Dioxins and dibenzofurans in adipose tissue of US Vietnam veterans and controls.

The primary reason for concern about the adverse effects of exposure to Agent Orange is attributable to its toxic contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or dioxin. We studied adipose tissues from 36 Vietnam veterans, a similar group of 79 non-Vietnam veterans, and 80 civilians; the tissue specimens were selected from the 8,000 archived tissues collected from the non-institutionalized general population by the US Environmental Protection Agency. The geometric mean (+/- standard deviation) dioxin levels in adipose tissue for Vietnam veterans, non-Vietnam veterans, and civilian controls were 11.7 (+/- 1.7), 10.9 (+/- 1.7), and 12.4 (+/- 1.9) parts per trillion on a lipid weight basis, respectively. The mean levels for these groups were not significantly different from each other with or without adjustment for age of individuals, body mass index, and specimen collection year. In addition, none of the surrogate measures of Agent Orange exposure such as military branch, service within specific geographic region, military occupation, and troop location in relation to recorded Agent Orange spray was associated with the dioxin levels in adipose tissue of Vietnam veterans. Our results suggest that heavy exposure to Agent Orange or dioxin for most US troops was unlikely.

Central nervous system malformations in relation to two polyvinyl chloride production facilities.

A modified case-control study was conducted for selected birth defects that occurred among residents who lived in areas that surrounded two vinyl chloride polymerization facilities in New Jersey. Odds ratios for central nervous system defects (ICD 9, 740-742) decreased as the distance the mothers' residences were located from the facilities increased. Higher odds ratios for central nervous system birth defects were found in the areas around the plant that had higher vinyl chloride emissions. None of the odds ratios, however, were statistically significant. The differences in concentrations of emissions from the different plants may contribute to the discrepancies reported in previous studies wherein the risk of environmental exposure to vinyl chloride was assessed.