Long-term exposure to air pollutants are associated with an increased risk of clinically diagnosed dementia in the elderly, new findings from researchers at National Taiwan University. This work has been selected as a Special Invited Article with a featured video and an Invited Commentary for publication in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring 1(2): 220-228 (2015) (An open access journal of the Alzheimer’s Association, USA).

[Photo: Photo: Dr. Yen-Ching Karen Chen and Ms. Yun-Chun Wu]

This is a four-year collaborative research between Dr. Yen-Ching Karen Chen and Ms. Yun-Chun Wu from Institute of Epidemiology and Preventive Medicine and Drs. Hwa-Lung Yu and Yuan-Chien Lin from department of bioenvironmental systems engineering at National Taiwan University. Only a small portion of cognitive impaired elderly progress to dementia each year. However, the association between air pollutants and clinically-diagnosed dementia in the elderly remains unclear.

This case-control study included 249 Alzheimer’s disease patients, 125 small-vessel vascular dementia and 497 controls from three teaching hospitals in Taipei, Taiwan. The data of particulate matter <10μm (PM₁₀) and ozone were obtained from the Taiwan Environmental Protection Administration for 12 and 14 years, respectively. A spatiotemporal tool Bayesian Maximum Entropy was used to estimate the individual exposure level of air pollutants. The long-term exposure data is especially important because the progression of dementia is slow.

Long-term exposure to ≥ 49µg/m³ of PM₁₀ and ≥22 µg/m³ of ozone were significantly associated with four- and two-fold risk of Alzheimer’s disease, respectively. Similar findings were observed for vascular dementia. Currently, no cure is available for Alzheimer’s disease. The identification of association between PM₁₀, ozone and dementia risk will be helpful to understand the complicated etiology of dementia.