Variation in lumbar spine bone mineral content by age and gender in apparently healthy Indians

A statistical lumbar spine geometry model accounting for variations by Age, Sex, Stature, and body mass index

The objective of this study was to develop a statistical lumbar spine geometry model accounting for morphological variations among the adult population. Five lumber vertebrae and lumber spine curvature were collected from CT scans of 82 adult subjects through CT segmentation, landmark identification, and template mesh mapping. Generalized Procrustes Analysis (GPA), Principal Component Analysis (PCA), and multivariate regression analysis were conducted to develop the statistical lumbar spine model. Two statistical models were established to predict the vertebrae geometry and lumbar curvature respectively. Using the statistical models, a lumbar spine finite element (FE) model could be rapidly generated with a given set of age, sex, stature, and body mass index (BMI). The results showed that the lumbar spine vertebral size was significantly affected by stature, sex and age, and the lumbar spine curvature was significantly affected by stature and age. This statistical lumbar spine model could serve as the geometric basis for quantifying effects of human characteristics on lumbar spine injury risks in impact conditions.

Influence of bone mineral density measurement on fracture risk assessment tool® scores in postmenopausal Indian women

AIM

Fracture risk assessment tool® calculations can be performed with or without addition of bone mineral density; however, the impact of this addition on fracture risk assessment tool® scores has not been studied in Indian women. Given the limited availability and high cost of bone mineral density testing in India, it is important to know the influence of bone mineral density on fracture risk assessment tool® scores in Indian women. Therefore, our aim was to assess the contribution of bone mineral density in fracture risk assessment tool® outcome in Indian women.

METHODS

Apparently healthy postmenopausal Indian women (n = 506), aged 40-72 years, without clinical risk factors for bone disease, were retrospectively selected, and their fracture risk assessment tool® scores calculated with and without bone mineral density were compared.

RESULTS

Based on WHO criteria, 30% women were osteoporotic, 42.9% were osteopenic and 27.1% had normal bone mineral density. Fracture risk assessment tool® scores for risk of both major osteoporotic fracture and hip fracture significantly increased on including bone mineral density (P < 0.0001). When criteria of National Osteoporosis Foundation, US was applied number of participants eligible for medical therapy increased upon inclusion of bone mineral density, (for major osteoporotic fracture risk number of women eligible without bone mineral density was 0 and with bone mineral density was 1, P > 0.05, whereas, for hip fracture risk number of women eligible without bone mineral density was 2 and with bone mineral density was 17, P < 0.0001).

CONCLUSION

Until the establishment of country-specific medication intervention thresholds, bone mineral density should be included while calculating fracture risk assessment tool® scores in Indian women.

Influence of Vitamin D Receptor Gene Fok1 Polymorphism on Bone Mass Accrual Post Calcium and Vitamin D Supplementation

OBJECTIVE

To examine the association of vitamin D receptor (VDR) gene polymorphisms of the Fok1 locus on bone mass accrual in Indian girls used to a low calcium intake.

METHODS

An intervention trial was undertaken in 102 girls aged 8-16 y, attending a state run school in Pune city, India. All girls received 500 mg calcium daily and 30,000 IU of vitamin D3 quarterly for one year. Dietary calcium intake was evaluated. Bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were measured at total body using Dual Energy X-ray Absorptiometry (Lunar DPX-PRO). Polymorphisms of the Fok1 locus of the vitamin D Receptor (VDR) gene were detected using SYBR Green quantitative polymerase chain reaction.

RESULTS

The prevalence of Fok1 polymorphism was 43.1% (Ff), 9.8% (ff) and 47.1% (FF). At baseline, FF genotype had significantly lower BMD as compared to ff and Ff genotype (p < 0.05). At baseline, majority of girls (82.4%) were hypocalcemic with low calcium intake. Post-supplementation, FF genotype had significantly lower bone mass as compared to ff and Ff genotype. Significant increase in BMC [Ff (17.9%); ff (18.1%); FF (17.4%)], and BMD [Ff (5.4 %); ff (6.3%); FF (4.8%)] was observed post supplementation (p value < 0.05), though percentage increase in BMC and BMD was similar for three Fok1 polymorphisms (p > 0.1).

CONCLUSIONS

VDR gene polymorphism, as defined by Fok1 genotype had no positive influence on bone mass accrual in response to calcium supplementation.

