Abstract
OBJECTIVES: Results from twin studies examining the genetic overlap between type 2 diabetes and depression are currently inconclusive. This question has not been addressed in non-western populations. We aimed to examine whether there are common genetic factors between type 2 diabetes and depression in a Sri-Lankan population, using genetic model-fitting analysis. METHOD: The Colombo Twin and Singleton Study-Phase 2 consists of 2019 singletons, 842 monozygotic and 578 dizygotic twin-pairs. The primary outcomes were self-reported type 2 diabetes diagnosis and Beck Depression Inventory scores. Standard bivariate twin models were fitted to estimate the genetic and environmental (co)variance of type 2 diabetes and depression. RESULTS: In the best-fitting model, the phenotypic correlation between type 2 diabetes and depression was significant in females only (r=0.15 (0.08-0.21)). This association was primarily attributed to a significant genetic correlation between the traits (rA=0.53 (0.19-0.98)). CONCLUSIONS: In females, but not males, we found a significant genetic overlap between type 2 diabetes and depression in the context of a modest phenotypic correlation.
