Robert H. Bradley

Moderate-to-vigorous physical activity from ages 9 to 15 years.

CONTEXT Decreased physical activity plays a critical role in the increase in childhood obesity. Although at least 60 minutes per day of moderate-to-vigorous physical activity (MVPA) is recommended, few longitudinal studies have determined the recent patterns of physical activity of youth. OBJECTIVE To determine the patterns and determinants of MVPA of youth followed from ages 9 to 15 years. DESIGN, SETTING, AND PARTICIPANTS Longitudinal descriptive analyses of the 1032 participants in the 1991-2007 National Institute of Child Health and Human Development Study of Early Child Care and Youth Development birth cohort from 10 study sites who had accelerometer-determined minutes of MVPA at ages 9 (year 2000), 11 (2002), 12 (2003), and 15 (2006) years. Participants included boys (517 [50.1%]) and girls (515 [49.9%]); 76.6% white (n = 791); and 24.5% (n = 231) lived in low-income families. MAIN OUTCOME MEASURE Mean MVPA minutes per day, determined by 4 to 7 days of monitored activity. RESULTS At age 9 years, children engaged in MVPA approximately 3 hours per day on both weekends and weekdays. Weekday MVPA decreased by 37 minutes per year [corrected], while weekend MVPA decreased by 39 minutes per year [corrected]. By age 15 years, adolescents were only engaging in MVPA for 50 minutes per weekday [corrected] and 36 minutes per weekend day [corrected]. Boys were more active than girls, spending 18 and 14 more minutes per day [corrected] in MVPA on the weekdays and weekends, respectively. The rate of decrease in MVPA was the same for boys and girls. The estimated age at which girls crossed below the recommended 60 minutes of MVPA per day was approximately 13.2 years for weekday [corrected] activity compared with boys at 14.9 years [corrected], and for weekend activity, girls crossed below the recommended 60 minutes of MVPA at 12.7 years [corrected] compared with boys at 13.6 years [corrected]. CONCLUSION In this study cohort, measured physical activity decreased significantly between ages 9 and 15 years.

Identifying Risk for Obesity in Early Childhood

OBJECTIVES. Our aim with this study was to assist clinicians by estimating the predictive value of earlier levels of BMI status on later risk of overweight and obesity during the middle childhood and early adolescent years. METHODS. We present growth data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, a longitudinal sample of 1042 healthy US children in 10 locations. Born in 1991, their growth reflects the secular trend of increasing overweight/obesity in the population. Height and weight of participating children in the study were measured at 7 time points. We examined odds ratios for overweight and obesity at age 12 years comparing the frequency with which children did versus did not reach specific BMI percentiles in the preschool- and elementary-age periods. To explore the question of whether and when earlier BMI was predictive of weight status at age 12 years, we used logistic regression to obtain the predicted probabilities of being overweight or obese (BMI ≥85%) at 12 years old on the basis of earlier BMI. RESULTS. Persistence of obesity is apparent for both the preschool and elementary school period. Children who were ever overweight (>85th percentile), that is, ≥1 time at ages 24, 36, or 54 months during the preschool period were >5 times as likely to be overweight at age 12 years than those who were below the 85th percentile for BMI at all 3 of the preschool ages. During the elementary school period, ages 7, 9, and 11 years, the more times a child was overweight, the greater the odds of being overweight at age 12 years relative to a child who was never overweight. Sixty percent of children who were overweight at any time during the preschool period and 80% of children who were overweight at any time during the elementary period were overweight at age 12 years. Follow-up calculations showed that 2 in 5 children whose BMIs were ≥50th percentile by age 3 years were overweight at age 12 years. No children who were <50th percentile for BMI at all points during elementary school were overweight at age 12 years. Children who have higher range BMIs earlier, but not at the 85th percentile, are also more likely to be overweight at age 12 years. Even at time points before and including age 9 years, children whose BMIs are between the 75th and 85th percentile have an ∼40% to 50% chance of being overweight at age 12 years. Children at 54 months old whose BMIs are between the 50th and 75th percentile are 4 times more likely to be overweight at age 12 years than their contemporaries who are <50th percentile, and those whose BMIs are between the 75th and 85th percentile are >6 times more likely to be overweight at age 12 years than those <50th percentile. CONCLUSIONS. The data from this study indicate that children with BMIs >85th percentile, as well as with BMIs in the high reference range are more likely than children whose BMI is <50th percentile to continue to gain weight and reach overweight status by adolescence. Pediatricians can be confident in counseling parents to begin to address the at-risk childs eating and activity patterns rather than delaying in hopes that overweight and the patterns that support it will resolve themselves in due course. Identifying children at risk for adolescent obesity provides physicians with an opportunity for earlier intervention with the goal of limiting the progression of abnormal weight gain that results in the development of obesity-related morbidity.

