Health impact of measles vaccination in the United States.

As a result of intensive efforts to vaccinate children, measles and its attendant complications of encephalitis and death have declined more than 99% from the prevaccine era. Similarly, subacute sclerosing panencephalitis has declined markedly. Measles vaccine has been demonstrated to be extremely safe, as well as extremely effective. The health and resource benefits due to vaccination against measles during the first 20 years of vaccine licensure have been enormous. In this period it is estimated that vaccination against measles has prevented 52 million cases, 5,200 deaths, and 17,400 cases of mental retardation, achieving a net savings of $5.1 billion. These substantial health and resource benefits of measles vaccination will continue to accrue in the future.

Chemical wastes, children's health, and the Superfund Basic Research Program.

Three to 4 million children and adolescents in the United States live within 1 mile of a federally designated Superfund hazardous waste disposal site and are at risk of exposure to chemical toxicants released from these sites into air, groundwater, surface water, and surrounding communities. Because of their patterns of exposure and their biological vulnerability, children are uniquely susceptible to health injury resulting from exposures to chemical toxicants in the environment. The Superfund Basic Research Program, funded by the U.S. Environmental Protection Agency and directed by the National Institute of Environmental Health Sciences, is extremely well positioned to organize multidisciplinary research that will assess patterns of children's exposures to hazardous chemicals from hazardous waste disposal sites; quantify children's vulnerability to environmental toxicants; assess causal associations between environmental exposures and pediatric disease; and elucidate the mechanisms of environmental disease in children at the cellular and molecular level.

The U.S. EPA Conference on Preventable Causes of Cancer in Children: a research agenda.

On 15-16 September 1997, the U.S. Environmental Protection Agency sponsored the Conference on Preventable Causes of Cancer in Children. The conference was convened to examine rising trends in reported incidence of childhood cancer and the association of these trends with environmental exposures. This paper summarizes recommendations for future research offered by participants. These recommendations included more collaborative research integrating epidemiology, molecular biology, toxicology, and risk assessment; the development of better protocols for toxicologic testing including carcinogenicity using young animals; and research focused on specific periods of development during which susceptibility to environmental agents may be enhanced. Also recommended was enhanced use and development of molecular biomarkers for identification of susceptible populations, and documentation of exposures and effects in epidemiologic and toxicologic studies. Although toxicologic testing is considered essential to determine the effects of potential carcinogens on biological organisms, participants emphasized the need to link these findings with epidemiologic and exposure assessment research.

Characteristics of ATSDR's adult and pediatric environmental neurobehavioral test batteries.

In 1991 the Agency for Toxic Substances and Disease Registry selected a group of neurobehavioral tests to be used in the screening of individuals living near hazardous waste sites. Data from a review of 185 work site studies show that the Adult Neurobehavioral Environmental Test Battery (AENTB) is comprised of tests that have been used to study a wide range of toxic chemicals and that have proved to be capable of detecting impaired populations. Efforts to evaluate potentially impaired populations will be aided by an extensive planning and test administration manual. Progress toward the development of a pediatric counterpart (Pediatric Neurobehavioral Environmental Test Battery [PENTB]) is also reviewed.

Assessment of mercury neurotoxicity through psychometric and neurobehavioral testing: session summary.

Neurobehavioral disorders are well-recognized among the adverse health effects of exposure to mercury. The effort to characterize these effects in animals and humans has progressed steadily over several decades. This has included a variety of study designs, and employed a variety of measurement techniques to evaluate exposure of individuals and populations. The Twelfth International Neurotoxicology Conference, Neurotoxicity of Mercury: Indicators and Effects of Low-Level Exposure, included a plenary session on the predictive value of psychometric and neurobehavioral testing of animals and humans in assessing neurotoxic effects. This session provided a broad view of the methods currently in use to measure adverse effects on the nervous system, in particular those effects that might be attributed to mercury exposure.

Assessment of reproductive disorders and birth defects in communities near hazardous chemical sites. I. Birth defects and developmental disorders.

