Peggy Auinger

The burden of respiratory syncytial virus infection in young children.

BACKGROUND The primary role of respiratory syncytial virus (RSV) in causing infant hospitalizations is well recognized, but the total burden of RSV infection among young children remains poorly defined. METHODS We conducted prospective, population-based surveillance of acute respiratory infections among children under 5 years of age in three U.S. counties. We enrolled hospitalized children from 2000 through 2004 and children presenting as outpatients in emergency departments and pediatric offices from 2002 through 2004. RSV was detected by culture and reverse-transcriptase polymerase chain reaction. Clinical information was obtained from parents and medical records. We calculated population-based rates of hospitalization associated with RSV infection and estimated the rates of RSV-associated outpatient visits. RESULTS Among 5067 children enrolled in the study, 919 (18%) had RSV infections. Overall, RSV was associated with 20% of hospitalizations, 18% of emergency department visits, and 15% of office visits for acute respiratory infections from November through April. Average annual hospitalization rates were 17 per 1000 children under 6 months of age and 3 per 1000 children under 5 years of age. Most of the children had no coexisting illnesses. Only prematurity and a young age were independent risk factors for hospitalization. Estimated rates of RSV-associated office visits among children under 5 years of age were three times those in emergency departments. Outpatients had moderately severe RSV-associated illness, but few of the illnesses (3%) were diagnosed as being caused by RSV. CONCLUSIONS RSV infection is associated with substantial morbidity in U.S. children in both inpatient and outpatient settings. Most children with RSV infection were previously healthy, suggesting that control strategies targeting only high-risk children will have a limited effect on the total disease burden of RSV infection.

Exposures to environmental toxicants and attention deficit hyperactivity disorder in U.S. children

Objective The purpose of this study was to examine the association of exposures to tobacco smoke and environmental lead with attention deficit hyperactivity disorder (ADHD). Methods Data were obtained from the National Health and Nutrition Examination Survey 1999–2002. Prenatal and postnatal tobacco exposure was based on parent report; lead exposure was measured using blood lead concentration. ADHD was defined as having current stimulant medication use and parent report of ADHD diagnosed by a doctor or health professional. Results Of 4,704 children 4–15 years of age, 4.2% were reported to have ADHD and stimulant medication use, equivalent to 1.8 million children in the United States. In multivariable analysis, prenatal tobacco exposure [odds ratio (OR) = 2.5; 95% confidence interval (CI), 1.2–5.2] and higher blood lead concentration (first vs. fifth quintile, OR = 4.1; 95% CI, 1.2–14.0) were significantly associated with ADHD. Postnatal tobacco smoke exposure was not associated with ADHD (OR = 0.6; 95% CI, 0.3–1.3; p = 0.22). If causally linked, these data suggest that prenatal tobacco exposure accounts for 270,000 excess cases of ADHD, and lead exposure accounts for 290,000 excess cases of ADHD in U.S. children. Conclusions We conclude that exposure to prenatal tobacco and environmental lead are risk factors for ADHD in U.S. children.

Full Breastfeeding Duration and Associated Decrease in Respiratory Tract Infection in US Children