IGFALS gene dosage effects on serum IGF-I and glucose metabolism, body composition, bone growth in length and width, and the pharmacokinetics of recombinant human IGF-I administration

CONTEXT

Acid labile subunit (ALS) deficiency, caused by IGFALS mutations, is a subtype of primary IGF-I deficiency (PIGFD) and has been associated with insulin resistance (IR) and osteopenia. Whether patients respond to recombinant human IGF-I (rhIGF-I) is unknown.

OBJECTIVE AND DESIGN

This study determined the 14-hour pharmacokinetic response of free and total IGF-I and IGF binding protein 3 (IGFBP-3) to a single sc dose of rhIGF-I (120 μg/kg) in four ALS-deficient patients, compared with severe PIGFD, moderate PIGFD, and controls. Intravenous glucose tolerance tests, fasting blood levels, dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, and metacarpal radiogrammetry were performed in the four patients and 12 heterozygous family members.

RESULTS

IGF-I and IGFBP-3 increased above baseline (P < .05) for 2.5 hours, returning to baseline 7 hours after rhIGF-I injection. Mean (SD) IGF-I Z-score increased by 2.49 (0.90), whereas IGFBP-3 Z-score increased by 0.57 (0.10) only. IGF-I elimination rates in ALS deficiency were similar, but the IGF-I increment was lower than those for severe PIGFD. Significant gene dosage effects were found for all IGF-I peptides, height, forearm muscle size, and metacarpal width. Bone analysis showed that ALS deficiency creates a phenotype of slender bones with normal size-corrected density. Abnormal glucose handling and IR was found in three of four patients and 6 of 12 carriers.

CONCLUSIONS

These gene dosage effects demonstrate that one functional IGFALS allele is insufficient to maintain normal ALS levels, endocrine IGF-I action, full growth potential, muscle size, and periosteal expansion. Similar gene dosage effects may exist for parameters of IR. Despite similar IGF-I elimination compared with severe PIGFD, ALS-deficient patients cannot mount a similar response. Alternative ways of rhIGF-I administration should be sought.

Vitamin D receptor gene polymorphisms and bone mass indices in post-menarchal Indian adolescent girls

To study the association between vitamin D receptor (VDR) gene polymorphisms and bone mass indices in adolescent girls, a cross-sectional study was conducted in 120 post-menarchal girls aged 15-18 years in Pune city, India. Serum levels of ionised calcium, inorganic phosphorous, parathyroid hormone and 25-hydroxy vitamin-D were measured. Bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were measured at total body (TB), lumbar spine (LS) and left femoral neck (FN) using dual energy X-ray absorptiometry. Polymorphisms of the VDR gene at the Fok1 and Bsm1 loci were detected using SYBR Green quantitative polymerase chain reaction. The overall distribution of genotypes at the Bsm1 locus in this study was 33.3 % Bb, 29.2 % bb and 37.5 % BB while that for the Fok1 locus was 44.2 % Ff, 7.5 % ff and 48.3 % FF. There were no significant differences in the blood parameters when classified according to Bsm1 or Fok1 genotypes. Subjects with BB genotype have significantly higher mean TBBMC, TBBA, TBBMD and LSBMD than Bb and bb (p < 0.05) and showed a tendency for association with LSBMC and LSBA (p < 0.1). Subjects with Ff genotype showed a tendency for association with left FNBMC and FNBA (p < 0.1). Bsm1 genotype did not show an association with FN bone indices whereas Fok1 genotype did not show association with TB or LS bone indices. In conclusion, the present study demonstrates VDR gene polymorphism, defined by Bsm1 genotype, has an influence on total body and lumbar spine bone mass indices in post-menarchal Indian girls.