Members of the workgroup on birth defects and developmental disorders discussed methods to assess structural anomalies, genetic changes and mutations, fetal and infant mortality, functional deficits, and impaired fetal and neonatal growth. Tier 1 assessments for all five adverse reproductive outcomes consist of questionnaires and reviews of medical records rather than laboratory testing of biologic specimens. The work-group members noted a role for neurodevelopmental testing and for limited genetic studies, such as karyotyping in Tier 2 assessments. Emerging methodologies to identify chromosomal aberrations, DNA adducts, and repair inhibition were reserved for Tier 3.

Assessment of reproductive disorders and birth defects in communities near hazardous chemical sites. II. Female reproductive disorders.

Members of the workgroup on female reproductive disorders discussed methods to evaluate five principal functions: menstrual dysfunction, infertility, pregnancy loss, lactation disorders, and pregnancy complications. To test each function, a nested strategy was considered, based on progressive levels of effort available to conduct field investigations. This strategy was analogous to the three-tier classification of biomarkers used by other workshops. The lowest level of effort, corresponding to Tier 1, consists only of questionnaires, diaries, and reviews of maternal and infant medical records. The medium level of effort (Tier 2) collects data from questionnaires and diaries, and some biologic specimens. Suggested laboratory analyses included measurement of progesterone in saliva and several glycoprotein hormones in urine that evaluate menstrual dysfunction, infertility, and pregnancy loss. The highest level of effort (Tier 3) involves prospective collection of diary information and simultaneous collection of biological specimens.

Neurobehavioral testing and hazardous chemical sites.

The Agency for Toxic Substances and Disease Registry (ATSDR) has focused its health assessment efforts on seven priority health conditions, including neurotoxic disorders, and has begun to select tests and associated measurement tools that can detect those health effects. The evaluation of community-level exposures has introduced new challenges beyond the earlier testing models based on occupational exposures. Community populations are far more diverse than those found in workplace settings, including children, elderly persons, and the infirm, and the neurotoxic agents present at most hazardous waste sites usually are incompletely characterized and commonly are found in complex mixtures. This article describes the background to the four following articles reporting on a 3-day national workshop convened to assist ATSDR in developing standardized neurobehavioral test batteries for studies of adverse health outcomes in communities.

Adoption of an adult environmental neurobehavioral test battery.

Nationally recognized experts participated in a 3-day workshop to discuss the complex issues associated with neurobehavioral testing in environmental health settings, and to propose basic and focused test batteries for use in evaluating populations living near hazardous chemical sites. The Adult Environmental Neurobehavioral Test Battery (AENTB), which evaluates major neurobehavioral domains and functions, was adopted by the Agency for Toxic Substances and Disease Registry (ATSDR) for use as a basic screening panel in field studies. Pilot testing of the AENTB demonstrated an examiner training requirement of 3-6 practice sessions, a mean total testing time of 58.0 min (SD = 9.6), and, for 9 of the component tests, a sample size requirement of fewer than 140 (alpha = 0.05, 95% power) to detect a 20% difference between study groups. ATSDR administered the AENTB to 467 persons, selected randomly from 1,382 participants in field study sites in three states. Total testing time varied noticeably by participant age and study site, suggesting an ongoing need for site-specific controls in each field study using the AENTB. Also planned is adoption of a pediatric test battery to evaluate the domains and functions most relevant at major stages of child development.

Selective approaches to basic neurobehavioral testing of children in environmental health studies.

To identify neurotoxic effects in children living near hazardous waste sites, the Agency for Toxic Substances and Disease Registry (ATSDR) has designed a basic Pediatric Environmental Neurobehavioral Test Battery (PENTB) for children 1 through 16 years of age. It emphasizes tests appropriate to the stages of a child's development. These stages were fundamental factors in selecting tests for the PENTB, which includes both informant- and performance-based assessment procedures. Assessment of children under 4 years of age is restricted to four informant-based instruments, to evaluate as many functions as possible while minimizing testing time and the professional expertise needed in the test setting. The assessment of children 4 through 16 years of age includes 10 performance-based tests to evaluate key functions within the cognitive, motor, and sensory domains analogous to functions affected by neurotoxic chemicals in adults. In all age groups, it is crucial to also assess family, cultural, economic, and other potentially confounding variables.

The Indian burden of illness and future health interventions.

