Vitamin D intake, serum 25-hydroxy vitamin D and pulmonary function in paediatric patients with cystic fibrosis: a longitudinal approach

Abstract

Pancreatic-insufficient children with cystic fibrosis (CF) receive age-group-specific vitamin D supplementation according to international CF nutritional guidelines. The potential advantageous immunomodulatory effect of serum 25-hydroxy vitamin D (25(OH)D) on pulmonary function (PF) is yet to be established and is complicated by CF-related vitamin D malabsorption. We aimed to assess whether current recommendations are optimal for preventing deficiencies and whether higher serum 25(OH)D levels have long-term beneficial effects on PF. We examined the longitudinal relationship between vitamin D intake, serum 25(OH)D and PF in 190 CF children during a 4-year follow-up period. We found a significant relationship between total vitamin D intake and serum 25(OH)D (β = 0·02; 95 % CI 0·01, 0·03; P = 0·000). However, serum 25(OH)D decreased with increasing body weight (β = –0·79; 95 % CI –1·28, –0·29; P = 0·002). Furthermore, we observed a significant relationship between serum 25(OH)D and forced expiratory volume in 1 s (β = 0·056; 95 % CI 0·01, 0·102; P = 0·018) and forced vital capacity (β = 0·045; 95 % CI 0·008, 0·082; P = 0·017). In the present large study sample, vitamin D intake is associated with serum 25(OH)D levels, and adequate serum 25(OH)D levels may contribute to the preservation of PF in children with CF. Furthermore, to maintain adequate levels of serum 25(OH)D, vitamin D supplementation should increase with increasing body weight. Adjustments of the international CF nutritional guidelines, in which vitamin D supplementation increases with increasing weight, should be considered.

Vitamin Status in Children with Cystic Fibrosis Transmembrane Conductance Regulator Gene Mutation

“…Seasonal variability in vitamin D concentrations and an inverse relationship of vitamin D concentrations to age were observed both in our study and in previous publications [ 27 , 28 , 29 , 30 , 31 ]. In our study, we did not confirm any correlation between vitamin D levels and the nutritional status.…”

Vitamin D Status in Pediatric and Young Adult Cystic Fibrosis Patients. Are the New Recommendations Effective?

“…Stephenson et al [13] supplemented 360 adult patients with 400-800 IU/day and only 12% reached levels above 30 ng/mL. Timmers et al [14] in a study with pediatric patients who received slightly higher Vitamin D doses, from 400-2000 IU/day, 40% of patients had deficient levels (<20 ng/mL), 38.4% insufficient (20-30 ng/mL) and 21.6% sufficient (>30 ng/mL). Brodlie et al [15] analyzed the impact of increasing the received dose of vitamin D by 475%.…”

Targeting Vitamin D Deficiency to Limit Exacerbations in Respiratory Diseases: Utopia or Strategy With Potential?

“…Associations between vitamin D status, lung function, and exacerbations are unclear. Indeed, some studies found positive associations with levels of vitamin D and lung function, as measured by FEV1 [47,[49][50][51][52][53][54] while others found no relationship [55][56][57][58]. When we focus on the relationship between serum 25(OH)D levels and exacerbations in CF, most studies reported that deficient vitamin D levels (25(OH)D < 20 ng/ml) are associated with more exacerbations [47,49,50] and more bacterial colonizations [59].…”