Heavy metals and antioxidant trace elements in children with recurrent wheezing

In their very interesting article Razi et al.¹ have investigated the relation between serum heavy metals and antioxidant trace elements (selenium and zinc) in children with recurrent wheezing. They conclude that children with hyper-responsiveness may be more susceptible to exposure to mercury and lead, as happens with environmental exposure to heavy metals. They believe that heavy metals are important factors contributing (if not primary) to frequent wheezing.¹ The authors are to be congratulated for making this pivotal study. We would like to raise some points regarding the methods used in determining heavy metals in serum samples. It is feasible that exposure to toxic metals may have made children more vulnerable to recurrent wheezing attacks in comparison with other subjects, as noted by the authors in their study.¹ Nevertheless, the speculation that both mercury and lead may cause recurrent wheezing via a direct contrast effect on antioxidant trace elements, would have been strengthened greatly if they had used whole blood instead of serum samples from children to assess environmental exposure to heavy metals. In fact, mercury and lead are bound to red blood cells in the bloodstream.² We have described elsewhere³ that both serum and/or plasma does not correctly reflect the degree of mercury and lead body burden.²

Given that there was an observed association between serum heavy metals and recurrent wheezing,^1,4,5 extending this research is of paramount importance. In the future, it will be essential to include whole blood toxic metals analysis for the assessment of wheezing disorders in childhood.

Conflict of interest statement

We have no conflicts of interest connected with this work.

Funding

None.