This article describes the burden of illness of Indians eligible for services from the Indian Health Service (IHS) and discusses strategies for reducing morbidity and mortality related to those conditions. To improve health to an extent that parallels the IHS's past achievements, the illnesses that now are prevelant among Indians require changes in personal and community behavior rather than intensified medical services. Analysis of these conditions leads to the conclusion that much of the existing burden of illness can be reduced or eliminated. IHS is responding to this challenge by continuing to ensure Indians' access to comprehensive health care services, by increasing educational efforts aimed at prevention, and by enlisting the support of other government and private organizations in activities that have as their purpose treating diseases if intervention will lessen morbidity and mortality (such as diabetes and hypertension) and encouraging of dietary changes, cessation of smoking, exercise, reduction in alcohol consumption, and other healthy behavior.

Measles in young adults. The case for vigorous pursuit of immunization.

Although the incidence of measles has reached record low levels in the United States, measles continues to occur in young adults. No single public health measure can ensure immunity for young adults, as school immunization laws do for young children. Therefore, to eliminate measles in this age-group, clinicians must take the initiative to vaccinate or revaccinate patients. To facilitate containment of outbreaks of measles, clinicians should include measles in the differential diagnosis of any illness characterized by fever and a generalized rash and should promptly report these cases as suspected measles to local health departments, without waiting for laboratory confirmation. If the suspected case is indeed measles, a significant outbreak could be avoided long before the first laboratory results are known.

Biomedical testing of the kidney for persons exposed to hazardous substances in the environment.

To identify kidney injury and dysfunction among persons exposed to hazardous substances in the environment, a battery of biomarker tests has been identified for systematic public health use. The standardized use of tests for conducting field epidemiology studies was reviewed in a 1995 joint American-European workshop, and recommended tests were selected by the Agency for Toxic Substances and Disease Registry (ATSDR) and the Centers for Disease Control and Prevention (CDC). These tests would be useful in conducting public health activities but are not recommended in a manner that would suggest changes in routine clinical practice. The tests selected include serum creatinine, urine analysis, urinary albumin, retinol-binding protein, N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase (AAP), and osmolality. Urinary creatinine was also included to adjust for urine concentration. The tests were chosen for use not only in epidemiologic field studies but also clinically oriented population screening and case studies of persons exposed to hazardous substances at waste sites. Studies using the battery may address the relationship between kidney damage and dysfunction and exposures to hazardous substances, especially in susceptible populations including children. Also, longitudinal studies should be conducted to evaluate the long-term health implications of abnormal tests and to measure the tests' predictive value for renal injury. These studies could evaluate the continuum of renal dysfunction as expressed by persistent decrements in glomerular filtration to the development of end-stage renal disease.

Imported measles in the United States.

In the period 1980-1981, two hundred nine imported measles cases were reported in the United States. These cases represent 1.3% of the total of 16,630 cases of measles reported to the Centers for Disease Control (CDC) during that period. An average of two imported measles cases were reported each week. The travelers with imported measles were United States citizens and foreign nationals who arrived from 47 different countries throughout the world. However, returning United States citizens have accounted for a rising proportion of imported measles cases. Approximately half (49.3%) of the imported cases were reported by four areas: California, New York State exclusive of New York City, New York City, and Florida. Seven measles outbreaks occurring following importations during the two-year period were identified. In addition to 114 imported measles cases reported to the CDC in 1981, 437 measles cases were reported to be caused directly or indirectly by those importations. The actual number of import-associated cases may have been considerably higher. Imported measles and associated cases together accounted for at least 17% (551/3,124) of reported measles cases in 1981.

Prevalence and assessment of attention-deficit/hyperactivity disorder in primary care settings.

Research literature relating to the prevalence of attention-deficit/hyperactivity disorder (ADHD) and co-occurring conditions in children from primary care settings and the general population is reviewed as the basis of the American Academy of Pediatrics clinical practice guideline for the assessment and diagnosis of ADHD. Epidemiologic studies revealed prevalence rates generally ranging from 4% to 12% in the general population of 6 to 12 year olds. Similar or slightly lower rates of ADHD were revealed in pediatric primary care settings. Other behavioral, emotional, and learning problems significantly co-occurred with ADHD. Also reviewed were rating scales and medical tests that could be employed in evaluating ADHD. The utility of using both parent- and teacher-completed rating scales that specifically assess symptoms of ADHD in the diagnostic process was supported. Recommendations were made regarding the assessment of children with suspected ADHD in the pediatric primary care setting.