Pediatric Environmental Health

1. Pediatric Environmental Health Christine L. Johnson, MD Maj, USAF, MC Assistant Professor of Pediatrics USUHS June 2001

2. Background • The field of Pediatric Environmental Health is rapidly evolving, yet, information pertinent to this field is widely scattered and infrequently evaluated by clinicians. • The field is still in the early stages of development with knowledge in some areas increasing and some areas where there are still more questions than answers.

3. Background • In 1995, the EPA formulated a national policy requiring that the health risks to children and infants, from environmental hazards, be considered when conducting environmental risk assessments. • Many new programs have been initiated to stimulated necessary research into the impact of the environment on the health of children. • Environmental hazards are among the top health concerns many parents have for their children.

4. Children Are Different Than Adults • Children are uniquely vulnerable to environmental hazards and they should not be treated as “little adults”. • Differences in exposure, absorption, metabolism, distribution, and target organ susceptibilities are age-specific factors affecting an individual’s risk for an environmentally related illness.

5. Exposure • Children, depending on their developmental stage, will have vastly different environments. • Remember to consider exposures in all environments, throughout the day. • Pre-ambulating children cannot remove themselves from a hazardous environment. • The metabolic rate of children is higher, because of their larger surface-to-volume ratio, therefore they have greater exposure to air pollutants. • The amount of food consumed per kilogram of body weight is much higher than adults, therefore, they have a greater risk of exposure to ingested toxins.

6. Absorption • Absorption occurs by one of four pathways: transplacental, percutaneous, respiratory and gastrointestinal. • Low molecular weight and lipophilic compounds cross the placenta easily (e.g. CO, PCBs, ethanol, calcium, methyl mercury and lead).

7. Absorption • The skin of a newborn is particularly absorptive because it takes time for the dermis to develop the protective, exterior, dead keratin layer. • The newborn has a three times larger, and the child a two times larger surface to mass ratio than an adult. Therefore, absorption of topical chemicals is 2-3 times greater than in an adult.

8. Absorption • The surface absorptive properties of the lung probably do not change during development. However, the lung continues to develop alveoli, from birth to adolescence and, therefore, develops increased surface absorptive area. • The GI tract undergoes many changes during development, affecting transport of particular nutrients, and or noxious agents.

9. Distribution • The tissue distribution of chemicals varies with developmental stage of the child. For example, many drugs in the newborn have higher apparent volumes of distribution. Lead may also be more readily accumulated in the bones of children.

10. Metabolism • Metabolism of a chemical may result in its activation or deactivation. • The activity in each step of metabolic pathways is determined by development and genetics. Therefore, some children may be more susceptible to certain exposures. • For example, those with G6PD are particularly at risk for developing hemolytic anemia if exposed to certain chemicals. • Enzymes may have different levels of activity depending on the developmental stage (e.g. P450).

11. Target Organ Susceptibility • Organs of children continue to undergo growth and differentiation. • These processes can be disrupted or altered by exposure to environmental hazards. • Some environmental agents may mimic hormones. • The brain and the lungs are especially vulnerable to toxic insults since they have a prolonged period of postnatal development.

12. The Environmental History • The right questions to ask!!! • What kind of home or other environment does the child live in, or spend time in? • What are the parent’s occupations? Is the child or adolescent employed? • Are there smokers in the household? • Does the child’s diet put him or her at risk? • Is the child at high risk for lead poisoning?

13. Home or Environment • Type of dwelling (home, apartment, mobile home, homeless) • Age and condition of the home/dwelling • Heating sources • Ongoing or planned renovations • Indoor or outdoor pesticides and chemical use • School- (same questions as above) • Hobbies • Outdoor environment/ community issues

14. Occupations • Possible contaminants in the workplace(e.g. lead, asbestos, mercury, etc.) • The nature of the job. Is it hazardous or illegal?

15. Smokers in the Household • Children exposed to second hand smoke are at increased risk for SIDS, otitis media exacerbations, asthma exacerbations, and adult lung cancer. • Children whose parents smoke are more likely to smoke themselves.

16. Diet • Breast feeding may pass along certain drugs, metabolites and chemicals to the infant (e.g. nicotine, PCBs, PBB,s). • Formula-fed babies are at risk from the tap water used to mix the formula. One minute of boiling is recommended for sterilization. Prolonged boiling may concentrate any lead. • Potential exposure to pesticides and chemical residues exists on fresh fruits and vegetables. Parents should encourage intake of these healthy foods, but aggressive washing with water should occur.

17. www.epa.gov

18. Lead Risks • Questionnaires should be completed to identify children at high risk for lead poisoning. Those children or symptomatic children, should be screened for elevated lead levels. • Questions: • House (lived in or visited) built before 1960 with chipping or peeling paint • Sibling or friend with an elevated lead level • Job or hobby that involves exposure to lead • Live near an active lead smelter, battery recycling plan or other industry likely to release lead

19. Regional Resources • ATSDR (Agency of Toxic Substances and Disease Registry) • PEHSU (Pediatric Environmental Health Specialty Units) • EPA (Environmental Protection Agency) • CDC (Centers for Disease Control and Prevention)

20. Websites • www.epa.gov (Environmental Protection Agency) • www.epa.gov/iaq • www.epa.gov/children • www.aap.org (American Academy of Pediatrics) • www.aap.org/pubserv • www.nhlbi.org (National Heart, Lung and Blood Institute) • www.cmhc-schl.gc.ca (Canadian Mortgage and Housing Corporation) • www.aaaai.org (American Academy of Allergy , Asthma and Immunology) • www.cdc.gov/nceh (Centers for Disease Control, National Center for Environmental Health) • www.lungusa.org (American Lung Association) • www.aanma.org (Allergy and Asthma Network, Mothers of Asthmatics) • www.njc.org (National Jewish Medical and Research Center) • www.niaid.nih.gov (National Institute of Allergy and Infectious Diseases) • www.cehn.org (Center for Environmental Health)

21. References • Handbook of Pediatric Environmental Health,, Etzel, Ruth A., Balk, Sophie J., American Academy of Pediatrics, 1999. • How are children different from adults? Bearer, Cynthia F., Environmental Health Perspectives, Sept 1995, V0l 103, Supp 6, 7-10. • The environmental history: Asking the right questions. Balk, Sophie J., Contemporary Pediatrics, Feb. 1996, 19-36.