Trace elements concentration in nails and association with airway inflammation in adolescents

Asthma is a multifactorial disease and its severity varies with the inflammatory status of the patient. It has been hypothesized that deficiency of trace elements has an important role in the etiology of asthma. The aim of the study was to evaluate the concentration of trace elements in nails of adolescents with different degrees of airway inflammation. We assessed the prevalence of active and severe asthma in adolescents (n = 106) through the ISAAC questionnaire. Subjects were allocated into two different groups according to the value of fraction exhaled nitric oxide (FeNO) measured. Also, nail specimens were collected in order to determine the concentration of accumulated trace elements (Cu, Zn, Mn, Se) by ICP-MS. It was performed Student's t test to evaluate statistical differences between inflammatory groups considering normally distributed data. On the other hand, when data presented non-normal distribution, Mann-Whitney U test was utilized. Spearman coefficients were calculated to investigate correlations between FeNO and mineral concentrations. Exhaled NO was increased in male subjects. We found association between active asthma and elevated exhaled NO. There was no significant difference in Cu (4.40 vs. 4.52), Zn (84.66 vs. 79.48), Mn (0.59 vs. 0.76), and Se (0.18 vs. 0.19) concentrations (μg/g) among distinct FeNO groups as well as was not observed correlation between exhaled NO levels and any element. Deficiency of trace elements in nails were not associated with increased FeNO.