Background: The association between psychological stress and coronary heart disease remains unclear. We conducted a prospective follow-up study based on national registers to investigate if the death of a child, one of the most severe stressors, increases the risk of myocardial infarction (MI) in parents.
Methods and results: From 1980 to 1996, 19 361 parents who lost a child (<18 years of age) in Denmark were recruited to the exposed cohort, and 295 540 parents matched on family structure were selected for the unexposed cohort. The Cox proportional hazards model was used to evaluate the relative risk (RR) of myocardial infarction (MI). The average RRs for a fatal MI and any first MI among the exposed were 1.36 (95% CI, 0.98 to 1.88) and 1.28 (95% CI, 1.08 to 1.51), respectively. The two cohorts had similar MI risk during the first 6 years of follow-up. From the 7th to the 17th year of follow-up, the exposed cohort had a RR of 1.58 (95% CI, 1.08 to 2.30) for fatal MI and a RR of 1.31 (95% CI, 1.09 to 1.57) for first MI. Parents who lost a child unexpectedly, especially from sudden infant death syndrome, experienced higher RRs.
Conclusions: The death of a child was associated with an increased risk of MI in bereaved parents.