Age-related changes and reference intervals of RANKL, OPG, and bone turnover markers in Indian women.

RANKL and OPG are cytokines involved in bone remodeling that makes them potential bone biomarkers. The reference interval for these cytokines, their ratio, and bone turnover markers CTX and PINP were established in Indian women, which may serve in diagnosis and management of osteoporosis. PURPOSE: The aim of the study was to establish reference interval for RANKL, OPG, RANKL/OPG, and bone turnover markers CTX and PINP in healthy Indian women. METHODS: This was a cross-sectional study on 374 healthy Indian women in the age group of 20-65 years. Serum levels of total RANKL, OPG, CTX, PINP, and estradiol were determined by commercial ELISA kits. The reference intervals for these cytokines and bone turnover markers were based on the 95% centrally distributed data. RESULTS: Median RANKL (245.6 pmol/L vs. 149 pmol/L) and RANKL/OPG (38.7 vs. 20.4) were higher, while sCTX (380 ng/L vs. 551 ng/L) and OPG levels (6.1 pmol/L vs. 7.4 pmol/L) were lower in premenopausal women than those in postmenopausal women. PINP levels were comparable in both groups. Women were classified into 5 groups according to decades of age and the reference intervals for RANKL, OPG, RANKL/OPG ratio, and CTX and PINP in each group were reported. CONCLUSION: We reported menopausal status-based and age-related reference intervals for serum RANKL, OPG, RANKL/OPG ratio, and CTX and PINP in healthy Indian women.

Screening and Assessment of Bone Health in Indian Women Using an Indigenous ELISA of Human Osteocalcin a Bone Turnover Marker.

Osteoporosis a major public health problem of the elderly, is associated with substantial morbidity and socio economic burden. The aim of the study was to screen women with low bone mass using the indigenously developed Osteocalcin (OC) ELISA kit and compare it with commercial ELISA kit and evaluate. The diagnostic potential of the assay was assessed in 359 samples from neighboring tertiary care hospitals over a period of 2 years. OC levels were estimated by the developed indigenous assay in samples, correlated with the Bone Mineral Density (BMD) measurements and compared by a commercial ELISA kit. On the basis of T-scores the women were stratified into Normal and case groups as Osteopenia and Osteoporosis. The serum biochemical parameters calcium and phosphorus were estimated on an auto-analyzer. To compare two different assays Bland-Altman plot and Deming linear regression analysis was performed. The prevalence of Osteopenia was high (56%) and Osteoporosis (13%) in the healthy Indian women aged 21-65 years with significant differences in OC levels in normal and women with low bone mass. Good correlation (p < 0.0001) in the OC levels by the two assays was observed. Cut off limits established earlier with indigenous assay (11.9 ng/mL and 14.9 ng/mL) for Osteopenia and Osteoporosis were similar to those with the commercial kit (13.2 ng/mL and 16.8 ng/mL) respectively. The diagnostic sensitivity, specificity and accuracy of the OC prototype was > 85%. The cost effective OC prototype can be used in screening and management of Indian women with low bone mass.

Effect of Vitamin D Levels on Bone Remodeling in Healthy Women.

BACKGROUND: Vitamin D deficiency is prevalent among Indian women. Subclinical vitamin D deficiency is a significant risk factor for osteopenia and fractures. However, its effect on bone metabolism and bone mineral density (BMD) is still debatable. OBJECTIVES: This study aimed to determine relationships of the vitamin D status with bone turnover markers, carboxy-terminal telopeptide of type-I collagen (CTX), N-terminal propeptide of type I procollagen (PINP), and BMD in healthy Indian women. METHODS: In this cross-sectional study, we determined serum levels of 25-hydroxy vitamin D (25(OH)D), parathyroid hormone, serum CTX, and PINP using commercial ELISA kits in 310 healthy Indian women aged 25 - 65 years who underwent BMD measurements with DXA scan. RESULTS: The prevalence of vitamin D deficiency was 53.87% and vitamin D insufficiency 31.29%. A direct correlation of BMD with vitamin D levels was not observed. PINP negatively correlated with vitamin D in both premenopausal (Spearman's r = -0.169, P < 0.05) and postmenopausal (Spearman's r = -0.241, P < 0.05) women. However, CTX positively correlated with vitamin D in both premenopausal (Spearman's r = 0.228, P < 0.01) and postmenopausal (Spearman's r = 0.244, P < 0.05) women. CONCLUSIONS: Vitamin D deficiency is more prevalent in premenopausal women than in postmenopausal ones. Although vitamin D does not show any association with BMD, it affects bone remodeling, which is reflected by changes in the bone formation marker PINP and the bone resorption marker CTX.