MedicalResearch.com Interview with:
Mitsuyoshi Urashima MD, PhD, MPH
Professor of Molecular Epidemiology
Jikei University School of Medicine
MedicalResearch.com: What is the background for this study?
Response: Serum levels of vitamin D, increase in response to exposure to sunlight, a vitamin D-rich diet, or vitamin D supplementation. In 1989, the risk of colon cancer was estimated to be 70% lower in people with serum vitamin D levels ≥ 20 ng/mL, compared with those < 20 ng/mL.
In a cohort study, higher vitamin D levels were associated with lower total cancer incidence and lower total cancer mortality, particularly digestive system cancer mortality. However, because of the studies’ observational nature, whether lower levels of vitamin D is merely a precursor to relapse and death or causally related to shorter survival cannot be determined.
To clarify this, a randomized, double-blind, placebo-controlled trial using vitamin D supplement was performed in patients with digestive tract cancer from esophagus to rectum; this is the first trial designed to evaluate the effect of vitamin D on survival of these patients. Continue reading