Background: Mortality risk tends to be higher among elderly individuals with higher serum adiponectin levels. The objective of this study was to clarify whether the relationship between adiponectin and a higher risk of disability or death can be explained by physical function, bone mineral density, depression, and malnutrition.
Methods: We analyzed 505 individuals who underwent comprehensive geriatric assessment and who agreed to provide information on long-term care insurance. The endpoint was the composite outcome of death and incident disability defined as a first certification for any level of care need. Relationships between adiponectin and incident disability or death were estimated using the Cox proportional hazards model.
Results: During 6 years of follow-up, 179 incident disabilities or deaths occurred. Among them, 20 and 23 died with and without disability, respectively. The risk of incident disability or death was significantly higher among participants with adiponectin greater than or equal to 22.4 (90%) than 8.0 or less (25%) mg/L (Hazard ratio: 95% confidence interval, 1.92: 1.01-3.64) in the model adjusted for age, sex, and metabolic risk factors. Adjustment for N-terminal pro-B-type natriuretic peptide and nutritional status did not substantially alter this risk estimate, although the association ceased to be statistically significant. Adjustment for physical function did attenuate the relationship, however, which ceased to be apparent upon exclusion of disability or death occurring within 3 years of follow-up.
Conclusion: The relationship between adiponectin and the composite outcome of incident disability and death was at least partly explained by reduced physical function and wasting in participants with higher adiponectin levels.