Vitamin D, parathyroid hormone levels and bone mineral density in community-dwelling older women: the Rancho Bernardo Study

Interaction between MARK3 (rs11623869), PLCB4 (rs6086746) and GEMIN2 (rs2277458) variants with bone mineral density and serum 25-hidroxivitamin D levels in Mexican Mestizo women

Introduction

Understanding the genetic factors contributing to variations in bone mineral density (BMD) and vitamin D could provide valuable insights into the pathogenesis of osteoporosis. This study aimed to evaluate the association of single nucleotide variants in MARK3 (rs11623869), PLCB4 (rs6086746), and GEMIN2 (rs2277458) with BMD in Mexican women.

Methods

The gene-gene interaction was evaluated in these variants in serum 25(OH)D levels and BMD. A genetic risk score (GRS) was created on the basis of the three genetic variants. Genotyping was performed using predesigned TaqMan assays.

Results

A significant association was found between the rs6086746-A variant and BMD at the total hip, femoral neck, and lumbar spine, in women aged 45 years or older. However, no association was observed between the variants rs11623869 and rs2277458. The rs11623869 × rs2277458 interaction was associated with total hip (p=0.002) and femoral neck BMD (p=0.013). Similarly, for vitamin D levels, we observed an interaction between the variants rs6086746 × rs2277458 (p=0.021). GRS revealed a significant association with total hip BMD (p trend=0.003) and femoral neck BMD (p trend=0.006), as well as increased vitamin D levels (p trend=0.0003). These findings provide evidence of the individual and joint effect of the MARK3, PLCB4, and GEMIN2 variants on BMD and serum vitamin D levels in Mexican women.

Discussion

This knowledge could help to elucidate the interaction mechanism between BMD-related genetic variants and 25OHD, contributing to the determination of the pathogenesis of osteoporosis and its potential implications during early interventions.

Vitamin D status and its associations with bone mineral density, bone turnover markers, and parathyroid hormone in Chinese postmenopausal women with osteopenia and osteoporosis

Background

Vitamin D is a key factor in bone metabolism, yet vitamin D insufficiency and deficiency are prevalent among postmenopausal women, with potential repercussions on bone mineral density (BMD), bone turnover markers (BTMs), and parathyroid hormone (PTH). Nonetheless, the findings from existing studies exhibit inconsistency, and a notable gap exists in the availability of large-scale investigations.

Methods

In this real-world study, 8,532 postmenopausal women over 50 years old with a diagnosis of osteopenia (50.9%) and osteoporosis (49.1%) at the first visit were enrolled in this study. Serum 25(OH)D level, PTH, osteocalcin (OC) and Beta-CrossLaps of type 1 collagen containing cross-linked C-telopeptide (β-CTX), were measured. BMD at all sites, including the lumbar spine, femoral neck, and total hip were obtained by dual-energy X-ray absorptiometry (DXA). The associations of serum 25(OH)D level with BMDs and BTMs were investigated using spearman correlation analysis and analysis of general linear model adjusted by age and body mass index.

Results

The serum 25(OH)D level was 22.17 ± 9.75 ng/mL among all patients included in this study. For the osteopenia group, the serum 25(OH)D level was 22.40 ± 9.41 ng/mL, while for the osteoporosis group, it measured 21.93 ± 10.08 ng/mL. In the osteopenia group, the prevalence of vitamin D deficiency, insufficiency and sufficiency was 45.8, 34.6, and 19.6%, respectively, which was close to that of the osteoporosis group (47.4, 34.3, and 18.3%) (p = 0.202). Spearman correlation analysis unveiled negative associations between serum 25(OH)D concentrations and both BTMs and PTH within both the osteopenia and osteoporosis group. In the osteoporosis group, there were positive correlations between 25(OH)D levels and femoral neck BMD (r = 0.040, p = 0.010) and total hip BMD (r = 0.053, p = 0.001). Furthermore, we found that for the osteopenia group, greater vitamin D levels were associated with greater femoral neck BMD (p = 0.020) and total hip BMD (p = 0.008) and lower β-CTX (p < 0.001), OC (p < 0.001), and PTH (p < 0.001). The same trends were seen in osteoporosis patients (p < 0.05), and with greater lumbar spine BMD with higher levels of 25(OH)D (p = 0.009).

Conclusion

This study showed high prevalence of vitamin D deficiency and insufficiency in Chinese postmenopausal women with osteopenia and osteoporosis and the relationships between vitamin D and BMD, BTMs and PTH. The results contribute to a more comprehensive understanding of how vitamin D may impact bone health.

Serum 25 hydroxyvitamin D concentrations in individuals over 80 years old and their correlations with musculoskeletal and health parameters

PURPOSE

The present study aims to evaluate the serum concentrations of 25 hydroxyvitamin D[25(OH)D] in individuals aged ≥80 years, independent, free-living in Sao Paulo, Brazil (Lat 23.5 ^oS), and to investigate their associations with musculoskeletal system, physical performance and health markers.

METHOD

This cross-sectional study included 212 community dwellers aged ≥80 years and evaluated serum 25(OH)D, PTH, calcium, albumin, phosphorus, creatinine, bone markers, and bone mineral density. Physical performance was evaluated with stationary march, Flamingo, and functional reach tests, questionnaires to assess falls and fractures in the previous year, energy expenditure (MET), and Charlson index. Physical activity was evaluated with the International Physical Activity Questionnaire.

RESULTS

Vitamin D deficiency (<20 ng/mL) was observed in 56% and severe vitamin D deficiency (<10 ng/mL) in 13% of those individuals. Serum concentrations of 25(OH)D were significantly and positively associated with BMD total hip (p = 0.001), femoral neck (p = 0.011) and 33% radius (p = 0.046) BMDs, MET (p = 0.03) and functional reach test (p = 0.037) and negatively with age (p = 0.021), PTH (p = 0.004) and osteoporosis diagnosis (p = 0.012). Long-lived individuals with 25(OH)D ≥ 20 ng/mL had higher total hip and femoral neck BMDs (p = 0.012 and p = 0.014, respectively) and lower PTH (p = 0.030). In multiple linear regression analysis, age and osteoporosis diagnosis remained negatively associated with 25(OH)D levels (p = 0.021 and p = 0.001, respectively), while corrected calcium and cholecalciferol use remained positively associated (p = 0.001 and p = 0.024, respectively).

CONCLUSION

We observed high vitamin D inadequacy prevalence in those Brazilian community dwellers' oldest old. Serum concentrations of 25(OH)D were positively associated with bone mass and dynamic balance, and negatively with PTH and osteoporosis diagnosis. Additionally, 25(OH)D ≥ 20 ng/mL was associated with better bone mass and lower PTH levels.

Effects of vitamin D deficiency on blood lipids and bone metabolism: a large cross-sectional study

To investigate the relationship between serum high-density lipoprotein (HDL-C) and spinal bone mineral density (BMD) under different serum 25-hydroxyvitamin D (25 (OH) D) levels in adults over 40 years old and to explore its mechanism. We include participants over the age of 40 with data on HDL-C, 25 (OH) D, spinal BMD, and other variables in the National Health and Nutrition Examination Survey 2007-2010 in the analysis. A weighted multiple linear regression model was used to evaluate the association between serum HDL-C and spinal BMD in different gender, ages, and serum 25 (OH) D levels. A total of 3599 subjects aged ≥ 40 years old were included in this study. Univariate analysis of the complete correction model showed a negative correlation between serum HDL-C and spinal BMD. In the two subgroups of serum 25 (OH) D, we found that the higher the serum HDL-C in the female with serum 25 (OH) D < 75 nmol/L aged 40-59 years old, the lower the total spinal BMD, and a similar relationship was found in the lumbar spine. However, no similar relationship was found in all populations with serum 25 (OH) D ≥ 75 nmol/L and males with serum 25 (OH) D < 75 nmol/L. These results suggest that among Americans over the age of 40, the increase in serum HDL-C is related to decreased BMD of spine only in women aged 40-59 years with vitamin D insufficiency or deficiency.

Associations between serum calcium, 25(OH)D level and bone mineral density in adolescents

BACKGROUNDS

It is important to improve our understanding of the roles of calcium and vitamin D in bone health for preventing osteoporosis. We aimed at exploring the associations between serum calcium, vitamin D level, and bone mineral density (BMD) in adolescents included in the National Health and Nutrition Examination Survey (NHANES) 2001-2006.

METHODS

Weighted multivariate linear regression models were used to estimate the associations of serum calcium, 25(OH)D level with total BMD. Smooth curve fitting was used to explore the potential non-linear relationship.

RESULTS

A total of 5990 individuals aged between 12 and 19 years were included in this study. The fully-adjusted model showed serum calcium positively correlated with total BMD. However, an inverted U-shaped relationship was found when we performed the smooth curve fitting method, and the inflection point was calculated at 9.6 mg/dL using the two-piecewise linear regression model. In contrast, there was a positive correlation between serum 25(OH)D and total BMD after adjusting for potential confounders.

CONCLUSIONS

The present study revealed a positive correlation between serum 25(OH)D level and total BMD, and an inverted U-shaped relationship between serum calcium and total BMD.

Associations between serum calcium, 25(OH)D level and bone mineral density in older adults

Background

Calcium and vitamin D play important roles in bone health as essential nutrients. We explored whether serum calcium, 25(OH)D were associated with bone mineral density (BMD) in older adults.

