Vitamin D deficiency was widespread in children, with higher BMI associated with lower levels in overweight groups.
Vitamin D deficiency in all study groups
The researchers evaluated blood levels of 25-hydroxyvitamin D in 364 children between the ages of 6 and 17 years from the Middle East and North Africa who were living in Qatar. Participants were stratified according to asthma status and body mass index (BMI), creating four groups: normal weight with asthma, overweight or obese with asthma, overweight or obese without asthma, and normal weight without asthma.
Vitamin D deficiencydefined as serum 25-hydroxyvitamin D <50 nmol/L, was common regardless of asthma status or weight. Deficiency was identified in 81.1% of overweight or obese children without asthma, 73.9% of overweight or obese children with asthma, 68.3% of normal-weight children without asthma, and 66.3% of normal-weight children with asthma.
Despite numerical variation, the prevalence of vitamin D deficiency did not differ significantly between groups. Vitamin D deficiency was uncommon, ranging from only 1.1% to 6.5% across the group.
High BMI associated with low vitamin D
A clearer relationship emerged when researchers examined BMI and vitamin D levels among children who were overweight or obese. Higher BMI is significantly associated with lower blood vitamin D concentrations between those with asthma and those without asthma.
No statistically significant relationship was observed between BMI and vitamin D in children of normal weight. Children who were overweight or obese but did not have asthma also had the lowest vitamin D concentrations overall.
Multivariate analysis adjusting for age, sex, BMI, and atopy found no significant independent association between asthma status and vitamin D status. The researchers also found no evidence that asthma and overweight or obesity interact to produce a combined effect on vitamin D.
The findings highlight the pervasive burden on children
The results suggest that excess body weight may be more closely related to vitamin D concentrations than asthma itself in this population. However, the cross-sectional design means that the study cannot establish causality or determine whether changes in BMI will alter vitamin D levels.
Interpretation is also limited by the lack of data on vitamin D supplementation, sunlight exposure, season, nutritional intake, and physical activity, along with recruitment from pediatric clinics rather than the general community. Therefore, the authors caution that the results may not be directly generalizable beyond the study.
However, with the majority of children in each group classified as vitamin D deficient, the study supports consideration of screening, nutritional and lifestyle measures, and vitamin D supplementation when clinically indicated, pending confirmation in longitudinal and interventional research.
reference
Ahmed LHM et al. Vitamin D deficiency in children with asthma and overweight/obesity in Qatar. J Allergy Asthma. 2026;19:594510.
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