Hypovitaminosis D as Predisposing Factor for Atrophic Type A Gastritis: a Case-Control Study and Review of the Literature on the Interaction of Vitamin D with the Immune System

1,25-Dihydroxyvitamin D displays immunoregulatory and anti-inflammatory properties, and the cells involved in innate and adaptive immune response express the vitamin D receptor and can both produce and respond to this hormone. This article aims at describing the complex immune regulatory role of vitamin D and depicting whether a correlation exists between atrophic type A gastritis and hypovitaminosis. We studied 62 autoimmune gastritis (AIG) patients and compared them to 54 lymphocytic gastritis patients, 21 gastritis patients and 212 healthy subjects. We also statistically analyzed vitamin D concentration in 36,384 outpatients referred to our clinical laboratories. 25-Hydroxyvitamin D levels, the measurable metabolite used to determine vitamin D status in plasma, were measured by a chemiluminescent method. Average level of 25-OHD in AIG subjects was 9.8 +/- 5.6 ng/mL (95% confidence interval (CI) 8.4-11.2), 11.1 +/- 8.4 (CI 7.5-14.7) in gastritis patients, 22.2 +/- 13.5 (CI 18.6-25.8) in nonspecific lymphocytic gastritis patients, 21.3 +/- 12.2 (CI 19.7-22.9) in healthy subjects, and 21.8 +/- 13.1 (CI 21.7-21.9) in the 36,384 outpatients. Vitamin D levels in AIG patients were significantly lower than in patients with nonspecific gastritis or in the general population, supporting the hypothesis that hypovitaminosis D might be a risk factor for the development of autoimmune diseases. The low vitamin D concentration in gastritis patients might act as predisposing factor for a more severe Th1-type aggression to the stomach epithelium.