Sex-specific all-cause mortality is associated with adiposity in the Malaysian Elders Longitudinal Research (MELoR) study

While adiposity has been found to be protective against adverse outcomes in older adults, the role of muscle in this association remains under explored. This study sought to evaluate sex-specific mortality associated with available adiposity indices in older adults and the potential role of muscle strength in this relationship. Individuals aged ≥55 years were recruited from 2013 to 2015. Adiposity indices obtained were body mass index (BMI), percentage body fat (%BF), waist-to-hip ratio (WHR), and waist circumference (WC). Vital status up to June 2022 was determined through the National Registry Department. Of the 1347 included participants, aged (mean±SD) 68.45±7.21 years and 57.1% women, 11.2% deaths were recorded. Men who were underweight had increased mortality compared to men with normal BMI (HR (95%CI)=3.17(1.35-7.47)). Mortality was greater in men with %BF within the highest quartile (Q4) compared to the lowest quartile (Q1) (HR (95% CI)=4.72 (2.07-10.78)). Increased mortality in both men and women in Q4 for WHR compared to Q1 was influenced by age, as was increased mortality in women in Q4 for %BF. WC did not predict mortality in men or women. Increased mortality risk was present in men with normal muscle strength and increased %BF, and reduced muscle strength in men with low BMI. Adiposity measured with BMI, WHR and WC had limited value in determining mortality risk at 9-year follow-up among individuals aged ≥55 years. Increased mortality was, however, observed in men with higher %BF but this could not be attributed to muscle strength.