Impact of air pollution on cognitive decline
Air pollution is a risk factor for cognitive impairment in elderly people. But where does this effect come from - is there a direct relation or is it mediated by lung function?
28.03.2018 · IUF – Leibniz Research Institute for Environmental Medicine · Research result · News · Life Sciences
A study from scientists at IUF – Leibniz Research Institute for Environmental Medicine in Düsseldorf, Germany, published in the European Respiratory Journal, indicates that poor lung function is not only a risk factor for cognitive impairment in elderly people but also partially mediates negative effects of air pollution on cognition.
Epidemiological studies show increasing evidence that there is an association between air pollution and cognitive decline in elderly people. This observed deterioration in information processing is in particular in regards to visual constructive abilities for example in tracing the outlines of geometric figures. So where does this effect come from? Is it mediated by lung function? Does an impaired lung function due to air pollution lead to cognitive impairment in the long term? Or is there also a direct relation between air pollution and cognitive impairment? One possible explanation would be that fine dust particles get via the circulatory system or the nose into the central nervous system and directly cause detrimental effects.
Scientists from IUF – Leibniz Research Institute for Environmental Medicine in Düsseldorf, Germany, investigated these questions in a causal mediation analyses on the basis of data on lung function and cognition of 587 elderly women of the SALIA health study. The analyses confirmed that lung function in adulthood is an important factor for the prediction of cognitive impairment in elderly people. Additionally, it was shown that only a small part of this relationship is mediated by the lung (max. 11 % for nitrogen dioxide). These results were recently published in the European Respiratory Journal.
“Thus, maintenance of a good lung function through adulthood seems to be also important for healthy brain aging”, said Dr. Tamara Schikowski from IUF in Düsseldorf, whose group conducted the study. “The fact that we found that only a part of the cognitive impairment is mediated by the lung supports the hypotheses that there is also a direct impact of air pollution on the brain. This finding has still to be confirmed in bigger cohorts and has also to be mechanistically investigated.”
The SALIA study (Study on the influence of air pollution on lung function, inflammation and aging) was started in 1985 in order to investigate the long-term effects of air pollution on health. The study group consists of elderly women from the Ruhr region and the Southern Münsterland region. The comparison of initial examination and follow-up allows drawing conclusions on different environmental-medical questions.
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