similar degrees of insulin resistance. Acute insulin response is increased in obesity group to compensate for the insulin resistance. Although the acute insulin response in the IGT group is similar to that in the control group, however, the compensation of islet beta cells in the IGT group is significantly decreased as compared with that in the obesity group, leading to glucose intolerance. There is a severe deficiency of acute insulin response to glucose in T2DM group.