Background: South Asians may be particularly susceptible to premature myocardial infarction (MI) owing both to classic cardiovascular risk factors and distinctive practices more common in South Asian populations. Hypothesis: Identifying modifiable risk factors for MI in South Asian populations should inform prevention strategies. Goal: To study conventional risk factors and several distinctive South Asian characteristics and practices in relation to the likelihood of first-ever MI in Bangladesh. Methods: In a case-control study involving 8,133 first MI cases and 8,122 controls, we calculated odds ratios (ORs) for MI (adjusted, when appropriate, for age, sex, smoking status, history of diabetes, history of hypertension, family history of MI, and LDL-cholesterol) and assessed their potential public health impact using population attributable fractions (PAFs). Results: The mean (SD) age of first MI was 53 (11) years. Adjusted ORs (95% CIs) were 2.75 (2.53-2.99) for cigarette smoking, 2.33 (2.08-2.60) for parental history of MI, 2.26 (2.07-2.48) for history of hypertension, 1.79 (1.61-1.98) for history of diabetes, and 1.61 (1.55-1.67) per 1-SD higher LDL-cholesterol. The highest PAFs (95% CIs) were for current cigarette smoking (48.9% [46.1%-51.6%]), higher LDL-cholesterol (32.4% [30.2%-34.4%]) and history of hypertension (14.7% [13.2%-16.1%]). As for regionally distinctive practices, ORs were 4.05 (3.15-5.21) with biri smoking, 2.04 (1.48-2.81) with chewing tobacco, and 1.26 (1.05-1.51) with parental history of first cousin marriage. Conclusion: In a large case-control study, we confirmed the relevance of several conventional risk factors to risk of first-onset MI in the Bangladesh population. We also identified significant associations with MI of practices distinctive to South Asian populations, including indigenous modes of tobacco consumption and parental first-cousin marriage, apparently independent of conventional risk factors. These findings should help identify opportunities for cardiovascular disease prevention in South Asia that embrace both conventional and regionally distinctive risk factors.
Read full abstract