Commentary: Is vitamin A playing a hidden role in children's lung function?

Evaluating for the first time the relationship between vitamin A status and respiratory lung function in children Kassaye et al. studied the vitamin A status and lung function in children aged 6-9 years in Wukro wereda Northern Ethiopia. Previous studies have shown a beneficial effect of short-term vitamin A supplementation on forced expiratory volume (FEV1) and/or forced vital capacity. Unadjusted analysis in the evaluation showed lower FEV1 values in vitamin A deficient children as assessed by Modified Relative Dose Response. Moreover adjusted analysis by age-gender-height reduced the difference in the FEV1 values between vitamin A deficient children and children with normal vitamin A reserves. When more variables were included in the adjusted analysis there was no difference in FEV1 values according to vitamin A reserve status though height and body mass index were directly associated with FEV1 values when vitamin A status and other personnel and health variables were controlled. The finding apparently diminishes the importance of vitamin A in explaining the lung function. However this is unreliable since the critical role vitamin A plays in growth and immunity must be emphasized as integrated in a complex process of reciprocal interactions with other crucial micronutrients.