Correlation between body fat percentage and body mass index in the elderly: role of sex and age

Background: Due to the growing elderly population, more of whom have a predisposition to obesity-related diseases, there is a need for precise tools that measure obesity. The objective of this study was to determine the correlation between body mass index (BMI) and body fat percentage (BF%) in the elderly. Additionally, the correlation would be observed adjusting for age and gender. Methods: This was a retrospective, cross-sectional, analytical study comprised of 50 individuals aged ≥60 attended in the "Geriatric Care of the Central Hospital of the Air Force of Peru" during the years 2019-2020. Body fat percentage was determined by two methods: dual-energy x-ray absorptiometry (DXA) and bioelectrical impedance (BIA). Results: Using logistic regression analysis, the significant variables associated with BMI were BF%, determined by BIA, in both men and women, as well as BF%, determined by DXA in women. Conclusions: Generally, the results showed a positive correlation between BMI and BF%, regardless of the apparatus utilized. The relationship was strongest in females. Age was reported to have a less significant effect.