title: Male fertility following occupational exposure to dichlorodiphenyltrichloroethane (DDT).
abstract: BACKGROUND
  The inconsistent epidemiological results of the endocrine disrupting effects of DDT fuel a harsh debate on its global ban.
  
  
  OBJECTIVE
  We tested the hypothesis that occupational exposure to dichloro-diphenyl-trichloroethane (DDT) causes impairment in male fertility in a cohort of DDT exposed workers, in Sardinia, Italy.
  
  
  METHODS
  We accessed official records on date of marriage and date of birth of the first child to estimate time to pregnancy (TTP) in the spouses of 1223 workers employed in a 1946-1950 anti-malarial campaign. The TTP calculation was censored at the 13th month after date of marriage. We used a modified Cox's proportional hazard model to calculate the fecundability ratio (FR) by job, by cumulative exposure to DDT, and by time window in relation to the anti-malarial operations, adjusting by paternal age at marriage.
  
  
  RESULTS
  Among the spouses of DDT applicators, fecundability did not vary during DDT use (FR=1.22, 95% CI 0.84-1.77) nor in the following decade (FR=1.01, 95% CI 0.67-1.50) with reference to the prior years. A significant increase occurred among the unexposed and the less exposed sub-cohorts, which generated a non-significantly reduced FR among the DDT applicator sub-cohort with reference to the unexposed following exposure.
  
  
  CONCLUSIONS
  We did not find evidence of an impairment in male fertility following heavy occupational exposure to DDT. However, although fecundability was highest among the spouses of the DDT applicators in the years prior to the anti-malarial campaign, we cannot exclude that DDT exposure prevented an increase parallel to that observed among the unexposed and the less exposed sub-cohorts.
authors: Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Asse Didattico E ss 554, km 4,500, 09042 Monserrato, Cagliari, Italy. Electronic address: makamp@libero.it.
authors: Marcello
authors: M
authors: Campagna
authors: Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Asse Didattico E ss 554, km 4,500, 09042 Monserrato, Cagliari, Italy. Electronic address: gianninasatta@tiscali.it.
authors: Giannina
authors: G
authors: Satta
authors: Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Asse Didattico E ss 554, km 4,500, 09042 Monserrato, Cagliari, Italy. Electronic address: faddadomenica@tiscali.it.
authors: Domenica
authors: D
authors: Fadda
authors: Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Asse Didattico E ss 554, km 4,500, 09042 Monserrato, Cagliari, Italy. Electronic address: serginho.pili@gmail.com.
authors: Sergio
authors: S
authors: Pili
authors: Department of Public Health, Clinical and Molecular Medicine, Occupational Health Section, University of Cagliari, Asse Didattico E ss 554, km 4,500, 09042 Monserrato, Cagliari, Italy. Electronic address: coccop@medicina.unica.it.
authors: Pierluigi
authors: P
authors: Cocco
mesh_terms: D000328:Adult; D003634:DDT / Q000633:toxicity*; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D005298:Fertility / Q000187:drug effects*; D006801:Humans; D007248:Infertility, Male / Q000139:chemically induced*; D007558:Italy; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D016016:Proportional Hazards Models; D055815:Young Adult
chemical_list: D052244:Endocrine Disruptors; D003634:DDT
keywords: DDT; Male fertility; Occupational exposure; Time to pregnancy