Association between Exposure to particulate matter and Newly Diagnosed Alzheimer's disease in the elderly - Elderly Cohort

Abstract

Background: Air pollution is a growing concern all over the world. Of air pollution compound, Particulate matter (PM) is known to have adverse health effects on cardiovascular and cerebrovascular disease. Also, several studies has been made about relationship between air pollution and cognitive decline, dementia. However, the actual impact of air pollution on Alzheimers disease (AD) in Korea has not been studied yet. Therefore, the purpose of this study is to investigate the association with air pollution and the risk of newly diagnosed Alzheimers disease. Method: We used Elderly Cohort data and the study periods were from 1 January, 2008 to 31 December, 2015 in this study. The Elderly Cohort participants composed of 558,147 individuals aged over 60 years were included at the baseline in 2002. The first diagnosed date was defined as newly diagnosed AD and selected as our outcome of interest. We regarded the annual average concentration (1, 2, 3, 4, 5 years) before event as exposure. Cox proportional hazard model was mainly implemented to investigate the association between air pollution and newly diagnosed AD. The effect of air pollution on the risk of newly diagnosed AD was estimated as the hazard ratio (HR) per 1 ㎍/㎥ increase in PM10(aerodynamic diameter equal to or less than 10㎛) with 95% confidence intervals (CIs). Result: The increased risk of newly diagnosed AD in relation to average 1 year concentration of PM10 was 1.15(95% CI: 1.05, 1.27), and 1.14(1.03, 1.25), 1.16(1.05, 1.28), 1.20(1.09, 1.32), 1.19(1.08, 1.30) for each 2, 3, 4, 5 years. After adjusting regional variables additionally from model 1, the risk of newly diagnosed AD was increased from 1.15 to 1.29 (95% CI: 1.14, 1.46) for average 1 year concentration, and increased from 1.14 to 1.34(95% CI: 1.17, 1.53), 1.16 to 1.41(1.23, 1.62), 1.20 to 1.50(1.31, 1.73), 1.19 to 1.49(1.30 1.71) for each average 2, 3, 4, 5 years concentration change of PM10. Conclusion: Air pollution exposure increased the risk of newly diagnosed AD in the elderly in Korea.