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Circulating Vitamin D and Colorectal Cancer Risk: An International Pooling Project of 17 Cohorts
Marjorie L McCullough1, Emilie S Zoltick2,3,4, Stephanie J Weinstein5
1Behavioral and Epidemiology Research Program, American Cancer Society, Atlanta, GA.
Journal of the National Cancer Institute
|June 19, 2018
Summary
Higher vitamin D levels significantly reduce colorectal cancer risk, especially in women. Optimal blood concentrations for prevention are higher than current bone health guidelines suggest.
Area of Science:
- Oncology
- Nutritional Science
- Epidemiology
Background:
- Vitamin D's role in preventing colorectal cancer is suggested but not conclusive.
- Optimal circulating 25-hydroxyvitamin D (25(OH)D) levels for risk reduction are unknown.
- Current vitamin D guidelines focus solely on bone health, not cancer prevention.
Purpose of the Study:
- To determine the association between circulating 25(OH)D concentrations and colorectal cancer risk.
- To identify optimal 25(OH)D levels for minimizing colorectal cancer risk.
Main Methods:
- Pooled data from 17 cohorts including 5706 colorectal cancer cases and 7107 controls.
- Measured and calibrated 25(OH)D concentrations across participants.
- Used conditional logistic regression and random effects models to estimate risk.
Main Results:
- Deficient 25(OH)D (<30 nmol/L) increased risk by 31%; levels of 75-100 nmol/L reduced risk by 19-27%.
- Risk reduction plateaued at 100 nmol/L.
- Associations were stronger in women than men and consistent across subgroups.
Conclusions:
- Higher 25(OH)D concentrations are linked to substantially lower colorectal cancer risk, particularly in women.
- Optimal 25(OH)D levels for risk reduction (75-100 nmol/L) exceed current recommendations.
- These findings suggest a need to re-evaluate vitamin D guidelines for cancer prevention.
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