Paternal occupational exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin birthweight and birth defects.
We studied pregnancy outcomes among wives of male chemical workers who were highly exposed to chemicals contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and among non-exposed neighborhood referents. Detailed information on reproductive, medical, lifestyle, and occupational factors was collected from current and former wives/partners via telephone interview. We estimated serum TCDD level at the time of conception using a pharmacokinetic model. The mean worker TCDD concentration was 254 parts per trillion (ppt), range 3-16,340 ppt. The mean referent concentration of 6 ppt was assigned to referent births and worker births conceived before exposure. Repeated measures analysis was used to assess the effect of TCDD on birthweight of live, singleton, term births (greater tan or equal to 37 weeks gestation). Mean birth weight was similar among referent births (n = 604), pre-exposure worker births (n = 259), and offspring born during or after exposure (n = 292): 7.5 pounds (lbs), 7.4lbs, and 7.6Ibs, respectively. There was no effect of paternal TCDD level on birth weight when adjusted for infant sex, mother's education, parity, prenatal smoking, and gestational age. An analysis to estimate the potential direct exposure of wives during workers' exposure yielded a non-significant increase of 0.29 lbs in the highest exposure group (TCDD greater tan or equal to 255 ppt) compared to referents (p = 0.09). Mothers' reports of birth defects showed no evidence of an exposure relationship, though numbers were small. These results do not support a causal relationship between paternal TCDD exposure and lowered birthweight.