Extra-skeletal impact of vitamin D supplementation protocol in an adult population with cystic fibrosis.

BACKGROUND: Due to lack of vitamin D absorption in patients with cystic fibrosis (CF), vitamin D supplementation becomes necessary. Our aim was to study the association between serum vitamin D levels and key clinical factors, such as nutritional status, pulmonary function and pulmonary exacerbations (PEx) frequency, in an adult CF population. METHODS: Prospective analysis of a published vitamin D (VitD3) supplementation protocol (N = 200 adult patients) over a follow-up period of 5 years. Data were collected from the medical files before (baseline) and after (follow-up) the implementation of the VitD3 supplementation protocol, between 2009 and 2014. Serum samples to measure vitamin D were also collected at baseline and follow-up. RESULTS: A positive relationship between serum vitamin D and lung function was observed at baseline (R = 0.158, P = 0.027), but it disappeared at follow-up (P = 0.454). There was no association between serum vitamin D levels and body mass index. At follow-up, patients with significantly higher serum vitamin D levels were women, older in age, had CF-related diabetes or had a history of recurring PEx. CONCLUSION: No direct link was observed between heightened serum vitamin D and lung function or BMI in an adult CF population. We suggest that better compliance to treatments and closer follow-up from health professionals could partially explain why such patients reached higher vitamin D serum levels.

Association between glucose intolerance and bacterial colonisation in an adult population with cystic fibrosis, emergence of Stenotrophomonas maltophilia.

BACKGROUND: Diabetes is common in cystic fibrosis (CF). Glucose can be detected in the airway when the blood glucose is elevated, which favours bacterial growth. We investigated the relationship between dysglycemia and lung pathogens in CF. METHODS: Cross-sectional and prospective analysis of CF patients (N=260) who underwent a 2h-oral glucose tolerance test. Clinical data was collected. RESULTS: Stenotrophomonas maltophilia (S. maltophilia) was the sole bacteria increased in dysglycemic (AGT: 20.2%, CFRD: 21.6%) patients compared to normotolerants (NGT: 8.7%). S. maltophilia positive patients with dysglycemia had more pulmonary exacerbation events compared to NGTs (1.22 vs 0.63, P=0.003). The interaction between S. maltophilia colonisation and glucose tolerance status significantly increases the risk of lower lung function (P=0.003). Its growth was not affected by the evolution of the glucose tolerance after three years follow-up. CONCLUSION: Prevalence of S. maltophilia was higher in dysglycemic patients, supporting the idea that S. maltophilia is a marker of disease severity in CF.