Exposure to traffic-related air pollution is associated with hyperactivity and inattention in adolescents

Traffic-related air pollution exposure is associated with higher hyperactivity/inattention scores in adolescents, according to a research performed with German children. The study, published in Environment International, results from a joint collaboration between ISGlobal and several German research centres.

An increasing number of studies confirm the association between air pollution and cardiovascular and respiratory disorders, but few studies have addressed its effect on behavioural problems and learning disorders during adolescence. While some recent studies, one of them performed with Spanish schoolchildren, have linked higher levels of air-pollutants to lower learning performance, these studies assessed attention deficit (ADHD) status and air pollution exposure only at one time point.

The goal of this study was to investigate the association between individual, long-term exposure to traffic-related air pollutants with the prevalence of hyperactivity/ inattention in a total of 4,745 German children born in urban (Munich and adjacent regions) and rural (Wesel and adjacent regions) areas. The authors used information on the estimated annual average of air pollutants (NO2, PM10 mass, PM2.5 mass and PM2.5 absorbance as carbon measure) around the residence of each child at three time points in life: birth, 10 and 15 years-old, and hyperactivity/ inattention scores were assessed at 10 and 15 years of age.

The results indicate that hyperactivity/inattention in 15-year old adolescents was associated with a higher exposure to PM2.5 and carbon at 10 and 15 years of age. This association held true after adjustment for several factors such as exposure to second-hand smoke and distance to green urban spaces. However, as ISGlobal researcher and first author of the study Elaine Fuertes points out, “given that the results were sensitive to how children with borderline scores were treated in the analysis, these results require replication by further studies”.

Although the mechanisms by which air pollution affects neurological development in children remain poorly defined, particulate matter is thought to trigger nervous system inflammation, as observed in some animal models. Given the ubiquitous presence of air pollution worldwide, “there is an urgent need to investigate its effect on neurodevelopment disorders that have a large societal and public health impact”, adds Fuertes.

Reference

Fuertes E, Standl M, Forns J, Berdel D, Garcia-Aymerich J, Markevych I, Schulte-Koerne G, Sugiri D, Schikowski T, Tiesler CM, Heinrich J. Traffic-related air pollution and hyperactivity/inattention, dyslexia and dyscalculia in adolescents of the German GINIplus and LISAplus birth cohorts. Environ Int 2016; 97: 85-92