Children’s Health Study

Particulate matter (PM) is associated with adverse human respiratory health effects. Although much research has focused on the fine particle component (PM2.5), recent results from the USC Children s Health Study suggest that the coarse fraction may also affect respiratory health in children. Specific components of the coarse fraction responsible for these effects have not been identified, but ambient endotoxin is a strong candidate, based on toxicologic and epidemiologic studies. This study is collecting... 

Wu J, Lurmann F, Winer A, Lu R, Turco R, Funk T (2005) Development of an individual exposure model for application to the Southern California children s health study. Atmos Environ 39 259-273... 

Salam MT, Millstein J, Li YF, et al. Birth outcome and prenatal exposure to ozone, carbon monoxide, and particulate matter Results from the Children s Health Study. Environ Health Perspect 2005 133(11) 1638—44. 

Gilliland FD, Islam T, Berhane K, et al Obesity and asthma incidence in school-aged children Results from the Children s Health Study. Am J Respir Crit Care Med 2001 163 A37. 

Salam, M, T., Li, Y, F., Langholx, B., and Gilliland, F, D. (2004). Early-life environmental risk factors for asthma Findings from the Children s Health Study. Environ. Health Perspect. 112,760-765. 

A similar study was conducted jointly by investigators at the Center for Research on Women s and Children s Health, the Mount Sinai School of Medicine, the University of North Carolina, Chapel Hill, the Kaiser Permanent... 

If you aren t set up to wash cloth diapers at home, conventional disposable diapers aren t a good option. One widely quoted study (published in Archives of Environmental Health and conducted by Anderson Laboratories back in 1999) found mice exposed to VOC chemicals emitted by conventional disposables had asthmalike reactions. They also contain chlorine and have high-tech chemical gel cores that activate when your baby pees to lock in moisture. The Children s Health Environmental Coalition says this absorbent material—sodium polyacrylate— could cause respiratory and skin irritations in occupational settings (where exposure is higher than with diaper use). We wonder how safe can that much chemical activity that close to a baby s genitals be twenty-four hours a day ... 

Very few studies have looked at how CDDs can affect children s health. Chloracne has been observed in children exposed to much higher than current background levels of 2,3,7,8-TCDD. 

Design and implement prospective cohort studies of pregnant women, infants, and children with longitudinal capture of exposures at critical windows and sensitive health end-points along the continuum of human development. Efforts to recruit couples prior to conception are needed to address critical data regarding periconceptional exposures and children s health. 

There is a pressing need to develop and validate sensitive, specific, and cost-effective biomarkers of exposure, susceptibility, and effect that can be applied to human studies so that the gaps in our understanding of the role of environmental stressors on children s health can be closed. 

Examples of commonly used clinical tools or tests that may be appropriate for children s health issues are summarized in Table 8. This table underscores the utility in evaluating children s overall health status rather than restricted focus on specific organ systems, except for circumstances when a particular exposure or health concern exists for a defined study population. 

Table 9 presents a comparison of basic epidemiological study designs for assessing child health outcomes by their inherent methodological strengths and limitations. While experimental study designs are included for completeness, none is appropriate for the evaluation of environmental influences on children s health when the exposure(s) cannot be randomized within acceptable research practices. 

Given that children, by definition, are in a state of continual growth and development, methodologies for the assessment of child health should be responsive to all organ systems. Prospective studies are particularly relevant, since they permit the capture of time-varying exposures and other relevant covariates for children s health. The short interval between many exposures and outcomes (e.g. in utero exposures and infant birth size) further supports the use of prospective studies. 

The risk assessor should be sensitive to certain dose-response patterns that are often encountered in studies on developmental toxicity. For example, the lowest effective doses in adults and young are often similar or may be the same, but the type of effects may be very different as well, the effects on the developing child may be permanent (or lead to latent effects), whereas the effects on the adult may be transient. Also, the end-points used in evaluating alterations in children s health may vary considerably. The difference between the maternal toxic dose and the developmental toxic dose may at times be related to the relative thoroughness with which end-points are evaluated. Also, the variability and level of severity within a particular end-point need to be defined, since end-point variability and level of severity can have a significant effect on the power of the study and the ability to establish an effect level. Approaches to carrying out dose-response assessments are described below. 

Considerable effort will be required to develop approaches to incorporating data from molecular studies and generated from new technologies (e.g. genomic) into a meaningful framework for children s health risk assessments. 

Research on the impact of environmental factors on children s health has most often focused on an exposure to specific chemicals or particular organ systems or end-points. Additional emphasis should be placed on prospective longitudinal studies capturing multiple exposures over various life stages. 

Anderson LM, Diwan BA, Fear NT, Roman E (2000) Critical windows of exposure for children s health Cancer in human epidemiological studies and neoplasms in experimental animals. Environ Health Perspect, 108(Suppl 3) 573-594. 

As of 1999,. studies of the effects of pesticide exposure on children s health were limited to those of birth defects, childhood cancer, and acute poisoning following ingestion. Some case-control studies have associated parental exposure to pesticides or pesticide use in the home with childhood brain tumors, leukemia and lymphomas, testicular cancers, and other cancers, Other studies have reported that parental exposure to pesticides or application of pesticides in the home are associated with cenain birth defects, including neural tube and other defects (Eskenazi et at., 1999). Evaluation.s iif OP and CM exposures, levels of expasures, and health impacts to children are needed. 

Children s Susceptibility. The information on health effects of endosulfan in humans is derived mainly from cases of accidental or intentional exposure of adults to high amounts of the pesticide, and the main adverse effect is neurotoxicity. No reports of adverse effects in endosulfan-exposed children were found, but it is reasonable to assume that children will exhibit similar signs and symptoms to those in adults under similar exposure conditions. Some studies in animals have provided evidence that young animals respond to endosulfan differently than adult animals (Kiran and Varma 1988 Lakshmana and Raju 1994 Sinha et al. 1995,1997 Zaidi et al. 1985), but there is no conclusive evidence to suggest that young animals are more susceptible than older ones. Further studies that evaluate a number of different end points in young as well as older organisms would provide valuable information. 

Pocock SJ, Ashby D, Smith MA. 1989. Lead exposure and children s intellectual performance The Institute of Child Health/Southhampton Study. In Smith M, Grant LD, Sors A, eds. Lead exposure and child development An international assessment. Lancaster, UK Kluwer Academic Publishers. 

Based on a combination of available human case studies and experiments with laboratory animals, the major public health concerns associated with exposure to 1,4-dichlorobenzene are effects on the liver, kidneys, and blood. Some immunological, dermatological, and neurological effects have also been reported in exposed humans. There is information from animal studies which raises the question of whether 1,4-dichlorobenzene can cross the placenta and elicit structural effects on the developing fetus. Data from a study conducted in rats using the intraperitoneal route have demonstrated sperm abnormalities. Cancer of the liver as a result of lifetime exposure to 1,4-dichlorobenzene has been shown in mice, and renal cancer has been reported in male rats. However, recent studies related to the mechanism of renal carcinogenesis in rats suggest that these tumors may not be expected to occur in exposed humans. Issues relevant to children are explicitly discussed in Section 2.6, Children s Susceptibility, and Section 5.6, Exposures of Children. 

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