New research published in the journal Inflammatory Bowel Disease reports that higher vitamin D status is associated with a decreased risk of hospitalization and surgery for patients suffering from inflammatory bowel disease.
Crohn’s disease and ulcerative colitis are inflammatory bowel diseases, both characterized by extreme gastrointestinal problems and discomfort. Almost two-thirds of patients with Crohn’s and one-fifth of those with ulcerative colitis will eventually require surgery for management of their disease. Many patients with inflammatory bowel diseases will require hospitalization at some point for issues related to their disease.
To date, cross-sectional studies have found an association between low vitamin D levels and increased disease activity in Crohn’s. There has also been a randomized controlled trial that has shown that vitamin D supplementation can lower the rate of relapse (when disease activity flares-up).
In this study, Dr. Ashwin N. Ananthakrishnan and colleagues wanted to know if vitamin D modified the risk of Crohn’s and ulcerative colitis patients needing surgery or hospitalization.
The researchers gathered data from electronic medical records of two Boston area medical centers. They found 3,217 patients with either Crohn’s or ulcerative colitis that met diagnostic criteria and had at least one vitamin D level drawn. They included these patients in this study’s cohort.
The researchers wanted to know, is there an association between vitamin D levels in inflammatory bowel disease and subsequent risk of getting surgery or going to the hospital?
Here’s what they found:
- According to the electronic medical records, 17% of Crohn’s patients who had vitamin D levels below 20 ng/ml had surgery for their condition. Only 10% of patients who had levels over 30 ng/ml had surgery for their condition. After adjustment, the odds ratio for surgery if you had a level below 20 ng/ml compared to 30 ng/ml was 1.76 (95% CI, 1.24–2.51).
- For ulcerative colitis, they found a similar relationship. After adjustment, the odds ratio for surgery if you had a level below 20 ng/ml compared to 30 ng/ml was 2.10 (95% CI, 1.32–3.34).
- The researchers found a similar relationship for risk of hospitalization in both Crohn’s and ulcerative colitis. The odds ratios for hospitalization if you had a level below 20 ng/ml compared to 30 ng/ml were 2.07 for Crohn’s (95% CI, 1.59–2.68) and 2.26 for ulcerative colitis (95% CI, 1.66–3.06).
Furthermore, the researchers looked at patients who had gotten two vitamin D blood tests, looking for patients who tested below 20 ng/ml their first test, and then “normalized” on their second test with a level above 30 ng/ml. They compared these patients to patients who did not normalize on the second test. They wanted to know, was there a protective association in raising levels? Here’s what they found:
- For Crohn’s patients, there was a significant risk reduction in getting surgery in patients that normalized their levels, with an odds ratio of 0.51 (0.32–0.82) compared to those who didn’t normalize their levels.
- For Crohn’s patients, there was a significant risk reduction in avoiding hospitalization in patients that normalized their levels, with an odds ratio of 0.64 (0.44–0.96) compared to those who didn’t normalize their levels.
- A similar relationship was found in patients with ulcerative colitis, too, but the findings were not significantly significant.
The researchers summarize,
“In a large inflammatory bowel disease cohort, we demonstrate that (1) low plasma 25(OH)D is an independent risk factor for both ulcerative colitis-related and Crohn’s disease-related surgery and hospitalization and (2) patients with Crohn’s disease who normalize their vitamin D status have a lower risk of subsequent Crohn’s disease-related surgery than those whose levels remained low.”
To the researchers’ knowledge, this is the largest cohort to date examining the relationship between vitamin D and inflammatory bowel disease-related outcomes.
However, there are limitations. It is an observational study and causality cannot be inferred. Normalizing vitamin D status could reflect general patient compliance as part of a more comprehensive treatment plan.
While there have been some small randomized controlled trials showing some benefit in vitamin D for patients with inflammatory bowel disease, the researchers call for larger cohort studies and larger randomized controlled trials to further clarify the effects of vitamin D on inflammatory bowel disease. In the meantime, there is some research suggesting that good vitamin D status may be important in inflammatory bowel disease.
Ananthakrishnan AN et al. Normalization of Plasma 25-Hydroxy Vitamin D Is Associated with Reduced Risk of Surgery in Crohn’s Disease. Inflamm Bowel Dis, 2013.