Comparing the BMI body fat relation between two distinct age groups of the Lebanese female population : adolescents and elderly

Abstract

Introduction – The aim of this study was to assess and compare the relation between BMI and body composition among two distinct age groups of Lebanese females. Methods and results – 160 subjects participated in this study. The subjects were divided into two groups, 64 Lebanese adolescent females aged 12-18 years and 96 Lebanese postmenopausal aged 65-84 years. Weight and height were measured, and age and years since menopause were recorded. Body Mass Index (BMI) was calculated as body weight divided by height squared (kg/m2 ). Body composition was assessed by Dual energy X-ray Absorptiometry (DXA). Results – In girls and elderly women, BMI was correlated with FM% and more with fat mass (FM). The correlation between BMI and fat mass percentage FM% was (r-value 0.84) in girls and (r-value 0.71) in elderly women. In girls, the correlation was (r-value 0.65) in the normal weight and (r-value 0.69) in the obese group. In elderly women, the correlation was (r-value 0.74) in the normal weight group. In the obese girls and elderly women the correlation was (r-value 0.69 and 0.36) respectively. Conclusion – Correlation between BMI and FM% is higher in girls than in elderly women. In the older group, correlation is stronger at a lower BMI. In the younger group it is high in normal weight and obese subjects. In both age groups, many subjects with a BMI below 30 have obesity levels of body fat. Obesity is more accurately assessed using measures of body fat instead of weight based indexes.