Prevalence of autism in a United States population: the Brick Township, New Jersey, investigation.

OBJECTIVE: This study determined the prevalence of autism for a defined community, Brick Township, New Jersey, using current diagnostic and epidemiologic methods. METHODS: The target population was children who were 3 to 10 years of age in 1998, who were residents of Brick Township at any point during that year, and who had an autism spectrum disorder. Autism spectrum disorder was defined as autistic disorder, pervasive developmental disorder-not otherwise specified (PDD-NOS), and Asperger disorder. The study used 4 sources for active case finding: special education records, records from local clinicians providing diagnosis or treatment for developmental or behavioral disabilities, lists of children from community parent groups, and families who volunteered for participation in the study in response to media attention. The autism diagnosis was verified (or ruled out) for 71% of the children through clinical assessment. The assessment included medical and developmental history, physical and neurologic evaluation, assessment of intellectual and behavioral functioning, and administration of the Autism Diagnostic Observation Schedule-Generic. RESULTS: The prevalence of all autism spectrum disorders combined was 6.7 cases per 1000 children. The prevalence for children whose condition met full diagnostic criteria for autistic disorder was 4.0 cases per 1000 children, and the prevalence for PDD-NOS and Asperger disorder was 2.7 cases per 1000 children. Characteristics of children with autism in this study were similar to those in previous studies of autism. CONCLUSIONS: The prevalence of autism in Brick Township seems to be higher than that in other studies, particularly studies conducted in the United States, but within the range of a few recent studies in smaller populations that used more thorough case-finding methods.

Increased risk for developmental disabilities in children who have major birth defects: a population-based study.

OBJECTIVE: We sought to quantify the strength of associations between each of four specific developmental disabilities (DDs) and specific types of major birth defects. METHODS: We linked data from 2 independent surveillance systems, the Metropolitan Atlanta Congenital Defects Program and the Metropolitan Atlanta Developmental Disabilities Surveillance Program. Children with major birth defects (n = 9142; born 1981-1991 in metro Atlanta) and 3- to 10-year-old children who were born between 1981 and 1991 in metro Atlanta and identified between 1991 and 1994 as having mental retardation, cerebral palsy, hearing impairment, or vision impairment (n = 3685) were studied. Prevalence ratio (PR), which is the prevalence of a DD in children with 1 or more major birth defects divided by the prevalence of the same DD in children without major birth defects, was measured. RESULTS: Among the 9142 children who were born with a major birth defect, 657 (7.2%) had a serious DD compared with 0.9% in children with no major birth defect, yielding a PR of 8.3 (95% confidence interval: 7.6-9.0). In general, the more severe the DD, the higher was the PR. Birth defects that originated in the nervous system and chromosomal defects resulted in the highest PRs for a subsequent DD. For all other categories of birth defects, PRs were lowest when all major birth defects present were confined to a single category (ie, isolated defects). PRs for any DD increased monotonically with the number of coded birth defects per child or the number of different birth defect categories per child, regardless of the severity of the defect or whether defects of the nervous system, chromosomal defects, or "other syndromes" were counted. CONCLUSIONS: These data highlight the possible early prenatal origins of some DDs and suggest that both the number of coded birth defects present and the number of anatomic systems involved are strongly related to functional outcomes.

Combined tobacco and alcohol use by pregnant and reproductive-aged women in the United States.

OBJECTIVE: To assess trends in the concurrent use of alcohol and tobacco among pregnant women. METHODS: Using behavioral risk factor surveillance system data from 1987 through 1997, we determined the prevalence of concurrent tobacco and alcohol use among women aged 18-44 years by pregnancy status and indirectly estimated pregnancy-related disuse rates. RESULTS: The percentage of women who used alcohol and tobacco decreased significantly from 1987 to 1990 among pregnant (5.4% to 3.0%) and nonpregnant women (17.6% to 14.2%), but thereafter did not change significantly. The estimated pregnancy-related disuse rate of tobacco and alcohol increased insignificantly from 70% in 1987 to 82% in 1997. Among women who used both substances, pregnancy-related disuse was slightly greater for alcohol alone (74%) than for tobacco alone (52%). There was not a significant decline in concurrent use of tobacco and alcohol between 1987 and 1997 among women 18-20 years old (pregnant, 4.4% to 3.6%; nonpregnant, 13.5% to 13.7%). That age group also showed a smaller pregnancy-related disuse rate than older women (1997, 74% versus 83%). CONCLUSION: The steady trend in concurrent use of tobacco and alcohol by young women emphasizes the need for enhanced efforts to reduce the initiation of tobacco and alcohol use by young people. Women who report abuse of tobacco or alcohol should be evaluated for abuse of both substances, and interventions should address abuse of both substances.

