title: Sex ratio of the offspring of New Zealand phenoxy herbicide producers exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.
abstract: Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has inconsistently been associated with a decreased sex ratio of the offspring (number of male births divided by total births). We conducted a study among men and women who were employed in a New Zealand phenoxy herbicide production plant between 1969 and 1984, to study their offspring sex ratio in relation to their back-calculated TCDD serum concentrations determined in 2007/2008.
  
  
  
  A total of 127 men and 21 women reported that 355 children were conceived after starting employment at the plant. The association between their lipid-standardised TCDD serum concentrations back-calculated to the time of their offspring's birth and the probability of a male birth was estimated through logistic regression, adjusting for the age of the exposed parent at birth, current body mass index and smoking.
  
  
  
  The overall sex ratio was 0.55 (197 boys, 158 girls). For fathers with serum TCDD concentrations ≥20 pg/g lipid at time of birth, the sex ratio was 0.47 (OR 0.49; 95% CI 0.30 to 0.79). The probability of a male birth decreased with higher paternal serum TCDD at time of birth (<4; 4-20; 20-100; ≥100 pg/g lipid), with ORs of 1.00 (reference); 1.00 (95% CI 0.50 to 2.02); 0.52 (95% CI 0.29 to 0.92); 0.45 (95% CI 0.23 to 0.89), p trend 0.007. For exposed mothers, the sex ratio was not reduced.
  
  
  
  This study indicates that paternal serum TCDD concentrations in excess of an estimated 20 pg/g lipid at time of conception are associated with a reduced sex ratio.
authors: Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors: Andrea
authors: A
authors: 't Mannetje
authors: Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors: Amanda
authors: A
authors: Eng
authors: Occupational Medicine Specialists, Auckland, New Zealand.
authors: Chris
authors: C
authors: Walls
authors: Occupational Medicine Specialists, Auckland, New Zealand.
authors: Evan
authors: E
authors: Dryson
authors: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.
authors: Manolis
authors: M
authors: Kogevinas
authors: Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors: Collin
authors: C
authors: Brooks
authors: Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors: Dave
authors: D
authors: McLean
authors: Centre for Public Health Research, Massey University, Wellington, New Zealand.
authors: Soo
authors: S
authors: Cheng
authors: School of Public Health, University of California, Berkeley, USA.
authors: Allan H
authors: AH
authors: Smith
authors: Centre for Public Health Research, Massey University, Wellington, New Zealand.|Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK.
authors: Neil
authors: N
authors: Pearce
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D004147:Dioxins / Q000009:adverse effects* / Q000097:blood; D005260:Female; D006540:Herbicides / Q000009:adverse effects; D006801:Humans; D007221:Industry; D007390:International Agencies; D007407:Interviews as Topic; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D016273:Occupational Exposure / Q000009:adverse effects*; D018812:Paternal Exposure / Q000009:adverse effects*; D011247:Pregnancy; D017678:Sex Distribution; D012744:Sex Ratio; D055815:Young Adult
chemical_list: D004147:Dioxins; D006540:Herbicides; C066841:2,3,7,8-tetrabromodibenzo-4-dioxin
keywords: TCDD; pesticide production; sex ratio