The Role of Vitamin D3 Therapy in Pediatric Bronchiectasis Severity (CF versus Non-CF Patients)

Objective: To determine and compare the effect of vitamin D3 supplementation on modifying the disease severity in cystic fibrosis (CF) and non-CF bronchiectasis pediatric patients. Methods: A randomized clinical trial eva-luating the role of oral vitamin D3 supplementation for six months, was performed in forty patients with CF and non-CF bronchiectasis under the age of 18 years with vitamin D deficiency or insufficiency. The primary outcome was to reach the sufficient Vitamin D level, the secondary outcome was to reevaluate bronchiectasis severity by following up the frequency, severity of pulmonary exacerbations and lung function after vitamin D3 supplementation. Results: Forty patients completed the trial. The percentage of improvement of vitamin D level after vitamin D3 supplementation for six months was significantly higher in CF (88.3%) than non-CF bronchiectasis patients (59.82%) (P = 0.03). Additionally, moderate to severe pulmonary exacerbations significantly decreased by more than 60%, 45% (P = 0.001, 0.005) and frequent exacerbations decreased by 15%, 10% (P = 0.327, 0.490), while the forced expiratory volume in 1 (FEV1) significantly increased by 17% and 15% in non CF bronchiectasis and CF patients respectively (p < 0.001). Conclu-sions: Vitamin D3 therapy was effective in decreasing the frequency and severity of pulmonary exacerbations and preserving lung function. Thereby, improving the disease severity even more in non-CF bronchiectasis than CF patients.


Introduction
Bronchiectasis is a chronic inflammatory respiratory disorder characterized by bronchial dilatation, and symptoms of productive cough, dyspnea and repeated respiratory infections requiring multiple courses of antibiotics [1]. Nowadays, bronchiectasis is classified as either related or unrelated to cystic fibrosis (CF), with the latter defined as non-CF bronchiectasis [2].
Vitamin D deficiency occurs commonly in patients with CF [3] & non-CF bronchiectasis. In these patients, vitamin D deficiency can be caused by multiple factors including pancreatic exocrine insufficiency, lack of sunlight exposure and decreased vitamin D-binding protein [3]. In addition, reduced outdoor physical activity which is a common consequence of chronic lung diseases, can lead to reduced exposure to sunlight and therefore vitamin-D deficiency [4].
Vitamin D down-regulates cytokines and chemokines that promote tissue destruction, that are found in abundance in CF and non-CF bronchiectatic lungs [5] [6]. It was shown that CF respiratory epithelial cells and macrophages incubated with 1.25(OH)2D showed a significant down-regulation in the neutrophil attracting chemokine, IL-8 [7], The anti-inflammatory activity of vitamin D may originate from the enhancement of anti-inflammatory/regulatory cytokines secretion, such as IL-10 [8]. Vitamin D, as it was aforementioned, may have anti-infective and anti-inflammatory properties and therefore may play some role in the pathogenesis of bronchiectasis [9].
Vitamin D may preserve lung function depending on several studies in cystic fibrosis and other chronic lung diseases which include improved airway remodeling, decreased airway inflammation, and decreased airway bacterial colonization [10]. In addition, vitamin D therapy may increase anti-microbial peptide production and decrease pro-inflammatory cytokines which could result in improved clinical outcomes [11].

Study Design
This was a randomized clinical trial. The study was registered at https://www.clinicaltrials.gov/ prior to inclusion of the patients in the study (NCT04411901), comparing the role of vitamin D3 therapy in pediatric patients with CF and non-CF bronchiectasis who were vitamin D deficient or insufficient. The patients' groups received maximum therapeutic dose of cholecalciferol (D3) orally daily for complete six months. All CF patients continued receiving their ordinary multivitamins supplementation unchanged apart from vitamin D. The study was open-label and consisted of six months of supplementation followed by two months of washout. The trial has been conducted at the children's Hospital, Ain Shams University hospitals located in Cairo (Egypt) during the interval from July 2018 to February 2019. The study was approved by the Research Ehical committee, faculty of medicine, Ain Shams University. All patients were welcomed to share in the study and informed consents were obtained from the parents and the patients older than 8 years before the inclusion within the study. A summary of the overall study design is presented in (Figure 1).