A survey of obstetrician-gynecologists on their patients' alcohol use during pregnancy.

OBJECTIVE: To examine knowledge, attitudes, current clinical practices, and educational needs of obstetrician-gynecologists regarding patients' alcohol use during pregnancy. METHODS: A 20-item, self-administered questionnaire on patients' prenatal alcohol use was sent to 1000 active ACOG fellows. Responses were analyzed using univariate and multivariate statistical techniques. RESULTS: Of the 60% of the obstetrician-gynecologists who responded to the survey, 97% reported asking their pregnant patients about alcohol use. When a patient reports alcohol use, most respondents reported that they always discuss adverse effects and always advise abstinence. One fifth of the respondents (20%) reported abstinence to be the safest way to avoid all four of the adverse pregnancy outcomes cited (ie, spontaneous abortion, central nervous system impairment, birth defects, and fetal alcohol syndrome); 13% were unsure about levels associated with all of the adverse outcomes; and 4% reported that consumption of eight or more drinks per week did not pose a risk for any of the four adverse outcomes. The two resources that respondents said they needed most to improve alcohol-use assessment were information on thresholds for adverse reproductive outcomes (83%) and referral resources for patients with alcohol problems (63%). CONCLUSION: Efforts should be made to provide practicing obstetrician-gynecologists with updates on the adverse effects of alcohol use by pregnant women and with effective methods for screening and counseling women who report alcohol use during pregnancy.

Association of very low birth weight with exposures to environmental sulfur dioxide and total suspended particulates.

This paper presents results of a population-based case-control study of the association between maternal exposures to environmental sulfur dioxide and total suspended particulates (TSP) and risk for having a very low birth weight (VLBW) baby, i.e., one weighing less than 1,500 g at birth. The study, which took place between April 1, 1986 and March 30, 1988, comprised 143 mothers of VLBW babies and 202 mothers of babies weighing 2,500 g or more living in Georgia Health Care District 9. Environmental exposure estimates (microg/m3) were obtained through environmental transport modeling that allowed us to assign environmental sulfur dioxide and TSP exposure estimates at the birth home of each study subject. Exposures less than or equal to 9.94 microg/m3, the median of TSP and sulfur dioxide exposures for the controls, were considered as referent exposures. Exposures to atmospheric TSP and sulfur dioxide above the 95th percentile (56.75 microg/m3) yielded an adjusted odds ratio of 2.88 (95% confidence interval (CI): 1.16, 7.13), that from above the 75th to the 95th percentile (25.18-56.75 microg/m3) yielded an adjusted odds ratio of 1.27 (95% CI: 0.68, 2.37), and that from above the median (9.94 microg/m3) to the 75th percentile, an adjusted odds ratio of 0.99 (95% CI: 0.51, 1.72). The trend demonstrated in these adjusted estimates suggests an association between VLBW and maternal exposures to high levels of air pollution.

Trends in pregnancy-related smoking rates in the United States, 1987-1996.

