Vitamin D deficiency is common among patients with inflammatory bowel diseases (IBD).
The effects of low plasma 25-hydroxy vitamin D (25[OH]D) on outcomes other than bone health are understudied in patients with IBD.
Dr Ashwin Ananthakrishnan and colleagues examined the association between plasma level of 25(OH)D and risk of cancers in patients with IBD.
From a multi-institutional cohort of patients with IBD, the research team identified those with at least 1 measurement of plasma 25(OH)D.
The primary outcome was development of any cancer.
The team examined the association between plasma 25(OH)D and risk of specific subtypes of cancer, adjusting for potential confounders in a multivariate regression model.
The research team analyzed data from 2809 patients with IBD, and a median plasma level of 25(OH)D of 26 ng/mL.
|Each 1-ng/mL increase in plasma 25(OH)D was associated with an 8% reduction in risk of colorectal cancer|
|Clinical Gastroenterology & Hepatology|
Nearly one-third had deficient levels of vitamin D (<20 ng/mL).
During a median follow-up period of 11 years, 7% of patients developed cancer, excluding nonmelanoma skin cancer.
The team found that patients with vitamin D deficiency had an increased risk of cancer compared with those with sufficient levels.
Each 1-ng/mL increase in plasma 25(OH)D was associated with an 8% reduction in risk of colorectal cancer.
The researchers also identified a weaker inverse association for lung cancer.
Dr Ananthakrishnan's team concluded, "In a large multi-institutional IBD cohort, a low plasma level of 25(OH)D was associated with an increased risk of cancer, especially colorectal cancer."