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in more than 20 different studies (see Abel and Sokol, 1987, 1991; Abel, in press), many of the estimates from the United States are based on high-risk populations living in lower-socioeconomic urban areas.

The incidence of FAS has been estimated from data of three main types: information collected passively for another or for many purposes, such as birth defects registries; information gathered either retrospectively or prospectively from hospital or clinic-based populations, including subjects in controlled epidemiologic studies of the effects of maternal substance abuse (which frequently measure the incidence or prevalence of traits or characteristics associated with FAS, not the incidence of FAS itself); and population-based active case ascertainment. A brief review of the literature of the incidence and prevalence of FAS and other possible alcohol-related effects follows. We have attempted to map findings to current terminology (see Chapter 4). Where this was not possible, we describe the diagnostic category employed but have avoided using fetal alcohol effects (FAE) or ARBD as they had been used historically (i.e., to designate other than FAS). The sections are organized according to the general methodological approach as specified above.

Registry-Based Studies

The Centers for Disease Control and Prevention monitors the rate of FAS in two birth defects surveillance programs. Chavez et al. (1988) reviewed the recording of major congenital malformations in CDC's Birth Defects Monitoring Program (BDMP). Cases were identified based on hospital discharge diagnoses using codes from the International Classification of Diseases, ninth edition (ICD-9-CM; U.S. Department of Health and Human Services, 1991a). Code 760.71 is "noxious influences affecting fetus via placenta or breast milk, specifically alcohol; includes fetal alcohol syndrome."

Data were collected in more than 1,500 hospitals across the United States from 1980 through 1986. The overall rate of FAS was 2.97 per 1,000 for Native Americans, 0.6 per 1,000 for African Americans, 0.09 for Caucasians, 0.08 for Hispanics, and 0.03 for Asians (Chavez et al., 1988). As might be expected, the rates of FAS ascertained from a birth certificate registry system were much lower than those for the clinic-based FAS-specific studies discussed later. The registry rate reported is about 1 per 10,000 rather than 1 to 2 per 1,000 as documented in epidemiologic studies.

A subsequent CDC article on data from the BDMP estimated the overall incidence of FAS from 1979 to 1993 at 0.22 per 1,000 (CDC, 1995a). For 1992 alone, however, the rate was 0.37 per 1,000 (CDC, 1993a), and for 1993 it was 0.67 per 1,000 (CDC, 1995a); these rates are substantially higher than in previous years. According to the CDC, this increase is leading to a study to examine the sensitivity and specificity of the monitoring system.

The CDC's Metropolitan Atlanta Congenital Defects Program (MACDP) is



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