OBJECTIVE. The American Academy of Pediatrics recommends exclusive breastfeeding for an infants first 6 months of life. When compared with exclusive breastfeeding for 4 months, greater protection against gastrointestinal infection, but not respiratory tract infection, has been demonstrated for the 6-month duration. The objective of this study was to ascertain if full breastfeeding of ≥6 months compared with 4 to <6 months in the United States provides greater protection against respiratory tract infection. METHODS. Secondary analysis of data from the National Health and Nutrition Examination Survey III, a nationally representative cross-sectional home survey conducted from 1988 to 1994, was performed. Data from 2277 children aged 6 to <24 months, who were divided into 5 groups according to breastfeeding status, were compared. Children who required neonatal intensive care were excluded. SUDAAN software was used to account for the complex sampling design. Logistic regression adjusted for confounding factors. Outcome measures included adjusted odds of acquiring pneumonia, ≥3 episodes of cold/influenza, ≥3 episodes of otitis media (OM), or wheezing in the past year or acquiring first OM at <12 months of age. RESULTS. In unadjusted analyses, infants who were fully breastfed for 4 to <6 months (n = 223) were at greater risk for pneumonia than those who were fully breastfed for ≥6 months (n = 136) (6.5% vs 1.6%). There were not statistically significant differences in ≥3 episodes of cold/influenza (45% vs 41%), wheezing (23% vs 24%), ≥3 episodes of OM (27% vs 20%), or first OM at <12 months of age (49% vs 47%). Adjusting for demographic variables, childcare, and smoke exposure revealed statistically significant increased risk for both pneumonia (odds ratio [OR]: 4.27; 95% confidence interval [CI]: 1.27–14.35) and ≥3 episodes of OM (OR: 1.95; 95% CI: 1.06–3.59) in those who were fully breastfed for 4 to <6 months compared with ≥6 months. CONCLUSIONS. This nationally representative study documents increased risk of respiratory tract infection including pneumonia and recurrent OM in children who were fully breastfed for 4 vs 6 months. These findings support current recommendations that infants receive only breast milk for the first 6 months of life.

Metabolic Syndrome Rates in United States Adolescents, from the National Health and Nutrition Examination Survey, 1999–2002

OBJECTIVE To report the prevalence rates of the metabolic syndrome in a nationally representative sample of adolescents in the United States using 4 previously reported definitions of the syndrome. STUDY DESIGN Data from 12- to 19-year-old adolescents included in the National Health and Nutrition Examination Survey from 1999 to 2002 (NHANES 99-02) were analyzed by cross-sectional methods, by using 4 definitions of the metabolic syndrome previously applied to adolescents. RESULTS In NHANES 99-02, the prevalence of the metabolic syndrome in all teens varied from 2.0% to 9.4% of teens in the United States, depending on the definition used. In obese teens, these prevalence rates varied from 12.4% to 44.2%. In the group of obese teens, application of the definition by Cruz produced a metabolic syndrome prevalence rate of 12.4%; that of Caprio produced a rate of 14.1%. However, none of the normal weight or overweight teens met either definition. Application of the definition by Cook produced a prevalence rate of 7.8% in overweight teens and 44% in obese teens. The adult definition of metabolic syndrome produced a prevalence rate of 16% in overweight teens and 26% in obese teens. CONCLUSIONS In the period between 1999 and 2002, the prevalence rate of metabolic syndrome varied from just >9% to as low as 2% of adolescents overall. Different definitions of metabolic syndrome generated prevalence rates in obese adolescents that varied widely from 12% to 44%. For this syndrome to be a useful construct, a more standardized set of criteria may be needed.

Prevalence and Trends of Severe Obesity Among US Children and Adolescents

OBJECTIVE To determine the extent to which the 2007 definitions for severe obesity (body mass index [BMI] > or = 99th percentile for age and gender) and morbid obesity (BMI > or = 40kg/m(2)) affects different groups of American children and adolescents and has increased over time. METHODS Analysis of nationally representative data from the National Health and Nutrition Examination Survey (NHANES) II, III, and 1999-2004; 12 384 US children and adolescents ages 2 to 19 years were included in the analysis. Outcome measures were the proportion of subjects with severe and morbid obesity, with age, gender, race, and poverty-income ratio (PIR) as key variables. RESULTS In 1999-2004, 3.8% of children 2 to 19 years old had a BMI in the > or = 99th percentile, with higher prevalence among boys than girls (4.6% vs 2.9%; P < .001). Prevalence was highest among blacks, 5.7% and Mexican Americans, 5.2%, compared with whites, 3.1% (P < .001). The prevalence differed by the PIR category as well (4.3% for those with PIR < or = 3 vs 2.5% for those with PIR>3; P=.002). BMI > or = 40kg/m(2) was found in 1.3% of adolescents ages 12 to 19 years, with similar associations with race and poverty. The overall prevalence of BMI > or = 99th percentile has increased by more than 300% since NHANES II (1976), and over 70% since NHANES III (1994) in children 2 to 19 years of age. CONCLUSIONS Rates of severe childhood obesity have tripled in the last 25 years, with significant differences by race, gender, and poverty. This places demands on health care and community services, especially because the highest rates are among children who are frequently underserved by the health care system.

