Maternal exposure to high levels of dioxins in relation to birth weight in women affected by Yusho disease

Background: Studies on the association of maternal exposure to polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) with decreased birth weight in humans have produced conflicting results. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease. Objective: The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on birth weight. Methods: Blood samples, obtained from 101 Yusho women (190 births) who gave birth after exposure, were analyzed for congeners of seven PCDDs, ten PCDFs, and four non-ortho PCBs. Results: Total PCDD TEQ (adjusted beta = -161.9 g; 95% CI, -265.3 to -58.6), total PCDF TEQ (adjusted beta = -105.9 g: 95% CI, -179.5 to -32.2), and total non-ortho PCBs (adjusted beta = -178.4 g; 95% CI, -318.3 to -38.5) levels were inversely associated with birth weight. Significant inverse associations with birth weight were also found for total PCDD TEQ total PCDF TEQ and total non-ortho PCB TEQ levels among male, but not female, infants. Significant inverse associations with birth weight were also found for nine congeners among all infants; the adjusted beta coefficients were largest for 1,2,3,6,7,8-HxCDD and smallest for 2,3,4,7,8-PeCDF. Conclusion: In the setting of exposure to high levels of dioxins, maternal blood levels of PCDDs, PCDFs and PCBs are associated with lower birth weight in Yusho patients. The association exhibited gender-specific differences, as male infants are more susceptible than females to growth restriction induced by in utero dioxin exposures. (C) 2011 Elsevier Ltd. All rights reserved.