Dietary factors and colorectal cancer risk in Asian populations: a systematic review and meta-analysis of cohort studies.

PURPOSE

Colorectal cancer (CRC) is the third most common cancer worldwide and a leading cause of cancer-related mortality. Few studies have examined the preventive effects of dietary factors against CRC in Asian populations. Thus, this systematic review and meta-analysis aimed to synthesize and analyze current evidence on the relationships between various dietary components and the risk of CRC, colon cancer, and rectal cancer in Asian populations.

METHODS

We included cohort studies from PubMed, Web of Science, Embase, and Scopus reporting an association between dietary factors and CRC risk in Asian populations. Relative risks (RRs) with 95% confidence intervals (CIs) were used to calculate the pooled risk estimates. Cochran's Q and I statistics were employed to assess heterogeneity. Funnel plots and Egger's tests were used to evaluate publication bias.

RESULTS

Eighty-two publications met the inclusion criteria. The findings indicated that healthy dietary patterns were associated with a reduced risk of colon cancer (RR = 0.85, 95% CI, 0.74-0.97), and calcium intake was linked to a slight reduction in CRC risk (RR = 0.93, 95% CI, 0.86-1.00). Conversely, high total meat consumption was associated with increased risks of CRC (RR = 1.18, 95% CI, 1.03-1.34), and white meat intake was associated with a potential 40% increased risk of rectal cancer (RR = 1.40, 95% CI, 1.00-1.96).

CONCLUSIONS

This review suggested that healthy dietary patterns and calcium intake are associated with a lower risk of CRC in Asian populations. Nonetheless, additional studies are warranted to clarify the associations between dietary patterns and CRC risk.