Ashlesha Datar

Physical Education in Elementary School and Body Mass Index: Evidence from the Early Childhood Longitudinal Study

OBJECTIVES We examined the effect of physical education instruction time on body mass index (BMI) change in elementary school. METHODS We examined data from a national sample of 9751 kindergartners in the United States who were reported on for 2 years. We used a difference-in-differences approach to examine the effect of an increase in physical education instruction time between kindergarten and first grade on the difference in BMI change in the 2 grades, using the same child as the control. RESULTS One additional hour of physical education in first grade compared with the time allowed for physical education in kindergarten reduces BMI among girls who were overweight or at risk for overweight in kindergarten (coefficient = -0.31, P <.001) but has no significant effect among overweight or at-risk-for-overweight boys (coefficient = -0.07, P =.25) or among boys (coefficient = 0.04, P =.31) or girls (coefficient = 0.01, P =.80) with a normal BMI. CONCLUSIONS Expanding physical education programs in schools, in the form in which they currently exist, may be an effective intervention for combating obesity in the early years, especially among girls.

Parent Perceptions of Neighborhood Safety and Children's Physical Activity, Sedentary Behavior, and Obesity: Evidence from a National Longitudinal Study

We examined the relationship between parent-perceived neighborhood safety and childrens physical activity, sedentary behavior, body mass, and obesity status using 9 years of longitudinal data (1999-2007) on a cohort of approximately 19,000 US kindergartners from the Early Childhood Longitudinal Study. Childrens height and weight measurements and parent perceptions of neighborhood safety were available in kindergarten and in the first, third, fifth, and eighth grades. Dependent variables included age- and gender-specific body mass index percentile, obesity status, and parent- or child-reported weekly physical activity and television-watching. Pooled cross-sectional and within-child longitudinal regression models that controlled for child, family, and school characteristics were fitted. Both cross-sectional and longitudinal models indicated that children whose parents perceived their neighborhoods as unsafe watched more television and participated in less physical activity, although the magnitude of this association was much weaker in longitudinal models. However, there was no significant association between parent-perceived neighborhood safety and childrens body mass index.

Changes in Body Mass During Elementary and Middle School in a National Cohort of Kindergarteners

OBJECTIVE: To analyze changes in BMI, according to gender and race/ethnicity, in a nationally representative cohort of children in the United States during their elementary and middle school years to identify critical periods of excess BMI gains. METHODS: The Early Childhood Longitudinal Study-Kindergarten Class monitored a nationally representative cohort of kindergarten students over 9 years (1998–2007). Height and weight measurements were available for 4240 white, 640 black, and 1070 Hispanic children in kindergarten and 1st, 3rd, 5th, and 8th grades. In each wave, we estimated the proportions of children with BMI values in each quartile of the Centers for Disease Control and Prevention reference-population distribution according to gender and race/ethnicity. We conducted nonparametric tests of differences in BMI distributions over time within racial/ethnic groups and across racial/ethnic groups in each wave. Piecewise linear growth models were estimated to test for specific time periods during which the largest gains in BMI percentiles occurred. RESULTS: Overall, nearly 40% of children started kindergarten with a BMI in the top quartile of the growth charts (BMI > 75th percentile). This proportion increased significantly during the elementary school years, and the largest gains were between 1st and 3rd grades (5.8 percentage points), but there was no further increase during middle school. Increases in BMI percentiles over time were most notable among Hispanic children and black girls. CONCLUSIONS: The early school years might be a critical time for excess BMI gains, even among children with normal BMI values at kindergarten entry.

Changes in Socioeconomic, Racial/Ethnic, and Sex Disparities in Childhood Obesity at School Entry in the United States

Changes in Socioeconomic, Racial/Ethnic, and Sex Disparities in Childhood Obesity at School Entry in the United States The National Health and Nutrition Examination Survey data suggest a plateauing of childhood obesity in the United States, with no trend among children younger than 11 years since 1999.1,2 However, studies have challenged this finding and cautioned that the overall static trend masks significant differences across subgroups.3,4 There is not much consensus about whether and how childhood obesity prevalence has changed for various age, sex, race/ethnicity, and socioeconomic subgroups.2,4 Available data on 2 nationally representative cohorts of US kindergarten-aged children 12 years apart provide a valuable opportunity to document changes in weight gain and obesity among young children and underlying sex, socioeconomic, and racial/ethnic disparities between 1998 and 2010. Methods | Sponsored by the National Center for Education Statistics, the Early Childhood Longitudinal Study kindergarten class (ECLS-K) consists of 2 separate nationally representative cohorts recruited as kindergarteners during the 1998 to 1999 and 2010 to 2011 school years (mean age, 5.7 years). Both cohorts first surveyed children in the fall of the kindergarten year, with additional waves in later grades. Only kindergarten data were available at the time of analysis; therefore, our analyses used only the fall kindergarten data from both cohorts. In both cohorts, body mass index (calculated as weight in kilograms divided by height in meters squared) was calculated using height and weight measurements taken by trained staff using standardized procedures described elsewhere.5,6 Measures of children who were overweight or obese (body mass index ≥ 85th percentile) and children who were obese (body mass index ≥ 95th percentile) were computed using the 2000 sexand age-specific Centers for Disease Control and Prevention growth charts.

