# Interactions Between BMI and Age on Fall Risk in Older Adults

## TL;DR

This study shows that obesity increases fall risk in older adults aged 60-79, but not in those over 80, possibly due to muscle loss.

## Contribution

The study reveals a 'weight paradox' in octogenarians where normal weight does not reduce fall risk due to sarcopenia.

## Key findings

- Obesity significantly increases fall risk in sexagenarians and septuagenarians compared to normal weight.
- In octogenarians, BMI differences do not significantly affect fall risk.
- The protective effect of normal weight disappears in the oldest adults, likely due to sarcopenia.

## Abstract

Background/Objectives: The aging process is typically marked by a reduction in functional fitness, which heightens the likelihood of falling. Although obesity is established as a determinant of poor mobility, the interplay between excess weight and advanced age is still a topic of research interest. Therefore, this research investigated how age, sex, and Body Mass Index (BMI) interact to influence fall risk among older adults living in the community. Methods: This cross-sectional investigation involved 815 participants (Mage = 70.45 ± 6.10 years), stratified by age (sexagenarians, septuagenarians, octogenarians) and BMI (normal weight, overweight, obesity). Fall risk was assessed using the Timed Up and Go test. A Three-Way ANOVA examined the main and interaction effects. Results: No significant three-way interaction (p = 0.334) or main effect of sex (p = 0.079) was found. However, a significant age x BMI interaction was observed (p = 0.007). In sexagenarians and septuagenarians, obesity was associated with significantly slower fall risk performance compared to normal weight (p < 0.001). Conversely, in octogenarians, this difference was not significant (p = 1.000) with normal-weight individuals. Conclusions: Obesity may be a significant risk factor for falls, especially in adults aged 60 to 79 years. In octogenarians, the protective benefit of normal weight disappears, revealing a “weight paradox” likely driven by sarcopenia. Fall risk assessments and weight management strategies should be tailored to age, focusing on preserving muscle mass in octogenarians.