Dairy products and colorectal cancer in middle eastern and north African countries: a systematic review

Background: This systematic review was conducted to explain the association between dairy products and colorectal cancer (CRC) risk in Middle Eastern and North African countries (MENA).

Methods: The database consulted were PubMed, Clinical Trials, and Cochrane to extract the relevant studies published till the 31stof December 2016, using inclusion and exclusion criteria according to Prisma Protocol. The characteristics of these studies comprised the consumption of all types of dairy products in relation to CRC risk.

Results: Seven studies were included in this review. For dairy products overall, no significant association was found. Regarding modern dairy products, included studies found controversial results with OR = 9.88 (95% CI: 3.80-24.65) and OR_a = 0.14 (95% CI: 0.02-0.71). A positive association was reported between traditional dairy products and CRC risk, to OR = 18.66 (95% CI: 3.06-113.86) to OR = 24 (95% CI: 1.74-330.82) to ORa = 1.42 (95% CI: 0.62-3.25), p_trend = 0.03. Calcium was inversely associated with the CRC risk with OR_a = 0.08 (95% CI: 0.04-0.17).

Conclusion: This is the first systematic review which illustrated the association between dairy consumption and CRC risk in MENA region. The results were inconsistent and not always homogeneous. Further specified studies may be warranted to address the questions about the association between CRC and dairy products in a specific context of MENA region.