Conventional and regionally distinctive risk factors for first-onset myocardial infarction: the Bangladesh Risk of Acute Vascular Events (BRAVE) case-control study.

BACKGROUND

South Asians may be particularly susceptible to premature myocardial infarction (MI) owing both to conventional cardiovascular risk factors and practices distinctive to South Asia. Identifying modifiable risk factors for MI in these populations could inform prevention strategies. We have, therefore, studied conventional risk factors and other characteristics in relation to occurrence of first MI in Bangladesh.

METHODS

In a case-control study involving 8133 first-onset MI cases and 8124 controls recruited in Bangladesh, we calculated odds ratios (ORs) for MI adjusted, for age, sex, smoking status, history of diabetes, history of hypertension, family history of MI, and LDL-cholesterol. We assessed the potential public health impact of risk factor modification using population attributable fractions (PAFs).

FINDINGS: The median (IQR) age of first MI was 53 (45-60) years. Adjusted ORs (95% CIs) were 2.80 (2.57-3.05) for cigarette smoking, 2.17 (1.94-2.43) for family history of MI, 2.27 (2.07-2.48) for history of hypertension, 1.91 (1.72-2.13) for history of diabetes, and 1.53 (1.47-1.58) per 1-SD higher LDL-cholesterol. The highest PAFs (95% CIs) were with current cigarette smoking (49% [46%-52%]), higher LDL-cholesterol (31% [29%-33%]) and history of hypertension (15% [13%-16%]). As for regionally distinctive practices, ORs were 4.02 (3.13-5.17) with biri/hukkah smoking, 2.09 (1.52-2.87) with chewing tobacco, and 1.26 (1.05-1.51) with parental history of first-cousin marriage.

INTERPRETATION: Our results confirm the relevance of several conventional risk factors to risk of first MI in Bangladesh, and identify associations with MI of practices distinctive to South Asia, including indigenous modes of tobacco consumption and parental first-cousin marriage. These findings suggest opportunities for cardiovascular disease prevention in Bangladesh that embrace both conventional and regionally distinctive risk factors.

FUNDING: The BRAVE Study Coordinating Centre is underpinned by grants from the British Heart Foundation, UK Medical Research Council and National Institute for Health Research Cambridge Biomedical Research Centre.