In this study, the investigators studied the association between carbohydrate quality and coronary heart disease using prospective cohort studies among US adults. Carbohydrate quality was evaluated using a variety of metrics including carbohydrate, starch, total fiber, cereal fiber, fruit fiber, and vegetable fiber intake, as well as the ratios of carbohydrate to total fiber, carbohydrate to cereal fiber, starch to total fiber, and starch to cereal fiber. The Nurses' Health Study (NHS) and the Health Professionals Follow Up Study (HPFS) started in 1984 and 1986, respectively, and were followed-up every 2-4 years thereafter until 2012. Participants include in this study had up to 28y of follow-up. All participants were free of known diabetes mellitus, cancer or cardiovascular disease at baseline. Cox proportional hazards regression models were used to assess the relationship between dietary measures of carbohydrate quality and incident CHD (nonfatal myocardial infarction and fatal CHD).