Principal Findings:

The study population includes 29,683 dentists; 10,098 veterinarians; 4,185 pharmacists; 3,745 optometrists; 2,218 osteopathic physicians; and 1,600 podiatrists. The study began in 1986 when participants completed a detailed dietary and medical history questionnaire sent through the mail. Follow-up questionnaires were submitted in 1988, 1990, and 1992 to ascertain newly diagnosed coronary disease events. The population was divided into quintiles by baseline fiber intake.

During 6 years of follow-up, there were 734 cases of MI (229 were fatal coronary heart disease). The age-adjusted relative risk (RR) for total MI was 0.59 (95% confidence interval [CI], 0.46 to 0.76) among men in the highest quintile of total dietary fiber intake (median, 28.9 g/d) compared with men in the lowest quartile (median, 12.4 g/d). The inverse association was strongest for fatal MI (RR, 0.45; 95% CI, 0.28 to 0.72).

When the fiber data were divided into sources of fiber, only the intake of cereal fiber (not vegetable or fruit fiber) was associated with a decreased risk for MI in the highest quintile of consumption (multivariate RR 0.73, CI 0.56 to 0.94, P for trend = 0.02); this pattern remained consistent after controlling for the intake of carotene, folate, and vitamin B6.

Men who consumed more fiber were older, leaner, less likely to smoke, and more likely to take vitamin E supplements. Men who reported a higher fiber intake consumed less saturated fat and cholesterol.

After controlling for smoking, physical activity and other known nondietary cardiovascular risk factors, dietary saturated fat, vitamin E, total energy intake, and alcohol intake, total fiber intake was still strongly inversely associated with risk of total MI.