Anger, adiposity, and glucose control in nondiabetic adults: findings from MIDUS II.

Anger has been linked to cardiovascular disease, but few studies have examined the relationship between anger and type 2 diabetes. The aim was to investigate associations among different indicators of anger expression, adiposity, and nondiabetic glucose metabolism in a national survey of adults. Participants were 939 adults without diabetes in the Midlife in the US study (MIDUS II). Glucose metabolism was characterized by fasting glucose, insulin, insulin resistance, and glycosylated hemoglobin (HbA1c). Spielberger's Anger Expression inventory was used to measure suppressed anger (anger-in), expressed anger (anger-out), and controlled anger (anger-control). We investigated the relationship between anger and glucose metabolism, and whether anger amplified the adverse relationship between body weight distribution (body mass index = BMI and waist-to-hip ratio = WHR) and glucose metabolism. Multivariate-adjusted analyses revealed an association between anger-out and both insulin and insulin resistance. As predicted, anger-in amplified the relationships between BMI and insulin and insulin resistance, while anger-out amplified the association between WHR and insulin and insulin resistance. Low anger-control was associated with higher glucose. None of the three anger measures was significantly associated with HbA1c. Our findings extend previous research on anger as a potential risk factor for type 2 diabetes by demonstrating that anger expression is associated with clinical indicators of glycemic control, especially among those with pre-existing risk due to obesity and high central adiposity.