Affiliations: [a] Division of Pulmonary, Allergy, and Critical Care, Department of Medicine, the University of Alabama at Birmingham, Birmingham, AL, USA
| [b] Department of Genetics, the University of Alabama at Birmingham, Birmingham, AL, USA
| [c] Department of Biostatistics and Data Science, The University of Southern California, Los Angeles, CA, USA
Correspondence:
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Correspondence to: Rui-Ming Liu, Department of Medicine, the University of Alabama at Birmingham, Birmingham, AL 35294, USA. Tel.: +1 205 934 7028; Fax: +1 205 934 1721; E-mail: [email protected].
Abstract: Alzheimer’s disease (AD), an aging-related neurodegenerative disease, is a major cause of dementia in the elderly. Although the early-onset (familial) AD is attributed to mutations in the genes coding for amyloid-β protein precursor (AβPP) and presenilin1/presenilin 2 (PS1/PS2), the cause for the late-onset AD (LOAD), which accounts for more than 95% of AD cases, remains unclear. Aging is the greatest risk factor for LOAD, whereas the apolipo protein E4 allele (APOEɛ4) is believed to be a major genetic risk factor in acquiring LOAD, with female APOE ɛ4 carriers at highest risk. Nonetheless, not all the elderly, even older female APOE ɛ4 carriers, develop LOAD, suggesting that other factors, including environmental exposure, must play a role. This review summarizes recent studies that show a potential role of environmental exposure, especially ozone and particulate matter exposure, in the development of AD. Interactions between environmental exposure, genetic risk factor (APOE ɛ4), and sex in AD pathophysiology are also discussed briefly. Identification of environmental risk factor(s) and elucidation of the complex interactions between genetic and environmental risk factors plus aging and female sex in the onset of AD will be a key to our understanding of the etiology and pathogenesis of AD and the development of the strategies for its prevention and treatment.
