Lifetime depression history and depression risk in type 2 diabetes: A case-control study.

Aims: To assess whether a personal history of depression assists in risk prediction for depression in type 2 diabetes.

Methods: Age- and sex-matched participants with and without diabetes from the Busselton Health Survey were assessed for current and previous depression using the 9-item Patient Health Questionnaire and the Brief Lifetime Depression Scale (BLDS). In the diabetic participants, the temporal relationship between first depression episode and diabetes onset was also explored.

Results: In 184 paired participants (age 70.2±10.1years, 50% female), those with diabetes had a higher prevalence of any current depression (12.5% vs 4.3%, P<0.01) and lifetime history of major depression (30.6% vs 21.1%, P=0.06) compared to those without diabetes. After adjustment, lifetime major depression history was independently associated with any current depression in the combined sample (odds ratio (95% CI): 5.55 (3.09-9.98), P<0.001), in those with diabetes (4.17 (2.00-8.71), P<0.001), in those without diabetes (8.29 (3.24-21.23), P<0.001) and in diabetes whether sub-divided by depression first occurring before or after diabetes onset (before: 3.16 (1.38-7.24), P=0.007; after: 2.77 (1.00-7.70), P=0.051).

Conclusions: Obtaining a lifetime history of major depression using the BLDS assists in depression risk prediction in type 2 diabetes regardless of whether depression preceded diabetes onset or not.