Clinical impact of vitamin D treatment in cystic fibrosis: a pilot randomized, controlled trial

BACKGROUND/OBJECTIVES: Vitamin D insufficiency in cystic fibrosis is common. Vitamin D3 is currently preferred over D2. We aimed to study the efficacy of vitamin D2 and D3 at increasing serum 25-hydroxyvitamin D (s25OHD) concentrations and their effect on respiratory health in cystic fibrosis. SUBJECTS/METHODS: Sixteen CF patients were randomized to receive vitamin D2 or D3 or to serve as controls. The starting dose of 5000 IU (< 16 years old) or 7143 IU/day (>= 16 years old) was further individually adjusted. Three months of intervention were followed by two of washout (ClinicalTrials. gov NCT01321905). RESULTS: To increase s25OHD, the mean daily dose of vitamin D2 and D3 had to be increased up to 15650 and 8184 IU, respectively. The combined group of vitamin D2 and D3 treated patients decreased plasma IL-8 (P < 0.05). Patients provided vitamin D3 improved FVC at the end of the trial (P < 0.05). Change in s25OHD was positively correlated with changes in the adult Quality-of-Life respiratory score at the end of supplementation (P = 0.006, r = 0.90), and with changes in FEV1 (P = 0.042, r = 0.62) and FVC (P = 0.036, r = 0.63) at one month of washout. CONCLUSIONS: Vitamin D supplementation may contribute to reduced inflammation and improved lung function in CF

Inverse relation between vitamin D and serum total immunoglobulin G in the Scandinavian Cystic Fibrosis Nutritional Study

Background/Objectives: The hallmark of cystic fibrosis (CF) is chronic lung inflammation. The severity of lung disease is closely correlated with immunoglobulin G (IgG) levels. Beyond its contribution to the bone health, the importance of vitamin D has not been fully recognized owing to the lack of human studies providing evidence of its benefit. In the context of the recently described immunomodulatory functions of vitamin D, we aimed to assess the relationship between vitamin D and IgG levels. Subjects/Methods: Eight hundred and ninety-six CF patients were included (0.53-65.9 years) from seven centers in Denmark, Norway and Sweden. Serum 25-hydroxyvitamin D (25OHD) and total IgG were measured, spirometry was carried out and vitamin D intake data were gathered using a 7-day dietary food record. Multiple linear regression analyses were performed for IgG and forced expiratory volume in 1 lambda s (FEV1) as dependent variables, and serum 25OHD, daily food and supplemented vitamin D sources of intake as independent variables. The model was controlled for age, gender, genotype, CF-related diabetes, season, infection/colonization status, long-term oral corticosteroid treatment, long-term treatment with macrolide antibiotics, pancreatic insufficient phenotype and body mass index z-score. Results: Serum total IgG levels were negatively associated with serum 25OHD (adjusted R-2=0.376; beta = -0.02; P<0.001), supplemented vitamin D intake per kg bodyweight (adjusted R-2=0.375; beta = -0.82; P<0.001) and total vitamin D intake per kg bodyweight (adjusted R-2=0.398; beta = -0.60; P=0.002). Serum 25OHD was positively associated with FEV1 (adjusted R-2=0.308; beta=0.0007; P=0.025). Conclusions: Increasing vitamin D intake may positively modulate inflammation in CF. This study supports the proposed role of vitamin D in the immune system during infection and substantiates prospective studies. European Journal of Clinical Nutrition (2011) 65, 102-109; doi:10.1038/ejcn.2010.194; published online 22 September 201