CONTEXT: Rates of smoking are increasing among adolescents and young adults, but trends in smoking among pregnant women have not been studied. OBJECTIVE: To assess pregnancy-related variations in smoking behaviors and their determinants among women of childbearing age in the United States. DESIGN: Analysis of data collected between 1987-1996 from the Behavioral Risk Factor Surveillance System survey. SETTING AND SUBJECTS: A total of 187302 (178499 nonpregnant and 8803 pregnant) noninstitutionalized women aged 18 to 44 years from 33 states. MAIN OUTCOME MEASURES: Prevalence rates of smoking initiation and current smoking, median number of cigarettes smoked, and adjusted odds ratios for smoking stratified by pregnancy status; prevalence rate ratio for current smoking comparing pregnant with nonpregnant women. RESULTS: The overall percentage of women who had ever initiated smoking decreased significantly from 44.1% in 1987 to 38.2% in 1996. During that 10-year period, the prevalence of current smoking also decreased significantly among both pregnant women (16.3% to 11.8%) and nonpregnant women (26.7% to 23.6%). Overall, pregnant women were about half (54%) as likely as nonpregnant women to be current smokers during 1987-1996. Over time, the median number of cigarettes smoked per day by pregnant smokers remained at 10, whereas among nonpregnant smokers it decreased from 19 to 15 (P<.05 for trend). In the same period, among young women (aged 18-20 years), prevalence rates of smoking initiation and current smoking increased slightly. Sociodemographic subgroups of women at increased risk for current smoking were the same for pregnant and nonpregnant women (ie, those with a completed high school education or less, whites, and those who were unmarried). CONCLUSIONS: In this analysis, the decline in smoking over time among pregnant women was primarily due to the overall decline in smoking initiation rates among women of childbearing age, not to an increased rate of smoking cessation related to pregnancy. To foster effective perinatal tobacco control, efforts are needed to further reduce the number of young women who begin smoking. Clinicians should query all pregnant women and women of childbearing age about smoking and provide cessation and relapse interventions to each smoker.

Relative and attributable risks for moderate to profound bilateral sensorineural hearing impairment associated with lower birth weight in children 3 to 10 years old.

OBJECTIVE: To determine the prevalence, relative risks, and attributable fractions for congenital bilateral sensorineural hearing impairment in relation to lower birth weight among children born in the 1980s and living in the metropolitan Atlanta area from 1991 through 1993. METHODS: We used the population-based, active case ascertainment Metropolitan Atlanta Developmental Disabilities Surveillance Program that conducts surveillance in the five-county metropolitan Atlanta area. Hearing impairment was defined as a bilateral, pure-tone hearing loss at frequencies of 500, 1000, and 2000 Hz averaging 40 dBs or more, unaided, in the better ear. Case children, 3 to 10 years of age, with sensorineural loss of presumed congenital origin were included in these analyses (n = 172). Prevalence rates and relative risks were computed for various birth weight categories by hearing level, sex, race, the presence or absence of coexisting developmental disabilities, and gestational age. Attributable fractions were calculated for low birth weight and very low birth weight children by race. RESULTS: The overall prevalence rate of presumed congenital bilateral sensorineural hearing impairment was 5.3 cases per 10 000 3-year survivors. The prevalence was 4.1 per 10 000 among children weighing >/=4000 g, 3.7 per 10 000 among those weighing 3000 to 3999 g, 6.6 per 10 000 among those 2500 to 2999 g, 12.7 per 10 000 among those 1500 to 2499 g, and 51.0 per 10 000 among those <1500 g. There was virtually no difference in birth weight-specific rates of hearing impairment across three hearing levels. The presence of coexisting developmental disabilities was associated with a much stronger inverse trend with birth weight. Black children weighing <2500 g had much higher rates of hearing impairment than comparable white children. The overall percentage of moderate to profound congenital bilateral sensorineural hearing loss in the entire study population that was attributable to children weighing <2500 g or <1500 g was estimated to be 18.9% and 9.4%, respectively. Prematurity did not alter the magnitude of risk among children weighing <2500 g. CONCLUSIONS: The results presented here provide recent estimates of the rates, relative risks, and attributable fractions for congenital bilateral sensorineural hearing impairment by birth weight among children in the United States. The elevated relative risks among children weighing 2500 to 2999 g and 1500 to 2499 g may have implications for future newborn hearing screening criteria.

Alcohol use prior to pregnancy recognition.

