For better and worse? The roles of closeness, marital behavior, and age in spouses' cardiometabolic similarity.

Spouses share common risks for cardiometabolic diseases: a person's diabetes or hypertension raises the partner's odds of developing the same condition. The mechanisms responsible for this disease concordance remain poorly understood. To examine three factors that may modulate partners' cardiometabolic similarity-closeness, hostile marital behavior, and age-and to explore whether health behavior concordance plays a role, on two separate occasions 43 healthy couples ages 24-61 provided fasting glucose, metabolic data (fat and carbohydrate oxidation), and resting blood pressure before discussing one of their most severe marital disagreements. Accounting for the fixed effects of sex, age, study visit, and abdominal fat on cardiometabolic levels, we found that aspects of health behavior concordance were associated with greater similarity in glucose, diastolic blood pressure (DBP), and carbohydrate and fat metabolism. Independent of health behavior concordance, partners who felt closer and behaved in a less hostile way had more similar rates of fat oxidation; less hostile partners also shared greater overlap in carbohydrate oxidation. Likewise, fasting glucose and DBP were more similar within older couples compared to younger pairs, beyond the effects of health behavior concordance. In sum, our data captured preclinical similarities in cardiometabolic health among disease-free couples, which may form the basis for their long-term overlapping disease risks. Closer, less hostile, and older couples shared more similar fasting glucose, metabolic data, and blood pressure; importantly, health behavior concordance did not explain all associations. These novel data suggest that multiple paths may lead to couples' shared disease risks.