Methods

This cross-sectional study was conducted on a sample of 4595 participants (2281 men and 2314 women) aged ≥ 50 years (from 50 to 85 years, 60.1 ± 8.7 years for men and 62.0 ± 9.7 years for women) from the National Health and Nutrition Examination Survey (NHANES) 2001–2006. The independent variables were serum calcium and 25(OH)D. The dependent variable was lumbar BMD. The other variables were considered potential effect modifiers. We performed weighted multivariate linear regression models and smooth curve fittings to evaluate the associations between them. Subgroup analyses were also performed.

Results

We observed a negative association between serum calcium and lumbar BMD in the fully adjusted model. In the subgroup analyses, this association was no longer significant among males and other race/ethnicity. On the other hand, there was a positive association between serum 25(OH)D and lumbar BMD in the fully adjusted model. In the subgroup analyses, this association did not differ in different age groups, between men and women. However, the association between serum 25(OH)D and lumbar BMD followed a U-shaped curve in Mexican Americans.

Conclusions

This cross-sectional study indicated that serum calcium negatively correlated with lumbar BMD, and serum 25(OH)D positively correlated with lumbar BMD in older adults. However, the association between serum calcium and lumbar BMD in males followed a U-shaped curve.

Calciotropic Hormones and the Prevalence of Vertebral Fractures in Chinese Postmenopausal Women with Vitamin D Insufficiency: Peking Vertebral Fracture Study

This case-control study aimed to examine the effect of high serum parathyroid hormone (PTH) level, especially the effect of secondary hyperparathyroidism (SHPT) related to hypovitaminosis D, on bone metabolism and bone phenotypes. We included a total of 830 Chinese postmenopausal women aged ≥ 50 years with serum 25-hydroxyvitamin D (25(OH)D) level < 30 ng/ml, among whom 415 women had prevalent vertebral fractures (VFs) and others were age-matched controls. We measured serum levels of 25(OH)D, PTH and bone turnover markers (BTMs), which included C-terminal telopeptide of type I collagen (β-CTX), N-aminoterminal prepeptide of type I procollagen (P1NP) and osteocalcin (OC). Bone mineral densities (BMDs) at lumbar spine and femoral neck were quantified by dual-energy X-ray absorptiometry. Morphometric VFs were validated by lateral radiograph of thoracolumbar spine. Compared to fracture-free controls, women with VFs exhibited a higher serum level of PTH and a higher percentage of SHPT (both p < 0.05), but had a similar serum level of 25(OH)D (p = 0.166). Positive correlations were depicted between PTH and BTMs (all p < 0.01), and between 25(OH)D and bone formation markers (p = 0.013 for OC, p = 0.068 for P1NP), whereas no significant correlation was identified between both calciotropic hormones and BMDs or between 25(OH)D and β-CTX (all p > 0.05). Increasing PTH was associated with an increased risk of VFs independent of 25(OH)D and BMD [odds ratio (OR) per SD increase in PTH 1.016, 95% confidence interval (95% CI) 1.006-1.027]. Moreover, women with SHPT (i.e., > 68 pg/ml) had about three times odds for VF compared to women with normal PTH levels (OR 3.270, 95% CI 1.581-6.760). These data suggest that evaluated serum PTH level might promote the bone remodeling and then lead to increased risks of VFs among Chinese postmenopausal women with vitamin D insufficiency.

Plasma 25-hydroxyvitamin D concentration and risk of type 2 diabetes and pre-diabetes: 12-year cohort study

BACKGROUND

It has been reported that higher plasma 25-hydroxyvitamin D is associated with lower risk of type 2 diabetes. However the results to date have been mixed and no adequate data based on a cohort are available for the high end of the normal range, above approximately 32 ng/ml or 80 nmol/L.

METHODS

We performed a cohort study of 903 adults who were known to be free of diabetes or pre-diabetes during a 1997-1999 visit to a NIH Lipid Research Centers clinic. Plasma 25(OH)D was measured at Visit 8 in 1977-1979. The mean age was 74 years. The visit also included fasting plasma glucose and oral glucose tolerance testing. Follow-up continued through 2009.

RESULTS

There were 47 cases of diabetes and 337 cases of pre-diabetes. Higher 25(OH)D concentrations (> 30 ng/ml) were associated with lower hazard ratios (HR) for diabetes: 30-39 ng/ml or 75-98 nmol/L: HR = 0.31, 95% CI = 0.14-0.70; for 40-49 ng/ml or 100-122 nmol/L: HR = 0.29, CI = 0.12-0.68; for > 50 ng/ml or 125 nmol/L: HR = 0.19, CI = 0.06-0.56. All HRs are compared to < 30 ng/ml or 75 nmol/L. There was an inverse dose-response gradient between 25(OH)D concentration and risk of diabetes with a p for trend of 0.005. Each 10 ng/mL or 25 nmol/L higher 25(OH)D concentration was associated with a HR of 0.64, CI = 0.48-0.86. 25(OH)D concentrations were more weakly inversely associated with pre-diabetes risk, and the trend was not significant.

CONCLUSION

Further research is needed on whether high 25(OH)D might prevent type 2 diabetes or transition of prediabetes to diabetes.

Vitamin D Insufficiency and Cognitive Function Trajectories in Older Adults: The Rancho Bernardo Study

BACKGROUND

Evidence of a role for vitamin D (VitD) in cognitive aging is mixed and based primarily on extreme VitD deficiency. We evaluated the association of VitD insufficiency with cognitive function in older, community-dwelling adults living in a temperate climate with year-round sunshine.

METHODS

A population-based longitudinal study of 1,058 adults (median age 75; 62% women) who had cognitive function assessed and serum levels of 25-hydroxyvitaminD (25OHD) measured in 1997-99 and were followed for up to three additional cognitive function assessments over a 12-year period.

RESULTS

Overall, 14% (n = 145) of participants had VitD insufficiency defined as 25OHD <30 ng/ml. Adjusting for age, sex, education, and season, VitD insufficiency was associated with poorer baseline performance on the Mini-Mental Status Exam (MMSE) (p = 0.013), Trails Making Test B (Trails B) (p = 0.015), Category Fluency (p = 0.006), and Long Term Retrieval (p = 0.019); differences were equivalent to 5 years of age. For those with VitD insufficiency, the odds of mildly impaired performance at baseline were 38% higher for MMSE (p = 0.08), 78% higher for Trails B (p = 0.017), and 2-fold higher for Category Fluency and Long Term Retrieval (both p = 0.001). VitD insufficiency was not related to the rate of cognitive decline on any test or the risk of developing impaired performance during follow-up.

CONCLUSION

In this population with little VitD deficiency, even moderately low VitD was associated with poorer performance on multiple domains of cognitive function. Low VitD did not predict 12-year cognitive decline. Clinical trials are essential to establish a causal link between VitD and cognitive well-being.

The levels of bone turnover markers 25(OH)D and PTH and their relationship with bone mineral density in postmenopausal women in a suburban district in China

This study evaluated the levels of bone turnover markers (BTMs) and investigated relationships between them and bone mineral density (BMD) in postmenopausal women in China suburban district. The prevalence of osteoporosis was 25.03 % at lumbar spine and 6.23 % at femoral neck, and BTMs were negatively correlated with BMDs.

INTRODUCTION

The aims of this study were to evaluate the levels of bone turnover markers (BTMs), including serum N-terminal procollagen of type I collagen (P1NP), beta C-terminal cross-linked of type I collagen (β-CTX), 25-hydroxyvitamin D [25(OH)D], and parathyroid hormone (PTH), and to investigate relationships between these markers and bone mineral density (BMD) as well the prevalence of osteoporosis in postmenopausal women of suburban district.

METHODS

A population of 4822 postmenopausal women aged 55-69 years old (62.22 ± 6.75) from the suburban district was recruited voluntarily. BMD was measured at the lumbar spine, femoral neck, and total hip using dual-energy X-ray absorptiometry; 2251 women in this group had the serum BTMs 25(OH)D and PTH tested.

RESULTS

The prevalence of osteoporosis was 25.03 % at lumbar spine and 6.23 % at femoral neck. The median (interquartile range) values of serum P1NP, β-CTX, 25(OH)D, and PTH were 59.3 ng/mL (44.7-75.52), 0.370 ng/mL (0.280-0.490), 23.0 ng/mL (17.1-30.5), and 31.4 pg/mL (24.9-39.7), respectively. Serum P1NP and β-CTX levels presented significantly negative correlations with BMDs at the all the sites (Beta_std = -0.098 to -0.208, respectively, P < 0.001), whereas PTH levels were negatively correlated with BMDs of the femoral neck and total hip (Beta_std = -0.062 and -0.054, P < 0.01, respectively). Serum 25(OH)D had positive associations with BMDs at total hip (Beta_std = 0.051, P < 0.01).

CONCLUSIONS

The BMD of postmenopausal women in China suburban area is higher than that in downtown area, and over 60 % of the participants had their serum 25(OH)D level over 20 ng/mL. BTMs were negatively correlated with BMDs, suggesting that BTMs are reliable factors for early declines in BMD.

