ESPE Abstracts

Background: While the primary function of vitamin D relates to calcium and bone metabolism, it is now recognised that vitamin D is a potent immunomodulator. In vitro, 1,25(OH)₂D has been shown to suppress pro-inflammatory cytokines, such as TNF-α and IL6, while up regulating synthesis of anti-inflammatory cytokines, IL10 and IL4. Previous in vitro studies have yielded inconsistent results on the relationship between 25OHD and cytokines in adults and preterm infants.

Objective and hypotheses: To examine if vitamin D status altered the cytokine profile in different groups of children; obese children and lean healthy control children.

Method: Healthy children attending a single tertiary paediatric hospital for minor medical or surgical illnesses were recruited. Obese children (BMI>98th centile) attending a weight management course were also recruited. Each had 25OHD level measured along with a cytokine panel (TNF-α, IL4, IL6, IL10 and adiponectin).

Results: We studied 46 healthy children (28 females) ranging in age from 4.4 to 15.6 years. The mean (S.D.) for 25OHD was 44.7(24.6) nmol/l and 54% had 25OHD levels <50 nmol/l. In the obese cohort there were 13 children (nine females) ranging in age from 7.6 to 5.8 years. The mean (S.D.) 25OHD level was 29.2 (17.0) nmol/l and 92% had 25OHD levels <50 nmol/l. There was no correlation between the cytokines examined and 25OHD levels. Cytokine concentrations did not differ between individuals with 25OHD levels above or below 50 nmol/l.

Conclusion: We believe this is the first study examining the relationship between 25OHD status and pro and anti-inflammatory cytokines in healthy children. We found no correlation. This may be a reflection of the different settings in which the research was performed (ex vivo vs in vivo) but it is also possible that that the 25OHD levels of our patients were below the threshold required for 25OHD to exert its immunomodulatory effects.