title: Long-term exposure to fine particulate matter, residential proximity to major roads and measures of brain structure.
abstract: OBJECTIVE
  Long-term exposure to ambient air pollution is associated with cerebrovascular disease and cognitive impairment, but whether it is related to structural changes in the brain is not clear. We examined the associations between residential long-term exposure to ambient air pollution and markers of brain aging using magnetic resonance imaging.
  
  
  METHODS
  Framingham Offspring Study participants who attended the seventh examination were at least 60 years old and free of dementia and stroke were included. We evaluated associations between exposures (fine particulate matter [PM2.5] and residential proximity to major roadways) and measures of total cerebral brain volume, hippocampal volume, white matter hyperintensity volume (log-transformed and extensive white matter hyperintensity volume for age), and covert brain infarcts. Models were adjusted for age, clinical covariates, indicators of socioeconomic position, and temporal trends.
  
  
  RESULTS
  A 2-μg/m(3) increase in PM2.5 was associated with -0.32% (95% confidence interval, -0.59 to -0.05) smaller total cerebral brain volume and 1.46 (95% confidence interval, 1.10 to 1.94) higher odds of covert brain infarcts. Living further away from a major roadway was associated with 0.10 (95% confidence interval, 0.01 to 0.19) greater log-transformed white matter hyperintensity volume for an interquartile range difference in distance, but no clear pattern of association was observed for extensive white matter.
  
  
  CONCLUSIONS
  Exposure to elevated levels of PM2.5 was associated with smaller total cerebral brain volume, a marker of age-associated brain atrophy, and with higher odds of covert brain infarcts. These findings suggest that air pollution is associated with insidious effects on structural brain aging even in dementia- and stroke-free persons.
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.). ewilker@bidmc.harvard.edu.
authors.forename: Elissa H
authors.initials: EH
authors.lastname: Wilker
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Preis
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Alexa S
authors.initials: AS
authors.lastname: Beiser
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Philip A
authors.initials: PA
authors.lastname: Wolf
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Rhoda
authors.initials: R
authors.lastname: Au
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Itai
authors.initials: I
authors.lastname: Kloog
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Wenyuan
authors.initials: W
authors.lastname: Li
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Charles
authors.initials: C
authors.lastname: DeCarli
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Sudha
authors.initials: S
authors.lastname: Seshadri
authors.affiliation: From the Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA (E.H.W., M.A.M.); Exposure, Epidemiology and Risk Program, Department of Environmental Health (E.H.W., J.S., P.K.) and Department of Epidemiology (W.L., J.S., M.A.M.), Harvard T.H. Chan School of Public Health, Boston, MA; Department of Biostatistics, School of Public Health (S.R.P., A.S.B., R.A.) and Department of Neurology, School of Medicine (A.S.B., P.A.W., S.S.), Boston University, MA; Framingham Heart Study, MA (S.R.P., A.S.B., P.A.W., S.S.); Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva, Israel (I.K.); and Department of Neurology and Center for Neuroscience, University of California, Davis (C.D.).
authors.forename: Murray A
authors.initials: MA
authors.lastname: Mittleman
mesh_terms: D000367:Age Factors; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects*; D001284:Atrophy; D001921:Brain / Q000473:pathology*; D002544:Cerebral Infarction / Q000453:epidemiology / Q000473:pathology; D004781:Environmental Exposure; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects*; D012959:Socioeconomic Factors; D066127:White Matter / Q000473:pathology
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: air pollution; brain infarcts; neuroimaging