Depression Onset After a Spouse's Cardiovascular Event.

IMPORTANCE: Although cardiovascular disease (CVD) is a known risk factor for depression, evidence is lacking regarding whether and to what extent a spouse's CVD is associated with the subsequent mental health of individuals.

OBJECTIVE: To examine the association between CVD onset in spouses and subsequent depression.

DESIGN, SETTING, AND PARTICIPANTS: This cohort study examined 277 142 matched married couples enrolled in the Japan Health Insurance Association health insurance program between April 2015 and March 2022, covering approximately 40% of the working-age population in Japan. Index individuals (primary insured) whose spouses (dependent) experienced incident CVD between April 2016 and March 2022 were 1:1 matched to controls whose spouses did not experience CVD. Matching was based on age, sex, income, or the onset date of the spouses' CVD. Data analysis was conducted from April 2016 to March 2022.

EXPOSURE: Spousal onset of CVD between fiscal years 2016 and 2021. The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes were used to identify the composite CVD outcomes (stroke, heart failure, and myocardial infarction).

MAIN OUTCOMES AND MEASURES: Multivariate Cox proportional hazards models were used to investigate the association between spouses' new-onset CVD and individuals' depression, adjusting for sociodemographic characteristics and comorbidities of index individuals (diabetes, hypertension, and CVD) and spouses (diabetes, hypertension, and depression). Subgroup analyses were conducted according to sex, age, income levels, and history of CVD.

RESULTS: Among 277 142 matched pairs of married couples, 263 610 (95.1%) had a male index individual; the mean (SD) age of index individuals was 58.2 (10.2) years. A new onset of depression was observed in 4876 individuals (1.8%). In multivariable Cox models, there was an association between the spouse's CVD and the individuals' depression (hazard ratio, 1.13 [95% CI, 1.07-1.20]). The subgroup analysis found no evidence of heterogeneity in sex, age, income level, or CVD history. The results were consistent when additionally adjusted for health behaviors (smoking, alcohol consumption, physical activity, and use of antihypertensive drugs) and objectively measured physical health conditions (body mass index, blood pressure, cholesterol levels, glucose levels, and estimated glomerular filtration rate) (hazard ratio, 1.16 [95% CI, 1.06-1.28]).

CONCLUSIONS AND RELEVANCE: In this nationwide cohort study of matched couples, a spouse's onset of CVD was associated with an increased risk of an individual's depression. These findings highlight the importance of preventive care for mental health disorders in individuals whose spouses experience incident CVD.