Obesity strengthens the associations between sarcopenia and both frailty and hospitalization, whereas reduces the risk of mortality.

OBJECTIVES

To assess the impact of different definitions of obesity on the association between sarcopenia and negative health outcomes in community-dwelling older adults.

DESIGN

A longitudinal analysis using data from the Toledo Study of Healthy Ageing

SETTING

Community-dwelling older adults.

PARTICIPANTS

1546 older adults (mean age 74.76 ± 5.75 years; 45.54% men).

MEASUREMENTS: Sarcopenia was defined using population-standardized Foundation for the National Institutes of Health criteria. Obesity was assessed using several criteria previously prosed in the literature: Body Mass Index (BMI: >28, >30, >33 kg/m²), waist circumference (WC: 88♀; >102♂; and 98♀; >109♂), waist-to-hip ratio (WHR: >0.85♀; >0.90♂), fat mass percentage (%FM: >38%♀, >27%♂; and >40%♀, >30%♂; and >43%♀, >31%♂), and population-based quartiles for trunk and appendicular fat mass. Frailty and disability were evaluated at baseline and 2.99 years later; hospitalization and mortality were tracked at 3.63 and 6.28 years, respectively. Regression models (logistic and Cox) and ROC analyses were conducted, adjusting for age, sex, comorbidities, and malnutrition.

RESULTS

350 (22.63%) met sarcopenia criteria. Obesity prevalence varied from 18.63% to 76.13%, depending on the definition. Obesity, regardless of the criterion, strengthened the associations between sarcopenia and frailty while only some of them did for hospitalization (BMI and WC), but not impacted disability. Sarcopenia was not significantly associated with death in the adjusted model, but the association became significant after adjustment for some obesity markers (WHR, truncal fat mass, and %FM. ROC curves results suggested that the capacity of sarcopenia to predict worsening frailty increased 2%, when the obesity markers were included.

CONCLUSION

Obesity-particularly defined by BMI and WC-strengthened the association between sarcopenia and adverse outcomes such as frailty and hospitalization. In contrast, higher fat mass was associated with lower mortality, suggesting a potential obesity paradox that warrants further research. These findings highlight the importance of assessing multiple obesity criteria alongside sarcopenia, while the potential protective role of obesity against mortality requires confirmation in further studies.