title: Associations between organochlorine pesticides and cognition in U.S. elders: National Health and Nutrition Examination Survey 1999-2002.
abstract: There is limited evidence about whether background exposure to organochlorine pesticides is related to impairment of cognitive function in general populations. This study was performed to investigate cross-sectional associations between serum concentrations of organochlorine pesticides and cognitive function, a predictor of dementia, among U.S. elders without overt dementia. Study subjects were 644 elders aged 60-85, participating in the National Health and Nutrition Examination Survey 1999-2002. We selected 6 organochlorine pesticides (p,p'-dichlorodiphenyltrichloroethane (DDT), p,p'-dichlorodiphenyldichloroethylene (DDE), trans-nonachlor, oxychlordane, heptachlor epoxide, and β-hexachlorocyclohexane) which were commonly detected in current general population. Cognitive function was assessed with the Digit-Symbol Substitution Test. All 6 compounds showed statistically significant or marginally significant inverse associations with cognitive score after adjusting for covariates including education levels. The strongest association was observed with p,p'-DDT. With the outcome of low cognitive score defined as <25th percentile, elders in the highest quartile of p,p'-DDT, p,p'-DDE, and β-hexachlorocyclohexane had 2 to 3 times higher risks than those in the lowest quartile. In particular, when their concentrations were further divided with the cutoff points of 90th and 95th percentiles, p,p'-DDT in the highest 5th percentile showed 6.5 (95% confidence interval: 2.6-16.3) times higher risk of low cognitive score. On the other hand, non-persistent pesticides like organophosphates or pyrethroid showed little association with this cognitive score. The potential role of background exposure to organochlorine pesticides in the development of dementia should be explored in future prospective studies and in-vitro/in-vivo experimental studies.
authors.affiliation: Department of Preventive Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Ki-Su
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Yu-Mi
authors.initials: YM
authors.lastname: Lee
authors.affiliation: Dept. of Neurology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu, Republic of Korea.
authors.forename: Ho-Won
authors.initials: HW
authors.lastname: Lee
authors.affiliation: Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Jacobs
authors.affiliation: Department of Preventive Medicine, School of Medicine, Kyungpook National University, Daegu, Republic of Korea; BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, Kyungpook National University, Daegu, Republic of Korea. Electronic address: lee_dh@knu.ac.kr.
authors.forename: Duk-Hee
authors.initials: DH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D003071:Cognition / Q000187:drug effects*; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000633:toxicity*; D008297:Male; D009749:Nutrition Surveys; D010575:Pesticides / Q000097:blood* / Q000633:toxicity; D014481:United States
chemical_list: D006843:Hydrocarbons, Chlorinated; D010575:Pesticides
keywords: Cognitive function; DDE; DDT; Dementia; Organochlorine pesticides