Glucose status and depressive symptoms: a cohort study of elderly people in northwest Finland

Objective: To assess the association between depressive symptoms and impaired glucose metabolism in the elderly population in arctic latitudes. Design: A population-based study. Setting. Community. Subjects: The study population consisted of 1,830 subjects born between the years 1915 and 1958 in the northernmost part of Finland, the Muonio-Enontekiö district, who participated in a health survey during 1974-1984. In 2014, a health questionnaire was sent to 1,037 subjects, and 757 participants (73%) answered it. Those (n = 629) living in the Muonio-Enontekiö district undergone a clinical examination in 2014 and 2015 including blood collections. Main outcome measures: Depressive symptoms defined by the Beck Depression Inventory II (BDI II) with a cut-off point of 14. Different diabetic states based on WHO's classification criteria defined by fasting plasma glucose and ADA's criteria by glycosylated haemoglobin (HbA1c) values. Results: According to logistic regression analysis, depressive symptoms (BDI-II ≥ 14) were associated statistically significantly with previously known type 2 diabetes, the odds ratio (OR) being 4.33 (95% CI 1.53-14.14). Regarding prediabetic fasting glucose/HbA1c values, the corresponding OR was 2.94 (95% CI 1.17-8.94). The prevalence of depressive symptoms (BDI-II ≥ 14) was 7.1%, (men 9.7% and women 5.4%) and 13.7% (men 9.9% and women 17.0%) in subjects living in Muonio-Enontekiö district and in those who had moved away from there, respectively. Conclusions: The association of depressive symptoms between prediabetes and diabetes seems to be present also in the northernmost latitudes of the world.