Later-Life Exposure to Moderate PM2.5 Air Pollution and Life Loss of Older Adults in Taiwan

Background: Few studies have directly estimated expected life loss attributable to lifetime exposure to fine particulate matter (PM2.5). Methods: We used claims data from Taiwan's National Health Insurance to create 63 study cohorts of 1.91 million residents aged 60-79 years old residing in small areas where air quality monitoring stations are situated. The survival status of each person was followed from 2001 to 2016. We applied an extrapolation algorithm to estimate the lifetime survival function so that we could directly estimate life expectancy (LE) and the lifetime exposure to PM2.5 of each cohort. We estimated the association between LE and lifetime exposure to PM2.5 among the 63 cohorts. We also fit a Cox proportional hazards model to all the data combined to estimate the relative risk of mortality. Results: Older adults who lived in an area with a higher lifetime weighted average PM2.5 of 10 mu g/m3 had a shortened LE by 0.34 (95% CI: 0.22-0.46) years. The hazard ratio of mortality was 1.0245 (1.0242-1.0248) per one mu g/m3 increase in lifetime average PM2.5. Conclusion: This study provides strong evidence that later-life exposure to moderate PM2.5 air pollution had a substantial impact on the life loss of older adults.