This is an analysis conducted in the Nurses Health Study and the Health Professional Follow-Up Study, both prospective cohort studies, where the investigators systematically investigated the association between carbohydrate quality using a variety of metrics in relation to coronary heart disease. This was a secondary data analysis of previously collected data in both cohorts.

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).

Inclusion Criteria:

• Participants of these two cohorts

Exclusion Criteria:

• Participants with diabetes, coronary heart disease, or cancer at baseline
• Participants with missing exposure information at baseline
• Participants with implausible food frequency questionnaire info (females: kcal < 500 or > 3500; males: kcal < 800 or > 4200)
• Participants who left 10 or more items blank on the food frequency questionnaire

The analysis was based on two cohorts: one of female registered nurses and the other of male health professionals only.

The Nurses' Health Study (NHS) was initiated in 1976 as a prospective cohort study, where 121,701 female registered nurses between the ages of 30 and 55 years were recruited from 11 US states. The Health Professionals Follow-up Study (HPFS) was initiated in 1986 and recruited 51,529 US men between the ages of 40-75. Every two years, participants updated their information on medical history, lifestyle, and incidence of chronic diseases using validated questionnaires. Follow-up rates are at least 90% of potential person-years of follow-up and mortality follow-up is more than 98%.