Ruth A. Etzel, MD, PhD


March 29, 2006

In This Article

The Importance of Taking a Careful History

A careful history is the first step in identifying potential risks to the child's health so that families can take precautions early in the child's life to prevent excessive exposure and possible adverse effects. These risks differ by age. The following questions should be asked to assess possible environmental risks in the home environment.

Does the drinking water have high nitrate concentrations?

In addition to the well-known risk of methemoglobinemia among infants under 4 months of age who are fed formula reconstituted with well water containing nitrate,[1] emerging evidence suggests that exposures to nitrate in drinking water may be associated with increased risks for some cancers in adults. These cancers include non-Hodgkin's lymphoma, gastric cancer, and bladder cancer.[14,15,16] Clinicians should suggest that families with private wells have this water tested periodically for nitrate.

Is the home water-damaged?

In immunocompetent children, indoor exposure to water damage and fungi is clearly linked to asthma and allergic diseases.[17,18,19] Some children who are exposed to fungi have persistent upper respiratory tract symptoms such as rhinitis, sinusitis, sneezing, and eye irritation, as well as lower respiratory tract symptoms such as coughing and wheezing.[20,21] Cases of acute pulmonary hemorrhage have occurred among infants living in homes with severe water damage and fungal growth.[22,23,24,25] Guidance is available to help clinicians recognize and manage health effects related to mold exposure and moisture indoors.[26]

Is there lead in the home?

Recent studies document that blood lead concentrations, even those below 10 micrograms per deciliter, are inversely associated with children's IQ scores at 3 and 5 years of age.[27,28] Because the source for most lead-poisoned children is the dust and chips from deteriorating lead paint on interior surfaces, clinicians should ask parents about the age and condition of the home and consult city, county, or state health departments to determine the appropriate screening recommendations for their jurisdiction.[1]

Is the home's radon concentration high?

Radon gas comes from radioactive decay of radium. Although most of the dose of radon and radon decay products is delivered to the lungs, increasing the risk of lung cancer, some goes to the bone marrow. An ecological study in France showed an association between indoor radon concentration and acute myeloid leukemia in children under 10 years of age.[29] Clinicians should suggest that all homes be tested for radon.

Has mercury been handled?

Elemental mercury, which exists as both a liquid and vapor at room temperature, holds an attraction for children and adolescents. Elemental mercury vapor, which is heavier than air, is almost completely absorbed when inhaled and primarily affects the central nervous system. Early nonspecific signs, including insomnia, forgetfulness, loss of appetite, and mild tremor, can be misdiagnosed as psychiatric illness. Continued exposure leads to progressive tremor and erethism, characterized by red palms, emotional lability, and memory impairment.[30,31,32] Children may present with rash, vomiting, muscle pain, and tachycardia. Clinicians may miss the diagnosis unless they ask the child about mercury exposures.

Has carbon monoxide been released?

Because the symptoms of carbon monoxide poisoning can mimic influenza, the diagnosis is easily missed. Infants and children have an increased susceptibility to carbon monoxide toxicity because organ systems with high metabolic rates and high oxygen demand are most severely affected by oxygen deprivation, the mechanism by which carbon monoxide affects health.[1] Teenagers are a high-risk group for fatal carbon monoxide poisoning.[33] Carbon monoxide detectors may provide warning of elevated carbon monoxide levels; however, significant exposure to children occurs before the alarm sounds.

Has exposure to ultraviolet light been high?

Childhood exposures to UV light sufficient to cause sunburn are associated with an increased risk for melanoma.[34,35,36] The risk for melanoma in adolescents with more than 5 blistering sunburns is twice as high as for those with none.[37] Migration studies show that high exposure to sunlight during childhood appears to set the stage for high rates of melanoma during adulthood.[38] Guidance about sun protection should be part of anticipatory guidance.

Have pesticides been used?

Epidemiologic studies demonstrate associations between pesticide exposures and certain childhood cancers, including leukemia, all brain cancers, and non-Hodgkin's lymphoma.[39,40,41] A comprehensive review of studies showing an association between pesticides and childhood leukemia revealed higher risks among children whose parents were exposed to pesticides at work or who used pesticides in the home or garden.[42] Several studies have linked home use of pesticides with childhood brain tumors.[43] Using sprays or foggers to dispense flea or tick treatments, flea collars, home pesticide bombs, fumigation for termites, and pest strips was associated with having brain tumors. Studies in agricultural workers have linked chronic exposures to chlorophenoxy herbicides with non-Hodgkin's lymphoma.[44] Clinicians should ask questions about exposures to pesticides at home and suggest adoption of integrated pest-management programs.

Using these questions, providers of healthcare to children can easily incorporate emerging knowledge about environmental health into discussions with parents. In a busy practice, the clinician must provide some guidance before all of the research questions have been answered definitively. Therefore, a preventive approach is recommended in keeping with the Hippocratic injunction to "do no harm."


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