Vehicular traffic density and cognitive performance in the ELSA-Brasil study

Despite the knowledge about the deleterious effects of air pollutants and their influence on mortality and morbidity due to respiratory and cardiovascular diseases, little is known about the relationship between atmospheric pollutants and neurological diseases. Recently, studies from high-income countries have suggested an association between exposures to air pollutants with cognitive impairment. Thus, we investigated the association of air pollution with cognitive performance in the participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Cognitive function was evaluated using the word list, the verbal fluency, and the trail making tests (TMT). Pollutant exposure was evaluated indirectly using the distance-weighted traffic density (DWTD) of participants' residence and workplace. We investigated the cross-sectional association between DWTD and cognitive test scores using adjusted linear regression models for sociodemographic and clinical variables.

3050 were included (mean age = 52.1 ± 9.2 years old, 56.5% women, and 63.6% white). In the simple linear regression models, participants in the higher tertile of combined DWTD (residence and workplace) presented better cognitive performance in all tests when compared to participants in the lower tertile. The DWTD was not associated with cognitive performance in adjusted linear models especially when adjusted for socioeconomic variables (age, sex, education, and race). We found similar results when we investigated the association of cognitive performance with DTWD near participants' workplace and residence separately.

Air pollutants were not associated with worse cognitive performance in a large sample of middle-aged and older adults.