title: The association between hand eczema and nickel allergy has weakened among young women in the general population following the Danish nickel regulation: results from two cross-sectional studies.
abstract: BACKGROUND
  An association between nickel contact allergy and hand eczema has previously been demonstrated. In 1990, Denmark regulated the extent of nickel release in the ear-piercing process as well as nickel release from consumer products.
  
  
  OBJECTIVE
  This study aimed to evaluate the effect of the Danish nickel regulation by comparing the prevalence of concomitant nickel allergy and hand eczema observed in two repeated cross-sectional studies performed in the same general population in Copenhagen.
  
  
  METHODS
  In 1990 and 2006, 3881 18-69 year olds completed a postal questionnaire and were patch tested with nickel. Data were analysed by logistic regression analyses and associations were expressed as odds ratios (ORs) with 95% confidence intervals (CIs).
  
  
  RESULTS
  The prevalence of concomitant nickel contact allergy and a history of hand eczema decreased among 18-35-year-old women from 9.0% in 1990 to 2.1% in 2006 (P < 0.01). The association between nickel contact allergy and a history of hand eczema decreased in this age group between 1990 (OR = 3.63; CI = 1.33-9.96) and 2006 (OR = 0.65; CI = 0.29-1.46). Among older women, no significant changes were observed in the association between nickel contact allergy and hand eczema.
  
  
  CONCLUSIONS
  Regulatory control of nickel exposure may have reduced the effect of nickel on hand eczema in the young female population.
authors.affiliation: National Allergy Research Centre, Department of Dermato-Allergology, Gentofte Hospital, University of Copenhagen, 2900 Hellerup Copenhagen, Denmark. jacpth01@geh.regionh.dk
authors.forename: Jacob Pontoppidan
authors.initials: JP
authors.lastname: Thyssen
authors.forename: Allan
authors.initials: A
authors.lastname: Linneberg
authors.forename: Torkil
authors.initials: T
authors.lastname: Menné
authors.forename: Niels Henrik
authors.initials: NH
authors.lastname: Nielsen
authors.forename: Jeanne Duus
authors.initials: JD
authors.lastname: Johansen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology* / Q000209:etiology*; D004485:Eczema / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006229:Hand Dermatoses / Q000191:economics* / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects*; D010328:Patch Tests; D015995:Prevalence
chemical_list: D009532:Nickel