BACKGROUND: Frequent alcohol use during the first 8 weeks of pregnancy can result in spontaneous abortion and dysmorphologic changes in the developing organ systems of the embryo, including the heart, kidneys, and brain. However, few population-based studies are available that describe the prevalence of frequent drinking (6 or more drinks per week) among women prior to and during early pregnancy (the periconceptional period), and the sociodemographic and behavioral factors that characterize these women. Such knowledge is fundamental to the design of targeted interventions for the prevention of fetal alcohol syndrome (FAS) and other prenatal alcohol-related disorders. METHODS: This cross-sectional study used survey data collected by the National Center for Health Statistics as part of the 1988 National Maternal and Infant Health Survey (NMIHS). Weighted prevalence estimates were calculated using SUDAAN, and multivariate analyses were used to determine risk factors for frequent drinking. RESULTS: Forty-five percent of all women surveyed reported consuming alcohol during the 3 months before finding out they were pregnant, and 5% reported consuming 6 or more drinks per week. Sixty percent of women who reported alcohol consumption also reported that they did not learn they were pregnant until after the fourth week of gestation. Risk factors for frequent drinking during the periconceptional period included 1 or more of the following: being unmarried, being a smoker, being white non-Hispanic, being 25 years of age or older, or being college educated. CONCLUSIONS: Half of all pregnant women in this study drank alcohol during the 3 months preceding pregnancy recognition, with 1 in 20 drinking at moderate to heavy levels. The majority did not know they were pregnant until after the fourth week of pregnancy, and many did not know until after the 6th week. Alcohol is a teratogen capable of producing a number of adverse reproductive and infant outcomes. Public health measures needed to reduce these potentially harmful exposures include alcohol assessment, education, and counseling for women of childbearing age, with referral sources for problem drinking, and family planning services for pregnancy postponement until problem drinking is resolved.

Is maternal age a risk factor for mental retardation among children?

The purpose of this study was to determine whether older or very young maternal age at delivery is associated with mental retardation in children. Ten-year-old children with mental retardation (an intelligence quotient of 70 or less) were identified in 1985-1987 from multiple sources in the metropolitan Atlanta, Georgia, area. These children were subdivided into two case groups according to whether they had concomitant developmental disabilities or birth defects affecting the central nervous system (codevelopmental retardation) or did not have such disabilities (isolated retardation). Control children were randomly chosen from the regular education files of the public school systems in the study area. Data on sociodemographic variables were gathered from birth certificates. Children of teenaged mothers were not at increased risk for either form of retardation and children of mothers aged > or =30 years were not at increased risk for isolated retardation, in comparison with children of mothers aged 20-29 years. A markedly elevated risk of codevelopmental retardation was seen among black children of mothers aged > or =30 years that was not attributable to Down syndrome. A modest increase in risk for codevelopmental retardation was observed among white children born to older mothers, but it was entirely due to Down syndrome.

Prevalence and characteristics of children with serious hearing impairment in metropolitan Atlanta, 1991-1993.

OBJECTIVES: There is a paucity of data describing the epidemiology of serious hearing impairment among children in the United States. This report provides information on the prevalence of serious hearing impairment among children born in the 1980s and living in the metropolitan Atlanta area in 1991-1993 and on the characteristics of children with serious hearing impairment. METHODS: Data for this report are drawn from the Metropolitan Atlanta Developmental Disabilities Surveillance Program, an ongoing, active case-ascertainment system for mental retardation, cerebral palsy, hearing impairment, and vision impairment among children 3 to 10 years of age. Hearing impairment was defined as a bilateral, pure-tone hearing loss at frequencies of 500, 1000, and 2000 Hz averaging 40 decibels or more, unaided, in the better ear. Both severity and type of hearing loss were examined. Cross-sectional as well as birth cohort prevalence rates of serious hearing impairment were computed by sex and by race. The presence of mental retardation, cerebral palsy, vision impairment, or a seizure disorder was also assessed. An attempt was made to determine the probable etiology of a subset of the cases. RESULTS: The average, annual prevalence rate for moderate to profound hearing loss was 1.1 per 1000. The prevalence rate increased steadily with age. Ninety percent of all cases for which the type of loss was recorded were sensorineural. The highest rate was seen among black male children (1.4 per 1000). Thirty percent of case children had another neurodevelopmental condition, most frequently mental retardation. Black male children also experienced the highest rate of presumed congenital hearing impairment. The mean age at which children with presumed congenital hearing impairment first met the surveillance case definition was 2. 9 years. A probable etiology could only be found for 22% of cases born in the study area. CONCLUSIONS: The data presented here provide information on the descriptive epidemiology of serious hearing impairment among United States children. The reasons for the higher rates among black children, especially males, may be a fruitful direction for further research.

Comparison of binge drinking among pregnant and nonpregnant women, United States, 1991-1995.

