Biological interaction between sleep quality and depression in type 2 diabetes.

OBJECTIVE: To explore the interaction of sleep quality and depression among patients with type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS: With multistage cluster sampling, the living quality of all participants was investigated. The indicator of interaction was calculated according to the delta method and non-conditional logistic regression model.

RESULTS: There were 944 residents involved in the final analysis including 365 males and 579 females. The average age was (64 ± 10.2) years. The rate of poor sleep quality and poor sleep quality combined depression were 33.6% and 40.1%, respectively. Due to poor sleep quality and depression in patients with T2DM, the combined interaction index was 2.48 (95% CI 1.44-4.29), the relative excess risk was 3.42 (95% CI 2.16-4.67), and the attributable proportion was 0.51 (95% CI 0.32-0.70).

CONCLUSIONS: An additive interaction rather than a multiplicative interaction of poor sleep quality and depression in affecting the quality of life was found in T2DM patients. When both factors existed at the same time, the interaction effect of these 2 factors was greater than the sum of the two factors.