Polter E, et al. - In the Atherosclerosis Risk in Communities study, researchers estimated the incidence of colorectal cancer in relation to serum and dietary magnesium. They classified the averaged measures, for both dietary and serum magnesium, into quintiles for analysis. For serum magnesium, they used 13,009 participants with 315 colorectal cancer cases (followed for a median of 20.4 years). For dietary magnesium, they used 256 cases among 10,971 participants (observed for a median of 17.5 years). According to the findings, Q2: 0.70; Q3: 0.68; Q4: 0.87; and Q5: 0.79 were the multivariable-adjusted hazard ratios (95% confidence intervals) of colorectal cancer for the highest four quintiles vs the first quintile of serum magnesium. Overall, a higher risk of colorectal cancer was evident in relation to lower serum magnesium among females, but not males, in this study.