Association between marital relationship and multimorbidity in middle-aged adults: a longitudinal study across the US, UK, Europe, and China

Background: Marital relationship plays an important role in health and wellbeing. However, how marriage is associated with multimorbidity (the co-occurrence of two or more chronic conditions) has not been comprehensively investigated. We aimed to assess the association between marriage and multimorbidity in middle-aged adults. Methods: We used nationally representative data on 23641 adults aged 50-60 years who participated in four longitudinal studies in the US, UK, Europe, and China (Health and Retirement Study, English Longitudinal Study on Ageing, Survey of Health, Ageing and Retirement in Europe, and China Health and Retirement Longitudinal Study). Respondents were followed up in 2010-11 (baseline), 2012-13, and 2014-15. We used generalized estimating equations to evaluate the associations between marital status (married/partnered or non-married [separated/devoiced/widowed/never married]), marriage duration and multimorbidity, adjusting for socioeconomic and lifestyle factors. Results: Over 4-year follow-up, 24% (n=5699) of respondents experienced separation, divorce, widowhood, or never-married status, and approximately 43% (n=10228) of respondents reported multimorbidity. Those who were not married had a higher odds of multimorbidity (age-, sex- and region-adjusted odds ratio 1.19; 95% confidence interval 1.14 to 1.25). Those who had been married for 21-30 years had a lower odds of experiencing multimorbidity than those married for less than 10 years. The associations remained robust after adjusting for socioeconomic and lifestyle factors. Conclusions: Marital relationship (status and length) was associated with multimorbidity in middle-aged adults, highlighting the role of marital relationship in shaping the trajectory of health and wellbeing across the life course. These findings provide insight for the prevention and management of chronic disease and multimorbidity.