Obesity is positively Associated with Depression in Older Adults: Role of Systemic Inflammation*

Objective We aimed to explore the association between obesity and depression and the role of systemic inflammation in older adults. Methods Adults >= 65 years old (n = 1,973) were interviewed at baseline in 2018 and 1,459 were followed up in 2021. General and abdominal obesity were assessed, and serum C-reactive protein (CRP) levels were measured at baseline. Depression status was assessed at baseline and at follow-up. Logistic regression was used to analyze the relationship between obesity and the incidence of depression and worsening of depressive symptoms, as well as the relationship between obesity and CRP levels. The associations of CRP levels with the geriatric depression scale, as well as with its three dimensions, were investigated using multiple linear regressions. Results General obesity was associated with worsening depression symptoms and incident depression, with an odds ratio (OR) [95% confidence interval (CI)] of 1.53 (1.13-2.12) and 1.80 (1.23-2.63), especially among old male subjects, with OR (95% CI) of 2.12 (1.25-3.58) and 2.24 (1.22-4.11), respectively; however, no significant relationship was observed between abdominal obesity and depression. In addition, general obesity was associated with high levels of CRP, with OR (95% CI) of 2.58 (1.75-3.81), especially in subjects free of depression at baseline, with OR (95% CI) of 3.15 (1.97-5.04), and CRP levels were positively correlated with a score of specific dimension (life satisfaction) of depression, P < 0.05. Conclusion General obesity, rather than abdominal obesity, was associated with worsening depressive symptoms and incident depression, which can be partly explained by the systemic inflammatory response, and the impact of obesity on depression should be taken more seriously in the older male population.