Vitamin D, calcium, and retinol intake, and pancreatic cancer in a population-based case–control study in the San Francisco Bay area
Lydia B. Zablotska, Zhihong Gong, Furong Wang, Elizabeth A. Holly, Paige M. Bracci
Objective The aim of this study was to evaluate a com- plex association among intake of dietary vitamin D, cal- cium, and retinol, and pancreatic cancer risk.
Methods Pancreatic cancer cases (n = 532) diagnosed in 1995–1999 were identified using rapid case ascertainment methods and were frequency matched to population-based controls (n = 1,701) in the San Francisco Bay Area. Detailed dietary data were collected during in-person interviews using a validated semi-quantitative food- frequency questionnaire. Adjusted unconditional logistic regression was used to estimate odds ratios (ORs) and confidence intervals.
Results In men, increased pancreatic cancer risk was associated with currently recommended dietary vitamin D intake levels (highest (C450 IU/day) vs. lowest (150 IU/ day) intake, OR = 2.6, trend-p = 0.009) and total vitamin D intake from diet and supplements (for 800 IU/day). ORs for dietary vitamin D intake remained increased after adjustment for intake of retinol and calcium, although confidence intervals included unity. Stratified analyses showed that ORs were higher among men with lower intake of retinol and lower physical activity but there was no evidence of statistical interaction. No associations with vitamin D intake were observed among women, although ORs typically were elevated. ORs increased with increased dietary calcium intake among men (trend-p = 0.008) and not women.