Background: Calcium and dairy product intakes have been positively associated with prostate cancer risk. An imbalance in concentrations of calcium and magnesium has been associated with multiple chronic diseases, although few studies have examined the relation with prostate cancer aggressiveness.
Objective: The goal of this study was to examine the association between dietary intakes of calcium and magnesium, the calcium-to-magnesium ratio (Ca:Mg), and dairy products and prostate cancer aggressiveness.
Design: Dietary intake was assessed with the use of an interviewer-administered modified National Cancer Institute Diet History Questionnaire in 996 African American and 1064 European American men with a recent histologically confirmed diagnosis of prostate cancer from the North Carolina-Louisiana Prostate Cancer Project (PCaP). High-aggressive disease was defined as Gleason sum ≥8, or prostate-specific antigen (PSA) >20 ng/mL, or Gleason score ≥7 and clinical stage T3-T4. The comparison group was all other prostate cancer cases. Logistic regression was used to determine the adjusted ORs and 95% CIs for high-aggressive prostate cancer by tertile of diet and supplement exposures.
Results: There was a positive association across tertiles of dietary Ca:Mg intake, with odds of high-aggressive prostate cancer in the upper tertiles as follows-OR for tertile 2 compared with tertile 1: 1.38 (95% CI: 1.01, 1.88); OR for tertile 3 compared with tertile 1: 1.46 (95% CI: 1.06, 2.02). When stratified by race, the positive association was more pronounced in African American men (OR for tertile 3 compared with tertile 2: 1.62; 95% CI: 1.04, 2.53). Men who reported the highest daily consumption of whole-fat milk had a 74% increased odds of high-aggressive prostate cancer compared with non-whole-fat milk drinkers, which was attenuated after adjustment for potential mediating factors, such as saturated fat and Ca:Mg intake.
Conclusions: Among both African American and European American men diagnosed with prostate cancer, a higher Ca:Mg and whole-milk intake were associated with higher odds of high-aggressive prostate cancer. This study was registered at www.clinicaltrials.gov as NCT03289130.