Bioavailable 25(OH)D but Not Total 25(OH)D Is an Independent Determinant for Bone Mineral Density in Chinese Postmenopausal Women

Total 25(OH)D levels were determined to assess bone health in elderly populations; however, the bioavailability of 25(OH)D is regulated by the albumin and vitamin D binding protein (DBP) levels and DBP variations. Whether bioavailable 25(OH)D level is a superior biomarker for vitamin D than total 25(OH)D level regarding the BMD and the bone metabolism were not yet fully understood. With a community based cross-sectional study of 967 postmenopausal women, we found that the variant rs7041, but not rs4588, of DBP was significantly associated with the blood DBP level, which was positively correlated with the total 25(OH)D level but negatively associated with bioavailable 25(OH)D levels. Both total and bioavailable 25(OH)D levels were significantly correlated with the BMD value in postmenopausal women; however, only the bioavailable 25(OH)D level was an independent determinant of the BMD values when adjusted for age, body mass index and bone turnover biomarkers (OST and β-CTX). The bioavailable and total 25(OH)D were negatively correlated with bone formation biomarkers (OST, PINP and ALP) and PTH levels, while they were positively correlated with osteoprotegerin (OPG) level; however, the bone resorption biomarker (β-CTX) was not correlated with the 25(OH)D levels. An increment of PTH level, along with reduced bioavailable 25(OH)D levels, was evident when the bioavailable 25(OH)D level was < 5 ng/mL, which may be the optimal cutpoint for sufficient vitamin D in Chinese elderly women. The blood calcium, magnesium, ALP, TSH, FGF23, and phosphorus levels were not correlated with the total or the bioavailable 25(OH)D levels. These results suggested that high bioavailable 25(OH)D levels were correlated with reduced bone turnover processes and were a biomarker superior to total 25(OH)D for vitamin D in assessing the risks of bone-related diseases. The results indicate that the bioavailable 25(OH)D level should be determined in assessing the bone health.

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DBP levels and variants on DBP were associated with the total and bioavailable 25(OH)D levels in the elderly populations.

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Both the total and bioavailable 25(OH)D levels were correlated with the BMD in postmenopausal women.

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Multivariate analyses suggested that the bioavailable but not total 25(OH)D was an independent determinant for the BMD.

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Higher bioavailable 25(OH)D levels were correlated with reduced bone turnover and lower PTH in postmenopausal women.

With a cross-sectional community study, we found that the variant rs7041, but not rs4588, of DBP was significantly associated with the blood DBP level, which was positively correlated with the total 25(OH)D levels but negatively associated with the bioavailable 25(OH)D levels. The bioavailable 25(OH)D level was an independent determinant for BMD but not total 25(OH)D. Higher vitamin D levels were correlated with the reduced bone turnover process and lower PTH levels, which might lead to the higher BMD value in postmenopausal women. These results suggested that bioavailable 25(OH)D was a superior biomarker than total 25(OH)D regarding the bone metabolism, and that vitamin D intervention may improve the bone health in elderly populations.

The benefits of utilising geo-mapping for visualising the vitamin D status of Dublin city and the surrounding urban districts

CONTEXT

There have been few published reports of visualising vitamin D status at a micro level, i.e., within large individual urban centres of countries.

OBJECTIVE

To produce a visual map of the vitamin D status [25-hydroxy vitamin D-25(OH)D] of a large urban centre (n > 350,000) incorporating the regions of Dublin city that constitute the general practitioner catchment area of a large academic teaching adult hospital.

DESIGN, SETTING AND PARTICIPANTS

An observational investigation of 5287 free living Irish adults (>18 years).

RESULTS

Approximately, 15.2 % of those sampled in the winter period (October-February) were vitamin D deficient (<30 nmol/L) compared with 10.8 % of those sampled in the summer period (March-September). Vitamin D tests requested from the most social economically deprived urban locations (Dublin 8 and Lucan postal districts) had the highest rates of deficiency (23.5 and 20.4 %, respectively, both seasons). On average, females had a significantly higher 25(OH)D concentration compared with males (57.9 vs 52.3 nmol/L, respectively), while the younger participants (18-50 years) mean 25(OH)D concentration was 27 % lower in winter and 20.7 % lower in summer in comparison with the older participants (>50 years) (P < 0.0001).

CONCLUSIONS

For the first time in Ireland, a visual depiction of data can be used to aid in the rapid identification of vitamin D status trends within a major urban area. These findings provide useful data to help inform public health policy regarding endemic vitamin D insufficiency to help target the population groups and resident location areas most at risk.

Relation of Age, Sex and Bone Mineral Density to Serum 25-Hydroxyvitamin D Levels in Chinese Women and Men

OBJECTIVE

To investigate the relation of circulating 25-hydroxyvitamin D (25[OH]D) levels to age, sex, and bone mineral density (BMD) in adults living in Guangzhou Province.

METHODS

This cross-sectional study comprised 188 women and 122 men aged 17-88 years who were randomly sampled among community-dwelling Guangzhou residents. BMD at the lumbar spine and femoral neck was measured by dual energy X-ray absorptiometry, and serum concentrations of 25(OH)D, parathyroid hormone (PTH), procollagen I N-terminal peptide, and beta C-telopeptide of collagen were assayed by electrochemiluminescence immunoassay. Serum 25(OH)D concentrations were divided into four subgroups: severe deficiency (<10 ng/mL), deficiency (10-20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (≥30 ng/mL).

RESULTS

The mean age of participants was 47.39 ± 19.32 years. Serum 25(OH)D levels were significantly lower in women than men (25.35 ± 6.59 ng/mL vs 27.25 ± 7.94 ng/mL, P < 0.05). The prevalence of 25(OH)D severe deficiency (<10 ng/mL) was 1.6% in men, zero in women; 25(OH)D deficiency (10-20 ng/mL) was 22.9% in women and 20.5% in men; and 25(OH)D insufficiency (20-30 ng/mL) was 73.4% in women and 65.6% in men. An inverse relationship between serum 25(OH)D levels and age (r = -0.249, P < 0.01) was observed in men, but no correlation was found in women (r = 0.130, P > 0.05). Serum 25(OH)D levels were positively associated with lumbar spine and femoral neck BMD (r = 0.382, P < 0.01; r = 0.384, P < 0.01, respectively) in elderly women and (r = 0.332, P < 0.05; r = 0.260, P < 0.05, respectively) and in young men. When adjustments were made for age, correlations between serum 25(OH)D levels and lumbar spine and femoral neck BMD persisted (r = 0.325, P < 0.05; r = 0.323, P < 0.05, respectively) in elderly women. However, age-adjusted serum 25(OH)D levels were positively correlated with BMD at lumbar spine (r = 0.278, P < 0.05) but not at femoral neck (r = 0.165, P > 0.05) in young men. No association between unadjusted or age-adjusted serum 25(OH)D levels and lumbar spine and femoral neck BMD was found in young and middle-aged women and in middle-aged and elderly men. Neither serum PTH levels nor bone turnover markers were related to unadjusted and age-adjusted serum 25(OH)D levels in our participants.

CONCLUSION

More than two-third of participants residing in Guangzhou had vitamin D insufficiency. Serum 25(OH)D level is an important biomarker for BMD in elderly women and young men.

The association between vitamin D and parathyroid hormone and bone mineral density: the Dong-gu Study

The primary objective of the present study was to investigate the relationship between 25-hydroxyvitamin D (25[OH]D) and areal bone mineral density (aBMD) in Korean subjects from the general population aged ≥50 years. This study included 8,857 individuals who completed the baseline survey of the Dong-gu study, which was conducted in Korea from 2007-2010. The participants who fulfilled the detailed inclusion criteria underwent assessment of the femoral neck and lumbar spine aBMD as well as measurement of serum 25(OH)D and parathyroid hormone (PTH) levels. After adjusting for other covariates and log-PTH values, the mean aBMD of the femoral neck exhibited a significant increase with increasing 25(OH)D levels in both males (p < 0.001) and females (p = 0.005). Additionally, the mean aBMD of the lumbar spine exhibited a significant increase with increasing 25(OH)D levels in males (p = 0.011) but not females (p = 0.252). After adjusting for covariates and log-25(OH)D values, the mean aBMD values of the femoral neck and lumbar spine showed significant decreases with increasing PTH levels in both males and females (p < 0.001). The present findings demonstrate that the aBMD of the femoral neck was significantly associated with 25(OH)D levels independent of PTH in both males and females and that the aBMD of the lumbar spine was significantly associated with 25(OH)D levels independent of PTH in males, but not females.

Relation of serum 25 hydroxyvitamin D levels to bone mineral density in southern Chinese postmenopausal women: A preliminary study

BACKGROUND & OBJECTIVES

Vitamin D insufficiency is prevalent in postmenopausal women and has been related to low bone mineral density (BMD). However, controversial results have been reported for the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels and BMD. This study was done to investigate whether serum 25(OH)D levels were associated with BMD in postmenopausal women living in Guangzhou in southern China.

METHODS

This cross-sectional study involved 119 asymptomatic postmenopausal women, aged 48-85 yr, who were consecutively selected from Guangzhou city. BMD was measured at the lumbar spine and femoral neck. The correlation between serum 25(OH)D levels and BMD wes investigated.

RESULTS

With increasing serum 25(OH)D levels categorized as <20, 20-30, and ≥ 30ng/ml, the PTH levels decreased gradually ( P=0.031). Bivariate correlation analyses showed an inverse relationship between serum 25(OH)D and PTH levels after controlling for age and BMI (r=-0.209, P=0.023). Although subjects with vitamin D<30 ng/ml had significantly lower BMD, age- and BMI-adjusted serum 25(OH)D was weakly correlated with BMD at femoral neck (r=0.185, P0.045), and not at lumbar spine (r=0.172, p =0 0.063). In multiple regression analyses, serum 25(OH)D was a predictor for BMD at femoral neck (R 2= 0.424). However, serum β-CTX was a determinant for BMD at lumbar spine (R 2= 0.361).

INTERPRETATION & CONCLUSIONS

Serum 25(OH)D levels showed a positive correlation with BMD at femoral neck and serum β-CTX levels were inversely correlated with BMD at lumbar spine in postmenopausal women. Further studies are needed to elucidate the clinical impact of these findings.

