MedPage Today – Higher calcium intake was consistently associated with a reduced risk of colorectal cancer (CRC) across calcium sources and tumor sites, according to a cohort study using data from the NIH-AARP Diet and Health Study.
Among over 470,000 participants who were cancer-free at baseline, higher total calcium intake was associated with a lower risk of CRC (HR 0.71, 95% CI 0.65-0.78, P<0.001 for trend), reported Erikka Loftfield, PhD, MPH, of the National Cancer Institute, and colleagues.
Dairy, nondairy, and supplemental sources contributed a mean of 42.1%, 34.2%, and 23.7% of total calcium intake, respectively, they noted in JAMA Network.
“Our study is larger than most and has a longer duration of follow-up for CRC incidence,” Loftfield told MedPage Today.
“We were able to take a deeper dive and study whether source of calcium, anatomic location of the tumor, or participant characteristics impacted the association between higher calcium intake and lower CRC risk.”
“We observed inverse associations for total calcium with risk of proximal colon, distal colon, and rectal cancer, as well as for subsites,” Loftfield noted.
The authors explained that calcium insufficiency is higher among Asian (48%) and Black (47%) adults compared with Hispanic (30%) and white (24%) adults in the U.S. Of note, Black people have a higher incidence of lactose intolerance and are less likely to use supplements.
“Calcium has preventative potential across population subgroups,” Loftfield said.
She and her colleagues noted that they found a dose-response relationship between higher calcium intake and lower relative risk of incident CRC overall.
For each additional 300 mg/day in total, dietary, and supplemental calcium intake, they found an 8%, 10%, and 5% decrease in CRC risk, respectively.
“We found no evidence of effect measure differences by sex or race/ethnicity, suggesting that increasing calcium intake in population subgroups with low calcium intake could help reduce avoidable differences in CRC risk” …