Exposure to Environmental Tobacco Smoke and Cognitive Abilities among U.S. Children and Adolescents

We used the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 to 1994, to investigate the relationship between environmental tobacco smoke (ETS) exposure and cognitive abilities among U.S. children and adolescents 6–16 years of age. Serum cotinine was used as a biomarker of ETS exposure. Children were included in the sample if their serum cotinine levels were ≤15 ng/mL, a level consistent with ETS exposure, and if they denied using any tobacco products in the previous 5 days. Cognitive and academic abilities were assessed using the reading and math subtests of the Wide Range Achievement Test–Revised and the block design and digit span subtests of the Wechsler Intelligence Scale for Children–III. Analyses were conducted using SUDAAN software. Of the 5,365 6- to 16-year-olds included in NHANES III, 4,399 (82%) were included in this analysis. The geometric mean serum cotinine level was 0.23 ng/mL (range, 0.035–15 ng/mL); 80% of subjects had levels < 1 ng/mL. After adjustment for sex, race, region, poverty, parent education and marital status, ferritin, and blood lead concentration, there was a significant inverse relationship between serum cotinine and scores on reading (β= −2.69, p = 0.001), math (β= −1.93, p = 0.01), and block design (β= −0.55, p < 0.001) but not digit span (β= −0.08, p = 0.52). The estimated ETS-associated decrement in cognitive test scores was greater at lower cotinine levels. A log-linear analysis was selected as the best fit to characterize the increased slope in cognitive deficits at lower levels of exposure. These data, which indicate an inverse association between ETS exposure and cognitive deficits among children even at extremely low levels of exposure, support policy to further restrict children’s exposure.

Association of tobacco and lead exposures with attention-deficit/hyperactivity disorder.

OBJECTIVE: The study objective was to determine the independent and joint associations of prenatal tobacco and childhood lead exposures with attention-deficit/hyperactivity disorder (ADHD), as defined by current diagnostic criteria, in a national sample of US children. METHODS: Data are from the 2001–2004 National Health and Nutrition Examination Survey, a cross-sectional, nationally representative sample of the US population. Participants were 8 to 15 years of age (N = 2588). Prenatal tobacco exposure was measured by report of maternal cigarette use during pregnancy. Lead exposure was assessed by using current blood lead levels. The Diagnostic Interview Schedule for Children was used to ascertain the presence of ADHD in the past year, on the basis of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria. RESULTS: A total of 8.7% (95% confidence interval [CI]: 7.3%–10.1%) of children met criteria for ADHD. Prenatal tobacco exposure (adjusted odds ratio [aOR]: 2.4 [95% CI: 1.5–3.7]) and higher current blood lead concentrations (aOR for third versus first tertile: 2.3 [95% CI: 1.5–3.8]) were independently associated with ADHD. Compared with children with neither exposure, children with both exposures (prenatal tobacco exposure and third-tertile lead levels) had an even greater risk of ADHD (aOR: 8.1 [95% CI: 3.5–18.7]) than would be expected if the independent risks were multiplied (tobacco-lead exposure interaction term, P < .001). CONCLUSIONS: Prenatal tobacco and childhood lead exposures are associated with ADHD in US children, especially among those with both exposures. Reduction of these common toxicant exposures may be an important avenue for ADHD prevention.

Do Parenting and the Home Environment, Maternal Depression, Neighborhood, and Chronic Poverty Affect Child Behavioral Problems Differently in Different Racial-Ethnic Groups?

