Sarcopenic obesity and its association with respiratory disease incidence and mortality

Summary Background Sarcopenic obesity is defined as a combination of sarcopenia and obesity. Previous studies have shown a positive association between sarcopenia and respiratory disease, while other studies have identified that obese individuals have a lower risk for respiratory diseases. This study aimed to investigate the association of obesity, sarcopenia and sarcopenic obesity with respiratory disease incidence and mortality. Methods Data from 170,083 participants from the prospective UK Biobank study were included. Sarcopenic obesity was defined as the combination of sarcopenia with one of the following obesity criteria: BMI ≥30 kg/m2, waist circumference (WC) ≥ 88 cm in women or ≥ 102 cm in men, or the two highest sex-specific quintiles of body fat. Respiratory disease incidence and mortality were the outcomes. Results The mean follow-up period was 7.0 years. 5459 (3.2%) participants developed respiratory diseases and 780 (0.5%) died from respiratory diseases. Compared to individuals without obesity or sarcopenia, those who were obese (Hazard Ratio (HR): 1.13 [95 CI: 1.03; 1.23]), sarcopenic (HR: 1.23 [95% CI: 1.10; 1.36]) or sarcopenic obese (based on BMI) (HR: 1.51 [95% CI: 1.30; 1.77]), had a higher risk of respiratory disease incidence. However, the risk of respiratory disease mortality was higher in sarcopenic individuals and lower in obese individuals. No associations were identified between sarcopenic obesity and respiratory mortality (HR: 1.12 [95% CI: 0.76; 1.63]). Similar patterns were found when obesity was defined using WC or body fat. Conclusion Obesity, sarcopenia and sarcopenic obesity were associated with a higher risk of respiratory disease incidence. However, while obesity was associated with lower, and sarcopenia with higher respiratory mortality risk, no associations between sarcopenic obesity and respiratory mortality were identified.