Relation of obesity to acute myocardial infarction in Japanese patients.

BACKGROUND It remains uncertain whether obesity is an independent risk factor for coronary heart disease in young adults, as well as adults, in Japan. METHODS AND RESULTS In the present study, 1,260 cases of acute myocardial infarction (AMI) and 3,775 community controls were recruited from the AMI-Kyoto Multi-Center Risk Study and Kyoto Citizen's Health and Nutrition Study, respectively. Obesity and other risk factors were retrospectively examined between cases and controls in each subgroup of young males (20-40 years), middle-aged males or females (40-60 years), older males or females (60-80 years), and very old males or females (80-100 years). In young, middle-aged, and older males, as well as in older females, cases had a higher body mass index (BMI) than controls. In young males, as well as in middle-aged and older females, cases had a higher prevalence of smoking than controls. Except for very old males, the prevalences of hypercholesterolemia, hypertension, and diabetes mellitus were higher in each subgroup of cases than in controls. Multivariate logistic regression analysis revealed that obesity (BMI >or=25) was an independent risk for AMI in young and middle-aged males, but not in females, whereas smoking was an independent risk for AMI in middle-aged and older females as well as in older males. CONCLUSIONS Obesity is significantly associated with AMI, independent of the classic coronary risk factors, in young and middle-aged males. These findings support the current emphasis on controlling obesity to prevent coronary events in young Japanese male adults.