Abstract 1886: Dietary scores and cancer incidence, mortality and survival: Epidemiologic evidence and meta-analysis

Abstract

Abstract Diet scores or indices assess the degree to which an individual's reported diet conforms to dietary recommendations or culturally-defined healthful diets. Characterizing diet exposures in this way provides a more complete picture of individual dietary behavior, and potentially captures additive and/or interactive effects on disease risk. Such metrics, where higher points reflect better diets, and lower scores reflect worse diets, have been examined in relation to cancer incidence, mortality and survival. To date, the literature on the association between diet scores and cancer risk is inconsistent across and within scores. We conducted a literature search for prospective cohort studies of a priori dietary scores or indices in relation to cancer incidence, mortality or survival using PubMed. Meta-analyses were performed when at least five separate studies published results on a cancer outcome, using the same diet score. When studies on both incident and fatal outcomes were available from the same cohort for the same cancer/s, estimates from incident outcomes were used. If more than one version of the same score in the same cohort was evaluated, we used the most recent score. Estimates in men and women were included separately. Meta-analyses of four out of six diet scores and the outcome “total cancer incidence or mortality” showed significant inverse associations comparing top vs bottom quantiles, often with significant study heterogeneity: the Alternate Healthy Eating Index (AHEI) Relative Risk (RR) = 0.88, 95% confidence interval (CI) 0.84-0.93, p heterogeneity = 0.02; Healthy Eating Index (HEI) RR = 0.84, 95% CI 0.77-0.92, p heterogeneity<0.001; Mediterranean Diet Score (MDS) RR = 0.81, 95% CI 0.78-0.85, p heterogeneity = 0.35; and WCRF/AICR RR = 0.77, 95% CI 0.68-0.86, p heterogeneity = 0.046. The associations with the Recommended Food Score (RFS) and Diet Quality Index (DQI) were not statistically significant. The MDS was associated with significantly lower colorectal cancer risk (RR = 0.82, 95% CI 0.73-0.91, p heterogeneity = 0.034). In studies of cancer survivors, less than three studies were available for each diet score/outcome combination; thus no meta-analyses of cancer survival were conducted. These results suggest that following recommended dietary guidelines or the Mediterranean healthy diet pattern may significantly reduce overall cancer risk. The limited number of studies in cancer survivors indicates a need for further research. Citation Format: Marjorie L. Mccullough, Ying Wang, Roma Shah, Susan Gapstur. Dietary scores and cancer incidence, mortality and survival: Epidemiologic evidence and meta-analysis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1886. doi:10.1158/1538-7445.AM2015-1886