A family history of myocardial infarction in 1, 2, or ≥3 first-degree relatives increased the risk of incident MI with IRRs of 1.46, 2.38, and 3.58, respectively.
Cohort (n=4,400,000)
Yes
Does a detailed family history of myocardial infarction (including second-degree relatives) increase the risk of incident myocardial infarction in the general population?
A detailed family history of myocardial infarction, including the number of affected first- and second-degree relatives, significantly and dose-dependently increases the risk of incident MI, particularly in middle-aged individuals.
Effect estimate: IRR 1.46 (95% CI 1.42-1.49)
BACKGROUND: Family history of myocardial infarction (MI) is an independent risk factor for MI. Several genetic variants are associated with increased risk of MI and family history of MI in a first-degree relative doubles MI risk. However, although family history of MI is not a simple dichotomous risk factor, the impact of specific, detailed family histories has not received much attention, despite its high clinical relevance. We examined risk of MI by MIs in first- and second-degree relatives and by number and age of affected relatives. METHODS AND FINDINGS: Using Danish national registers, we established a nationwide cohort of persons born between 1930 and 1992 with identifiable first- or second-degree relatives. Incident MIs in both cohort members and relatives aged ≥20 years were identified. We calculated incidence rate ratios (IRRs) for MI by family history of MI, by Poisson regression. In 4.4 million persons followed for 104 million person-years, we identified 128,384 incident MIs. IRRs with 95% confidence intervals CIs for MI by history of MI in 1, 2 or ≥3 first-degree relatives were 1.46 (1.42-1.49), 2.38 (2.22-2.56) and 3.58 (2.66-4.81), respectively. Corresponding estimates for second-degree relatives were 1.17 (1.05-1.30), 1.87 (1.46-2.38) and 2.18 (1.09-4.36). A history of MI in combinations of first- and second-degree relatives increased risks 1.8- to 7-fold in middle-aged persons (36 to 55 years). Estimates were robust to adjustment for diabetes, hypertension, dyslipidemia and use of cardiovascular medications. CONCLUSION: A detailed family history, particularly number of affected first- and second-degree relatives, contributes meaningfully to risk assessment, especially in middle-aged persons. Future studies should test for potential improvement of risk algorithm prediction using detailed family histories.
Ranthe et al. (Tue,) conducted a cohort in Myocardial Infarction (n=4,400,000). Family history of myocardial infarction vs. No family history of myocardial infarction was evaluated on Incident myocardial infarction (IRR 1.46, 95% CI 1.42-1.49). A family history of myocardial infarction in 1, 2, or ≥3 first-degree relatives increased the risk of incident MI with IRRs of 1.46, 2.38, and 3.58, respectively.