Abstract:
Objective: 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, and 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 female individuals
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 female individuals, but not male individuals, we found a significant genetic overlap between type 2 diabetes and depression
in the context of a modest phenotypic correlation.
Key words: type 2 diabetes, depression, genetic, twin, structural equation modeling
