Trait Anger, Hostility, and the Risk of Type 2 Diabetes and Diabetes- Related Complications: A Systematic Review of Longitudinal Studies

BACKGROUND: Research suggests associations between trait anger, hostility, and type 2 diabetes and diabetes-related complications, though evidence from longitudinal studies has not yet been synthesized. OBJECTIVE: The present systematic review examined findings from longitudinal research on trait anger or hostility and the risk of incident type 2 diabetes or diabetes-related complications. The review protocol was pre-registered in PROSPERO (CRD42020216356). METHODS: Electronic databases (MEDLINE, PsychINFO, Web of Science, and CINAHL) were searched for articles and abstracts published up to December 15, 2020. Peer-reviewed longitudinal studies with adult samples, with effect estimates reported for trait anger/hostility and incident diabetes or diabetes-related complications, were included. Title and abstract screening, full-text screening, data extraction, and quality assessment using the Newcastle-Ottawa Scale were conducted by two independent reviewers. A narrative synthesis of the extracted data was conducted according to the Synthesis Without Meta-Analysis guidelines. RESULTS: Five studies (N = 155,146 participants) met the inclusion criteria. While results were mixed, our synthesis suggested an overall positive association between high trait-anger/hostility and an increased risk of incident diabetes. Only one study met the criteria for the diabetes-related complications outcome, which demonstrated a positive association between hostility and incident coronary heart disease but no significant association between hostility and incident stroke. CONCLUSION: Based on the available longitudinal evidence, trait anger and hostility are associated with an increased risk of diabetes. Longitudinal studies are needed to investigate the association between trait-anger or hostility and the risk of diabetes-related complications.