Trends in environmentally related childhood illnesses.

Tracking incidence or prevalence of diseases and using that information to target interventions is a well-established strategy for improving public health. The need to track environmentally mediated chronic diseases is increasingly recognized. Trends in childhood illnesses are 1 element of a framework for children's environmental health indicators, which also includes trends in contaminants in the environment and in concentrations of contaminants in bodies of children and their mothers. This article presents data on 3 groups of important childhood diseases or disorders that seem to be caused or exacerbated, at least in part, by exposure to environmental agents and for which nationally representative data are available. They are asthma, childhood cancers, and neurodevelopmental disorders. Data were used from the National Health Interview Survey for asthma and neurodevelopmental disorders; the Surveillance, Epidemiology, and End Results Program for childhood cancer incidence; and the National Vital Statistics System for childhood cancer mortality. The prevalence of children with asthma doubled between 1980 and 1995, from 3.6% in 1980 to 7.5% in 1995. The annual incidence of childhood cancer increased from 1975 until approximately 1990 and seems to have become fairly stable since. Childhood cancer mortality has declined substantially during the past 25 years. Incidence of certain types of cancers has increased since 1974, including acute lymphoblastic leukemia, central nervous system tumors, and non-Hodgkin's lymphoma. Approximately 6.7% of children aged 5 to 17 were reported to have attention-deficit/hyperactivity disorder in 1997-2000, and approximately 6 of every 1000 children were reported to have received a diagnosis of mental retardation during the same period.