Age and weight related bone mineral density in North Indian subjects

Abstract

The aim of this study is to assess the bone mineral density in different age and sex groups and to study the relationship between T-score and other parameters like age, sex and body weight. A population based cross sectional study of 398 subjects was conducted in the Department of Endocrinology and Metabolism, S.S. Hospital, BHU, Varanasi. Calcaneal bone mineral density was measured using an ultrasound bone densitometer (Pegasus). The subjects were subclassified for statistical analysis into age groups 15-30 years, 31-45 years, 46-60 years and above 60 years. Below the age of 45 years, mean T-score among females was significantly lower than males (-2.5 Vs - 1.79; p<0.01). Among females, a positive correlation between the weight and T-score was noted across all the age groups, with strongest correlation in 31-45 years age group (r=0.43). The strength of positive correlation declined after 45 years of age (r=0.18 below 45 years age, and r=0.11 above 60 years). Among males, there was a positive correlation between weight and T-score below 60 years, whereas the weight was negatively correlated with T-score (r=-0.17) beyond 60 years. The results of this cross sectional study suggest the bone mineral density varies with age, sex and body weight among North Indian subjects. Males had higher bone mineral density than females in all age groups particularly under the age of 45 years which might reflect the higher bone mass attained by males in their adulthood. The negative influence of age on bone mineral density was evident in females over 45 years and in males above 60 years of age. The positive correlation between weight and T-score was significant only in certain age groups in our study.