A case-control study on dietary calcium intake and risk of glioma

Limited evidence exists regarding the association between dietary calcium intake and risk of glioma. The objective of this study was to determine the relationship between dietary calcium intake and risk of glioma in Iranian adults. In this hospital-based case-control study, we enrolled 128 newly-diagnosed cases of glioma and 256 age- and sex-matched controls. Patients with pathologically confirmed glioma (without any other cancers) were selected. Dietary intakes of study participants were collected through a validated 126-item food-frequency questionnaire. Dietary calcium intake was computed from dairy products in the questionnaire. Participants were categorized into quartiles of dietary calcium intake. Binary logistic regression was used to examine the association between dietary calcium intake and glioma. Higher dietary intake of calcium was associated with younger age, long duration of cell phone use, and frequent canned foods intake. After taking age, sex, and energy intake into account, participants with the greatest dietary calcium intake had 84% lower odds of glioma than those with the lowest intake [odds ratio (OR): 0.16; 95% confidence interval (CI), 0.07-0.37]. Further adjustment for other potential confounders including nutrient intakes did not significantly alter the association (OR: 0.22; 95% CI, 0.08-0.64). Even after additional adjustment for BMI, we found a significant inverse association between dietary calcium intake and odds of glioma (OR: 0.23; 95% CI, 0.08-0.65). We found an inverse protective association between high dietary calcium intake and odds of glioma. Further prospective cohort studies are needed to confirm these findings.