The Baltimore-Washington Infant Study, the first of its kind, is an exploratory population-based case-control investigation aimed at defining the etiologic factors contributing to abnormal human cardiogenesis. The a priori possibilities included the existence of major genetic determinants, whose presence was obscured by nontraditional inheritance patterns that manifest the influence of genetic background, and the existence of major environmental determinants which may or may not require a genetic predisposition for expression of the disease phenotype. These hypotheses were based largely on small and often contradictory studies and on anecdotal, albeit voluminous, clinical experience. The authors contend that a large-scale, comprehensive, and well-controlled epidemiological study was necessary to address the issue of etiology of congenital heart disease. Their arguments are sound.
The Baltimore-Washington Infant Study is a collaborative effort to prospectively identify and characterize all cases of congenital heart disease that are diagnosed before 1 year of age and occur within a defined target region that encompasses all of Maryland and parts of northern Virginia. Controls are selected each year as a random sample of the area births and are stratified by the hospital of birth. Families are evaluated by questionnaire, by interview, by record review, and with a variety of diagnostic procedures, when indicated. The data base includes information regarding family history of cardiac and non-cardiac malformations, syndromes, and/or chromosomal abnormalities, maternal medical and reproductive characteristics, and a survey of environmental exposures as a consequence of home environment, occupation, hobbies, medical therapy. or lifestyle.
This volume presents the data collected between 1981 and 1989. Chapters 1-7 deal with demographics, clinical characterization of the study population, and experimental design, methods, and execution. Sufficient detail is provided to allow the reader to fully appreciate all aspects of the study. These include the creation of diagnostic categories based upon anatomic and embryological considerations, enrollment of study subjects with comment upon participation rates and representativeness of the study group, preparation of the data base, complete with quality control assurances, and statistical methods.
Chapter 8 details the distribution of congenital heart disease relative to year, season, and place of residence. The infants and families are well characterized with