Link Between Middle Ear Infections In Children And Air Pollutants From Traffic
In view of the fact that on the one hand air pollutants generated by traffic are a permanent source of pollution and on the other hand inflammations of the middle ear are one of the most freqeuent acute infections in young children with many different late consequences to their health, these findings have also significance for the health risk assessment of exposure to ambient fine particles.
It has long been known that environmental factors, such as passive smoking, may also have an influence on the development of otitis media, acute infection of the middle ear, in young children. Little had been known, however, about possible connections with pollutants in the ambient air. Together with scientists from the Dutch universities of Utrecht, Rotterdam, Groningen and Bilthoven Dr. Joachim Heinrich and Prof. Dr. Dr. H.-Erich Wichmann from the GSF - Institute of Epidemiology now first investigated systematically this question in a comprehensive study. Heinrich and his colleagues recorded prenatal data of 4150 Dutch children and 670 children from the Munich LISA study in two prospective studies back in 1997 to 1999 starting at the time of the pregnancy.
On the basis of air pollution measurements the individual exposure was assessed for each child, including nitrogen dioxide and fine particles in the PM 2.5 range. When the parents were interviewed, Heinrich obtained detailed information on the occurrence of inflammations of the middle ear in the children included in the study from birth until the age of two. Other potential risk factors, such as social influences, parental allergies or passive smoking, were also enquired.
The result was amazing even for the scientists themselves: "Both in the Dutch and in the German populations studied we found clear associations between the occurrence of otitis media and the exposure of the children to traffic-related air pollutants," says Joachim Heinrich from the GSF.
The results in detail: approx. 35 per cent of the children of both cohorts had an acute inflammation of the middle ear at least once in their first two years. The adjusted odds ratios, calculated parameters for a statistical association, are 1.13 and 1.24 for the Dutch and the German cohorts, respectively, for an increment of the PM 2.5 fine particle concentration by 3 micrograms per cubic meter (ug/m3) and exactly 1.14 for an increment of the nitrogen dioxide pollution (NO2) by 10 ug/m3 in both studies. This corresponds to a 13 - 24 per cent higher risk of otitis for a moderate increase in fine particles by 3 ug/m3 as well as a 14 per cent higher risk for an increase in NO2 by 10 ug/m3.
The scientists suspect that the same mechanism is responsible for the association between air pollutants and otitis as is assumed for the known association between passive smoking and otitis: Elevated ambient air pollution causes inflammations in the airways and restricts the functionality of the cilia in the upper airways. They are responsible for the removal of inhaled particles, their reduced functionality has been shown to increase the risk of respiratory infections - one of the known causes for the development of middle ear infections.
Original publication:
Brauer, M. et al. (2006): Traffic-Related Air Pollution and Otitis Media
Environmental Health Perspectives Vol.114, No.9:1414-1418
GSF - Forschungszentrum fur Umwelt und Gesundheit
http://www.gsf.de
Legãtura între urechii mijlocii infectii la copii ºi poluanþi atmosferici din trafic - Link Between Middle Ear Infections In Children And Air Pollutants From Traffic - articole medicale engleza - startsanatate