Polychlorinated biphenyls (PCBs) are industrial chemicals that were used widely for approximately 50 years. Now banned, they are still ubiquitous because of their persistence in the environment, the food chain, and human fatty tissue. High in utero exposures cause developmental deficits accompanied by growth retardation. Studies examining intrauterine growth at lower exposures have been inconsistent, with most such investigations having relied on surrogate exposure indicators such as consumption of fish from contaminated bodies of water.
In the 1960s, serum specimens were collected from pregnant women participating in the Child Health and Development Study in the San Francisco Bay Area. The women were interviewed and their serum samples stored at −20°C. At 5 years of age, detailed anthropometric measurements were made on children born in the years 1964–1967. We measured PCBs in specimens from 399 mothers using gas chromatography/electron capture detection. We conducted multiple linear regression to examine the relationship between these organochlorine concentrations and both intrauterine and 5-year growth, with adjustment for medical, lifestyle, sociodemographic, and specimen characteristics.
In male infants, higher total in utero PCB exposure was associated with reduced birth weight, head circumference, and weight-for-gestational age. An increase from the 10th to 90th percentile in total PCBs was related to 290 g lower birth weight, a 0.7-cm decrease in head circumference, and for weight for gestational age, a reduction in z-score of 0.6. In girls, smaller head circumference and shorter gestations were observed. In contrast, prenatal PCBs were associated with greater growth in 5-year-old girls, with no apparent effect in 5-year-old boys.
Maternally mediated exposure to PCBs may be detrimental to fetal growth, particularly in boys. These effects apparently are not persistent. Interpretation of greater childhood growth of girls is unclear.
From the *Department of Epidemiology, School of Public Health, University of North Carolina-Chapel Hill, Chapel Hill, NC; †Department of Environmental Toxicology, University of California-Davis, Davis, CA; and the ‡Department of Behavioral & Developmental Medicine, School of Medicine, University of North Carolina-Chapel Hill, Chapel Hill, NC.
Submitted 30 March 2004; final version accepted 12 May 2005.
Supported by grants from the U.S. National Institutes of Health: National Institute of Environmental Health Sciences (NIEHS) #R01-ES08316 and #1P01-ES11269; National Cancer Institute (NCI) #R01-CA96525; and National Institute of Child Health and Development (NICHD) #N01-HD-1-3334.
Current affiliation of Irva Hertz-Picciotto is Division of Epidemiology, Department of Public Health Sciences, School of Medicine, University of California-Davis, Davis, CA. Eric Willman is currently affiliated with Ecolab, Mendota Heights, MN 55110.
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Correspondence: Irva Hertz-Picciotto, Division of Epidemiology, Department of Public Health Sciences, One Shields Avenue, TB #168, University of California, Davis, CA 95616. E-mail: firstname.lastname@example.org.