Association between different skeletal muscle mass indices, physical function, and inflammation in obese pre-frail older adults

Objectives: There is lack of consensus on measurement of muscle mass and quality in obese older adults. We aim to evaluate the association of four muscle mass indices (appendicular skeletal muscle mass (ASM) over height2(ASMIht), ASM/weight (ASMwt), ASM/body fat percentage (ASMbfp)and ASM/body mass index (BMI) ASMIbmi) with physical function and inflammation in pre-frail obese older adults. Methods: Cross-sectional study of 407 community dwelling pre-frail older adults. Data on demographics, cognition, and physical function(gait speed, handgrip strength (HGS) and Short Physical Performance Battery (SPPB) test), body composition and inflammation biomarkers were collected. Participants were analysed based on BMI tertiles(T1 lowest,T3 highest). Results: The mean age was 72.67 years, mean BMI 25.42 kg/m2 and 59.5 % were females. Participants in T3 had a mean BMI of 30.75 kg/m2, younger with lower education levels, multimorbidity, polypharmacy and lower prevalence of sarcopenia. In BMI T3, ASMIbmi was significantly associated with EQ-5D index (8 0.53, 95 % CI 0.04 to 1.03, p = 0.033),HGS (8 5.28, 95 % CI 0.27 to 10.29, p = 0.039), SPPB (8 2.19, 95 % CI 0.47 to 3.91, p = 0.013) and IL-6 (8 -4.13, 95 % CI -7.46 to -0.81, p = 0.017). ASMIwt was associated with EQ-5D index (8 0.17, 95 % CI 0.02 - 0.33, p = 0.047). ASMbfp was associated with HGS (8 6.97, 95 % CI 0.051 to 13.92, p = 0.049). There was significant association of HGS with all muscle mass indices in BMI T2, and ASMbfp in BMI T1. Conclusion: ASMIbmi was significantly associated with SPPB, HGS, EQ-5D index and IL-6 in BMI T3. ASMbfp was associated with HGS in all the tertiles. Our results need further validation at population level.