Abstract 5262: Associations between intake of calcium, magnesium, and phosphorus and risk of pancreatic cancer in a population-based case-control study in Minnesota

Pancreatic cancer is the fourth leading cause of cancer death among both men and women in the U.S. and has a dismal prognosis among all cancers due to its aggressive nature and lack of effective screening tests. Pancreatic cancer etiology remains elusive, with few well-established risk factors aside from cigarette smoking; therefore, it is critical to identify other modifiable risk factors for primary prevention. Calcium, magnesium, and phosphorus are essential minerals for bone health and other important metabolic processes. Emerging evidence indicates that these minerals are involved in the carcinogenesis of the colon and other organs through their influence on cellular proliferation, systematic inflammation, immune functions, and/or genomic stability. In the present study, we aimed to investigate the associations between intake of calcium, magnesium, and phosphorus and risk of pancreatic cancer in a case-control study conducted during 1994-1998 in Minnesota. Cases (n=150), aged 20 years or older, were ascertained from all hospitals in the metropolitan area of the Twin Cities and the Mayo Clinic; from the latter, only cases residing in the Upper Midwest of the U.S. were recruited. Controls (n=459) were randomly selected from the general population and frequency matched to cases by age (within 5 years) and sex. Dietary and supplemental intake of three minerals of interest and other nutrients was estimated from a validated food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression. After adjustment for age, sex, race, education, physical activity, cigarette smoking, alcohol use, and intake of energy, total fat, fiber, fruits, and vegetables, risk of pancreatic cancer decreased with an increasing dietary intake of calcium [OR (95% CI) for quartiles 2, 3, and 4 vs. quartile 1: 0.96 (0.54-1.67), 0.65 (0.35-1.17), and 0.58 (0.23-1.40), p-trend = 0.09. A similar inverse but not significant association was observed for total calcium intake. A significantly reduced risk of pancreatic cancer was found among subjects in the third quartile of total magnesium intake compared with those in the first (lowest) quartile [OR (95% CI): 0.35 (0.17-0.69)], although it may be a chance finding due to multiple comparisons. No apparent associations existed between dietary and total intake of phosphorus and risk of pancreatic cancer. Our study shows that there are suggestive, but inconsistent beneficial effects of dietary and/or supplemental intake of calcium and magnesium on the occurrence of pancreatic cancer. This observation warrants confirmation in other epidemiologic studies. Citation Format: Hao Fan, Andrew Marley, Margaret Hoyt, Haocheng Nan, Kristin Anderson, Jianjun Zhang. Associations between intake of calcium, magnesium, and phosphorus and risk of pancreatic cancer in a population-based case-control study in Minnesota [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5262.