Measurements
After consent was obtained, detailed history and baseline data about the patients were collected. Additionally, a therapeutic history including any vitamin D supplements was obtained. Clinical data including sex, age, height, weight, body mass index, pulmonary function testing results using standardized spirometry (just for cooperative patients older than six years) and radiological investigations (chest X-ray, HRCT using Bhalla score) at the baseline and throughout the pulmonary exacerbations were obtained. Basal serum vitamin D level was also recorded.

Description of Study Procedures
Twenty CF and twenty non-CF bronchiectasis patients with vitamin D deficiency or insufficiency were assigned to receive the utmost therapeutic dose of vitamin D3 (cholecalciferol). The vitamin D3 therapy included oral daily doses which were consistent with age (2000 IU for infants up to 1 year, 4000 IU for children aged 1 -10 years, and 10,000 IU for those aged from 10 -17 years) [20].
Additionally, 60 mg per kg of calcium supplement was administrated to decrease the risk of hypocalcemia for all patients and pancreatic enzyme replacement therapy (PERT) was given for the CF patients for a complete six months.

Statistical Analysis
Data were analyzed statistically in terms of mean ± standard deviation (± SD), and range, or frequencies and percentages and P-values less than 0.05 was considered statistically significant while P less than 0.01was considered highly sig-

Results
The forty studied patients received vitamin D3 for six months followed by two Open Journal of Pediatrics months wash-out. No significant adverse effects were recorded. Baseline characteristics and statistical analysis were done for the 40 patients who completed the study visits and had follow-up laboratory and clinical assessments.
The basic demographic, anthropometric and radiological data of the studied patients are presented in Table 1 There was a highly statistically significant improvement in both groups as regard the vitamin D level after supplementation (P-value < 0.001) (as shown in Table 2). In addition, the percentage of improvement of vitamin D level was significantly higher in group B (CF patients) (88.3%) than in group A (non-CF patients) (59.82%) after vitamin D3 supplementation for six months (P-value = 0.030) (Figure 2).  As presented in (Table 3 & Table 4), there was a highly statistically significant difference in the severity of pulmonary exacerbations in both non CF bronchiectasis and CF groups after vitamin D3 supplementation (P = 0.001, 0.005) respectively where moderate to severe exacerbations significantly decreased in non-CF bronchiectasis patients (60%) which was higher than among CF patients (45%).

Lung functions and vitamin D supplementation:
As shown in (Table 5), There was a highly statistically significant improvement in FEV1 in both groups after vitamin D3 supplementation where the degree of improvement in FEV1) after vitamin D supplementation was 17%, 15% in non-CF bronchiectasis and cystic fibrosis respectively (P-value < 0.001).