Parathyroid hormone response to two levels of vitamin D deficiency is associated with high risk of medical problems during hospitalization in patients with hip fracture

BACKGROUND

Vitamin D and the parathyroid hormone (PTH) response play an important role in hip fracture patients. This study was carried out to determine the factors associated with the PTH response to different levels of vitamin D deficiency during hospitalization.

METHODS

This was a cross-sectional study of patients over 64 years of age admitted with an acute fragility hip fracture between March 1st 2009 and November 30th 2012. Demographic, clinical, functional, and cognitive function were evaluated at admission and during hospitalization. Levels of 25-hydroxyvitamin D (25-OHD) and PTH were analyzed. Two 25-OHD cut-off points were considered, <12 ng/ml and 12-20 ng/ml. Multivariate logistic regression analysis was used.

RESULTS

Mean age of the 607 patients included was 84.7 years (SD 7.10), and 81.9 % were women. The mean 25-OHD level in the total sample was 13.2 (SD 11.1) ng/ml. Levels of 25-OHD <12 ng/ml were present in 347 patients (57.2 %), of whom 158 (45.5 %) had secondary hyperparathyroidism (SHPT) (PTH >65 pg/ml). 25-OHD levels of 12-20 ng/ml were present in 168 (27.7 %) patients, of whom 47 (28 %) had SHPT. Following logistic regression, SHPT was associated in both groups (25-OHD <12 and 12-20 ng/ml) with a greater number of medical problems during hospitalization. In the 25-OHD group <12 ng/ml, SHPT was also associated with poorer glomerular filtration rates.

CONCLUSION

The PTH response to vitamin D deficiency in hip fracture patients may be a marker for patients with higher risk of developing multiple medical problems, both when considering severe (<12 ng/ml) and moderate (12-20 ng/ml) vitamin D deficiency.

Characteristics of hyperparathyroid states in the Canadian multicentre osteoporosis study (CaMos) and relationship to skeletal markers

CONTEXT

PTH is an essential regulator of mineral metabolism; PTH hypersecretion may result in hyperparathyroidism including normocalcaemic, primary and secondary hyperparathyroidism.

OBJECTIVE

To examine the characteristics of participants with hyperparathyroid states and the relationship to bone mineral density (BMD).

DESIGN AND PARTICIPANTS

A cross-sectional study of 1872 community-dwelling men and women aged 35+ years (mostly Caucasian) with available serum PTH from Year 10 Canadian Multicentre Osteoporosis Study follow-up (2005-07). PTH was determined using a second-generation chemiluminescence immunoassay.

OUTCOME MEASURES

L1-L4, femoral neck and total hip BMD.

RESULTS

We established a PTH reference range (2·7-10·2 pmol/l) based on healthy participants (i.e. normal serum calcium, serum 25-hydroxyvitamin D, kidney function and body mass index, who were nonusers of antiresorptives, glucocorticoids and diuretics and not diagnosed with diabetes or thyroid disease). Participants with PTH levels in the upper reference range (5·6-10·2 pmol/l), representing a prevalence of 10·7%, had lower femoral neck and total hip BMD, by 0·030 g/cm(2) [95% confidence interval: 0·009; 0·051] and 0·025 g/cm(2) (0·001; 0·049), respectively, than those with levels 2·7-5·6 pmol/l. Participants with normocalcaemic and secondary hyperparathyroidism also had lower total hip BMD than those with levels 2·7-5·6 pmol/l, and CaMos prevalences of normocalcaemic, primary and secondary hyperparathyroidism were 3·3%, 1·4% and 5·2%, respectively.

CONCLUSION

We found reduced BMD in participants with accepted hyperparathyroid states but also a notable proportion of other participants that might benefit from having lower PTH levels.

Parathyroid-hormone variance is only marginally explained by a panel of determinants: a cross-sectional study of 909 hip-fracture patients

Several factors affect the levels of parathyroid hormone (PTH) in hip-fracture patients. We hypothesized that a panel of easily assessable determinants could account for both a substantial proportion of PTH variance and the occurrence of secondary hyperparathyroidism. We evaluated 909 of 981 hip-fracture inpatients admitted consecutively to our Rehabilitation division. In each patient we assessed PTH, 25-hydroxyvitamin D, albumin-adjusted total calcium, phosphate, magnesium, and creatinine on a fasting blood sample 21.3 ± 6.1 (mean ± SD) days after fracture occurrence. Glomerular filtration rate (GFR) was estimated by the 4-variable Modification of Diet in Renal Disease Study equation. Functional level was assessed using the Barthel index. On multivariate analysis, six factors (phosphate, albumin-adjusted total calcium, estimated GFR (eGFR), 25-hydroxyvitamin D, age, and magnesium) were significantly associated with PTH levels. Overall, the panel of variables accounted for 23.7 % of PTH variance. Among the 909 patients, 304 (33.4 %) had PTH levels exceeding the normal range. Six factors (phosphate, albumin-adjusted total calcium, eGFR, 25-hydroxyvitamin D, age, and Barthel index scores) were significantly associated with the category of PTH level (either normal or elevated). The model correctly classified 70.4 % of cases. For the optimal cut-off point, sensitivity was 80 % and specificity was 61 %. Data shows that six factors were significantly associated with PTH levels in hip-fracture inpatients. However, the six factors accounted for only 23.7 % of PTH variance and the presence or absence of secondary hyperparathyroidism was correctly categorized in a modest proportion of cases. We conclude that more knowledge is needed on the factors affecting PTH levels after hip fracture.

Bone biomarkers in patients with chronic traumatic spinal cord injury

BACKGROUND CONTEXT

Bone loss after spinal cord injury (SCI) occurs because of pathologic changes in osteoblastic and osteoclastic activities due to mechanical unloading. Some biochemical changes in bone metabolism after SCI are described before that were related to bone mineral loss.

PURPOSE

Our purpose was to determine bone markers' changes and related effective factors in patients with chronic traumatic SCI.

STUDY DESIGN

This investigation was designed as an observational cross-sectional study.

PATIENT SAMPLE

All patients with chronic SCI who were referred to Brain and Spinal Injury Research Center and did not meet our exclusion criteria entered the study.

OUTCOME MEASURES

Self-reporting measures including patient's demographic features and date of accident were obtained using a questionnaire and physiologic measures including spinal magnetic resonance imaging to determine the level of injury accompanied with physical examination along with dual-energy X-ray absorptiometry were performed. Blood samples were analyzed in the laboratory.

METHODS

Dual-energy X-ray was used to determine bone mineral density in femoral and spinal vertebrae bone sites. Serum level of C-telopeptide cross-linked Type 1 collagen (CTX), parathyroid hormone, calcitonin, osteocalcin, and bone alkaline phosphatase (BALP) were measured.

RESULTS

We detected a negative association between CTX level and bone mineral density in femoral and spinal bone sites that confirms that CTX is a bone resorption marker. C-telopeptide cross-linked Type 1 collagen and BALP levels did not show any significant correlation with postduration injury. Patients with spinal injury at lumbar level had the highest calcitonin level (p<.04). C-telopeptide cross-linked Type 1 collagen was positively related with osteocalcin and BALP (p<.0001, r=0.51), and osteocalcin was positively related with BALP (p<.0001, r=0.44). Osteocalcin was related negatively only to femoral intertrochanteric zone bone mineral density.

CONCLUSIONS

Some bone biomarkers undergo noticeable changes after SCI. C-telopeptide cross-linked Type 1 collagen was positively correlated with BALP and osteocalcin that shows the coincidental occurrence of osteoblastic and osteoclastic activities. Our data also support this fact that although bone reduction after 2 years is slower than acute phase after SCI, bone resorption rate is higher than bone formation. These bone markers also revealed different site of action as osteocalcin level only affected femoral intertrochanteric bone mineral density. Generally, it seems that the coincidental consideration of these factors that influence bone mineral density can lead to a better understanding of bone changes after SCI.

Prevalence of vitamin D inadequacy in European women aged over 80 years

Inadequate vitamin D status is associated with secondary hyperparathyroidism and increased bone turnover and bone loss, which in turn increases fracture risk. The objective of this study is to assess the prevalence of inadequate vitamin D status in European women aged over 80 years. Assessments of serum 25-hydroxyvitamin D levels (25(OH)D) were performed on 8532 European women with osteoporosis or osteopenia of which 1984 were aged over 80 years. European countries included in the study were: France, Belgium, Denmark, Italy, Poland, Hungary, United Kingdom, Spain and Germany. Two cut-offs of 25(OH)D inadequacy were fixed: <75 nmol/L (30 ng/ml) and <50 nmol/L (20 ng/ml). Mean (SD) age of the patients was 83.4 (2.9) years, body mass index was 25.0 (4.0) kg/m(2) and level of 25(OH)D was 53.3 (26.7) nmol/L (21.4 [10.7] ng/ml). There was a highly significant difference of 25(OH)D level across European countries (p<0.0001). In these women aged over 80 years, the prevalence of 25(OH)D inadequacy was 80.9% and 44.5% when considering cut-offs of 75 and 50 nmol/L, respectively. In the 397 (20.0%) patients taking supplemental vitamin D with or without supplemental calcium, the mean serum 25(OH)D level was significantly higher than in the other patients (65.2 (29.2) nmol/L vs. 50.3 (25.2) nmol/L; P<0.001). This study indicates a high prevalence of vitamin D (25(OH)D) inadequacy in old European women. The prevalence could be even higher in some particular countries.

Vitamin D and PTH status among adolescent and young females with severe dysmenorrhea

OBJECTIVE

To investigate Vitamin D and parathyroid hormone (PTH) status among adolescent and young females with severe and very severe dysmenorrhea.

