Volume: 5, 2026
5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: H010
DOI: https://doi.org/10.24326/ICDSUPL5.H010
Published online: 22 April 2026
Vitamin D levels and respiratory diseases in children and adolescents
Petr Kraus*1, Jan Bedrníček1, Pavel Smetana1 and Miloš Velemínský Sr.2
1 Department of Food Biotechnologies and Agricultural Product Quality, University of South Bohemia in České Budějovice, 1668 Studentská St., 370 05 České Budějovice, Czech Republic
2 Institute of Physiotherapy and Selected Medical Disciplines, University of South Bohemia in České Budějovice, 1167/27 J. Boreckého St., 370 11 České Budějovice, Czech Republic
Corresponding author: krausp06@jcu.cz
Vitamin D has positive effects on the immune system, influences intestinal calcium transport, is important for proper mental and physical development and growth in children – even during pregnancy – and helps prevent various diseases. Vitamin D deficiency is a global problem, affecting not only children but also adults. In Europe, more than 50% of children suffer from a deficiency. This study investigates the effect of vitamin D on respiratory diseases in relation to serum levels. The aim of the study was to measure vitamin D (25-hydroxyvitamin D) levels in the blood and to evaluate the relationship between these levels and respiratory diseases in children. These values were compared based on health status (healthy vs. ill), gender, age (childhood: up to 14 years vs. adolescence: 15 to 18 years), and the season in which samples were collected (summer and winter). The results were evaluated in relation to the cutoff value of 50 nmol/L. The sample consisted of 127 respondents aged 1 to 18. Health status was assessed by the paediatrician, who categorized the patients as healthy or ill, based on signs of respiratory diseases.
The analysis of the study did not show that serum vitamin D levels influenced the incidence of respiratory diseases (p>0.05). Age has no statistically significant effect (p>0.05) on 25(OH)D saturation. There was also no statistical significance (p>0.05) found in the relationship between sex and 25(OH)D saturation. The influence of the season in which the sample was taken (summer vs. winter) on 25(OH)D saturation did not have a statistically significant effect (p>0.05), but there was a potential influence (p=0.056) of this variable.
The research was supported by the Grant Agency of the University of South Bohemia in České Budějovice (GAJU 107/2025/Z).
Keywords: respiratory diseases; serum levels; sources; vitamin D
How to cite
Kraus P., Bedrníček J., Smetana P., Velemínský M. Sr., 2026. Vitamin D levels and respiratory diseases in children and adolescents. In: 5th International PhD Students’ Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL5.H010