A prospective study of diet quality and mortality in women

Context  Most studies of diet and health care have focused on the role of single nutrients, foods, or food groups in disease prevention or promotion. Few studies have addressed the health effects of dietary patterns, which include complex mixtures of foods containing multiple nutrients and nonnutrients. Objective  To examine the association of mortality with a multifactorial diet quality index. Design and Setting  Data from phase 2 (1987-1989) of a prospective cohort study of breast cancer screening, the Breast Cancer Detection Demonstration Project, with a median follow-up of 5.6 years. Participants  A total of 42,254 women (mean age, 61.1 years) who completed the food frequency questionnaire portion of the survey. Main Outcome Measure  All-cause mortality by quartile of Recommended Food Score (RFS; the sum of the number of foods recommended by current dietary guidelines [fruits, vegetables, whole grains, low-fat dairy, and lean meats and poultry] that were reported on the questionnaire to be consumed at least once a week, for a maximum score of 23). Results  There were 2065 deaths due to all causes in the cohort. The RFS was inversely associated with all-cause mortality. Compared with those in the lowest quartile, subjects in the upper quartiles of the RFS had relative risks for all-cause mortality of 0.82 (95% confidence interval [CI], 0.73-0.92) for quartile 2, 0.71 (95% CI, 0.62-0.81) for quartile 3, and 0.69 (95% CI, 0.61-0.78) for quartile 4 adjusted for education, ethnicity, age, body mass index, smoking status, alcohol use, level of physical activity, menopausal hormone use, and history of disease (²₁ for trend=35.64, P<.001 for trend). Conclusions  These data suggest that a dietary pattern characterized by consumption of foods recommended in current dietary guidelines is associated with decreased risk of mortality in women.