The impact of air pollution and pollutants on the progression of dementia

Abstract

AbstractBackgroundAir pollution is known to increase the incidence of dementia, but whether dementia in areas with high air pollution likely to get worse is still unclear. We investigate the impact of high air pollution areas on the progression in dementia, and which air pollutants have more obvious influences.MethodA retrospective case‐control study was performed using the data from the Kaohsiung Medical University Hospital Research Database and Environmental Protection and Administration, Taiwan. Clinical data and air pollution data were concatenated with addresses to assess the exposure to each case. Further, divide Kaohsiung into areas with severe air pollution and compare them with general areas. Exacerbation of dementia was defined as detection with use of advanced medications. We constructed conditional logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs).ResultThere were 529 cases in the group of worsening dementia and 2351 cases in the control group. The OR of dementia exacerbation in the general area is significantly lower than that of the high SO2 exposure area (OR: 0.745, 95% CI: 0.616‐0.901). Exposure to SO2 and PM2.5 at all five time points studied were significantly associated with an increased risk of worsening dementia of all types and non‐degenerative types. The maximum total peak ORs (95% CI) were 1.285 (1.154–1.431) in the first year with exposure to high SO2 and 1.111 (1.043–1.183) in the four years with exposure to high PM2.5, respectively. In the dementia of degenerative types, exposure to SO2 were significantly associated with an increased risk of worsening dementia. The maximum total peak ORs (95% CI) were 1.386 (1.174–1.638) in the first year.ConclusionThis study confirms that cumulative exposure in the previous one to five years in high‐exposure areas has a significantly higher risk of all dementia worsening. SO2 pollutant has the obvious effect on the progression of dementia of all types, degenerative and non‐degenerative types. PM2.5 pollutant has the obvious effect on the progression of dementia of all types and non‐degenerative types. The protection from air pollution, especially SO2 and PM2.5 pollutants is very important in the treatment of dementia.