A research study has found that long-term exposure to air pollution may lead to loss of white matter in the brain.
In the study, older women who lived in places with higher air pollution had significantly reduced white matter in the brain. White matter in the brain is made of axon cells, which enable the nerves to communicate.
“Investigating the impact of air pollution on the human brain is a new area of environmental neurosciences,” said lead author of the study Jiu-Chiuan Chen from Keck School of Medicine, University of Southern California in the US.
“Our study provides the convincing evidence that several parts of the ageing brain, especially the white matter, are an important target of neurotoxic effects induced by long-term exposure to fine particles in the ambient air.”
For the study, the researchers took brain scans of 1403 women who were 71 to 89 years old and used residential histories and air monitoring data to estimate their exposure to air pollution in the previous six to seven years.
The results suggest that ambient particulate air pollutants may have a deleterious effect on brain ageing.
The study was published in the journal Annals of Neurology.
The U.S. government is shutting down a planned study testing whether moderate drinking has health benefits over concerns that its funding by the alcohol industry would compromise its credibility.
The National Institutes of Health said Friday that the results of the planned $100 million study could not be trusted because of the secretive way that employees negotiated with beer and liquor companies to underwrite the effort.
Government officials say it is legal to use industry money to pay for government research as long as all rules are followed. However, in this case, NIH officials say employees did not follow proper procedures, including keeping their interactions with industry officials secret.
NIH Deputy Director Lawrence Tabak said the interactions between the employees and industry representatives appeared to “intentionally bias” the study so that it would have a better chance to conclude that moderate drinking is beneficial.
An NIH review panel was also concerned that the study’s proposed span of 10 years was too short a time period to adequately test the potential problems of a daily drink, such as an increased risk of cancer or heart failure.
NIH Director Francis Collins temporarily suspended the study last month after reporting by The New York Times first raised questions about the funding policy violations. Collins said Friday that he was completely shutting down the research.
“This is a matter of the greatest seriousness,’’ he said.
The study had planned to track two groups of people, one group drinking a glass of alcohol a day and another abstaining from alcohol. The study had planned to compare new cases of cardiovascular disease and the rate of new cases of diabetes among participants.
Some of the world’s largest alcoholic beverage makers, including Anheuser-Busch InBev and Heineken, had contributed to the study, although Anheuser-Busch InBev had recently withdrawn its contribution.
The NIH said of the $67.7 million raised from private donations, nearly all from the alcohol industry, $11.8 million, had been spent for the study.