title: Environmental and occupational exposure to chemicals and telomere length in human studies.
abstract: Telomeres are complexes of tandem repeats of DNA (5'-TTAGGG-3') and protein that cap eukaryotic chromosomes and play a critical role in chromosome stability. Telomeres shorten with aging and this process can be accelerated by increased oxidative stress and episodes of inflammation. Evidence is rapidly growing that telomere length (TL) may be affected by environmental chemicals that have frequently been associated with chronic diseases. In this article, we review the published data on TL in relation to environmental and occupational exposure to several chemicals based on our own and others' studies. The environmental and occupational exposures associated with shorter TL include traffic-related air pollution (ie, particulate matter (PM), black carbon (BC), and benzene and toluene), polycyclic aromatic hydrocarbons (PAHs), N-nitrosamines, pesticides, lead, exposure in car mechanical workshops, and hazardous waste exposure. Arsenic, persistent organic pollutants (POPs) and short-term exposure to PM are associated with longer TL. We discuss the possible reasons for the differences in results, including time- and dose-related issues, study design, and possible mechanisms involved in telomere regulation. We also discuss the future directions and challenges for TL-related environmental and occupational health research, such as investigation of TL in subpopulations of blood leukocytes, and the study of genetic and epigenetic factors that may regulate telomere integrity using longitudinal designs.
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Shao
authors.initials: S
authors.lastname: Lin
authors.forename: William E
authors.initials: WE
authors.lastname: Funk
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D006256:Hazardous Waste / Q000009:adverse effects; D006801:Humans; D007854:Lead / Q000009:adverse effects; D016273:Occupational Exposure / Q000009:adverse effects*; D009930:Organic Chemicals / Q000009:adverse effects*; D010575:Pesticides / Q000009:adverse effects; D011084:Polycyclic Aromatic Hydrocarbons / Q000009:adverse effects; D016615:Telomere / Q000187:drug effects*; D059506:Telomere Shortening / Q000187:drug effects*
chemical_list: D000393:Air Pollutants; D006256:Hazardous Waste; D009930:Organic Chemicals; D010575:Pesticides; D011084:Polycyclic Aromatic Hydrocarbons; D007854:Lead
keywords: Materials, exposures and occupational groups