Urinary trace metals and heavy metals levels in obese and non-obese Portuguese children

Introduction: Some metals have been associated with obesity and associated comorbidities. However, typically those relations have typically focused on individual metals. Thereat, there is a growing interest in evaluating the health effects of cumulative exposure to metals in trace levels. Methodology: The aim of the study was to determine the exposure to suspected or confirmed (endocrine disruptors and/or obesogens. Children were recruited from the pediatric appointment at Hospital de S. João, and several local schools, in 2014 and 2015. Children lived in Oporto and Aveiro, two Portuguese districts, in the North and Central region of the country. The children were divided in two groups: the group “regular diet” included healthy children which were normal-/underweight not changing their regular diet; the group “healthy diet” included children diagnosed for obesity/overweight without other known associated diseases, counselled for healthy and balanced nutrition and thus set on a prescribed diet, for at least 3 months. First morning urine samples were collected from each participating child. The study was approved by the ethics committee of the Centro Hospitalar S. João/FMUP and all the parents provided written consent. Urine analysis was performed by inductively coupled plasma-mass spectrometry (ICP-MS). Results: Urinary concentrations of several elements (Cadmium, Cobalt, Molybdenum, Lead, Manganese, Nickel, Cooper, Arsenic, Tin, Antimony and Thallium) were investigated in 110 urine samples, from 4 to 18 years old Portuguese children. The study group was composed of 55 % girls and 55 % boys, with a median age of 10 years old. The majority of the children was overweight/obese and underwent a diet with nutritional guidance (healthy diet group) (61 %; n=67). Statistical differences (in μg/L) were observed (p<0.05), between the two studied groups, for Manganese, Cooper, Tin and Antimony. Obese/overweight children on a healthy diet presented higher median values for these compounds compared to the normal-weight children following their regular diet. Conclusions and relevance: Risk assessment showed that the maximum values determined for the Portuguese children were some orders of magnitude above reference values thus, alerting for further need of research on this topic/field (future monitoring interventions in the country).