Concordance of Characteristics and Metabolic Syndrome in Couples: Insights from a National Survey.

Background and Objective: There is insufficient evidence on whether the concordance of sociodemographic, behavioral, and nutritional characteristics between spouses correlates with the concordance of metabolic syndrome (MetS) between spouses, or if a spouse's characteristics are directly linked to their own MetS. This study seeks to evaluate the association between the concordance of characteristics and the concordance of MetS in couples and investigate whether a spouse's attributes are linked to their partner's MetS. Methods: Analyzing data from the Korea National Health and Nutrition Examination Survey 2019-2021, 1824 couples with complete data, including MetS parameters, sociodemographic details, health behaviors, and dietary information, were included. General linear model and logistic regression were employed. Results: Among couples, 10.7% exhibited concordant MetS, with spousal concordance ranging from 1.3% to 81.5% for nonoptimal characteristics. Multivariate analysis revealed that the odds of both partners having MetS increased by 1.04-1.61 times with a higher mean age of the couple and higher concordance in lower education, poor subjective health, insufficient strength exercise, and excessive carbohydrate consumption. When accounting for both individual and spousal factors, the odds of MetS rose with the higher mean age of the couple, having a spouse with MetS, their own characteristics (lower education, poor subjective health, insufficient strength exercise, and sedentary behavior for husbands and wives; alcohol consumption and insufficient walking for husbands; and excessive carbohydrate intake for wives), and spousal factors such as smoking (in husbands) and lower education, lower economic status, and excessive carbohydrate intake (in wives). In wives, spousal sedentary behavior and poor subjective health were linked to decreased odds. Conclusions: The findings suggest a connection between MetS concordance and shared characteristics in couples, as well as an association between both spousal MetS status and characteristics and their own MetS.