Environmental Health Indicators

Daniela Niutta

The issue of environmental health began more than a century ago, and the problem has continued to worsen over the years, in part because of the chemicals that have been introduced by modern technology. Studying environmental health, however, is a difficult procedure because of the complications involved with accurately measuring an individual’s exposure to a certain contaminant. For example, the toxicity of a substance is influenced by absorption, distribution, elimination, and accumulation within the body, the pathway of entry, the stability of the chemical, and synergistic interactions with other substances. Monitoring environmental health effects is also complicated by the long latency period involved with many diseases, multiple causes of the same effect, and the cost of conducting large studies.

Environmental health indicators, measures that provide information about patterns or trends of specific diseases, can be an effective means of assessing environmental health, depending on the availability of and feasibility of collecting pertinent information. Data already collected by the Rhode Island Department of Health, such as birth and death records, lead screening data, and hospital discharge data, in combination with additional data that can be collected, would provide a sound basis for the development of a number of environmental health indicators.

After investigating the health data collected in Rhode Island and researching the background data of a group of selected diseases, I made recommendations regarding what additional data would be useful, and how this information could be gathered.

The State data regarding the incidence of asthma, a lung disease characterized by shortness of breath resulting from hyperresponsiveness to a variety of stimuli, are based on hospital discharge records. Additional information about less severe cases could be gathered from physicians by defining asthma as a reportable disease, or by implementing a sentinel or electronic reporting system. Another possibility would be to monitor the sale of asthma medication either through the number of prescriptions filled at pharmacies or through inventories taken at various drug companies.

Data on melanomas, the most severe type of skin cancer, are collected in the State Cancer Registry. In addition to knowing the rate of the disease, it would be useful to evaluate the efficacy of prevention programs and educational efforts. This could be done by monitoring the sale of sunscreen through inventories at drug stores or by assessing its use by incorporating questions into health surveys.

Data regarding lung disease, a term that encompasses a variety of respiratory problems, are obtained from hospital discharge records and data regarding lung cancer are obtained from the Cancer Registry. More specific information regarding the various causes of these diseases can be obtained in a variety of ways. Examination of chest X-rays can be used to evaluate asbestos exposure; the rate of sales of radon testing kits can indicate the success of prevention and public education; and the level of cotinine, a chemical associated with second hand smoke, in donated blood can be used to estimate exposure to environmental tobacco smoke.

The state maintains a lead screening database that contains information about blood lead levels in children. In addition to this, the concentration of lead in dust samples taken from homes could be one means of evaluating exposure. X-ray fluorescence could be used to evaluate long-term accumulation in the bones.

The state does not conduct regular screening for other metals, such as mercury, cadmium, and arsenic. Information regarding exposure to these metals is compiled from mandatory reports made by physicians when they diagnose a health effect caused by these metals or determine that exposure has taken place. The body burden of heavy metal can be assessed through blood tests or tissue tests, and ambient concentrations from water samples can be an indicator of exposure.

Carbon monoxide poisoning results when CO binds to hemoglobin and causes an oxygen deficiency in the brain. Low level exposure to this colorless, odorless gas can be evaluated from blood tests taken from samples donated to the blood bank.

Miscarriages and birth defects are noted on medical records and birth records, but some do not manifest themselves until later in life. These health problems can be tracked over time by establishing registries. The valuable information compiled in these registries could serve as indicators that link outcomes with exposure.