Düsseldorf, Germany—A new study has shown that air pollution presents an independent risk factor for cognition and is not mediated by function.

This study was conducted by German and Swiss researchers from the Swiss Tropical and Public Health Institute in Basel and the Leibniz Research Institute for Environmental Medicine (IUF), with the full results presented at the 2015 American Thoracic Meeting.

Data were analyzed from the cohort Study on the Influence of Air Pollution on Lung function, Inflammation and Aging (SALIA). The 834 elderly German women who participated in this study were tested to see if impaired lung function was linked to cognitive impairment. Lung function measured by force expiratory volume in one second and forced volume capacity. They then measured cognitive changes using a neuropsychological assessment battery to gauge progression of Alzheimer’s disease.

The results showed the strongest association between the two factors in a test used to gauge visuospatial ability (i.e., the ability to understand visual information). However, in the second portion of the study, which used these same tests in presence of particulate matter and nitrogen dioxide, two factors known to reduce lung health, no corresponding decline in visuospatial ability. This suggests that rather than air pollution leading to impaired lung function resulting in cognitive decline, as was previously thought, air pollution itself may be behind the decline.

Study leader Mohammad Vossoughi, Ph.D. student at the IUF, remarked, “Our findings disprove the hypothesis that air pollution first decreases lung function and this decline, in turn, causes cognitive impairment by releasing stress signals and humoral mediators into the body.”

He adds that several other hypotheses on the relationship between air pollution and cognitive function have developed due to these study results. One possibility is that particulate matter and other pollutants are translocated to the central nervous system via our sense of smell, leading to mild cognitive impairment. Ultimately, Vossoughi explains that while these results provide some insight, further studies will be needed to determine how this relationship plays out with other demographics, particularly men and the non-elderly.

Published in WholeFoods Magazine, August 2015(online 7/16/15)