title: Serum DDT, age at menarche, and abnormal menstrual cycle length.
abstract: BACKGROUND
  Although dichlorodiphenyl trichloroethane (DDT) exposure is known to affect human endocrine function, few previous studies have investigated the effects of DDT exposure on age at menarche or menstrual cycle length.
  
  
  METHODS
  A cross sectional study was conducted to study the effects of DDT exposure on age at menarche and menstrual cycle length among 466 newly married, nulliparous female Chinese textile workers aged 20-34 years enrolled between 1996 and 1998. Serum was analysed for DDT and its major metabolites. Multivariate linear regression was used to estimate DDT exposure effects on age at menarche and multivariate logistic regression was used to estimate DDT exposure effects on odds of experiencing short or long cycles.
  
  
  RESULTS
  Relative to those in the lowest DDT quartile, the adjusted mean age at menarche was younger in those in the fourth quartile (-1.11 years). Modeled as a continuous variable, a 10 ng/g increase in serum DDT concentration was associated with an adjusted reduction in age at menarche of 0.20 years. Relative to those in the lowest DDT quartile, odds of any short cycle (<21 days) in the previous year were higher for those in the fourth quartile (odds ratio = 2.78; 95% CI 1.07 to 7.14). There were no associations between serum DDT concentrations and odds of experiencing a long cycle (>40 days).
  
  
  CONCLUSIONS
  Results suggest that DDT exposure was associated with earlier age at menarche and increased risk of experiencing a shortened menstrual cycle.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: F
authors.initials: F
authors.lastname: Ouyang
authors.forename: M J
authors.initials: MJ
authors.lastname: Perry
authors.forename: S A
authors.initials: SA
authors.lastname: Venners
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.forename: F
authors.initials: F
authors.lastname: Yang
authors.forename: Z
authors.initials: Z
authors.lastname: Fang
authors.forename: T
authors.initials: T
authors.lastname: Zang
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.forename: X
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D002681:China; D003634:DDT / Q000097:blood* / Q000633:toxicity; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood; D004781:Environmental Exposure; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008572:Menarche / Q000097:blood / Q000187:drug effects*; D008597:Menstrual Cycle / Q000097:blood / Q000187:drug effects*; D010575:Pesticides / Q000097:blood* / Q000633:toxicity
chemical_list: D010575:Pesticides; D003633:Dichlorodiphenyl Dichloroethylene; D003634:DDT