Association of Vitamin D Concentrations with subjective health complaints in children and adolescents: the CASPIAN-V study.

Background: Vitamin D deficiency (VDD) is recognized as a global pandemic. Identification, any association between VDD and subjective health complaints (SHC), can be helpful to realize critical mechanisms and improve psychological and somatic symptoms. Given few studies published on this issue and the importance of its clarification, the main objective of this study was to examine the association between VDD and the SHC in children and adolescents.
Methods: In this national cross-sectional study, 2596 Iranian children and adolescents aged 8-18 years were included. Data on SHC, anthropometric indices, physical activity, and serum levels of vitamin D were collected. Logistic regression models (crude, adjusted) were applied to examine the association between the VDD and the SHC. Statistical analysis was performed using STATA version 11. P-values< 0.05 were considered as statistically significant.
Results: Serum levels of vitamin D in approximately 70% of Iranian children and adolescents were lower than 30 ng/mL. Among the SHC, irritability (40.9%) and feeling anxiety (33.7%) were the most prevalent ones. Multiple complaints in students with the VDD was 2.5 times greater than those with sufficient vitamin D concentrations (p <  0.001). Compared to the reference group, the strongest association was found between vitamin D status and difficulties in getting to sleep (OR: 2.5, 95%CI: 1.18, 3.53, p <  0.001).
Conclusion: VDD was observed in the considerable percentage of the study population. There were no significant differences between the two gender groups. In addition, there were significant associations between vitamin D status and most of the somatic and psychological symptoms, particularly for getting to sleep. It seems national interventional programs for vitamin D supplementation or food fortifications can be helpful.