DESIGN

Cross-sectional study in specific selected sample.

SETTING

One Jordanian university.

PARTICIPANTS

Fifty-six females, ages between 17 and 24 years, with severe and very severe dysmenorrhea were surveyed regarding demographics, pain with menstruation, and dietary intake of dairy products. Plasma Vitamin D, PTH levels were measured.

RESULTS

About 61% of the studied population experience very severe dysmenorrhea. Half of participants had dairy intake less than 1 serving per day. The majority of participants (80%) had insufficient plasma vitamin D and 48% of them had hyperparathyroidism.

CONCLUSION

A high prevalence of vitamin D insufficiency and secondary hyperparathyroidism and/or low dietary calcium intake among adolescent and young adult females who experience severe and very severe dysmenorrhea may negatively affect bone metabolism during achievement of peak bone mass at a young age and adverse bone health at older age.

Serum free and bio-available 25-hydroxyvitamin D correlate better with bone density than serum total 25-hydroxyvitamin D

In the circulation 25-hydroxyvitamin D (25(OH)D) is bound to vitamin D-binding protein (DBP) and albumin. Only a small fraction is in the unbound, free form. According to the 'free-hormone-hypothesis' only the free form is biologically active. Genetic differences in DBP may affect the binding to 25(OH)D and thereby the amount of free 25(OH)D. In the present study sera were obtained from 265 postmenopausal women with low bone mass density (BMD). Serum 25(OH)D, DBP and albumin were measured and the free and bio-available (free + albumin-bound) 25(OH)D calculated. Based on genotyping of the polymorphisms rs7041 and rs4588, the six common DBP phenotypes were identified and the free and bio-available 25(OH)D calculated according to the corresponding binding coefficients. Relations between measures of 25(OH)D and PTH and BMD were evaluated with linear regression adjusted for age and BMI. The calculated amount of free and bio-available 25(OH)D was 0.03% and 13.1%, respectively, of the measured total serum 25(OH)D. Adjusting for DBP phenotype affected the calculated free and bio-available 25(OH)D levels up to 37.5%. All measures of 25(OH)D correlated significantly with PTH, whereas a significant association with BMD was only seen for the free and bio-available 25(OH)D measures. Adjusting for the DBP phenotypes improved the associations. These relations were almost exclusively seen in subjects not using vitamin D and/or calcium supplements. In conclusion, the free and bio-available forms of 25(OH)D may be a more informative measure of vitamin D status than total 25(OH)D. Adjustment for DBP phenotype may improve this further.

Estimated GFR and risk of hip fracture in older men: comparison of associations using cystatin C and creatinine

BACKGROUND

Higher serum cystatin C level is associated with an increased risk of hip fracture in postmenopausal white women, but there is a paucity of data for men. Whether estimated glomerular filtration rate (eGFR) based on cystatin C (eGFRcys) is superior in predicting hip fracture risk to eGFR based on creatinine (eGFRcr) or the combination (eGFR(cr-cys)) also is uncertain.

STUDY DESIGN

Nested case-cohort.

SETTING & PARTICIPANTS

Participants enrolled in the Osteoporotic Fractures in Men (MrOS) Study (5,994 men aged ≥ 65 years from 6 US centers) including a random subcohort of 1,602 men and 168 men with incident hip fractures (51 of whom were in the subcohort).

PREDICTOR

eGFR(cys), eGFR(cr), and eGFR(cr-cys) computed using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations and expressed in categories of <60, 60-74, and ≥ 75 mL/min/1.73 m(2) (referent group).

OUTCOME

Incident hip fracture ascertained by participant contacts every 4 months and confirmed with radiographic reports.

RESULTS

Median eGFR(cys) was 72.9 (IQR, 60.5-85.7) mL/min/1.73 m(2). In unadjusted models, all measures of eGFR were associated with increased hip fracture risk. However, after adjustment for age, race, site, and body mass index, the association of lower eGFR(cys) (but not lower eGFR(cr) or lower eGFR(cr-cys)) with higher hip fracture risk remained: for <60 versus ≥ 75 mL/min/1.73 m(2), HRs were 1.96 [95% CI, 1.25-3.09], 0.84 [95% CI, 0.52-1.37], and 1.08 [95% CI, 0.66-1.77] for eGFR(cys), eGFR(cr), and eGFR(cr-cys), respectively. Similarly, after adjustment for age, race, site, and body mass index, eGFR < 60 mL/min/1.73 m(2) defined by eGFR(cys), but not eGFR(cr) or eGFR(cr-cys), was associated with higher hip fracture risk. The association between eGFR(cys) and hip fracture was not explained by levels of calciotropic hormones or inflammatory markers, but the relationship was attenuated and no longer reached significance (for <60 vs ≥ 75 mL/min/1.73 m(2): HR, 1.43; 95% CI, 0.88-2.34) after consideration of additional clinical risk factors and bone mineral density.

LIMITATIONS

Findings not generalizable to other populations; residual confounding may exist.

CONCLUSIONS

Older community-dwelling men with lower eGFR(cys) have an increased risk of hip fracture that is explained in large part by greater burden of risk factors among men with lower eGFR(cys). In contrast, lower eGFR(cr) or lower eGFR(cr-cys) was not associated with a higher age-adjusted hip fracture risk.

Genetic analysis of recently identified osteoporosis susceptibility genes in southern Chinese

CONTEXT

Fifty-six genomic loci recently were identified as associated with bone mineral density (BMD) in a large meta-analysis study of mainly European-descent subjects. Circulating factors related to calcium and phosphate metabolism, eg, serum levels of calcium, phosphate, vitamin D metabolites, PTH, and alkaline phosphatase (ALP), may affect bone turnover and metabolism.

OBJECTIVE AND DESIGN

We aimed to investigate the effects of these reported variants, as well as their interactions with 5 studied circulating factors, on BMD in a southern Chinese prospective cohort (n = 2670). The identified interactions were further replicated in an independent cohort of 800 Chinese females.

RESULTS

Approximately half (n = 27) of the reported variants were successfully replicated in our sample of southern Chinese individuals. We further demonstrated a significant interaction between MARK3 and serum ALP levels (Pmeta = 9.89 ×10(-6)); the effect of MARK3 rs11623869 on BMD was stronger in the presence of high serum levels of ALP. In addition, several interactions between other genes and circulating factors were suggested.

CONCLUSIONS

Our study has provided an independent replication of associations between several reported loci and BMD in a large sample of southern Chinese individuals. These replicated loci may represent osteoporosis susceptibility genes in both Chinese and European-descent populations. Furthermore, we have shown that serum ALP levels modified the association of MARK3 with BMD. Understanding the mechanisms of the interactions between BMD-related loci and circulating factors may help to determine the pathogenesis of susceptibility to osteoporosis and could have implications for clinical care.

Additive association of vitamin D insufficiency and sarcopenia with low femoral bone mineral density in noninstitutionalized elderly population: the Korea National Health and Nutrition Examination Surveys 2009-2010

Vitamin D insufficiency and sarcopenia are crucial risk factors for osteoporosis. In a study of noninstitutionalized elderly subjects, we investigated the simultaneous effect of vitamin D and sarcopenia on bone mineral density (BMD) and found that sarcopenia was associated with low BMD in the femur, especially in those with suboptimal vitamin D levels.

INTRODUCTION

Although vitamin D insufficiency and sarcopenia are prevalent in the elderly population worldwide, their possible influence on BMD has not been determined. We aimed to investigate the different effect of vitamin D insufficiency and sarcopenia on BMD in the elderly Korean population.

METHODS

Individuals aged 60 or older were selected from those who participated in the Fourth and Fifth Korea National Health and Nutrition Examination Surveys conducted in 2009 and 2010; 1,596 males and 1,886 females were analyzed. Appendicular skeletal muscle mass (ASM) and BMD were assessed by dual-energy X-ray absorptiometry; serum 25-hydroxyvitamin D [25(OH)D] and a panel of clinical and laboratory parameters were also measured.

RESULTS

The study population was divided into four groups according to their vitamin D and sarcopenic status. BMD in total femur and in the femoral neck but not the lumbar spine was markedly decreased in sarcopenic subjects with vitamin D insufficiency [25(OH)D < 20 ng/ml] comparing to other groups, regardless of gender. Multivariable linear regression models showed that BMD was significantly associated with ASM and high daily calcium intake as well as conventional risk factors such as age, body mass index (BMI), and history of fracture. Independent predictors for low femur BMD included sarcopenia, low daily calcium intake, low 25(OH)D levels, age, and BMI.

CONCLUSIONS

These data showed that an association between vitamin D insufficiency and low BMD was more prominent in elderly subjects with sarcopenia.

High serum 25-hydroxyvitamin D levels do not retard postmenopausal bone loss in Japanese women: the Yokogoshi study

We conducted a cohort study exploring an association between serum 25-hydroxyvitamin D (serum 25(OH)D) and parathyroid hormone (PTH) levels and 5-year changes in bone mineral density (BMD) in 482 postmenopausal women. High serum 25(OH)D levels do not retard postmenopausal bone loss within the lumbar spine or femoral neck, and high PTH levels potentially increase hip bone loss.

PURPOSE

The aim of this study was to explore an association between serum 25(OH)D levels and 5-year changes in BMD in postmenopausal women.

METHODS

This 5-year cohort study included 482 women between 55 and 74 years of age who lived in a community in Japan. Medical examinations were conducted in 2005 and 2010. Data were obtained on baseline serum 25(OH)D and intact parathyroid hormone (iPTH) levels. Outcomes of this study were 5-year changes in BMDs of the lumbar spine and femoral neck. Covariates included years since menopause, body mass index (BMI), lifestyle factors, and weight change. Changes in BMDs among quartiles of serum 25(OH)D were compared with analysis of covariance.

