Diet quality and subsequent cancer incidence and mortality in a prospective cohort of women

BACKGROUND: We have previously reported on the utility of the Recommended Foods Score (RFS), a measure of overall diet quality, in detecting associations between diet and mortality in a cohort of older women. Using additional follow-up, we have now extended our analysis to detailed studies of associations between RFS and the mortality and incidence from common cancers. METHODS: The RFS, the sum of 23 recommended food items consumed at least weekly, was computed from a 62-item food frequency questionnaire completed at baseline by 42 254 women with a mean age of 61 years. Multivariate adjusted relative risk (RR) of cancer mortality and incidence of the cancers for which we were able to obtain data in relation to quartiles of RFS were examined using proportional hazards regression analyses after a median follow-up period of 9.5 years. RESULTS: We observed that RFS was inversely associated with total mortality (RR = 0.8; P < 0.001) cancer mortality (RR = 0.74; P < 0.001) as well as mortality from cancers of the breast (RR = 0.75; P < 0.06), colon/rectum (RR = 0.49; P < 0.01) and lung (RR = 0.54; P < 0.001). The risk of incident lung cancer (RR = 0.62; P < 0.001) was reduced in women in the highest vs the lowest quartile of RFS; for incident cancers of the breast, colorectum, endometrium, ovaries, and bladder, there was no RFS association. CONCLUSION: A dietary pattern reflecting a higher RFS was associated with decreased overall mortality in women, specifically cancers of the lung, colon/rectum, and to a lesser extent breast. Incidence was only decreased for lung cancers. These observations are consistent with the hypothesis that a high RFS dietary pattern, or associated lifestyle factors, might affect cancer progression and survival.