Death of a Parent and the Risk of Ischemic Heart Disease and Stroke in Denmark and Sweden

Importance: Increasing evidence suggests that parental death is associated with unhealthy behaviors and mental ill-health. Knowledge regarding the link between parental death and the risk of ischemic heart disease (IHD) and stroke remains limited. Objectives: To investigate whether parental death is associated with an increased risk of IHD and stroke and whether these associations differ by the characteristics of the loss. Design, Setting, and Participants: This population-based cohort study, involving linkages between several nationwide registers, included 3 766 918 individuals born between 1973 and 1998 in Denmark and between 1973 and 1996 in Sweden. Participants were followed up until 2016 in Denmark and 2014 in Sweden. Data were analyzed from December 2019 to May 2021. Exposures: Death of a parent. Main Outcomes and Measures: Diagnosis with or death due to IHD or stroke. Poisson regression was used to analyze the associations between parental death and IHD and stroke risk. Results: Altogether, 48.8% of the participants were women, and 42.7% were from Denmark. A total of 523 496 individuals lost a parent during the study period (median age at loss, 25 years; IQR, 17-32 years). Parental death was associated with a 41% increased risk of IHD (incidence rate ratio [IRR], 1.41; 95% CI, 1.33-1.51) and a 30% increased risk of stroke [IRR, 1.30; 95% CI, 1.21-1.38). The associations were observed not only if the parent died because of cardiovascular or other natural causes but also in cases of unnatural deaths. The associations were stronger when both parents had died (IHD: IRR, 1.87; 95% CI, 1.59-2.21; stroke: IRR, 1.64; 95% CI, 1.35-1.98) than when 1 parent had died (IHD: IRR, 1.37; 95% CI, 1.28-1.47; stroke: IRR, 1.27; 95% CI, 1.19-1.36) but did not differ substantially by the offspring's age at loss or the deceased parents' sex. The risk of acute myocardial infarction was highest in the first 3 months after loss. Conclusions and Relevance: In this cohort study, parental death in the first decades of life was associated with an increased risk of IHD and stroke. The associations were observed not only in cases of parental cardiovascular and other natural deaths but also in cases of unnatural deaths. Family members and health professionals may need to pay attention to the cardiovascular disease risk among parentally bereaved individuals.