Abstract 13469: A Detailed Family History of Myocardial Infarction Provides Detailed Information on Risk of Myocardial Infarction, a Nationwide Cohort Study
Background: Ischemic heart disease clusters in families, but most cardiovascular risk score systems (e.g. HeartScore) are not taking the potential risk associated with a positive family history into account. The weight of this risk factor may depend on the relatedness to the affected relative. To elucidate on this we aimed to examine the effect of a detailed family history of myocardial infarction (MI) on the risk of MI in a nationwide cohort.
Methods: In Danish national registers, we established a cohort of persons born from 1930 with identifiable first- (parents, children or siblings) or second- (grandparents/children and half-siblings) degree relatives. We registered incident MIs in persons aged ≥20 years. In cohort members we registered diagnoses of diabetes mellitus and arteriel hypertension, and use of cardiovascular medication. We used Poisson regression to calculate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for MI by family history of MI. All IRRs were adjusted for age, sex, calendar period, hypertension, diabetes and use of diuretics, calcium-antagonists, beta-blockers, lipid-lowering drugs, and drugs affecting the renin-angiotensin system.
Results: In 3.6 million cohort-members followed for 48 million person-years, we identified 70,536 incident MIs. Fully adjusted IRRs (95% CI) for MI by family history of MI in one, two or three first degree relatives were 1.47 (1.42-1.60), 2.42 (2.20-2.66) and 3.40 (2.24-5.17), respectively. Corresponding estimates for second degree relatives were 1.15 (0.99-1.33), 1.89 (1.35-2.65) and 2.26 (0.85-6.03). For MI in a same-sex twin the IRR was 10.27 (5.02-21.02), MIs in opposite-sex twins or full-siblings conferred risks of 2.62 (0.36-18.87) and 2.74 (2.43-3.09). The IRRs by MI in parents and grandparents were 1.77 (1.71-1.84) and 1.18 (0.99-1.41), respectively. IRRs increased with younger age of cohort member and of relative at time of MI.
Conclusion: Lower risks in parents as compared to siblings suggests gene-environment interactions. A dose-response pattern was evident when comparing first and second degree relatives and examining number of relatives with MI. This supports inclusion of a detailed family history in risk-assessment in patients with a family history of MI.
- © 2012 by American Heart Association, Inc.