Role of B₁₂ and homocysteine status in determining BMD and bone turnover in young Indians

Vitamin B(12) (B(12)) deficiency and hyperhomocysteinemia (HHcy) are independent risk factors for low bone mineral density (BMD) and fracture risk. We studied the role of HHcy and B(12) deficiency in determining the peak bone mass in Indians. Randomly selected 151 healthy young adult subjects (females 100, mean age: 26 yr) underwent evaluation of dietary intake of calcium and B(12); sun exposure; estimation of BMD by dual-energy X-ray absorptiometry at total hip, forearm, and lumbar spine; serum 25(OH)D(3); intact parathyroid hormone; B(12); homocysteine (Hcy); and bone turnover markers (BTMs) serum crosslaps, N-mid osteocalcin, and bone-specific alkaline phosphatase. Hypovitaminosis D (serum 25OHD(3)<20 ng/mL) and serum ALP level >150 IU/L were seen in 83% and 27%, respectively. Median serum B(12) and Hcy levels were 140 pg/mL (interquartile range [IQR]: 72-230 pg/mL) and 18 μmol/L (IQR 14-32 μmol/L); B(12) deficiency (serum B(12)<200 pg/mL) and HHcy (serum Hcy>30 μmol/L) were present in 71% and 68%, respectively. Low BMD (Z-score <-2.0) was present in 17% of subjects. There was no significant correlation between serum Hcy, folate, B(12), BTM, and BMD. BMD was predicted by height, weight, and body mass index. Young Indian healthy adults have high prevalence of hypovitaminosis D, B(12) deficiency, and HHcy. There is no correlation of serum B(12), folate, and Hcy status with BTMs and BMD in young, healthy, vegetarian Indian adults. Anthropometric variables predict BMD in young Indians.

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.

Importance of bone mineral density measurements in evaluating fragility bone fracture risk in Asian Indian men

We evaluated the effect of BMD on fracture risk prediction using FRAX® among Asian Indian men when used in conjunction with clinical risk factors. A majority of our subjects were either osteopenic or osteoporotic, and their fracture risk increased when FRAX® was used in conjunction with femur neck T-scores.

INTRODUCTION

Asian Indian men living in the United States may represent a population that is at high and underappreciated risk for fragility bone fractures.

PURPOSE

To evaluate the effect of BMD on fracture risk prediction using FRAX® among Asian Indian men when used in conjunction with clinical risk factors.

METHODS

Forty four Asian Indian men (mean age 64.9 (±8.4) years) who had lived in the United States for an average of 33.6 (±10.6) years underwent BMD measurement at the proximal femur. Subjects were subjected to a general physical exam and history of fracture, hip fracture in a parent, current smoking and alcohol use, and diagnosis of inflammatory arthritis was obtained. Data from each subject were entered into the FRAX® algorithm and 10-year fracture probabilities were calculated using clinical risk factors (CRFs) alone and in combination with femur neck T-scores.

RESULTS

Thirteen subjects (29.5%) had femur neck T-scores ≥ -1.0, 28 (63.6%) T-scores between -1.0 and -2.5, and three (6.8%) T-scores < -2.5. The 10-year probability of a major osteoporotic fracture based on a combination of clinical risk factors and femur neck T-scores was significantly higher than the fracture probability based on clinical risk factors alone (t(43) = 2.58, p = 0.01).

CONCLUSIONS

Among Asian Indian men, the 10-year probability of a major osteoporotic fracture increases when femur neck T-scores are added to clinical risk factors in the FRAX® algorithm, and this population have a high fracture probability even in the absence of clinical risk factors.

Vitamin D supplementation suppresses age-induced bone turnover in older women who are vitamin D deficient

There is a lack of evidence that improving vitamin D status, without changing calcium intake, has a positive effect on bone turnover as indicated by bone marker changes. The objective was to measure the effect of vitamin D supplementation, in vitamin D deficient women (25(OH)D concentration<50 nmol/L), on osteocalcin (OC) and C-telopeptide (CTX). The study design was a randomised controlled intervention administering 4000 IU vitamin D3 or placebo daily for 6 months to South Asian women, aged>20 years. Subjects were stratified by age and menopausal status. Median (25th, 75th percentile) serum 25(OH)D increased significantly from 21 (11, 40) to 75 (55, 84) nmol/L with supplementation. In women>49 years or postmenopausal (n=26), who were not supplemented (n=13), CTX and OC levels increased (P=0.001, P=0.004 respectively), indicating an increased rate of bone turnover. With supplementation CTX decreased (P=0.012) and there was no significant change in OC. In women who were under 49 years and premenopausal (n=55; 29 supplemented), there was no significant response to supplementation in either CTX or OC. We conclude that correcting vitamin D deficiency in older women suppresses the age-induced increase in bone turnover and reduces bone resorption which would normally be exacerbated in conditions of low serum 25(OH)D.