Do health behaviors mediate associations between personality traits and diabetes incidence?

Purpose: Personality traits have been reported to be associated with type 2 diabetes (T2DM) risk. The objective of this study was to examine whether and to what extent the associations between personality traits (dispositional optimism, hostility, and negative emotional expressiveness) and risk of T2DM were mediated by health behaviors and obesity.
Methods: Postmenopausal women (n = 110,992) aged 50-79 years without diabetes at enrollment in the Women's Health Initiative study (1993-1998) were followed up to 25 years. Incident diabetes was assessed via a validated self-report of physician-diagnosed diabetes treated with insulin or other hypoglycemic medications. Mediation analyses were performed using approaches under a counterfactual framework.
Results: An inverse association of optimism with diabetes was significantly mediated by a factor primarily extracted from physical activity, diet quality, and sleep quality with a mediated proportion of 28%. Positive associations for hostility and negative emotional expressiveness were substantially mediated by a factor primarily composed of body mass index and waist circumference with mediated proportions of 32% and 44%, respectively.
Conclusions: Our data revealed that less than half of the associations between personality traits and risk of T2DM were explained by indirect health behavior pathways. Women's personality traits should be considered in prevention of diabetes in addition to promoting health behaviors.
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