Body Fat Percentage Is More Strongly Associated With Handgrip Strength Than Body Mass Index Among North Indian Adults

Background Muscle strength is a key factor determining metabolic health, physical performance, and morbidity. Although body mass index (BMI) is used widely to assess obesity, it does not assess body composition adequately. Percentage body fat (PBF) could provide a better estimate of adiposity and its association with muscle strength, particularly in Asian populations with higher body fat at lower BMI levels. We aimed to evaluate the associations of BMI and PBF with HGS and lower limb muscle strength among North Indian adults and to compare the independent associations of BMI and PBF with HGS. Methodology This cross-sectional study included 1,513 apparently healthy adults aged 18 to 60 years. Anthropometric measurements, BMI, and PBF were measured using bioelectrical impedance analysis. HGS was measured using a Jamar hydraulic dynamometer, and lower limb muscle strength was tested using a handheld dynamometer. Correlation and multiple regression analyses were performed to assess the association of BMI and PBF with muscle strength. Results The average age of the participants was 38.25 ± 9.76 years, and 54.5% were males. PBF showed a significant inverse association with HGS for both hands. For the right HGS, the regression coefficient B was -0.619 with an R² of 0.331, while for the left HGS, B was -0.594 with an R² of 0.336 (p < 0.001 for both). However, BMI showed a comparatively weaker association with HGS, explaining less than 2% of the variation. Higher BMI was significantly associated with greater lower limb muscle strength (p < 0.001), while no significant association was found between BMI categories and HGS. Multivariable regression analysis further showed that PBF remained independently associated with HGS (p-value < 0.001 for both hands). Conclusions According to our study, PBF demonstrated a stronger association with muscle strength than BMI. These findings show that relying on BMI alone is insufficient and suggest including body composition assessment to identify individuals at risk of reduced muscle strength and related health complications.