O2-08-03: long-term exposure to air pollution and dementia: a large clinicopathological study

Air pollution is ubiquitous, but unevenly distributed. For instance, people living close to busy roads are more vulnerable than neighbors living farther away. Epidemiological studies suggest an association between exposure to air pollution and cognitive impairment,1,2although no data are available for Latin America, a region expected to receive more than 17 million of the dementia cases by 20503and where pollution levels recently increased in some regions4. This study investigates whether a long-term exposure to air pollution associates to cognitive impairment. We investigated 196 individuals who underwent autopsy at the Sao Paulo Autopsy Service and were enrolled for both Brazilian Brainbank for Aging Studies and MODAU (The use of modern autopsy techniques to investigate human diseases). We measured long-term exposure to air pollution at the individual level by: 1) the proportion of black patches (carbon deposits) on pleural surface in relation to clean area (anthracosis index) and 2) estimation of long-term exposure in traffic between home and work, corrected by occupational exposure. Clinicofunctional data were obtained via structured and validated interviews with an informant. Dementia was defined by a Clinical Dementia Rating5,6 score ≥1. Data were summarized using means and standard deviations for continuous variables and frequencies and percents for categorical variables. Associations between variables used linear correlation and ANOVA was used to test differences between continuous variables and dementia. We used binary logistic models adjusted for possible confounders to verify if pollution (time in traffic and anthracosis index) could predict dementia, adjusting for tobacco burden and gender. Mean age was 70.3(±14.7) years, 51% males, 28% had dementia. The degree of anthracosis and long-term exposure in traffic were both significantly different between the dementia group and controls (Antracosis, p<0.001; Traffic p=0.046). Time spent in traffic (p=0.003) and increased anthracosis (p=0.008) were independently and significantly associated with dementia in binary logistic models adjusted for tobacco burden and gender. Males had higher anthracosis index and spent more hours in traffic. Long-term exposure to air pollution predicted dementia in people living in Sao Paulo. We are currently adding neuropathological data to the analysis to investigate the neurobiological basis of this association.