Body Mass Index and Muscle Strength in Older Adults: A Cross-Sectional Study

Abstract

Introduction: Declines in muscle mass and strength are major contributors to reduced functional capacity and quality of life among older adults. Body mass index (BMI) is often used as a proxy for body composition; however, its association with muscle strength remains unclear. This study aimed to examine the relationship between BMI and muscle strength, specifically handgrip and lower limb strength, in community-dwelling older adults.

Methods: A cross-sectional study was conducted from December 2023 to February 2024 at Tamalanrea Community Health Center, Makassar. Ninety older adults were recruited through purposive sampling according to predefined inclusion criteria. BMI was calculated using measurements obtained with a digital scale and microtoise. Handgrip strength was measured with a handgrip dynamometer, while lower limb strength was assessed using the 30-Second Chair Stand Test. Statistical analysis was performed using Somers’ d correlation test.

Results: There was no significant correlation between BMI and handgrip strength (p = 0.941, r = 0.006), nor between BMI and lower limb strength (p = 0.476, r = 0.049). These results indicate that BMI status—whether within normal or abnormal ranges—does not significantly influence muscle strength in older adults.

Conclusion: BMI alone may not be a reliable indicator of muscle strength in older adults. Other factors such as muscle composition, physical activity, and nutritional status may play more critical roles in determining functional capacity.