Serum vitamin D levels in children with cystic fibrosis

Abstract

Osteopenia is increasingly recognized in adults with cystic fibrosis (CF), and is potentially related to vitamin D deficiency in both adulthood and childhood. Vitamin D supplements are recommended and prescribed to all pancreatic-insufficient patients. We aimed to ascertain whether vitamin D deficiency in children with CF was prevalent. 25-hydroxyvitamin D (25-OHD) was measured in 290 children attending a specialist pediatric CF clinic for annual assessment. 25-OHD levels were compared with reference values and to other biochemical markers, lung function, and growth. Levels were also analyzed by pancreatic status and by the presence of CF-related liver disease. Median 25-OHD was 65 (range, 9-190) nmol/l. One percent had levels below 15 nmol/l, and 6% had levels less than 25 nmol/l. Levels were lower in adolescents (P < 0.001) and during the "winter" months (P < 0.001). No relationship was found with pancreatic status or liver disease. In conclusion, the majority of children had normal 25-OHD levels. Interpretation is difficult due to a lack of knowledge of optimal levels of 25-OHD required for healthy bone accretion. Lower levels in adolescents may be a precursor to low levels in adulthood, and did not seem to be simply related to poor compliance with supplementation. This may reflect normal physiology.

Vitamin D Deficiency Is Associated with Pulmonary Exacerbations in Children with Cystic Fibrosis

“…Other studies have examined the prevalence of vitamin D deficiency in CF and examined its association with FEV 1 cross-sectionally. Similar to our results, most of these studies have found no association between vitamin D deficiency and FEV 1 (10,12,23,37). We did, however, see a linear relationship between vitamin D level and FEV 1 in the adolescent age group.…”

“…We did, however, see a linear relationship between vitamin D level and FEV 1 in the adolescent age group. The former studies may not have seen a linear relationship, as they did not adjust for age, and two had a mean age of 9 and 11 years, younger than the adolescent population with significant findings in our study (12,37). In the third study, 81% of patients were vitamin D deficient or insufficient and may not have had enough patients with 25-OHD levels greater than 30 mg/L to see a significant trend.…”

“…This has been found in both ORIGINAL RESEARCH healthy adolescent-aged children and adolescents with CF (10,12,39). One would speculate change in dietary habits, such as decreased milk and increased soda consumption.…”

“…Vitamin D deficiency is common in the cystic fibrosis (CF) population and ranges from 40 to 90%, depending on age and definition of deficiency (9)(10)(11)(12)(13)(14). The cause of vitamin D deficiency in CF is multifactorial, including pancreatic insufficiency, reduced sunlight exposure, poor body fat stores, and decreased vitamin D-binding protein (14,15).…”

Sunlight is an important determinant of vitamin D serum concentrations in cystic fibrosis

“…As a natural consequence, all nutritional guidelines insist on preventing this deficiency by means of a daily oral supplement (Borowitz et al, 2002;Sinaasappel et al, 2002;Aris et al, 2005). Data on serum concentrations of 25-OH cholecalciferol (25 (OH) D) in CF are, however, not unequivocal, as they have been reported as too low by some authors (Donovan et al, 1998;Mortensen et al, 2000;Rovner et al, 2007), whereas others disagree (Buntain et al, 2004;Chavasse et al, 2004). Moreover, the failure of oral supplement treatments is common and has been widely published (Donovan et al, 1998;Boyle et al, 2005;Green et al, 2008;Green et al, 2010).…”