Healthy dietary patterns and risk and survival of breast cancer: a meta-analysis of cohort studies

PurposesDietary patterns have been found to be associated with the overall cancer risk and survival. However, the associations of healthy dietary patterns and breast cancer remain unclear. We aimed to conduct a meta-analysis of prospective cohort studies to estimate the pooled results of the association of healthy dietary patterns with breast cancer risk and survival.MethodsPubMed, EMBASE, and Web of Science were searched for literature published until June 24th, 2018 that examined the associations between healthy dietary patterns and breast cancer risk and survival. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated by using a random-effects model for meta-analysis.ResultsThere were 32 articles retrieved for the meta-analysis, with 27 for breast cancer risk and five for breast cancer survival. There was a statistically significant lower risk of breast cancer associated with healthy dietary patterns (RR=0.93, 95% CI: 0.88, 0.98). Subgroup analysis results suggested that there was an inverse association between breast cancer risk and posterori-derived healthy patterns, but no statistically significant associations were found in other stratified subgroups (a priori-derived diet, study region, menopausal status, or breast cancer subtypes). Healthy dietary patterns were associated inversely with all-cause mortality (RR=0.76, 95% CI: 0.63, 0.92); however, no association was found for breast cancer-specific mortality.ConclusionsThe results suggested that healthy dietary patterns might be associated with a reduced risk of breast cancer and all-cause mortality among breast cancer patients. It could be clinically relevant to promote healthy dietary patterns for breast cancer prevention and improve survival among breast cancer patients.