RESULTS

The mean age of subjects was 63.1 years, and mean serum 25(OH)D levels were 56.0 nmol/L. Age and decrease in weight were significantly associated with decreases in BMDs of both the lumbar spine (P for trend < 0.001 and =0.002, respectively) and femoral neck (P for trend = 0.026 and <0.001, respectively); low BMI was associated with a decrease in lumbar spine BMD (P for trend < 0.001). No significant associations were found between serum 25(OH)D levels and changes in BMDs. High serum iPTH levels were associated with a greater decrease in femoral neck BMD (P for trend = 0.026).

CONCLUSIONS

High serum 25(OH)D levels do not retard postmenopausal bone loss within the lumbar spine or femoral neck, and high PTH levels potentially increase hip bone loss.

A systematic review of vitamin D status in populations worldwide

Vitamin D deficiency is associated with osteoporosis and is thought to increase the risk of cancer and CVD. Despite these numerous potential health effects, data on vitamin D status at the population level and within key subgroups are limited. The aims of the present study were to examine patterns of 25-hydroxyvitamin D (25(OH)D) levels worldwide and to assess differences by age, sex and region. In a systematic literature review using the Medline and EMBASE databases, we identified 195 studies conducted in forty-four countries involving more than 168 000 participants. Mean population-level 25(OH)D values varied considerably across the studies (range 4·9-136·2 nmol/l), with 37·3 % of the studies reporting mean values below 50 nmol/l. The highest 25(OH)D values were observed in North America. Although age-related differences were observed in the Asia/Pacific and Middle East/Africa regions, they were not observed elsewhere and sex-related differences were not observed in any region. Substantial heterogeneity between the studies precluded drawing conclusions on overall vitamin D status at the population level. Exploratory analyses, however, suggested that newborns and institutionalised elderly from several regions worldwide appeared to be at a generally higher risk of exhibiting lower 25(OH)D values. Substantial details on worldwide patterns of vitamin D status at the population level and within key subgroups are needed to inform public health policy development to reduce risk for potential health consequences of an inadequate vitamin D status.

Consumption of yogurts fortified in vitamin D and calcium reduces serum parathyroid hormone and markers of bone resorption: a double-blind randomized controlled trial in institutionalized elderly women

CONTEXT

Nutritional prevention of bone deterioration with fortified foods seems particularly suitable in institutionalized elderly women at risk of vitamin D deficiency, secondary hyperparathyroidism, increased bone resorption, and osteoporotic fracture.

OBJECTIVE

The objective was to evaluate whether fortification of yogurts with vitamin D and calcium exerts an additional lowering effect on serum PTH and bone resorption markers as compared with isocaloric and isoprotein dairy products in elderly women.

DESIGN

A randomized double-blind controlled-trial, 56-day intervention was conducted in institutionalized women (mean age 85.5 years) consuming 2 125-g servings of either vitamin D- and calcium-fortified yogurt (FY) at supplemental levels of 10 μg/d vitamin D₃ and 800 mg/d calcium or nonfortified control yogurt (CY) providing 280 mg/d calcium.

MAIN OUTCOMES

The endpoints were serum changes from baseline (day 0) to day 28 and day 56 in 25-hydroxyvitamin-D (25OHD), PTH, and bone resorption markers tartrate-resistant acid phosphatase isoform-5b (TRAP5b), the primary outcome, and carboxyl-terminal cross-linked telopeptide of type I collagen (CTX).

RESULTS

At day 56, serum 25OHD increased (mean ± SEM) by 25.3 ± 1.8 vs 5.2 ± 2.5 nmol/L in FY (n = 29) and CY (n = 27), respectively (P < .0001). The corresponding changes in PTH were -28.6% ± 7.2% vs -8.0% ± 4.3% (P = .0003); in TRAP5b, -21.9% ± 4.3% vs 3.0% ± 3.2% (P < .0001); and in CTX, -11.0% ± 9.7% vs -3.0% ± 4.1% (P = .0146), in FY and CY, respectively. At day 28, these differences were less pronounced but already significant for 25OHD, PTH, and TRAP5b.

CONCLUSIONS

This study in institutionalized elderly at high risk for osteoporotic fracture suggests that fortification of dairy products with vitamin D₃ and calcium provides a greater prevention of accelerated bone resorption as compared with nonfortified equivalent foods.

Calcium and vitamin D intake by postmenopausal women with osteoporosis in Spain: an observational calcium and vitamin D intake (CaVIT) study

Background

Osteoporotic fractures are important causes of morbidity, mortality, and increased health care costs. However, the risk of osteoporotic fractures can be decreased, with clinical studies supporting the use of calcium and vitamin D supplements to promote bone health. Vitamin D insufficiency is widespread, particularly among postmenopausal women with osteoporosis, and this indicates that dietary intake is suboptimal, even though vitamin D supplements are widely available.

Methods

We conducted an observational study, using telephone surveys, to estimate vitamin D and calcium intake and the use of prescription osteoporosis medications in Spanish women aged ≥ 50 years with osteoporosis.

Results

Among the study participants, mean dietary calcium intake was 1239 mg/day and generally appeared sufficient in terms of the recommended daily intake guidance documents. Participants aged ≥ 75 years had a significantly lower mean dietary calcium intake (988 mg/day), thus one-half were below the level advised by the World Health Organization. Daily calcium intake was also lower in participants who were not taking prescription medications for bone health. Dietary vitamin D intake was 167 IU/day, which is well below both the established target dose (400 IU/day) and the more recent, higher guideline recommended for postmenopausal women (800–1300 IU/day). Dietary vitamin D intake was even lower for participants aged ≥ 75 years (120 IU/day) and was not related to the use of bone health prescription medications.

Conclusion

These results support the need for greater promotion of the benefits of higher vitamin D intake in Spanish women with osteoporosis.

Cystatin C and risk of hip fractures in older women

To test the hypothesis that older women with higher cystatin C are at increased risk of hip fracture independent of traditional risk factors including hip bone mineral density (BMD), we performed a case-cohort analysis nested in a cohort of 4709 white women attending a Year 10 (1997-1998) examination of the Study of Osteoporotic Fractures that included a random sample of 1170 women and the first 300 women with incident hip fracture occurring after Year 10 examination. Serum cystatin C and creatinine were measured in Year 10 sera. In a model adjusted for age, clinical site, body mass index, and total hip BMD, higher cystatin C was associated with an increased risk of hip fracture (p for linear trend 0.008) with women in quartile 4 having a 1.9-fold higher risk (hazard ratio [HR] 1.91; 95% confidence interval [CI], 1.24-2.95) compared with those in quartile 1 (referent group). Further adjustment for additional risk factors only slightly attenuated the association; the risk for hip fracture was 1.7-fold higher (HR 1.74; 95% CI, 1.11-2.72) in women in quartile 4 compared with those in quartile 1. In contrast, neither serum creatinine nor creatinine-based estimated glomerular filtration rate (eGFRCr ) were associated with risk of hip fracture. Older women with higher cystatin C, but not higher serum creatinine or lower eGFRCr , have an increased risk of hip fracture independent of traditional risk factors. These findings suggest that cystatin C may be a promising biomarker for identification of older adults at high risk of hip fracture.

Impact of hepatitis C virus infection on bone mineral density in renal transplant recipients

BACKGROUND

The average prevalence of hepatitis C virus (HCV) infection in renal transplant recipients is 10%. Studies of these patients with HCV infection usually focuses on long-term graft survival and patient survival. Studies of the correlation between HCV infection and bone mineral density (BMD) in renal transplant patients are limited. The aim of this study was to investigate whether HCV infection is a risk factor for BMD change during a short follow-up period.

METHODS

Seventy-six renal transplant recipients underwent 2 separate dual-energy X-ray absorptiometry (DXA) scans during a mean period of 14 months. Fifteen patients were HCV infection. First bone mineral density (BMD) at the lumbar spine, hip, and femoral neck was determined using dual-energy X-ray absorptiometry (DXA) between September 2008 and March 2009. After that, 34 patients took alendronate sodium 70 mg per week. Subgroups risk factors analysis was also performed into with or without alendronate. Immunosuppressive agents, bisphosphonates, patient characteristics, and biochemical factors were analyzed to identify associations with BMD.

RESULTS

After 14 months, in 76 patients, BMD of the lumbar spine had significantly increased (from 0.9 g/cm² to 0.92 g/cm², p<0.001), whereas BMD of the hip and femoral neck had not. Multiple linear regression analysis showed that HCV infection was negatively associated with BMD change in the lumbar spine ( β: -0.247, 95% CI, -0.035 to -0.002; p = 0.028). Moreover, in subgroup analysis, among 42 patients without alendronate, multiple linear regression analysis showed HCV infection was a risk factor for adverse BMD change of the lumbar spine ( β: -0.371, 95% CI, -0.043 to -0.003; p = 0.023).

CONCLUSION

HCV infection in renal transplant recipients was a negative risk factor for BMD change in the lumbar spine. Moreover, alendronate may be able to reverse the negative effect of HCV infection on bone in renal transplant recipients.

Association of vitamin D status with socio-demographic factors in Calgary, Alberta: an ecological study using Census Canada data

BACKGROUND

Low 25-hydroxyvitamin D levels are a global health problem with northern countries such as Canada at particular risk. A number of sociodemographic factors have been reported to be associated with low vitamin D levels but prior studies have been limited by the ability of the researchers to gather this data directly from clinical trial participants. The purpose of this study was to use a novel methodology of inferring sociodemographic variables to evaluate the correlates of vitamin D levels in individuals dwelling in the City of Calgary, Alberta, Canada.

