The association between dietary magnesium intake, and the risk of colorectal cancer has been examined by many prospective studies, but remains controversial because of inconsistent results.
Dr Qu Xinhua and colleagues carried out a meta-analysis to investigate this.
The team assessed this association with categorical and dose–response meta-analysis of data from prospective cohort studies.
Relevant studies were identified by searching MEDLINE, EMBASE, and OVID for studies published before 2012, with no restrictions.
Heterogeneity and publication bias was investigated, and subgroup, sensitivity, and meta-regression analyses were carried out.
The doctors reported that the analysis included 333,510 participants with 7435 colorectal cancers from 7 prospective cohort studies.
|For men, the pooled relative risk was 0.76 |
|European Journal of Gastroenterology & Hepatology|
Relative risks for the highest versus the lowest intake of dietary magnesium was 0.81 for colorectal cancer, 0.76 for colon cancer, and 0.82 for rectal cancer.
The research team examined that for men and women, the pooled relative risk was 0.76 and 0.81, respectively.
Significant inverse associations of colorectal cancer and dietary magnesium emerged in nonlinear models.
The greatest risk reduction was observed when dietary magnesium intake increased from very low levels.
Dr Xinhua's team concludes "Dietary magnesium intake has a statistically significant nonlinear inverse association with the risk of colorectal cancer."
"The greatest reduction for magnesium intake is 200–270 mg/day."
"Whether the association is causal or because of confounding warrants further investigation."