Socioeconomic Status, Parenting, and Child Development

Contents: M.H. Bornstein, Series Foreword. Socioeconomic Status, Parenting, and Child Development: An Introduction. Part I:SES: Measurement and Ecology. M.E. Ensminger, K. Fothergill, A Decade of Measuring SES: What It Tells Us and Where We Go From Here. M.H. Bornstein, C-S. Hahn, J.T.D. Suwalsky, O.M. Haynes, Socioeconomic Status, Parenting, and Child Development: The Hollingshead Four-Factor Index of Social Status and the Socioeconomic Index of Occupations. G.J. Duncan, K.A. Magnuson, Off With Hollingshead: Socioeconomic Resources, Parenting, and Child Development. A.J. Fuligni, H. Yoshikawa, Socioeconomic Resources, Parenting, Poverty, and Child Development Among Immigrant Families. L.W. Hoffman, Methodological Issues in Studies of SES, Parenting, and Child Development. Part II:SES: Parenting and Child Development. E. Hoff, Causes and Consequences of SES-Related Differences in Parent-to-Child Speech. R.H. Bradley, R.F. Corwyn, Age and Ethnic Variations in Family Process Mediators of SES. A.W. Gottfried, A.E. Gottfried, K. Bathurst, D.W. Guerin, M.M. Parramore, Socioeconomic Status in Childrens Development and Family Environment: Infancy Through Adolescence. T. Leventhal, J. Brooks-Dunn, Moving on Up: Neighborhood Effects on Children and Families. R.M. Lerner, What Are SES Effects Effects of?: A Developmental Systems Perspective.

Home environment and cognitive development in the first 3 years of life: A collaborative study involving six sites and three ethnic groups in North America.

Attempted to examine the generalizability of environment/development relationships among 3 ethnic groups across the first 3 years of life. Social status did not show a consistent relationship to either quality of home environment or childrens developmental status across the various groups. Results indicated a fairly consistent relationship between HOME scores and childrens developmental status, although there were some ethnic and social status differences in the relationship. Measures of specific aspects of the childs home environment, such as parental responsivity and availability of stimulating play materials, were more strongly related to child developmental status than global measures of environmental quality such as SES. When the childs early developmental status and early home environment were both very low, the likelihood of poor developmental outcomes was markedly increased compared with cases when only one was low.

Parenting styles and overweight status in first grade

OBJECTIVE. The goal was to determine the relationship between the 4 parenting styles (authoritative, authoritarian, permissive, and neglectful) and overweight status in first grade. METHODS. Data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development were analyzed. Children with complete data for parenting parameters at 54 months and measured weight and height in first grade were included in the analysis. Overweight was defined as BMI of ≥95th percentile. The 4 parenting styles were constructed with 2 scales, namely, maternal sensitivity and maternal expectations for child self-control. Multivariate logistic regression analysis was used to evaluate the relationship between parenting style and overweight in first grade, controlling for gender, race, maternal education, income/needs ratio, marital status, and child behavior problems. RESULTS. A total of 872 children, 11.1% overweight and 82.8% white, were included in the analysis. Children of authoritarian mothers (n = 298) had an increased risk of being overweight, compared with children of authoritative mothers (n = 179). Children of permissive (n = 132) and neglectful (n = 263) mothers were twice as likely to be overweight, compared with children of authoritative mothers. Of the covariates, only income/needs ratio was significant and did not alter the relationship between parenting style and overweight risk. CONCLUSIONS. Among the 4 parenting styles, authoritarian parenting was associated with the highest risk of overweight among young children. Understanding the mechanisms through which parenting styles are associated with overweight risk may lead to the development of more-comprehensive and better-targeted interventions.

Home Environment and School Performance: A Ten-Year Follow-up and Examination of Three Models of Environmental Action.

The home environments of 42 10- and 11-year-old children were examined when they were infants and again during middle childhood. Significant correlations were observed between home environments measured at both 2 years and 10 years and the childrens SRA achievement test scores and their classroom behavior. However, the home environment at 6 months was only related to a limited number of classroom behaviors. Partial correlations were used to test 3 models of environmental action: Model I (primacy of early experience), Model II (predominance of the contemporary environment), Model III (cumulative effects in stable environments). Strongest relations were noted for the contemporary environment, but all 3 models received some support. Correlations between HOME scores and childrens competence in middle childhood revealed a complex portrait that was not explainable with reference to a single model of environmental action. The version of the HOME Inventory used with families of elementary school children is also introduced.

