title: Exposure to particulate air pollution and cognitive decline in older women.
abstract: BACKGROUND
  Chronic exposure to particulate air pollution may accelerate cognitive decline in older adults, although data on this association are limited. Our objective was to examine long-term exposure to particulate matter (PM) air pollution, both coarse ([PM 2.5-10 μm in diameter [PM(2.5-10)]) and fine (PM <2.5 μm in diameter [PM(2.5)]), in relation to cognitive decline.
  
  
  METHODS
  The study population comprised the Nurses' Health Study Cognitive Cohort, which included 19,409 US women aged 70 to 81 years. We used geographic information system-based spatiotemporal smoothing models to estimate recent (1 month) and long-term (7-14 years) exposures to PM(2.5-10), and PM(2.5) preceding baseline cognitive testing (1995-2001) of participants residing in the contiguous United States. We used generalized estimating equation regression to estimate differences in the rate of cognitive decline across levels of PM(2.5-10) and PM(2.5) exposures. The main outcome measure was cognition, via validated telephone assessments, administered 3 times at approximately 2-year intervals, including tests of general cognition, verbal memory, category fluency, working memory, and attention.
  
  
  RESULTS
  Higher levels of long-term exposure to both PM(2.5-10) and PM(2.5) were associated with significantly faster cognitive decline. Two-year decline on a global score was 0.020 (95% CI, -0.032 to -0.008) standard units worse per 10 μg/m(3) increment in PM(2.5-10) exposure and 0.018 (95% CI, -0.035 to -0.002) units worse per 10 μg/m(3) increment in PM(2.5) exposure. These differences in cognitive trajectory were similar to those between women in our cohort who were approximately 2 years apart in age, indicating that the effect of a 10-μg/m(3) increment in long-term PM exposure is cognitively equivalent to aging by approximately 2 years.
  
  
  CONCLUSIONS
  Long-term exposure to PM(2.5-10) and PM(2.5) at levels typically experienced by many individuals in the United States is associated with significantly worse cognitive decline in older women.
authors.affiliation: Rush Institute for Healthy Aging, Rush University Medical Center, Chicago, IL 60625, USA. Jennifer_Weuve@rush.edu
authors.forename: Jennifer
authors.initials: J
authors.lastname: Weuve
authors.forename: Robin C
authors.initials: RC
authors.lastname: Puett
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Jeff D
authors.initials: JD
authors.lastname: Yanosky
authors.forename: Francine
authors.initials: F
authors.lastname: Laden
authors.forename: Francine
authors.initials: F
authors.lastname: Grodstein
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology*; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005260:Female; D006801:Humans; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D011446:Prospective Studies
chemical_list: D052638:Particulate Matter