METHODS

We utilized data on vitamin D test results from Calgary Laboratory Services between January 1 2010 and August 31 2011. In addition to vitamin D level, we recorded age, sex, and vitamin D testing month as individual-level variables. We inferred sociodemographic variables by associating results with census dissemination areas and using Census Canada data to determine immigration status, education, median household income and first nations status as clustered variables. Associations between vitamin D status and the individual- and dissemination area-specific variables were examined using the population-averaged regression model by a generalized estimating equations approach to account for the clustering in the data.

RESULTS

158,327 individuals were included. Age, sex, month of vitamin D testing (at an individual level), and education, immigrant status, first nations status and income (at an aggregate level) were all statistically significant predictors of vitamin D status.

CONCLUSIONS

Vitamin D status was associated with a number of sociodemographic variables. Knowledge of these variables may improve targeted education and public health initiatives.

Association between serum 25-hydroxyvitamin d levels, bone geometry, and bone mineral density in healthy older adults

PURPOSE

The association between serum 25-hydroxyvitamin D values and cortical/trabecular bone parameters in older adults has been incompletely explored. This study was designed to investigate the relationship between serum 25-hydroxyvitamin D levels and bone parameters for the tibia and radius using peripheral quantitative computed tomography in free-living healthy older adults.

METHODS

The study involved 134 older adults attending a twice-weekly low-intensity fitness program. In addition to clinical history and serum parameters, we assessed fat-free mass using dual-energy X-ray absorptiometry, total bone and cortical bone cross-sectional areas, and trabecular and cortical bone mineral density for the tibia and radius by peripheral quantitative computed tomography.

RESULTS

After applying multivariate linear regression models, adjusting for sex, age, body mass index, fat mass and fat-free mass, and creatinine, the association between 25-hydroxyvitamin D and bone parameters was significant for total bone and cortical bone cross-sectional areas in the radius (partial R (2) = 0.05 and 0.09, respectively) and for trabecular bone mineral density and cortical bone cross-sectional area in the tibia (partial R (2) = 0.11 and 0.02, respectively).

CONCLUSION

These findings support the idea that serum 25-hydroxyvitamin D levels and bone parameters are linked in older adults. Longitudinal studies are needed to establish whether vitamin D levels over time are associated with changes in these parameters.

Cardiovascular diseases in older patients with osteoporotic hip fracture: prevalence, disturbances in mineral and bone metabolism, and bidirectional links

BACKGROUND

Considerable controversy exists regarding the contribution of mineral/bone metabolism abnormalities to the association between cardiovascular diseases (CVDs) and osteoporotic fractures.

AIMS AND METHODS

To determine the relationships between mineral/bone metabolism biomarkers and CVD in 746 older patients with hip fracture, clinical data were recorded and serum concentrations of parathyroid hormone (PTH), 25-hydroxyvitamin D, calcium, phosphate, magnesium, troponin I, parameters of bone turnover, and renal, liver, and thyroid functions were measured.

RESULTS

CVDs were diagnosed in 472 (63.3%) patients. Vitamin D deficiency was similarly prevalent in patients with (78.0%) and without (82.1%) CVD. The CVD group had significantly higher mean PTH concentrations (7.6 vs 6.0 pmol/L, P < 0.001), a higher prevalence of secondary hyperparathyroidism (SPTH) (PTH > 6.8 pmol/L, 43.0% vs 23.3%, P < 0.001), and excess bone resorption (urinary deoxypyridinoline corrected by creatinine [DPD/Cr] > 7.5 nmol/μmol, 87.9% vs 74.8%, P < 0.001). In multivariate regression analysis, SHPT (odds ratio [OR] 2.6, P = 0.007) and high DPD/Cr (OR 2.8, P = 0.016) were independent indictors of CVD. Compared to those with both PTH and DPD/Cr in the normal range, multivariate-adjusted ORs for the presence of CVD were 17.3 (P = 0.004) in subjects with SHPT and 9.7 (P < 0.001) in patients with high DPD/Cr. CVD was an independent predicator of SHPT (OR 2.8, P = 0.007) and excess DPD/Cr (OR 2.5, P = 0.031). CVD was predictive of postoperative myocardial injury, while SHPT was also an independent predictor of prolonged hospital stay and in-hospital death.

CONCLUSION

SHPT and excess bone resorption are independent pathophysiological mediators underlying the bidirectional associations between CVD and hip fracture, and therefore are important diagnostic and therapeutic targets.

Calcium homeostasis influences radiological fracture healing in postmenopausal women

INTRODUCTION

Recent studies suggest that calcium and 25-[OH]-cholecalciferol represent substantial co-factors in fracture healing. However, there still seems to be no sustainable consensus regarding the influence on fracture healing patterns. In this study, the influence of calcium and vitamin D levels on fracture callus formation was prospectively analysed using pQCT scan.

METHODS

94 postmenopausal females with distal radius fractures and consecutive surgery were included. Calcium, 25-[OH]-cholecalciferol, parathyroid hormone and bone-specific alkaline phosphatase levels were obtained prior surgical treatment and after 6 weeks. A pQCT scan was performed on both sites. Bone mineral density and fracture callus area were determined after detecting the outer border contour at a threshold of 280 mg/ccm. Patients received daily supplements of 1000 mg calcium and 880 IU 25-[OH]-cholecalciferol.

RESULTS

Mean 25-[OH]-cholecalciferol level was 19.61 ± 21.87 ng/ml, mean parathyroid hormone level was 52.6 ± 58.9 ng/l and mean Ca level was 2.23 ± 0.35 mmol/l. After 6 weeks of supplementation a significant increase of calcium (p < 0.001) and 25-[OH]-cholecalciferol (p < 0.001), and a significant decrease of parathyroid hormone (p < 0.001) levels were observed. Sixth week follow-up fracture callus area correlated significantly with postoperative normal range calcium levels on the fractured site (p = 0.006). Bone mineral density correlated with age (p < 0.001), but not with calcium and 25-[OH]-cholecalciferol levels after 6 weeks. All fractures presented timely adequate callus formation.

CONCLUSION

Calcium and parathyroid hormone serum levels influence fracture callus area interpreted as fracture callus formation patterns. Calcium levels within physiological range accounted for highest fracture callus area. Therefore, a balanced calcium homeostasis is required for appropriate callus formation.

Parathyroid hormone response to severe vitamin D deficiency is sex associated: an observational study of 571 hip fracture inpatients

OBJECTIVES

To investigate the association between sex and parathyroid hormone response to severe vitamin D deficiency after hip fracture.

DESIGN

Cross-sectional study.

SETTING

Rehabilitation hospital in Italy.

PARTICIPANTS

571 consecutive inpatients with hip fracture and severe vitamin D deficiency (serum 25-hydroxyvitamin D < 12ng/ml), without hypercalcemia or estimated glomerular filtration rate (GFR) < 15ml/min.

MEASUREMENTS

In each patient we assessed PTH (by two-site chemiluminescent enzyme-labelled immunometric assay), 25-hydroxyvitamin D (by immunoenzymatic assay), albumin-adjusted total calcium, phosphate, magnesium, and creatinine 21.3 ± 6.1 (mean ± SD) days after fracture occurrence. Functional level was assessed using the Barthel index. PTH response to vitamin D deficiency was classified as either secondary hyperparathyroidism (serum PTH >75pg/ml) or functional hypoparathyroidism, i.e., inappropriate normal levels of PTH (≤75pg/ml).

RESULTS

Among the 571 patients, 336 (59%) had functional hypoparathyroidism, whereas 235 (41%) had secondary hyperparathyroidism. PTH status was significantly different between sexes (p=0.003): we found functional hypoparathyroidism in 61% of women and 43% of men (secondary hyperparathyroidism in 39% of women and 57% of men). The significance of the between-sex difference was maintained after adjustment for age, estimated GFR, phosphate, albumin-adjusted total calcium, albumin, Barthel index scores, 25-hydroxyvitamin D, and hip fracture type (either cervical or trochanteric). The adjusted odds ratio was 1.85 (95%CI from 1.09 to 3.13; p=0.023).

CONCLUSIONS

Data shows that PTH response to vitamin D deficiency was sex-associated following a fracture of the hip. The higher prevalence of secondary hyperparathyroidism may play a role in the known prognostic disadvantage found in hip-fracture men.

The impact of secondary hyperparathyroidism on the efficacy of antiresorptive therapy

BACKGROUND

The aim of the present study was to assess whether the efficacy of bisphosphonate treatment is influenced by PTH levels measured in newly diagnosed osteoporotic patients and to identify the threshold value, beyond which PTH level negatively influences therapeutic efficacy.

METHODS

One hundred and thirty-eight osteoporotic patients were enrolled into the study. All subjects underwent laboratory screening, bone densitometry with DEXA, and x-ray imaging. The changes in bone density were evaluated after a mean follow-up period of 13.37 ± 1.29 months. Correlation analysis was performed on the clinical data of patients, the percentage changes of BMD values, and the PTH levels measured at the beginning of study, using SPSS software.

RESULTS

The mean age of the subjects was 64.82 ± 10.51 years, and the female-to-male ratio was 116/22. Baseline BMD value measured with AP DEXA scanning was 0.854 ± 0.108 g/cm(2) in the L(1-4) vertebrae and 0.768 ± 0.115 g/cm(2) in the left femoral neck. By the end of the follow-up period, these values changed to 0.890 ± 0.111 g/cm(2) and 0.773 ± 0.111 g/cm(2), respectively. We found a statistically significant, negative correlation between PTH levels and the percentage changes of lumbar BMD values measured at the end of the follow-up (correlation coefficient R(2) = 0.121, p < 0.0001). The analysis of frequency histograms suggested that negative effects on bone might be expected above a PTH level of 60 pg/mL (7.3 pmol/L).

