Depressive Symptoms Score Predicts Incident Type 2 Diabetes in Community Dwelling Old Icelandic People

Background. Depression is related to incident type 2 diabetes (T2D). However, little is known on this topic in older people from the Nordic countries and how health and lifestyle characteristics of participants affect this relationship. Thus, the aim of the present study was to investigate whether baseline depressive symptoms predict incident T2D in Icelandic older people and whether health and lifestyle characteristics of participants, can explain the relation between depression and diabetes. Methods. We used data from the Age-Gene/Environment-Susceptibility-Reykjavik-Study (65-96 years). From the original sample of 3316 participants who finished follow-up, 2823 non-diabetic participants with a complete dataset on depressive symptoms and incident T2D at endpoint were included in this analysis. Depressive symptoms were assessed using the 15-item Geriatric Depression Scale (GDS). During a mean follow-up of 5.2 years, 103 (3.6%) of the 2823 participants developed T2D. According to the fully adjusted logistic regression model, baseline depressive symptoms in the highest category predicted incident T2D when compared to the lowest category (OR: 3.2; 95%CI: 1.3-8.2; p = 0.014). Statistical adjustment did only marginally alter the results. Subgroup analysis revealed that GDS was a significant predictor of incident T2D in most subgroups. Conclusions. In older Icelandic people, having high depressive symptoms is a predictor of incident T2D during a follow-up period of 5.2 years. These associations are independent from health and lifestyle related covariates and are observed in most subgroups of our study population.