title: Smoking and use of hair treatments in relation to risk of developing systemic lupus erythematosus.
abstract: OBJECTIVE
  To examine the association between smoking and hair treatments (dyes, permanents) and risk of developing systemic lupus erythematosus (SLE).
  
  
  METHODS
  Patients (n = 265) diagnosed between January 1, 1995, and July 31, 1999, were recruited through 4 university based and 30 community based rheumatology practices in eastern North Carolina and South Carolina. Controls (n = 355) were identified through driver's license records and were frequency matched to patients by age, sex, and state. Data collection included a 60 min in-person interview. Analyses were limited to experiences that occurred before age at diagnosis (patients) or reference age (controls). Because the prevalence of use of hair treatments among men was very low, the analyses of those exposures were limited to women.
  
  
  RESULTS
  There was no association with smoking history and risk of developing SLE when analyzed as status (current, former, or never-smoker) or measures of dose (duration or pack-years). Use of permanent hair dyes in women was associated with a small increased risk of developing SLE (OR 1.5, 95% CI 1.0, 2.2). This association increased with longer duration of use (compared with nonusers, OR 1.7, 95% CI 1.0, 2.7 for 6 or more years). There was little evidence of an association between SLE and use of temporary dyes or of permanents and straighteners.
  
  
  CONCLUSIONS
  These results suggest at most a weak association between SLE risk and permanent hair dyes or smoking. Genetic variability in the metabolism of these products may be important to assess in future studies.
authors.affiliation: From the Epidemiology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina 27709, USA. cooper1@niehs.nih.gov
authors.forename: G S
authors.initials: GS
authors.lastname: Cooper
authors.forename: M A
authors.initials: MA
authors.lastname: Dooley
authors.forename: E L
authors.initials: EL
authors.lastname: Treadwell
authors.forename: E W
authors.initials: EW
authors.lastname: St Clair
authors.forename: G S
authors.initials: GS
authors.lastname: Gilkeson
mesh_terms: D016022:Case-Control Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006202:Hair Dyes / Q000009:adverse effects*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D009657:North Carolina / Q000453:epidemiology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D013022:South Carolina / Q000453:epidemiology
chemical_list: D006202:Hair Dyes