Particulate matter exposure from motorized traffic and risk of conversion from mild cognitive impairment to dementia: An Italian prospective cohort study

Teresa Urbano; Annalisa Chiari; Carlotta Malagoli; Andrea Cherubini; Roberta Bedin; Sofia Costanzini; Sergio Teggi; Giuseppe Maffeis; Marco Vinceti; Tommaso Filippini

doi:10.1016/j.envres.2023.115425

Particulate matter exposure from motorized traffic and risk of conversion from mild cognitive impairment to dementia: An Italian prospective cohort study

Environ Res. 2023 Apr 1:222:115425. doi: 10.1016/j.envres.2023.115425. Epub 2023 Feb 3.

Authors

Affiliations

¹ Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
² Neurology Unit, University Hospital of Modena, Modena, Italy.
³ TerrAria s.r.l., Milan, Italy.
⁴ Neurology Unit, University Hospital of Modena, Modena, Italy; Center for Neurosciences and Neurotechnology, Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.
⁵ DIEF - Department of Engineering 'Enzo Ferrari', University of Modena and Reggio Emilia, Modena, Italy.
⁶ Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA. Electronic address: marco.vinceti@unimore.it.
⁷ Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; School of Public Health, University of California Berkeley, Berkeley, CA, USA.

PMID: 36740156
DOI: 10.1016/j.envres.2023.115425

Abstract

Background: Based on epidemiologic and laboratory studies, exposure to air pollutants has been linked to many adverse health effects including a higher risk of dementia. In this study, we aimed to evaluate the effect of long-term exposure to outdoor air pollution on risk of conversion to dementia in a cohort of subjects with mild cognitive impairment (MCI).

Methods: We recruited 53 Italian subjects newly-diagnosed with MCI. Within a geographical information system, we assessed recent outdoor air pollutant exposure, by modeling air levels of particulate matter with equivalent aerodynamic diameter ≤10 μm (PM₁₀) from motorized traffic at participants' residence. We investigated the relation of PM₁₀ concentrations to subsequent conversion from MCI to any type of dementia. Using a Cox-proportional hazards model combined with a restricted cubic spline model, we computed the hazard ratio (HR) of dementia with its 95% confidence interval (CI) according to increasing PM₁₀ exposure, adjusting for sex, age, and educational attainment.

Results: During a median follow up of 47.3 months, 34 participants developed dementia, in 26 cases diagnosed as Alzheimer's dementia. In non-linear restricted spline regression analysis, mean and maximum annual PM₁₀ levels positively correlated with cerebrospinal fluid total and phosphorylated tau proteins concentrations, while they were inversely associated with β-amyloid. Concerning the risk of dementia, we found a positive association starting from above 10 μg/m³ for mean PM₁₀ levels and above 35 μg/m³ for maximum PM₁₀ levels. Specific estimates for Alzheimer's dementia were substantially similar. Adding other potential confounders to the multivariable model or removing early cases of dementia onset during the follow-up had little effect on the estimates.

Conclusions: Our findings suggest that exposure to outdoor air pollutants, PM₁₀ in particular, may non-linearly increase conversion from MCI to dementia above a certain ambient air concentration.

Keywords: Air pollution; Alzheimer's dementia; Dementia; Mild cognitive impairment; Particulate matter; Vehicular traffic.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / toxicity
Air Pollution* / analysis
Alzheimer Disease* / chemically induced
Cognitive Dysfunction* / chemically induced
Environmental Exposure / analysis
Humans
Particulate Matter / analysis
Prospective Studies

Substances

Particulate Matter
Air Pollutants