Obesity indicators and risk of mortality and functional health outcomes in Asian community-dwelling older adults: A systematic review and meta-analysis

Obesity in older adults is associated with adverse health outcomes, and its coexistence with sarcopenia may accelerate these risks. While diagnostic criteria for sarcopenic obesity were recently proposed in Europe, the applicability of obesity indicators and cutoffs for Asian older adults remains unclear. We aimed to identify optimal obesity indicators and cutoffs for adverse health outcomes in Asian older adults. Five electronic databases were searched from inception to January 2025. Pooled relative risks (RRs) with 95 %CI were calculated using random-effects model. Fifty-eight studies were included in systematic review, with 35 longitudinal studies on mortality and disability included in meta-analysis. BMI-defined obesity and overweight were associated with lower mortality risk (pooled RR = 0.82[0.77-0.87] and 0.81[0.78-0.84], respectively), whereas underweight was associated with higher risk (pooled RR = 1.64[1.45-1.83]). A reverse J-shaped relationship between BMI and mortality was observed, with lower risk between 25 and 30 kg/m². WC-defined abdominal obesity was not associated with mortality risk (pooled RR = 0.91[0.70-1.11]). No significant association between BMI-defined obesity and disability was demonstrated (pooled RR = 1.01[0.86-1.17]). Although meta-analysis for abdominal obesity and functional health outcomes could not be conducted, two individual studies suggest WC is positively associated with falls and weight-adjusted waist index with disability. The current evidence suggests that BMI may better reflect mortality risk in a reverse J-shaped relationship. However, the association between WC-defined abdominal obesity and mortality remains inconclusive due to the limited number of the studies. WC appears to be more consistently associated with functional health outcomes, implying that different indicators distinctly contribute to adverse health outcomes.