Our goal was to measure the pregnancy-related reduction in the prevalence of reported binge drinking (>/=5 alcoholic drinks per occasion) and to characterize binge drinkers among pregnant and nonpregnant women aged 18-44 years, in the United States, 1991-1995. We used the Behavioral Risk Factor Surveillance System data from 46 states. We used the prevalence rate ratio between pregnant and nonpregnant women to determine the magnitude of the reduction in reported binge drinking and multiple logistic regression models to identify characteristics associated with binge drinking. Between 1991 and 1995, the prevalence of binge drinking among pregnant women increased significantly from 0.7% (95% confidence interval 0.2-0.9) to 2.9% (95% confidence interval 2.2-3.6), whereas among nonpregnant women the prevalence changed little (11.3% vs 11.2%). Over the study period pregnant women were one fifth (prevalence rate ratio 0.2, 95% confidence interval 0.1-0.2) as likely as nonpregnant women to binge drink. Among various population subgroups of women, pregnancy-related reduction in binge drinking was smallest among black women and largest among women aged

Reported biomedical causes and associated medical conditions for mental retardation among 10-year-old children, metropolitan Atlanta, 1985 to 1987.

This report describes biomedical causes of mental retardation (MR) among school-age children and associated medical conditions in children for whom no cause was reported. This study involved 715, 10-year-old children with MR (intelligence quotient [IQ] 70 or less) born between 1975 and 1977. We determined biomedical causes of MR using a hierarchical approach based on the timing of the event (i.e. prenatal, perinatal, or postneonatal). Among children with no identified biomedical cause the occurrence of associated medical conditions was examined. No reported biomedical cause could be found in 78% of children with MR (87% mild, IQ 50 to 70; 57% severe, IQ < 50). Prenatal causes were present in 12%, perinatal causes in 6%, and postneonatal causes in 4%. On the basis of these findings it was concluded that intensive use of public health prevention strategies can reduce the number of children who receive a diagnosis of MR.

Prenatal magnesium sulfate exposure and the risk for cerebral palsy or mental retardation among very low-birth-weight children aged 3 to 5 years.

OBJECTIVE: To examine the relationship between prenatal magnesium sulfate exposure and the risk for cerebral palsy (CP) or mental retardation (MR) among very low-birth-weight (VLBW; <1500 g) children. Secondarily, to investigate the effect of prenatal magnesium sulfate exposure on VLBW infant mortality. DESIGN: Cohort study with follow-up to 1 year of age; a subset followed up to 3 to 5 years. SETTING: Twenty-nine Georgia counties, including the 5-county Atlanta metropolitan area. PARTICIPANTS: All VLBW births (N=1097) occurring during 2 years (1986-1988); all metropolitan Atlanta VLBW neonates who survived infancy (N=519). MAIN OUTCOME MEASURES: Infant mortality as determined from vital statistics records. Development of CP or MR by 3 to 5 years of age among metropolitan Atlanta VLBW survivors as determined from the Metropolitan Atlanta Developmental Disabilities Surveillance Program. RESULTS: For the entire cohort, there was no association between prenatal magnesium sulfate exposure and infant mortality (adjusted rate ratio, 1.02; 95% confidence interval [CI], 0.83-1.25). Among Atlanta-born survivors, those exposed to magnesium sulfate had a lower prevalence of CP or MR than those not exposed (CP: magnesium sulfate, 0.9%, no magnesium sulfate, 7.7%, crude odds ratio [OR], 0.11, 95% CI, 0.02-0.81; MR: magnesium sulfate, 1.8%, no magnesium sulfate, 5.8%, crude OR, 0.30, 95% CI, 0.07-1.29). Multivariable adjustment had no appreciable effect on the ORs for CP or MR, but the CIs included 1.0. CONCLUSIONS: A reduced risk for CP, and possibly MR, among VLBW children is associated with prenatal magnesium sulfate exposure. The reduced risk for childhood CP or MR does not appear to be due to selective mortality of magnesium sulfate-exposed infants.

The relationship between idiopathic mental retardation and maternal smoking during pregnancy.

