Department of Health
John J. Dreyzehner, MD, MPH, Commissioner

Derek A. Chapman, PhD

Stanton-Chapman, T. L., Chapman, D. A., & Scott, K. G. (in press). Identification of Early Risk Factors for Language Impairment. Research in Developmental Disabilities.

The current study is a population-based investigation of birth risk factors for school-identified specific language impairment (SLI). The sample consisted of 244,619 students (5,862 SLI) born in Florida between 1989 and 1990 who were in the Florida public school system at ages 6 to 7. Epidemiological measures of effect were used to investigate both individual- and population-level risk for SLI. Very low birth weight, low 5 minute Apgar score, late or no prenatal care, high birth order, and low maternal education were associated with highest individual-level risk. Low maternal education and having an unmarried mother was associated with the highest population-level risk. The results not only suggest who needs to be screened for a future developmental disability, but identify a group of children who are at-risk for an SLI placement in school. Early intervention services for these children may be the most effective approach to reducing the incidence of school-identified SLI.

The predictive value of maternal age and maternal education at delivery in relation to rates of administratively defined mental retardation (MR) in a three-year birth cohort (n=267,277) was studied. Low maternal education placed individuals at increased risk for both educable mentally handicapped (EMH) placements (RR=10.9) and trainable mentally handicapped placements (RR=3.2). In terms of maternal age, the youngest mothers (15 to 19 years) were at greatest risk for having a child with an EMH placement (RR=2.7), while children born to oldest mothers (40 to 44 years) most at greatest risk for a TMH placement (RR=3.5). Stratified analyses indicated that for EMH, there was a maternal age effect only for mothers with <12 years of education. In terms of population-level risk, it was younger mothers (15 to 24 years of age) with 12 years of education or less whose births were associated with the greatest proportion of cases of both EMH (PAF%=56%) and TMH (PAF%=34%) in the population. From a public policy viewpoint, children born to mothers with low levels of education are an important group to target for prevention/early intervention efforts.

[Abstract not available at this time]

The current study is a population-based investigation of the association of biological and environmental risk factors present on birth certificates of children with LD. Electronic data linkage methchool-identified LD at ages 6 to 7. Epidemiological measures of effect were used to investigatodology was used to investigate how various risk factors listed on birth certificate records could predict se both individual- and population-level risk for LD. In terms of individual-level risk, low birth weight, a low 5 minute Apgar score, and low maternal education were the most salient predictors of school-identified LD. Other risk factors associated with a sizeable increase in risk were late or no prenatal care, maternal tobacco use, maternal alcohol use, pre-term births, and the presence of a congenital anomaly. Low maternal education was associated with the highest population-level risk. The results not only show who needs to be screened for a future developmental disability, but identify a group of children who are at-risk for an LD placement in school. Early intervention services could target these at-risk children prior to the onset of LD and be a more effective approach to reducing the incidence of school-identified LD.

An important, but often overlooked area of investigation in developmental psychology is that of intergenerational risk factors. A body of research spanning over 60 years clearly demonstrates the impact of maternal intergenerational factors on physical growth. In addition to operating through this biological mechanism, intergenerational risk factors have been shown to influence the infant/child development through the child-rearing environment. For example, the association between factors in a mother's own developmental history and developmental outcomes for their children has been well-documented by attachment researchers. The implications of these studies for cognitive development are clear. It is likely that the same intergenerational factors which influence intrauterine physical growth affect the development of the brain as well through both biological and environmental pathways. In order to fully address the issue of childhood disadvantage, a broadening of the time frame of intervention to include women's health status prior to conception is needed. Researchers studying intergenerational risk factors are encouraged to consider using epidemiological methods to provide an additional, population-based perspective on the study of risk.

This article discusses the computation and application of various epidemiological measures of effect in educational and developmental research. Specifically, epidemiology provides a potentially important perspective for studies identifying risk factors for healthy child development. For example, it allows for the examination of both individual-level risk (the impact of risk factors on individuals experiencing them) and community-level risk (the impact of risk factors on the overall number of cases within a population). In terms of individual-level risk, issues related to the use and interpretation of the risk-ratio, the odds-ratio, and the logistic regression odds-ratio are reviewed. In addition, community-level measures of effect, such as the population attributable fraction percentage, are examined. Implications of the design methodology (cohort study, case-control study, or representative study) on the choice and use of these measures of effect are discussed. Data from a large-scale ongoing project in developmental epidemiology are presented throughout the article for illustrative purposes.

Epidemiological methodology is used to examine the relationship between early childhood risk factors and future identification as having Severe Emotional Disturbance or as having an Emotional Handicap (SED/EH) at age 13. Data were obtained from 1979/1980 Florida birth records that were electronically linked with 1992/1993 Florida school records. An epidemiological perspective was chosen due to its ability to model both individual and community-level risk. In regards to increasing an individual's risk of SED/EH, two factors, gender (being male) and low maternal education (mother not completing high school at the time of birth), were found to have particularly strong effects. When examining effects of these risk factors upon overall rates of SED/EH in the community, maternal education and marital status (being unmarried at the time of the child's birth), were associated with a large proportion of the cases. Health/biological markers were moderately associated with SED/EH on the individual level, but were related to a relatively small percentage of cases in the population. In addition, effects varied based upon ethnic/cultural heritage. Researchers are encouraged to consider using an epidemiological perspective and its potential utility in the field of community psychology and public policy is discussed.

To best influence policy makers, researchers need to provide information and measures of effects that reflect the nature of policy decisions. Specifically, policy makers are often interested in factors associated with changes in the number of cases or rate of disorders in a community. Regression/analysis of variance (ANOVA) models, which focus on the prediction of means, slopes, and variances, do not directly address such questions. In contrast, epidemiological statistics, which focus on differences in proportions of cases, do provide such information. Three epidemiological measures of effect (the risk-ratio, the odds-ratio, and the population attributable fraction) are reviewed; their value as tools for informing public policy is discussed; and examples are provided illustrating their use. Researchers are encouraged to consider adopting an epidemiological perspective as part of their work.