Association of Marital Status with all-cause and cause-specific Mortality in Women and Men from the Moli-sani Study Cohort

Objective: To study the relationship between marital status and all-cause and cause-specific mortality in Italian women and men, and to further analyse the role of potential mediating factors such as socioeconomic (e.g., number of cohabitants, education, housing), behavioural (e.g., smoking, leisure time physical activity, BMI), and physiological factors (e.g. blood glucose, lipid levels). Methods: We conducted longitudinal analyses on 12,139 women and 11,166 men from the Moli-sani Study: Exposure and mediation variables were collected only at baseline (2005-2010), while participants were followed up for vital status for 14.5 years (IQR: 12.2–17.3) (median). Marital status was categorized as married/cohabiting, divorced/separated, single/unmarried, or widowed. Mortality outcomes included all-cause, cardiovascular, cancer, and other causes. Mediation analyses examined explanatory mechanisms, and subgroup analyses evaluated generational differences. Results: Compared to married/cohabiting, single women showed elevated rates for all-cause and cancer mortality (HR:1.33; 95%CI1.04-1.69 and HR:1.92; 95%CI: 1.32-2.79, respectively). All unmarried men categories faced higher mortality rates for all-cause mortality as compared to married/cohabiting (HR:2.03; 95%CI:1.51-2.72, HR:1.40; 95%CI1.09-1.81, HR:1.32; 95%CI1.11-1.56, for divorced/separated, single and widowed, respectively. Mediation analyses revealed that smoking, cystatin C levels, and heart rate were relevant mediating factors for single women, divorced/separated men and single men. While behavioural factors like leisure time, physical activity, diet quality, and heart rate played significant role in widowed men. Conclusions: Single women and all unmarried categories in men face significantly elevated rates of mortality. Part of these associations were explained by behavioural and physiological factors.