Prevalence of diabetes and depressive symptomatology and their effect on mortality risk in elderly Italians: The Italian Longitudinal Study on Aging

AIM: This study assessed the prevalence of depressive symptomatology (DS) in older individuals with diabetes to determine whether diabetes and DS are independent predictors of mortality, and if their coexistence is associated with an increased mortality risk. METHODS: Analyses were based on data from the Italian Longitudinal Study on Aging (ILSA), a prospective community-based cohort study in which 5632 individuals aged 65-84years were enrolled. The role of diabetes and DS in all-cause mortality was evaluated using the Cox model, adjusted for possible confounders, for four groups: 1) those with neither diabetes nor DS (reference group); 2) those with DS but without diabetes; 3) those with diabetes but no DS; and 4) those with both diabetes and DS. RESULTS: Type 2 diabetes mellitus (T2DM) was present in 13.8% of the participants; they presented with higher baseline rates of DS compared with the non-diabetic controls. During the first follow-up period, participants with DS but not diabetes had a 42% higher risk of all-cause mortality compared with the reference control group (HR=1.42; 95% CI: 1.02-1.96), while participants with diabetes but not DS had an 83% higher risk of death than the reference group (HR=1.83; 95% CI: 1.19-2.80). The risk of death for those with both disorders was more than twice that for the reference group (HR=2.58; 95% CI: 1.55-4.29). Analyses of deaths from baseline to the second follow-up substantially confirmed these results. CONCLUSION: The prevalence rate of DS is higher in elderly people with diabetes and their coexistence is associated with an increased mortality risk.