The Relationship Between Body Mass Index and Bone Mineral Density in Premenopausal and Postmenopausal North Indian Women

Purpose: Present study aims to examine the relationship of the bone mineral density (BMD) with body mass index (BMI) in an apparently healthy premenopausal and postmenopausal north Indian female population.

Methods: Two hundred and fifty-five apparently healthy women were evaluated by a detailed questionnaire including all possible factors that could affect the BMD. The height and weight of all the subjects were recorded and BMI was calculated. Bone mineral density was measured by DXA (Dual Electron X-ray Absorptiometry) at L1-L4 Lumbar spine (LS) and femur neck (FN) by using the Prodigy DXA system (software version:8.50) manufactured by GE medical systems LUNAR.

Results: The population was divided into pre and postmenopausal groups. The BMD at all sites increased with BMI in both groups. In a multiple regression model, the attributability of BMI and age to variation in LSBMD and FNBMD was 10.3 and 13.9 %, respectively. In postmenopausal women, age, BMI, and a previous history of fracture together attributed to a variance in BMI of 40.1 and 27.6 % at lumbar spine and femur neck, respectively. BMI was found to be significantly associated with low BMD at both sites in premenopausal women, while the association was lost in postmenopausal females.

Conclusion: BMI is an important determinant of BMD in Indian females. However, the association is not present in postmenopausal women with osteopenia. In addition, the effect of increase in BMI on BMD has a ceiling effect, and moderate to morbid obesity might not actually be a preventive factor for osteopenia.