title: The risk of infertility among hairdressers. Five-year follow-up of female hairdressers in a Danish national registry.
abstract: BACKGROUND
  One in seven married couples is involuntarily infertile. Several chemical exposures in the work environment have been hypothesized to affect female reproduction, and some are present in products used in hairdressing and related trades. Recent Swedish findings indicate that employment in hairdressing poses a risk for female reproductive function. This study examined the possible association between work as a hairdresser and subsequent hospital contact due to female infertility.
  
  
  METHODS
  A cohort of all women in Denmark aged 20-44 years on 1 January 1998 (baseline) and registered as economically active hairdressers, according to national registers, was formed to calculate age-standardized risk ratios (RRs) for hospital contacts due to female infertility during a 5-year follow-up period. Hairdressers were compared to a standard population, that is, all economically active women in Denmark aged 20-44 years at baseline, and to women working as shop assistants.
  
  
  RESULTS
  Sixty-eight cases of hospital contact due to female infertility were observed among the female hairdressers. On the basis of the standard population, the expected number was 73.27, which gives an observed RR of 0.928 (95% CI: 0.72-1.18). Hairdressers and shop assistants exhibited similar rates of hospital contact due to female infertility (1.01; 95% CI: 0.77-1.29).
  
  
  CONCLUSIONS
  The findings are not corroborating the hypothesis that hairdressers are at increased risk of infertility, but small risks in the entire group or high risks in small subgroups may not be detected by the study.
authors.affiliation: National Institute of Occupational Health, Copenhagen, Denmark. ksh@ami.dk
authors.forename: K S
authors.initials: KS
authors.lastname: Hougaard
authors.forename: H
authors.initials: H
authors.lastname: Hannerz
authors.forename: J P
authors.initials: JP
authors.lastname: Bonde
authors.forename: H
authors.initials: H
authors.lastname: Feveile
authors.forename: H
authors.initials: H
authors.lastname: Burr
mesh_terms: D000328:Adult; D001461:Barbering; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005298:Fertility; D005500:Follow-Up Studies; D006801:Humans; D007247:Infertility, Female / Q000175:diagnosis* / Q000453:epidemiology; D016017:Odds Ratio; D012042:Registries; D012307:Risk Factors