Ambient Air Pollution and Cognition in India

Abstract

OPS 53: Air pollution and neurological outcomes, Room 217, Floor 2, August 27, 2019, 10:30 AM - 12:00 PM Background/Aim: Indians experience some of the highest air pollution levels in the world. We aimed to study if ambient PM2.5 levels are associated with poorer cognition in older Indians. Methods: We used data from the Longitudinal Aging Study in India - Diagnostic Assessment of Dementia (LASI-DAD). LASI-DAD is a study nested within a nationally representative sample of older (>45 years) Indians. During the first phase of LASI-DAD, a subsample of participants (>60 years) underwent a battery of cognitive tests, including verbal fluency, word recall, and the Hindi Mental State Examination (HMSE). Participants also self-reported sociodemographic data. We estimated ambient PM2.5 for each participant’s residence using the Data Integration Model for Air Quality, which fuses satellite information on aerosol optical depth with ground level monitoring data and local geographic information. We then used linear regression models to estimate associations between ambient PM2.5 and cognitive scores, adjusting for age, gender, socioeconomic status, and region (North, Delhi, south). Results: Among 1,480 participants, the average age was 69±7 years and 55% were female. Greater PM2.5 concentrations (117±24 µg/m3) and lower cognitive scores (HMSE: 16±11) were found in northern India (excluding Delhi) as compared to southern India (45±13 µg/m3 and 22±8, respectively). Ambient PM2.5 was suggestively associated with worse cognition after adjustment for region and other sociodemographic confounders. For example, we observed associations of -0.07 (95%CI:-0.2, 0.03) lower HMSE scores per 10 µg/m3 of PM2.5. Conclusions: Among older adults living throughout India, we observed associations between higher ambient PM2.5 and poorer cognition even after adjustment for individual sociodemographic characteristics and regional trends.