Air pollution may accelerate cognitive decline in women
By Liz Lockhart
Chronic exposure to particulate air pollution may accelerate cognitive decline in older adults according to a study by Rush University Medical 
Centre.
Women who were exposed to higher levels of ambient particulate matter (PM) over the long-term, a period of four years, experienced more decline in their cognitive function, according to researchers. Their results of the study are published in Archives of Internal Medicine.
Higher levels of long-term exposure to both coarse PM (PM 2.5-10) and fine PM (PM 2.5) were associated with considerably faster cognitive decline. PM air pollution is a suspension of small particles in the air. Particles which are smaller than 2.5 microns in diameter are called ‘fine’ PM and ‘coarse’ PM particles are 2.5 – 10 microns. Fine PM particles are 1/30th the width of a human hair.
Few recent studies have analysed air pollution and cognitive function in older adults and this study is the first to examine alteration in cognitive function over a period of time. It also investigated whether exposure to the size of particulate matter is important.
Researchers from the Rush Institute of Healthy Aging, led by Jennifer Weuve, MPH., ScD., assistant professor, evaluated air pollution, both fine and coarse, in relation to cognitive decline in older women. The participants in the study were from the Nurses’ Health Study Cognitive Cohort and included 19,409 U.S. women aged between70 and 81. They were studies from 1988 over a period of 14 years.
Weuve said ‘Our study explored chronic exposure to particulate air pollution in relation to decline in cognitive functioning among older women. Very little is known about the role of particulate matter exposure and its association with cognitive decline.’
It is thought that exposure to particulate air pollution may play a role in causing accelerated cognitive decline due to the fact that it is associated with cardiovascular risk.
‘Unlike other factors that may be involved in dementia such as diet and physical activity, air pollution is something we can intervene on as a society at large through policy, regulation and technology. Therefore, if our findings are confirmed in other research, air pollution reduction is a potential means for reducing the future population burden of age-related cognitive decline and eventually dementia,’ Weuve said.
In a further study which can be found in the Archives of Internal Medicine, researchers from Beth Israel Deaconess Medical Centre found that air pollution, even at levels generally considered safe by regulations, increases the risk of stroke by 34%. Researchers studied more than 1,700 stroke patients in the Boston area over a period of 10-years and found that exposure to ambient fine particulate matter, usually from vehicle traffic, was associated with this significantly higher risk
