Understanding the way the environment affects children's health is central to the prevention of illness. While the effects of air pollution are well known, less is understood about the impact of environmental noise.

Impaired Reading Comprehension

In the largest study of its kind to date, Stephen Stansfeld of Barts and the London, Queen Mary's School of Medicine and Dentistry, University of London, UK, and colleagues assessed the effects of road traffic and aircraft noise on children s cognitive development and health.

Over 2,800 children, aged 9-10 years, from 89 primary schools located near three major airports -- Schiphol in the Netherlands, Barajas in Spain and Heathrow in the UK -- took part in the study.

The investigators assessed aircraft and road traffic noise levels around the schools, and then compared these levels to the results of cognitive tests and health questionnaires.

Pooling the data from the three countries, the researchers found exposure to aircraft noise impaired reading comprehension -- even after adjustment for socioeconomic differences between high-noise and low-noise schools.

Reading age in children exposed to high levels of aircraft noise was delayed by up to two months in the UK and by up to one month in the Netherlands for a five-decibel change in noise exposure.

Road-traffic noise did not have an effect on reading and, unexpectedly, was found to improve recall memory.

Increased exposure to both aircraft and road traffic noise was associated with increased stress in children and reduced quality of life.

Exposure to Aircraft Noise Is Unhealthy

The authors conclude that schools exposed to high levels of aircraft noise are not healthy educational environments. They state that the effects of exposure to noise at home, as well as at school, and what can be done to overcome these effects, now needs to be examined.

"These exposure-effect associations, in combination with results from earlier studies, suggest a causal effect of exposure to aircraft noise on children's reading comprehension," Professor Stansfeld comments. "This effect is significant though small in magnitude, but does show a linear exposure-effect relation.

"In practical terms, aircraft noise might have only a small effect on the development of reading, but the effect of long-term exposure remains unknown," Professor Stansfeld continues. "Our results are relevant to the design and placement of schools in relation to airports, to the formulation of policy on noise and child health, and to a wider consideration of the effect of environmental stressors on children's cognitive development."

In an accompanying comment, Peter Rabinowitz of Yale University School of Medicine, New Haven, Connecticut, states: "Stansfeld and co-workers' study adds to developing literature about the negative effect of noise on learning.

"Schools located near airports have come under particular scrutiny," Rabinowitz notes. "In one study, 326 German school children matched for socioeconomic status were followed up prospectively as the old Munich airport was replaced by a new international facility.

"Children attending schools near the airport improved their reading scores and cognitive memory performance as the airport shut down, while children going to school near the new airport experienced a decrease in testing scores," he points out.