Background: Routine zinc supplementation is a potential intervention for the prevention of acute lower respiratory infections in developing countries. However discrepant findings from recent randomized trials remain unexplained.
Methods: Single centre, single arm, prospective non-randomized, open label interventional study, of effect of zinc supplementation in zinc deficient children aged 6 months to 5 years. 465 healthy children aged 6 months to 5 years were enrolled in the study. The primary outcome was the prevalence of serum zinc deficiency. Children having zinc deficiency were recruited for the study of effect of oral administration of zinc 20 mg for 2 weeks. The secondary outcomes were incidence and duration of acute upper respiratory and acute lower respiratory infections per child-year and side effects after giving zinc therapy.
Results: There was significant difference in mid arm circumference in between zinc deficient and non-zinc deficient groups (p < 0.001). Also the number of episodes of acute upper respiratory infections (AURI) and mean duration of AURI and acute lower respiratory infections (ALRI) was significantly different in the two groups (p < 0.001). There was no significant difference in ALRI episodes in two groups. After zinc supplementation in zinc deficient children, there was significant decrease in the number of episodes and mean duration of AURI (p < 0.001) and ALRI (p < 0.001) in six months after supplementation as compared to preceding six months before supplementation.
Conclusion: This study sheds light on the efficacy of short course prophylactic zinc supplementation in reducing the burden of ARI among zinc deficient children. Future studies should assess the effectiveness of delivering prophylactic zinc supplementation at scale, comparing the feasibility and cost benefit of short course and continuous regimens.
Clinical Trial Number: As it was a Non Randomized observational single arm study, study was not registered. Only RCT needs to be registered.
Funding Statement: This study was funded by All India Institute of Medical Sciences (AIIMS), Manuscript Jodhpur, India, as a part of Intramural project conducted in the department of Pediatrics, AIIMS Jodhpur.
Declaration of Interests: We declare no competing interests.
Ethics Approval Statement: The study was approved by Institutional Ethics committee of All India Institute of Medical Sciences, Jodhpur, India. The study was conducted in accordance with ICH-GCP and other applicable regulatory guidelines.
BACKGROUND: Airway epithelium is the first line of defense against a variety of exposures. Inflammatory processes, hyperresponsiveness and zinc deficiency cause epithelial damage. Zinc is involved in apoptosis and microtubule formation. However, its role in the integrity of bronchial mucosa and cilia is unclear.
METHODS: To assess the effect of zinc on the integrity of the bronchial epithelium, 24 male Rattus norvegicus strain Wistar rats were randomized into four experimental groups: normal zinc diet group without zinc supplementation, normal zinc diet group with 60 ppm zinc supplementation, zinc deficient diet group without zinc supplementation, and zinc deficient diet group with 120 ppm zinc supplementation. Bronchial mucosal integrity was measured with the number of epithelial cells, and the number and length of cilia.
RESULTS: Number of cell in normal zinc diet group was 8.8±1.82, while it was only 8.1±1.08 in zinc deficient diet group (p<0.001). Number of cilia per cell was 4.6±1.08 in normal zinc diet group, compared to 4.0±0.79 in zinc deficient diet group (p<0.001). Ciliary length also differ by 7.68±0.66 μm in normal zinc diet group and only 5.16±0.91 μm in zinc deficient diet group (p<0.001).
CONCLUSION: Zinc supplementation of the normal zinc diet group affected the length of bronchial cilia. Zinc supplementation of the zinc deficient diet group affected the integrity of the bronchial epithelium, which was shown by the number and length of cilia, and the number of epithelial cells.