Weight Status in Young Girls and the Onset of Puberty

OBJECTIVE. We sought to examine the association between weight status in early childhood and onset of puberty. PATIENTS AND METHODS. The study included 354 girls from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. Girls were followed longitudinally with height and weight measurements at 36 and 54 months and grades 1, 4, 5, and 6 and with assessment of pubertal stage by physical examination and maternal report in grades 4 through 6. The main outcome was the presence of early puberty, indexed as follows: (a) breast development at or more than Tanner stage 2 by physical examination at grade 4; (b) breast development at or more than Tanner stage 3 by physical examination at grade 5; (c) maternal report of breast development at or more than Tanner stage 3 at grade 5; and (d) maternal report of menarche having already occurred (yes versus no) at grade 6. Multiple logistic regression models predicting early versus late puberty were constructed by using the covariate BMI z score at 36 months, rate of change of BMI and accelerated BMI between 36 months and grade 1, race, maternal education, and maternal age of menarche. RESULTS. BMI z score at 36 months, rate of change of BMI between 36 months and grade 1, an earlier age of maternal menarche, and nonwhite race were each consistently and positively associated with an earlier onset of puberty across the various measures of puberty. CONCLUSIONS. Higher BMI z score in girls as young as 36 months of age and higher rate of change of BMI between 36 months old and grade 1, a period well before the onset of puberty, are associated with earlier puberty, which suggests that increasing rates of obesity in the United States may result in an earlier average age of onset of puberty for US girls.

Shorter sleep duration is associated with increased risk for being overweight at ages 9 to 12 years

OBJECTIVE. The potential association between short sleep duration or sleep problems and childhood overweight has not been well described. The objective of this study was to test the independent associations of sleep duration and problems with overweight risk in children. METHODS. Data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development were analyzed. In 3rd and 6th grades, sleep duration and problems were obtained by maternal report, and height and weight were measured, with overweight defined as a BMI of ≥95th percentile for age and gender. Logistic regression evaluated the association of sleep duration and problems with overweight at 6th grade cross-sectionally adjusting for gender, race, and maternal education. Additional covariates tested individually included the level of chaos at home, the quality of the home environment, the lax-parenting subscale score of the Raising Children Checklist, and the Child Behavior Checklist internalizing and externalizing subscale scores. Logistic regression also evaluated the relationship of sleep duration at 3rd grade and overweight at 6th grade, adjusting for gender, race, maternal education, and the childs BMI z score in 3rd grade. RESULTS. Of 785 children, 50% were male, 81% were white, and 18% were overweight in 6th grade. Shorter sleep duration in 6th grade was independently associated with a greater likelihood of overweight in 6th grade. Shorter sleep duration in 3rd grade was also independently associated with overweight in 6th grade, independent of the childs weight status in 3rd grade. Sleep problems were not associated with overweight. CONCLUSION. One preventive approach to overweight may be to ensure adequate sleep in childhood.

Infant temperament, parenting, and externalizing behavior in first grade: A test of the differential susceptibility hypothesis

BACKGROUND This study examines the differential susceptibility hypothesis as it pertains to relations between infant temperament, parenting, and behavior problems in first grade. METHOD Data from the NICHD Study of Early Child Care were used in a series of hierarchical regression analyses focused on interactions between three aspects of parenting (harshness, sensitivity, productive activity) and temperament as they affect teacher-reported externalizing behavior in first grade. Step #1 included family income-to-needs, maternal education, gender, life events, and amount of child care as control variables, plus infant temperament and the three parenting variables. Step #2 included a single interaction term, the interaction between one of the key parenting variables and child temperament. RESULTS Results showed stronger relations between maternal sensitivity and behavior problems for children with difficult temperaments. Likewise, relations between opportunities for productivity and behavior problems were stronger for children with difficult temperaments. Trends were in the same direction for harsh parenting but did not quite reach statistical significance. CONCLUSIONS Having access to experiences that promote coping and build self-regulatory capacities seems particularly valuable for children with difficult temperaments.

Weight Status as a Predictor of Being Bullied in Third Through Sixth Grades

OBJECTIVES: Childhood obesity and bullying both are pervasive public health problems. The objective of this study was to determine the relationship between childhood obesity and being bullied in third, fifth, and sixth grades while testing for potential confounding and moderation. METHODS: A total of 821 children who were participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (50% male, 81% white, 17% obese, 15% overweight in third grade) were studied. Generalized estimating equations were used to evaluate the relationship between child weight status and the odds of being bullied as reported by child, mother, and teacher, accounting for repeated measures and adjusting for grade level in school, child gender, child race, family income-to-needs ratio, school racial and socioeconomic composition, and mother- and teacher-reported child social skills and child academic achievement. RESULTS: In sixth grade, 33.9%, 44.5%, and 24.9% of the children were reported to be bullied per teacher-, mother-, and self-report, respectively. There was a significant independent association between being obese and being bullied (odds ratio: 1.63 [95% confidence interval: 1.18–2.25]). The relationship between being obese and being bullied was attenuated but not eliminated by all covariates except gender. The relationship was not moderated by any of the covariates. CONCLUSIONS: Children who are obese are more likely to be bullied, regardless of a number of potential sociodemographic, social, and academic confounders. No protective factors were identified. Effective interventions to reduce bullying of obese children need to be identified.