A Retrospective Study to Investigate Association among Age, BMI and BMD in the Postmenopausal Women

Abstract

Bone strength (and, hence, fracture risk) is dependent on many qualities of bone, of which bone mineral density (BMD) is the most commonly measured. Association between advancing age and lower body mass index (BMI) is an important risk factor in the occurrence of low BMD. This study was aimed at evaluation of the association among age, BMI and status of BMD among 159 age matched postmenopausal women who underwent Dual-Energy X-ray Absorptimetry (DEXA) scan. The study population was divided into three groups on the basis of body mass index (BMI) as normal weight, obese and severely obese. The mean bone mineral density (BMD) of obese and severely obese postmenopausal women was found to be significantly higher (P value < 0.001) as compared to the mean BMD of normal weight women. Significant negative correlation was found between the age and BMI except in severely obese group (P value < 0.05). Age and BMD in all the three groups correlated negatively (P value < 0.01) in all the three groups. BMD and BMI in the normal weight group significantly correlated negatively (P value < 0.05) while a very weak positive but insignificant correlation existed between the same in the obese and severely obese postmenopausal women. The study revealed that with advancing age BMD is lowered and that higher BMI might have a positive influence (although not significant as observed in the present study) on the BMD. Other factors like exposure to sunlight, calcium intake, diet etc should also be investigated which could not be probed in the present study as it was a retrospective analysis.