title: Nickel allergy--prevalence in a population of Swedish youths from patch test and questionnaire data.
abstract: BACKGROUND
  The prevalence of body piercing and orthodontic treatment has increased during recent decades. Such changes in lifestyle may influence the occurrence of nickel allergy.
  
  
  OBJECTIVE
  The aim of this study was to describe the prevalence of nickel allergy in a Swedish youth population.
  
  
  METHODS
  In a cross-sectional survey, 6095 adolescents answered a questionnaire on their lifestyle and medical history, and 4439 consented to patch testing for contact allergy. Patch test results were adjusted for dropouts by a missing value analysis.
  
  
  RESULTS
  The prevalence of self-reported dermatitis from contact with metal items was 14.8%. Patch testing showed nickel sensitization in 9.9% of the subjects, and in significantly more girls than boys, 13.3% versus 2.5%, respectively. Taking the dropout into account, the estimated true prevalence of nickel sensitivity evaluated by test reading at D4 is 11.8% in girls and 1.6% in boys.
  
  
  CONCLUSIONS
  The prevalence of nickel sensitization was higher for girls and slightly lower for boys compared with previous Swedish data. Self-reported information on metal dermatitis as an estimate of nickel allergy has low validity. When possible, missing value analysis should be performed to account for dropouts.
authors.affiliation: Department of Odontology, Orthodontics, Umeå University, SE 901 87 Umeå, Sweden. ronny.fors@odont.umu.se
authors.forename: Ronny
authors.initials: R
authors.lastname: Fors
authors.forename: Maurits
authors.initials: M
authors.lastname: Persson
authors.forename: Erik
authors.initials: E
authors.lastname: Bergström
authors.forename: Hans
authors.initials: H
authors.lastname: Stenlund
authors.forename: Birgitta
authors.initials: B
authors.lastname: Stymne
authors.forename: Berndt
authors.initials: B
authors.lastname: Stenberg
mesh_terms: D000293:Adolescent; D000328:Adult; D003035:Cobalt / Q000009:adverse effects; D003430:Cross-Sectional Studies; D003625:Data Collection; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D004485:Eczema / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009532:Nickel / Q000009:adverse effects*; D010328:Patch Tests; D010352:Patient Dropouts; D015995:Prevalence; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology
chemical_list: D003035:Cobalt; D009532:Nickel