Low bone mineral density and its risk factors in an urban adult population of South India

BACKGROUND AND OBJECTIVES: Low bone mineral density (BMD) is widely prevalent in Indian populations. Very few studies that reported risk factors for low BMD and osteoporosis did not explore its relationship with age and sex. Objectives were to determine the prevalence of low BMD and osteoporosis in urban adults, and study the age- and sex-wise trends of changing BMD.METHODOLOGY: BMD of 521 healthy adults aged 20 years or more was tested using quantitative ultrasound of right tibia, and T-scores thus obtained indicated normal or low BMD. Multivariate analysis was done to calculate odds ratios for risk factors for low BMD and osteoporosis.RESULTS: Eighty-four percent participants had low BMD. Low BMD increased significantly with increasing age in both genders. An increase in age per standard deviation (SD) was associated with four-fold increase in risk of low BMD for both women (odds ratio [OR]: 4.83, 95% confidence interval [CI]: 2.61–8.92) and men (OR: 4.14, 95% CI: 2.44–7.05). Age per SD (OR: 2.28, 95% CI: 1.37–3.81) and age–gender interaction (OR: 1.09, 95% CI: 1.02-1.17) was positively associated with osteoporosis. Increasing age by one SD was associated with seven-fold increase (OR: 7.35, 95% CI: 3.51–15.40) in risk of osteoporosis among women.CONCLUSIONS: Low BMD is highly prevalent in South Indian urban population. Low BMD and osteoporosis were positively associated with increasing age. Loss of BMD appeared to begin at young ages thereby indicating the need for early institution of prevention measures.