Do personality traits moderate the manifestation of type 2 diabetes genetic risk?

Objective. To test whether personality traits moderate type 2 diabetes (T2D) genetic risk. Methods. Using a large community-dwelling sample (n = 837, M-age = 69.59 +/- 0.85 years, 49% males) we fitted a series of linear regression models predicting glycated haemoglobin (HbA1c) from T2D polygenic risk - aggregation of small individual effects of a large number of single nucleotide polymorphisms (SNPs) - and five personality traits. We tested the main effects of personality traits and their interactions with T2D polygenic risk score, controlling for age and sex. The models in the final set were adjusted for cognitive ability, highest educational qualification, and occupational class. Results. Lower levels of openness were associated with heightened levels of HbA1c (beta = -0.014, p = .032). There was a significant interaction between T2D polygenic risk score and agreeableness: lower agreeableness was related to a stronger association between T2D polygenic risk and HbA1c (beta = -0.08,p = .021). In the model adjusted for cognitive ability, the main effect of openness was not significant (beta = -0.08, p = .057). The interaction between agreeableness and T2D polygenic risk was still present after controlling for cognitive ability and socioeconomic status indicators, and the interaction between conscientiousness and polygenic risk score was also significant: lower conscientiousness was associated with a stronger association between T2D polygenic risk and HbA1c levels (beta = 0.09, p = .04). Conclusions. Personality may be associated with markers of diabetes, and may moderate the expression of its genetic risk. (C) 2015 The Authors. Published by Elsevier Inc.