Spousal similarities in cardiometabolic risk factors: A cross-sectional comparison between Dutch and Japanese data from two large biobank studies

Background and aims: Few studies have examined and compared spousal concordance in different populations. This study aimed to quantify and compare spousal similarities in cardiometabolic risk factors and diseases between Dutch and Japanese populations. 
Methods: This cross-sectional study included 28,265 Dutch Lifelines Cohort Study spouse  pairs (2006–2013) and 5,391 Japanese Tohoku Medical Megabank Organization (ToMMo) Cohort Study pairs (2013–2016). Spousal similarities in cardiometabolic risk factors were evaluated using Pearson's correlation or logistic regression analyses adjusted for spousal age.  
Results: The husbands’ and wives’ average ages in the Lifelines and ToMMo cohorts were 50.0 and 47.7 years and 63.2 and 60.4 years, respectively. Significant spousal similarities occurred with all cardiometabolic risk factors and diseases of interest in both cohorts. The age-adjusted correlation coefficients ranged from 0.032 to 0.263, with the strongest  correlations observed in anthropometric traits. Spousal odds ratios [95% confidence interval] for the Lifelines vs. ToMMo cohort ranged from 1.45 (1.36–1.55) vs. 1.20 (1.05–1.38) for hypertension to 6.86 (6.30–7.48) vs. 4.60 (3.52–6.02) for current smoking. An increasing trend in spousal concordance with age was observed for sufficient physical  activity in both cohorts. For current smoking, those aged 20–39 years showed the strongest concordance between pairs in both cohorts. The Dutch pairs showed stronger similarities in anthropometric traits and lifestyle habits (smoking and drinking) than their Japanese counterparts. 
Conclusions: Spouses showed similarities in several cardiometabolic risk factors among 61 Dutch and Japanese populations, with regional and cultural influences on spousal 62 similarities.