title: Association of hypothyroidism with low-level arsenic exposure in rural West Texas.
abstract: It has been reported recently that a higher airborne arsenic level was correlated with higher urinary arsenic concentration and lower serum thyroxin level among urban policemen and rural highway workmen in Italy. The current study was to determine whether exposure to low-level arsenic groundwater (2-22µg/L) is associated with hypothyroidism among 723 participants (118 male and 267 female Hispanics; 108 male and 230 female non-Hispanic whites, NHW) living in rural West Texas counties. Arsenic and iodine levels in their groundwater used for drinking and or cooking were estimated by the inverse distance weighted (IDW) interpolation technique. Groundwater arsenic was ≥8µg/L in 36% of the subjects' wells while iodine concentration was <1µg/L in 91% of their wells. Logistic regression analysis showed that arsenic in groundwater ≥8µg/L and cumulative arsenic exposure (groundwater arsenic concentration multiplied by the number of years living in the current address) but not groundwater iodine concentration were significant predictors for hypothyroidism among Hispanics (p<0.05) but not NHW after adjusting for covariates such as age, gender, annual household income and health insurance coverage. The ethnic difference may be due to a marginally higher percentage of Hispanics (p=0.0622) who lived in areas with groundwater arsenic ≥8µg/L compared with NHW. The prevalence of hypothyroidism was significantly higher in Hispanics or NHW of this rural cohort than the national prevalence. Measures should be taken to reduce arsenic in drinking water in order to prevent hypothyroidism in rural areas.
authors.affiliation: F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Sciences Center, Lubbock, TX, USA. Electronic address: gordon.gong@ttuhsc.edu.
authors.forename: Gordon
authors.initials: G
authors.lastname: Gong
authors.affiliation: F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Sciences Center, Lubbock, TX, USA; Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Basom
authors.affiliation: Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA.
authors.forename: Sravan
authors.initials: S
authors.lastname: Mattevada
authors.affiliation: Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
authors.forename: Frederick
authors.initials: F
authors.lastname: Onger
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001151:Arsenic / Q000032:analysis* / Q000097:blood / Q000633:toxicity; D004781:Environmental Exposure; D005260:Female; D060587:Groundwater / Q000737:chemistry*; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced / Q000453:epidemiology*; D007455:Iodine / Q000032:analysis; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012424:Rural Population; D013781:Texas / Q000453:epidemiology; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D007455:Iodine; D001151:Arsenic
keywords: Hypothyroidism; Low-level arsenic exposure; Rural Texas