Barry EL, et al. - Contradictory to the previous trial (Calcium Polyp Prevention Study, CPPS, 1988–1996), researchers in a recent randomized, controlled trial (Vitamin D/Calcium Polyp Prevention Study, VCPPS, 2004–2013) achieved no significant reduction in colorectal adenomas via calcium supplementation (1,200 mg/day). Consequently, they sought the participant characteristics that differed between the study populations and possibly influenced the effect of calcium supplementation on adenomas or high-risk findings (advanced or multiple adenomas). Outcomes suggest individuals with normal body mass index (BMI) may achieve a reduction in the risk of colorectal adenomas with 1,200 mg/day calcium supplementation, but overweight or obese individuals may not. Differences in BMI distribution seemed to partially explain the apparent difference between the two trials in terms of the efficacy of calcium.