Serum vitamin A, zinc and visual function in children with moderate to severe persistent asthma

Abstract

Background: Asthma is a common childhood disorder with complex pathobiologic components that may include aspects of nutritional deficit. The contribution of vitamin deficiency, specifically vitamin A, as part of the disease complex has not been well studied, particularly among at risk children. In this study, we examined the prevalence of vitamin A as well as zinc deficiency in conjunction with visual function among an urban pediatric population sample with moderate–severe persistent asthma. Methods: A cross-sectional case–control assessment of serum vitamin A, zinc and visual function among urban children with and without asthma was undertaken. Inclusion criteria involved (1) well-controlled pediatric asthmatic patients between the ages of 8–18 with corrected vision of at least 20/25 in each eye and (2) chronic use of a combination beta agonist-steroid inhaler. Visual function was assessed by Snellen visual acuity and Peli Robson contrast sensitivity assessment. Results: Overall, 24 patients were enrolled for study with body mass index and age matched between asthmatic and control groups. Median serum vitamin A and zinc levels among control subjects was statistically higher compared to asthmatics (p = 0.0303 and p = 0.0111, respectively). Based on age-based reference levels there was no evidence of vitamin A or zinc deficiency among asthmatics or controls. Serum vitamin A and zinc were found to directly correlate with body mass index (p = 0.0074 and p = 0.0474, respectively), but not age or measures of visual function. Contrast sensitivity was however significantly reduced among asthmatic subjects (p = 0.0003). Conclusions: Children with chronic asthma demonstrate reduced levels of vitamin A and zinc that may be related to disease pathobiology however, evidence of frank zinc or vitamin A deficiency was not demonstrated. Reduced contrast sensitivity found in the asthmatic group appears unrelated to serum vitamin A and/or zinc levels.

Keywords:

• Nutrition
• vision
• retinol
• cataract
• pediatric

Acknowledgment

The authors acknowledge the support of the Rush University Research Committee in the conduct of this work.

Declaration of interests

In accordance with Taylor & Francis policy and my ethical obligation as a researcher, I am reporting that I no financial and/or business interests associated with this manuscript from a company that may be affected by the research reported in the enclosed paper.