Background: Dietary factors are known to influence colorectal cancer (CRC) risk, however, their association with CRC survival is unclear. Therefore, we prospectively examined the association between diet quality scores, dietary patterns and colorectal cancer (CRC) survival.
Methods: 1201 women diagnosed with stage I-III CRC between 1986 and 2008, were followed through 2010. Diet was assessed via a food frequency questionnaire administered at least 6 months after diagnosis. We computed the Alternate Healthy Eating Index-2010 (AHEI-2010), alternate Mediterranean Diet score (aMED) and Dietary Approaches to Stop Hypertension score (DASH) and derived two dietary patterns, Western (unhealthy) and prudent (healthy), by principal component analysis for each woman.
Results: During follow-up, we documented 435 deaths, including 162 from CRC. After adjusting for potential confounders, only a higher AHEI-2010 score was significantly associated with lower overall mortality (HR comparing extreme quintiles = 0.71, 95% CI 0.52-0.98, p trend = 0.01) as well as borderline significantly with lower risk of CRC mortality by the trend test (HR Q5 vs Q1 = 0.72, 95% CI = 0.43-1.21, p trend = 0.07). When AHEI-2010 components were examined separately, inverse associations for overall mortality were primarily accounted for by moderate alcohol intake (HR comparing abstainers vs 5-15 g/d = 1.30, 95%CI = 1.05-1.61) and lower intake of sugar sweetened beverages and fruit juices combined (HR for each additional serving = 1.11, 95% CI = 1.01-1.23). No other diet quality score or dietary pattern was associated with overall or CRC-specific mortality.
Conclusion: Higher AHEI-2010 score may be associated with lower overall mortality, moderate alcohol consumption and lower consumption of sugar sweetened beverages and juices combined appeared to account for most of the observed associations.