Children who live or attend schools near airports - within hearing range of loud takeoffs and landings - tend to show impaired reading comprehension, according to the results of an international study.

In short, “chronic exposure to high levels of aircraft noise impairs children’s reading,” study author Dr. Stephen A. Stansfeld, of the University of London, told Reuters Health.

“The findings are important because they suggest specific causal effects of aircraft noise on school performance in children that could have long term effects on children’s education,” he added.

Findings of a 2002 study previously reported by Reuters Health revealed that regular exposure to aircraft noise may hinder a child’s ability to learn and memorize difficult material. Previous research has also shown an association between chronic exposure to the noise of aircraft and road traffic and decreased reading comprehension among primary school children.

Stansfeld and his colleagues further investigated the association among more than 2,000 children, ages 9 and 10, attending schools around Amsterdam’s Schiphol airport, Madrid’s Barajas airport, and London’s Heathrow airport.

The children were exposed to aircraft noise that ranged from 30 to 77 decibels, although Spanish children were exposed to lower noise levels than their peers in the Netherlands or the United Kingdom. Road traffic noise, which was similar in all three countries, ranged from 32 to 71 decibels.

Overall, increasing exposure to aircraft noise at school or home was associated with poorer scores on nationally standardized tests of reading comprehension in all three countries, the team reports in the American Journal of Epidemiology.

The association held up even when the authors took into consideration the child’s working memory, sustained attention and episodic memory, or the ability to recall concepts and information, as well as any dyslexia, hearing impairment or acute noise present during the testing. The children’s socioeconomic status also did not appear to influence the findings.

The mechanism of the association between aircraft noise and reading scores is unclear, according to Stansfeld.

On one hand, aircraft noise may interrupt parent-child communication at home, but it could also be that aircraft noise reduces children’s motivation to work or that noisy situations cause children to “narrow the focus of their attention to tasks to exclude noise and this process also excludes useful sound,” the researcher speculated.

Exposure to chronic road traffic noise, however, did not seem to affect children’s reading comprehension - a finding inconsistent with previous studies, the report indicates. The reason for this may be due to the low noise level of road traffic in the current study in comparison to that found in other studies, the investigators offer.

Also, they write, “aircraft noise is more intense and less predictable than road traffic noise.”

While acknowledging that the “magnitude of the effect of aircraft noise on reading was small,” the researchers maintain that “the consequences of long-term exposure on reading comprehension remain unknown.”

Most parents need not be concerned, however, since it was not “not an enormous” effect and was most apparent in schools with very high aircraft noise levels, Stansfeld told Reuters Health.

Yet, he added, “the results have implications for the siting of new schools - don’t place them near to runways.”

SOURCE: American Journal of Epidemiology, January 1, 2006.