The more the heavier? Family size and childhood obesity in the U.S

Childhood obesity remains a top public health concern and understanding its drivers is important for combating this epidemic. Contemporaneous trends in declining family size and increasing childhood obesity in the U.S. suggest that family size may be a potential contributor, but limited evidence exists. Using data from a national sample of children in the U.S. this study examines whether family size, measured by the number of siblings a child has, is associated with child BMI and obesity, and the possible mechanisms at work. The potential endogeneity of family size is addressed by using several complementary approaches including sequentially introducing of a rich set of controls, subgroup analyses, and estimating school fixed-effects and child fixed-effects models. Results suggest that having more siblings is associated with significantly lower BMI and lower likelihood of obesity. Children with siblings have healthier diets and watch less television. Family mealtimes, less eating out, reduced maternal work, and increased adult supervision of children are potential mechanisms through which family size is protective of childhood obesity.

Outsourcing Meals: Effects of Maternal Work on Children’s School Meal Participation

Maternal work may affect how mothers allocate time toward activities related to children’s diet and overall well-being. One potential consequence is that mothers may outsource meal preparation. In particular, school meals might replace brown-bag meals because they are subsidized, convenient, and nutritionally regulated. This study examines whether increases in maternal work influence children’s school breakfast and lunch participation, addressing the endogeneity of maternal work using local labor market indicators as instrumental variables. Results suggest that children whose mothers work are more likely to participate in school lunch. However, these children are less likely to participate in school breakfast and more likely to eat breakfast at home with family than are children of nonworking women. These results are qualitatively similar across full- and part-time work status and various socioeconomic groups, although the magnitudes vary. The article concludes with a discussion of the potential mechanisms underlying the findings and their policy implications.

School Entry Age and Children’s Social-Behavioral Skills Evidence From a National Longitudinal Study of U.S. Kindergartners

Prior research evaluating school entry-age effects has largely overlooked the effects on social-behavioral skills despite the growing recognition of returns to such skills. This study is the first to examine the effects of kindergarten entry age on children’s social-behavioral outcomes using 9 years of panel data on a national sample of U.S. children. We leverage exogenous variation in birth dates and kindergarten entrance age policies to estimate instrumental variables models. Our results show that entering kindergarten a year later is associated with significantly better social-behavioral outcomes during elementary school. However, these effects largely disappear by the end of middle school. Larger gains over time among younger entrants support the notion that the estimated effects are age-at-test effects.

Parental Deployment, Adolescent Academic and Social–Behavioral Maladjustment, and Parental Psychological Well-Being in Military Families

Objective: Increases in the frequency and length of military deployments have raised concerns about the well-being of military families. We examined the relationship between a military parent’s deployment and (1) adolescent academic and social–behavioral maladjustment and (2) parental psychological well-being. Methods: We collected data from April 2013 through January 2014 from 1021 families of enlisted US Army personnel with children aged 12 or 13 during the Military Teenagers’ Environments, Exercise, and Nutrition Study. Through online parent surveys, we collected data on deployment, adolescent academic and social–behavioral maladjustment, and parental psychological well-being. We estimated adjusted logistic and linear regression models for adolescents (all, boys, girls), military parents (all, fathers, mothers), and civilian parents. Results: Compared with no or short deployments, long deployments (>180 days in the past 3 years) were associated with significantly higher odds of decreases in adolescent academic performance (adjusted odds ratio [AOR] = 1.54), independence (AOR = 2.04), and being responsible (AOR = 1.95). These associations were also significant for boys but not for girls. Among parents, long deployments were associated with significantly higher odds of being depressed (AOR = 2.58), even when controlling for adolescent maladjustment (AOR = 2.54). These associations did not differ significantly between military and civilian parents and were significant for military fathers but not military mothers. Recent deployment (in the past 12 months) was not associated with either adolescent or parent outcomes. Conclusion: Long deployments are associated with adolescents’ academic and social–behavioral maladjustments and diminished parental well-being, especially among boys and military fathers.