Relation of Marital Status and QT Interval Prolongation (from the Third National Health and Nutrition Examination Survey)

Abstract

Although the link between marital status and mortality is well established, the pathophysiological basis is unclear. An investigation of the association of marital status with prolonged QT interval may highlight the underlying mechanism for poor outcomes associated with being unmarried. This analysis included 6,562 participants (mean age 58.6 years, 52% women, 50.1% non-Hispanic whites) without a history of cardiovascular disease from the Third National Health and Nutrition Examination Survey. QT was automatically measured from digital 12-lead electrocardiogram in a central reading center. Marital status was defined by self-report as married and unmarried (never married, divorced/separated or widowed). A multivariable logistic regression model was used to examine cross-sectional association between marital status and prolonged QT interval (≥450 ms in men, ≥460 ms in women). Compared with married, unmarried was associated with 46% higher odds of the prolonged QT interval (odds ratio [OR] 95% confidence interval [95% CI]: 1.46[1.16-1.83]). This association was stronger among men versus women (OR[95% CI]: 1.75[1.27-2.41] vs 1.26[0.92-1.73] respectively; interaction p value = 0.03) and in younger versus older participants (OR [95% CI]: 1.72[1.21-2.42] vs 1.40[1.05-1.88], respectively; interaction p value = 0.002). When the types of unmarried were compared to married, a dose-response relation with prolonged QT was observed with the highest odds in never married followed by divorced/separated, and then widowed. In conclusion, marital status is associated with a prolonged QT interval, especially among men and younger participants. Prolonged QT interval may indicate a biologic substrate through which social isolation defined by unmarried state increases the risk of poor outcomes in the future.