CONCLUSION

Our findings imply that a baseline PTH level over 60 ng/mL can reduce the efficacy of bisphosphonate treatment.

Kidney function and progression of coronary artery calcium in community-dwelling older adults (from the Rancho Bernardo Study)

Longitudinal studies of the association of estimated glomerular filtration rate (eGFR) and albuminuria with coronary artery calcium (CAC), a measure of cardiovascular disease burden, are few and contradictory. In this study, 421 community-dwelling men and women (mean age 67 years) without known heart disease had eGFRs assessed using the Modification of Diet in Renal Disease (MDRD) equation and albuminuria assessed by urine albumin/creatinine ratio (ACR) from 1997 to 1999. The mean eGFR was 78 ml/min/1.73 m(2), and the median ACR was 10 mg/g. CAC was measured using electron-beam computed tomography from 2000 to 2001, when the median total Agatston CAC score was 77; 4.5 years later, 338 participants still without heart disease underwent repeat scans (median CAC score 112); 46% of participants showed CAC progression, defined as an increase ≥2.5 mm(3) in square root-transformed CAC volume score. Cross-sectional and longitudinal logistic regression analyses showed no separate or joint association between eGFR or ACR and CAC severity or progression. In conclusion, this study does not support the use of eGFR or ACR to identify asymptomatic older adults who should be screened for subclinical cardiovascular disease with initial or sequential scanning for CAC. In the elderly, kidney function and CAC may not progress together.

A global representation of vitamin D status in healthy populations

PURPOSE

This paper visualizes the available data on vitamin D status on a global map, examines the existing heterogeneities in vitamin D status and identifies research gaps.

METHODS

A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011. Studies were eligible if they included samples of randomly selected males and females from the general population and assessed circulating 25-hydroxyvitamin D [25(OH)D] levels. Two different age categories were selected: children and adolescents (1-18 years) and adults (>18 years). Studies were chosen to represent a country based on a hierarchical set of criteria.

RESULTS

In total, 200 studies from 46 countries met the inclusion criteria, most coming from Europe. Forty-two of these studies (21 %) were classified as representative. In children, gaps in data were identified in large parts of Africa, Central and South America, Europe, and most of the Asia/Pacific region. In adults, there was lack of information in Central America, much of South America and Africa. Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L.

CONCLUSIONS

This study provides an overview of 25(OH)D levels around the globe. It reveals large gaps in information in children and adolescents and smaller but important gaps in adults. In view of the importance of vitamin D to musculoskeletal growth, development, and preservation, and of its potential importance in other tissues, we strongly encourage new research to clearly define 25(OH)D status around the world.

Secondary hyperparathyroidism and mortality in hip fracture patients compared to a control group from general practice

INTRODUCTION

Previously, little attention has been paid as to how disturbances in the parathyroid hormone (PTH)-calcium-vitamin D-axis, such as secondary hyperparathyroidism (SHPT), relate to mortality amongst hip fracture patients. This study aimed to (1) determine if SHPT is associated with mortality in this group of patients, (2) investigate the association between serum (s-) PTH, s-total calcium, s-25-hydroxyvitamin D (s-25(OH)D) and mortality and (3) determine the prevalence of SHPT amongst hip fracture patients and a control group.

METHOD

The study included 562 hip fracture patients (HF) (age ≥ 70 years) admitted to a Danish university hospital. The hip fracture patients were prospectively enrolled in a dedicated hip fracture database. Each hip fracture patient was exactly matched according to age and sex with two controls randomly chosen from a control population of 21,778 subjects who had s-PTH, s-total calcium and s-25(OH)D measured at the Copenhagen General Practitioners Laboratory after referral from their general practitioner. The control group (Con) thus consisted of 1124 subjects.

RESULTS

General 1-year mortality: Con-female 8.4%, Con-male 15.3%, HF-female 24.6%, HF-male 33.3%, p<0.0001 (log rank). SHPT AND RELATED 1-YEAR MORTALITY: Con-no SHPT 8.9%, Con-SHPT 16.8%, HF-no SHPT 22.7%, HF-SHPT 34.9%, p<0.0001 (log rank). The mortality rates were higher for controls with SHPT (OR 2.06, 95% CI: 1.32-3.23), hip fracture patients without SHPT (OR 3.00, 95% CI: 2.14-4.20) and hip fracture patients with SHPT (OR 5.46, 95% CI: 3.32-8.97) compared to the controls without SHPT. PREVALENCE OF SHPT: Con 16%, HF 20%, p=0.09 (Chi-square).

CONCLUSIONS

Our study clearly shows that SHPT is significantly associated with mortality in both hip fracture patients and the control group. In the multivariate Cox regression analysis, s-PTH and s-total calcium were both significantly associated with mortality, whereas s-25(OH)D was not associated with mortality in this analysis. Our study furthermore indicates that SHPT is almost equally prevalent amongst the hip fracture patients and the control group.

Relationship between vitamin D, parathyroid hormone, and bone mineral density in elderly Koreans

There is controversy regarding definition of vitamin D inadequacy. We analyzed threshold 25-hydroxyvitamin D (25[OH]D) below which intact parathyroid hormone (iPTH) increases, and examined age- and sex-specific changes of 25(OH)D and iPTH, and association of 25(OH)D and iPTH with bone mineral density (BMD) in elderly Koreans. Anthropometric parameters, serum 25(OH)D and iPTH, lumbar spine and femur BMD by dual-energy radiography absorptiometry (DXA) were measured in 441 men and 598 postmenopausal women. iPTH increased below serum 25(OH) of 36.7 ng/mL in men, but failed to reach plateau in women. Femur neck BMD above and below threshold differed when threshold 25(OH)D concentrations were set at 15-27.5 ng/mL in men, and 12.5-20 ng/mL in postmenopausal women. Vitamin D-inadequate individuals older than 75 yr had higher iPTH than those aged ≤ 65 yr. In winter, age-associated iPTH increase in women was steeper than in summer. In conclusion, vitamin D inadequacy threshold cannot be estimated based on iPTH alone, and but other factors concerning bone health should also be considered. Older people seemingly need higher 25(OH)D levels to offset age-associated hyperparathyroidism. Elderly vitamin D-inadequate women in the winter are most vulnerable to age-associated hyperparathyroidism.

The levels of bone turnover markers in Chinese postmenopausal women: Peking Vertebral Fracture study

OBJECTIVE

The aim of this study was to evaluate serum N-aminoterminal propeptide of type I collagen (P1NP), C-terminal telopeptide of type I collagen (β-CTX), and vitamin D status in healthy Chinese postmenopausal women. The study was also designed to investigate their possible relationships with osteoporosis phenotypes.

METHODS

A community-based population of 1,724 postmenopausal women in Beijing was randomly selected. Serum bone turnover markers and 25-hydroxyvitamin D [25(OH)D] were tested by an automated Roche electrochemiluminescence system. Dual-energy x-ray absorptiometry was used to measure bone mineral density (BMD).

RESULTS

The mean (SD) values of serum β-CTX and P1NP were 0.439 (0.210) and 56.7 (27.9) ng/mL, respectively. The 25(OH)D level of postmenopausal women in Beijing was remarkably low (13.2 ± 5.4 ng/mL). Serum β-CTX and P1NP levels were negatively correlated with BMDs of lumbar spine, femoral neck, and total hip (all P < 0.01). The cubic regression model better fitted the relationships of BMD and bone turnover markers. Serum β-CTX levels were significantly higher in women with sustained osteoporotic fracture or vertebral fracture (P = 0.006 and 0.012, respectively). No association between P1NP and fracture or vertebral fracture was detected. The same situation applied to 25(OH)D. 25(OH)D was negatively correlated with β-CTX and P1NP (r = -0.073 and -0.088, P = 0.002 and <0.001, respectively).

CONCLUSIONS

Serum β-CTX and P1NP levels were negatively correlated with BMD. β-CTX was significantly higher in postmenopausal women with sustained fracture or vertebral fracture. Vitamin D deficiency was highly prevalent in postmenopausal women in Beijing.

Peak bone mineral density and its determinants in an Asian Indian population

Data on peak bone mineral density (BMD) and its determinants in Asian Indians are limited. We studied the peak BMD and its determinants in Asian Indians. A total of 1137 young (age: 25--35yr) healthy volunteers of either sex (558 men and 579 women) were recruited for dietary evaluation, analyses of serum calcium, inorganic phosphorus, alkaline phosphatase, 25-hydroxyvitamin D [25(OH)D], and intact parathyroid hormone (iPTH) levels, and measurement of BMD with dual-energy X-ray absorptiometry. In men and women, peak bone mass (PBM) at the femoral neck, femoral trochanter, total femur, and lumbar spine was achieved between 25 and 30yr of age, whereas PBM at the femoral intertrochanter occurred between 30 and 35yr of age. Peak BMD was lower than that of Caucasians by 15.2--21.1% in men and 14.4--20.6% in women. On stepwise multiple regression, height and weight were the most consistent predictors of BMD at all sites in both groups. In men, 25(OH)D positively predicted BMD at the hip, whereas in women, serum iPTH negatively predicted BMD at the femoral trochanter and total femur. The study concluded that Asian Indians have significantly lower peak BMD than Caucasians and that weight and height are the most consistent predictors of BMD at all sites in both men and women.