Discussion
To our knowledge, this is the first study to determine and compare the effec- previous studies [20].
The current study showed that the mean age, weight and height were significantly lower among CF patients than among non-CF bronchiectasis patients (  Our study has identified a significant relation between vitamin-D3 supplementation and the improvement of bronchiectasis severity, unexpectedly, more in non-CF bronchiectasis than in CF patients. The current study found that the overall mean increase in 25(OH)D was (16.15, 11.75) ng/mL and 15/20 (75%), 11/20 (55%), achieved a 25(OH)D concentration ≥ 30 ng/mL in both CF and non-CF bronchiectasis patients respectively (data not shown in the results). Therefore, the percentage of improvement of vitamin D level after vitamin D supplementation for six months was significantly higher in CF (88.3%) than non-CF bronchetasis patients (59.82%) ( Table   2) which may be due to more adherence of the CF patients to treatment than the non-CF bronchiectasis patients.
Our results go parallel with a recent study conducted by Bartely et al. [23] on "32 adults with non-CF bronchiectasis received an initial 2. On the same hand, Simoneau et al. [24] in "a randomized controlled trial Also, our study has demonstrated a link between vitamin D3 supplementation, severity and frequency of pulmonary exacerbations where moderate to severe exacerbations significantly decreased by (60%, 45%) in non-CF and CF patients respectively (P = 0.001, 0.005). Moreover, the frequent ones decreased by 15% and 10% in non-CF and CF patients (P = 0.327, 0.490) ( Table 3).
Our findings were supported by McCauley et al. [3] who reported that having a higher serum 25-hydroxyvitamin D in children was protective of having a pulmonary exacerbation. Similarly, several previous studies [9] [25] reported that the high dose vitamin D3 therapy in CF patients rapidly improved vitamin D status and was associated with improved re-hospitalization rates by pulmonary exacerbations and lung function.
On the contrary, Bartely et al. [23] found no significant association between supplemented 25(OH)D levels and frequency or severity of exacerbations. His explanation was that the study was not powered to detect effects on exacerbation frequency.
In Both CF and non-CF bronchiectasis, vitamin D concentrations have been  [10]. "The mechanisms by which vitamin D may confer beneficial effects on lung function are unclear, but may be through induction of anti-microbial peptides such as human cathelicidin (LL-37) and beta-defensins, improved anti-oxidant status, improved lung remodeling and decreased airway bacterial colonization" [9].
The current study assessed the change in, FEV1 (percent predicted) ( Similarly, several studies [10] [27] found that higher 25(OH)D concentrations correlate with improved lung function in non-CF bronchiectasis. Furthermore, "a recently conducted study [28] in adult CF patients reported that a bolus of vitamin D instantly increased its concentration in serum, and significantly improved lung functioning".
To our knowledge, Our study is the first study to prove the improvement in parameters of lung functions and not only FEV1 after vitamin D3 supplementation in both CF and non-CF pediatric bronchiectasis patients.
These findings are consistent with the results of the Third National Health and Nutrition Examination Survey (NHANES III), where "there was a positive correlation between vitamin D status and lung function as assessed by (FEV1) and (FVC) [29] and patients with the highest vitamin D concentration had 126 ml higher (FEV1) and 173 ml higher (FVC), in comparison with patients with significant hypovitaminosis D. The protective effect of vitamin D in the course of chronic lung disease is mainly discerned in its anti-inflammatory and immune modulatory properties [9]".
Thus, the current study supports the hypothesis that bronchiectasis severity is associated with low 25-hydroxyvitamin D (25(OH)D) levels [10] and that Vitamin D therapy may enhance anti-microbial peptide production, decrease pro-inflammatory cytokines and decrease colonization of airway pathogens which precipitate the pulmonary exacerbations [9] which could result in improved clinical outcomes [11].
Depending on our results, vitamin D3 supplementation could be a reasonable cost-effective therapeutic approach for all patients with bronchiectasis. Addi-Open Journal of Pediatrics tionally, more concerted efforts should be undertaken to ensure that vitamin D status is optimized in all patients with CF and non-CF bronchiectasis.

Study Limitations
This study has some limitations, first, the adherence data may be limited as it was self reported by the studied patients. Second, the number of the studied patients may be small to generalize the results on all bronchiectasis patients.

Conclusion
We demonstrated the efficacy of therapeutic vitamin D3 in elevating the serum vitamin D level to the sufficient level in CF and non-CF bronchiectasis patients and concluded that elevated vitamin D level is associated with decreased frequency and severity of pulmonary exacerbations and improvement of lung function in both groups of patients especially non-CF bronchiectasis patients. Therefore, decreasing the disease severity. However, further future studies are still needed to document the use of vitamin D3 as a therapeutic tool and determine the most effective dose (not only in CF but also in non-CF bronchiectasis patients.