© 1992 Oxford University Press
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Body Mass lndex and the Initial Manifestation of Coronary Heart Disease in Women Aged 40–59 Years
Department of Health Sciences Research, Section of Clinical Epidemiology, Mayo Clinic and Mayo Foundation 200 First Street SW, Rochester, MN 55905, USA
Beard C M (Department of Health Sciences Research, Section of Clinical Epidemiology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA), Orencia A, Kottke T and Ballard D J. Body mass index and the initial manifestation of coronary heart disease in women aged 40–59 years. International Journal of Epidemiology 1992; 21: 656–664.
A population-based case-control study was conducted to evaluate body mass as a coronary heart disease (CHD) risk factor among women 40–59 years of age. Cases were women aged 40–59 whose first manifestation of CHD was angina (No. = 133, nonfatal mymardial infarction (No. = 90). and sudden unexpected death (No. = 18) during 1960–1982. Two randomly selected controls were matched on age and time of the initial disease manifestation of the case.
The adjusted relative risk for weight and body mass index respectively demonstrabxl a moderate amxiation with all CHD as well as with angina, but no association with definite CHD (myocardial infarction or sudden unexpected death). To determine if the observed association between body mass index and angina was possibly attributable to differential misclassification bias (i.e. obese women were, in contrast to non-obese women, preferentially labelled as having coronary artery disease) data for angina were stratified by confirmed versus unconfirmed cardiac origin. In the unconfirmed angina analysis, the 75th percentile for weight contrasted with the 25th percentile was associated with a 50% increase in the risk of being labelled as having angina (adjusted odds ratio (OR) = 1.59, 95% confidence interval (CI): 1.11–2.28). while a similar contrast for Quetelet lndex was also associated with a nearly 2-fold increase in'the risk of being labelled as having angina (adjusted OR = 1.74, 95% CI: 1.18–2.57). A 3-fold statistically significant increase in risk of being labdled as having angina was atso oobsetved for similar contrasts of weight and Quetelet lndex among women with confirmed cardiac origin for their symptoms.
These data from the Rochester Coronary Heart Disease project suggest that anthropometric attributes are independent risk factors for angina but not for first myocardial infarction and sudden unexpected death among women aged 40–59 years dd. These findings cannot be explained by differential misclassification of obese women. Additional studies of the association between body mass index and CHD among women age 40–59 should precisely define CHD and obesity measures to avoid possible differential misclassification bias.
Received 1 February 1992