OBJECTIVES: Smoking has been linked to small cognitive, achievement, and behavioral deficits but has not been associated with more severe cognitive impairments. This investigation evaluated the relationship between maternal smoking during pregnancy and idiopathic mental retardation (MR). METHODS: Data on maternal smoking during pregnancy were obtained during face-to-face interviews with the mothers of 221 children with idiopathic MR and the mothers of 400 children attending public school. All children had been born in the five-county metropolitan Atlanta area in 1975 or 1976 and were living in the area when they were 10 years of age. We used exposure odds ratios (ORs) to assess the relationship between maternal smoking and MR, controlling for sex, maternal age at delivery, race, maternal education, economic status, parity, and alcohol use. RESULTS: Maternal smoking during pregnancy was associated with slightly more than a 50% increase in the prevalence of idiopathic MR (adjusted OR, 1.6; 95% confidence interval, 1.0-2.4), and children whose mothers smoked at least one pack a day during pregnancy had more than a 75% increase in the occurrence of idiopathic MR (OR, 1.9; 95% confidence interval, 1.0-3.4). This increase was neither accounted for by other sociodemographic risk factors for MR nor explained by an increase in the prevalence of low birth weight among the children of smokers. CONCLUSIONS: Our data suggest that maternal smoking may be a preventable cause of mental retardation.

Low birthweight and the risk for mental retardation later in childhood.

Data from the population-based Metropolitan Atlanta Developmental Disabilities Study were used in a case-control study to assess the association between low birthweight and mental retardation (intelligence quotient < or = 70) among 10-year-old children who were born in 1975 or 1976. Children with mental retardation were identified from existing records at multiple sources and control children were selected from public school rosters. Data on birthweight and other covariates (sex, birth order, maternal age, maternal race, maternal education and gestational age) came from birth certificates. We used multiple logistic regression modelling to obtain adjusted odds ratios for mental retardation, with normal birthweight children (those weighing > or = 2500 g) as the referent group. For low birthweight children as a whole, the odds ratio for mental retardation was 2.8 (95% CI 1.9-4.2). The risk was higher for very low birthweight (< 1500 g) children than for moderately low birthweight (1500-2499 g) children, and higher for severe mental retardation (intelligence quotient < 50) than for mild mental retardation (intelligence quotient 50-70). Adding gestational age to the models revealed that normal birthweight children who were born preterm also were at increased risk of having mental retardation at age 10 years.

The relationship between maternal education and mental retardation in 10-year-old children.

We conducted a case-control study of mental retardation (MR) in which case children (aged 10 years) were identified from existing records at multiple sources, primarily the public school systems. Control children were drawn from a roster of public school students not receiving special education services. We found that maternal educational level at the time of delivery was strongly and inversely related to a form of MR not accompanied by other serious neurologic conditions. For this isolated form of MR, maternal educational level was by far the most important predictor from among seven sociodemographic variables examined. There was a significant race-education interaction that indicated a steeper gradient in risk among white mothers than among black mothers. Relative to children of white mothers with 12 years of education, all children of black mothers, except those whose mothers had 16 or more years of education, were at increased risk. The results may be useful as a guide for selecting high-risk groups as candidates for early childhood intervention programs.

The administrative prevalence of mental retardation in 10-year-old children in metropolitan Atlanta, 1985 through 1987.

OBJECTIVES: In this study, data from the Metropolitan Atlanta Developmental Disabilities Study were used to determine the administrative prevalence (i.e., the number of children previously identified for service provision) of mental retardation among 10-year-old children during the years 1985 through 1987. METHODS: Children with mental retardation (intelligence quotient [IQ] of 70 or lower) were identified by review of records from multiple sources, with the public schools as the primary source. RESULTS: The overall administrative prevalence of mental retardation was 12.0 per 1000 children. The rate for mild mental retardation (IQ of 50 to 70) was 8.4 per 1000 and the rate for severe mental retardation (IQ lower than 50) was 3.6 per 1000. The prevalence was higher in Black children than in White children (prevalence odds ratio [POR] = 2.7) and in boys than in girls (POR = 1.4). Children with severe mental retardation had more coexisting disabilities than did children with mild mental retardation. CONCLUSIONS: The mental retardation prevalence rates reported here, especially the race-specific rates, may reflect social and demographic features unique to the metropolitan Atlanta area and therefore should be used with caution in making comparisons with other populations.