OBJECTIVE. To determine whether the processes through which parenting practices, maternal depression, neighborhood, and chronic poverty affect child behavioral problems are similar or different in minority and nonminority children in the United States. METHODS. Data from 884 white, 538 black, and 404 Latino families with children who were 6 to 9 years of age in the National Longitudinal Survey of Youth were analyzed. The outcome, child behavioral problems, was measured using the Behavior Problems Index externalizing and internalizing subscales. The effects of chronic poverty, neighborhood, maternal depression, and parenting on the outcome were analyzed using multigroup structural equation modeling. RESULTS. Chronic poverty affected child behavioral problems indirectly through the other variables, and parenting practices had direct effects in each racial/ethnic group. The effects of maternal depression were partially mediated through parenting in the white and Latino samples but were direct and unmediated through parenting practices in the black sample. Neighborhood effects were present in the white and black samples but were not significant for the Latino sample. CONCLUSIONS. Chronic poverty, neighborhood, maternal depression, and parenting practices have effects on child behavioral problems in white, black, and Latino children, but the processes and mechanisms through which they exert their effects differ among the groups. The differences may be related to social stratification mechanisms as well as sociocultural differences in family and childrearing practices.

Elevated blood pressure and decreased cognitive function among school-age children and adolescents in the United States

OBJECTIVE To evaluate the relationship between elevated blood pressure (BP) and cognitive test performance in a nationally representative sample of children. Study design The National Health and Nutrition Examination Survey III provides cross-sectional data for children 6 to 16 years, including BP and cognitive test scores. Elevated BP was defined as systolic or diastolic BP >or=90th percentile. Cognitive tests were compared for children with elevated and normal BP. Linear regression was used to evaluate the relation between elevated BP and decreased test scores. RESULTS Among the 5077 children, 3.4% had systolic BP >or=90th percentile and 1.6% diastolic BP >or=90th percentile. Children with elevated systolic BP had lower average scores compared with normotensive children for digit span (7.9 vs 8.7, P=.01), block design (8.6 vs 9.5, P=.03), and mathematics (89.6 vs 93.8, P=.01). Elevated diastolic BP was associated with lower average scores on block design (9.5 vs 11, P=.01). Linear regression showed that elevated systolic BP was independently associated with lower digit span scores (P=.032). CONCLUSION Children with elevation of systolic BP are at risk for central nervous system end-organ damage, as manifested by decreased digit span test scores.

Growth Curves for Cardio-Metabolic Risk Factors in Children and Adolescents

OBJECTIVE This study developed percentile curves for anthropometric (waist circumference) and cardiovascular (lipid profile) risk factors for US children and adolescents. STUDY DESIGN A representative sample of US children and adolescents from the National Health and Nutrition Examination Survey from 1988 to 1994 (NHANES III) and the current national series (NHANES 1999-2006) were combined. Percentile curves were constructed, nationally weighted, and smoothed using the Lambda, Mu, and Sigma method. The percentile curves included age- and sex-specific percentile values that correspond with and transition into the adult abnormal cut-off values for each of these anthropometric and cardiovascular components. To increase the sample size, a second series of percentile curves was also created from the combination of the 2 NHANES databases, along with cross-sectional data from the Bogalusa Heart Study, the Muscatine Study, the Fels Longitudinal Study and the Princeton Lipid Research Clinics Study. RESULTS These analyses resulted in a series of growth curves for waist circumference, total cholesterol, LDL cholesterol, triglycerides, and HDL cholesterol from a combination of pediatric data sets. The cut-off for abnormal waist circumference in adult males (102 cm) was equivalent to the 94(th) percentile line in 18-year-olds, and the cut-off in adult females (88 cm) was equivalent to the 84(th) percentile line in 18-year-olds. Triglycerides were found to have a bimodal pattern among females, with an initial peak at age 11 and a second at age 20; the curve for males increased steadily with age. The HDL curve for females was relatively flat, but the male curve declined starting at age 9 years. Similar curves for total and LDL cholesterol were constructed for both males and females. When data from the additional child studies were added to the national data, there was little difference in their patterns or rates of change from year to year. CONCLUSIONS These curves represent waist and lipid percentiles for US children and adolescents, with identification of values that transition to adult abnormalities. They could be used conditionally for both epidemiological and possibly clinical applications, although they need to be validated against longitudinal data.