Prevalence of Overweight Among Third- and Sixth-Grade Children -- New York City, 1996

Childhood overweight is the leading cause of pediatric hypertension, and overweight children are at high risk for developing long-term chronic conditions, including adult-onset diabetes mellitus, coronary heart disease, orthopedic disorders, and respiratory disease (1). Overweight among children and adolescents in the United States increased from 1976-1980 to 1988-1994 (2-4). Information is needed to describe overweight in smaller geographic areas for local health planning. This report presents findings from a study examining the weight status of third- and sixth-graders in New York City (NYC) in 1996. The findings indicate a high prevalence of overweight among NYC third- and sixth-graders, regardless of sex or racial/ethnic characteristics.

A three-stage probability design was used to select a representative sample of third- and sixth-grade students attending public and private schools in NYC. Schools were initially stratified by socioeconomic status (lower-, middle-, and upper-income groups) and by racial/ethnic composition on the basis of the predominant characteristic of the student population in each school (non-Hispanic white, non-Hispanic black, Hispanic, and mixed {i.e., no one racial/ethnic group predominated}). A separate stratum was created for private and parochial schools because the database used for the sampling frame did not include racial/ethnic characteristics of students for those schools.

Stage one of the sampling involved a stratified random selection and recruitment of 32 schools for participation in the study. A larger-than-necessary random sample of schools was selected in each stratum. Schools refusing to participate were replaced by another randomly selected school from the respective stratum. In stage two, one random sample of up to four homeroom classrooms from each grade level was selected from each school, yielding 137 total classrooms. The size of the school determined the number of classrooms sampled. Finally, interviewers randomly selected students within classrooms who had received informed parental consent to participate. An average of five students was randomly selected from each classroom, the number varying depending on the size of the classroom. Data collection occurred in February and March 1996.

Height and weight were measured by trained interviewers using standard anthropometric techniques and equipment (5). Body mass index (BMI) (weight in kilograms divided by height in meters squared) was used as the indicator of weight status. Children were considered overweight when their BMI was at or above the age- and sex-specific 95th percentile from the second and third National Health and Nutrition Examination surveys (CDC, unpublished data, 1995). Interviewers conducted a dietary assessment for each child using a quantitative 24-hour dietary recall. Interviewers were trained by nutritionists to use standardized probing techniques to obtain the foods and quantity consumed throughout the previous day. Two-dimensional models and measuring devices were used to assist with quantifying the amount of food consumed. The University of Minnesota Nutrient Data System was used to convert dietary recall data into nutrient values. Physical activity was assessed on the basis of reported frequency of participation in a fixed list of sports and other common physical activities.

Statistical weights were constructed to account for the complex sampling design and the underlying population of school children in NYC. Weighted statistical analysis was carried out using SUDAAN software for calculating variance estimates (6). Eleven third-grade and seven sixth-grade children were excluded from the analysis because of missing height and/or weight measurements. The final analysis included 307 third-graders and 337 sixth-graders averaging 8.1 and 11.2 years of age, respectively.

The analysis indicated that 19.7% of third-graders and 21.2% of sixth-graders were overweight (Table_1). The reported mean daily energy consumption was 1839 calories for third-graders and 1953 calories for sixth-graders. Overweight was more prevalent among NYC boys (21.7 among third-graders and 22.7 among sixth-graders) and black non-Hispanic children (24.9 among third-graders and 27.2 among sixth-graders) in both grades, but these differences were not statistically significant.

Reported by: TA Melnik, DrPH, AT Jesaitis, MPH, KR Wales, Div of Chronic Disease Prevention and Adult Health; SB Bonam, MS, Div of Nutrition, New York State Dept of Health. Div of Health Examination Statistics, National Center for Health Statistics; Div of Nutrition and Physical Activity, National Center for Chronic Disease Prevention and Health Promotion, CDC.

Editorial Note

Editorial Note: The high prevalence of overweight among children has been well documented in national surveys conducted since 1976. However, the national surveys do not provide information at the state and local levels for planning community interventions. This study was designed to capture such information in a geographically defined area within New York state for use in local health planning activities. The grades were specifically chosen to plan interventions targeted to mid-elementary and early middle-school children.

The findings suggest that children in NYC are substantially more overweight than children of comparable age in the United States. The prevalence of overweight among children aged 6-11 years in the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994, was 13.7%: 14.7% and 12.5% for boys and girls, respectively (4). However, the findings from the study in NYC should be compared with the national survey findings with caution. This NYC study relied on a small sample size that limits the ability to compare groups within the study population and to national surveys. In addition, the racial/ethnic composition of children in NYC is different from that of children nationally.

The higher prevalence of overweight among non-Hispanic black children in this study is probably related to environmental factors, including differences in diet and physical activity. Compared with non-Hispanic white sixth-graders, non-Hispanic black sixth-graders on average reported consuming approximately 200 more calories and more servings of less nutritious snack foods per day. Non-Hispanic black sixth-graders also reported lower levels of physical activity compared with non-Hispanic whites, particularly girls. Socioeconomic factors also may influence differences in diet and physical activity among non-Hispanic blacks compared with other children. Further analysis to better understand the racial/ethnic differences in diet and physical activity for this study population is being conducted.

The findings of this study are subject to at least three limitations. First, the health profile of students in schools not willing to participate may differ from that of schools that participated. However, every effort was made to randomize the selection and to obtain a representative sample of schools by socioeconomic status, racial/ethnic composition, and geographic location. Second, biases may occur because of the parents' or guardians' unwillingness to provide informed consent for their child's participation in the study. Third, the small sample size reduces the precision of these findings.

The reported mean daily energy consumption in this study is comparable to the 1897 calories reported for children aged 6-11 years in NHANES III (7). The small difference in reported mean daily intake between third- and sixth-grade NYC children observed in this study may be, in part, due to the dietary assessment methodology used. For example, younger children may have difficulty recalling foods consumed or estimating the amount consumed using two-dimensional food models.

The substantial prevalence of overweight observed in this study increases the likelihood that NYC children will suffer the morbidity and health costs associated with chronic disease later in life. Overweight ultimately results from an excess intake of calories relative to energy expenditure. Because excessive caloric restriction may be detrimental to children going through a phase of rapid growth and development, the emphasis should be placed on increasing energy expenditure through physical activity, while maintaining balanced caloric intake and improving eating habits, to achieve health promotion and disease prevention goals.

Culturally sensitive prevention efforts targeted to diverse urban populations at an early age will be needed to reduce health-care costs and the morbidity and mortality associated with overweight during adolescence and adulthood. The New York State Department of Health has identified overweight as a public health priority in its report, Communities Working Together for a Healthier New York: Opportunities to Improve the Health of New Yorkers. This includes a goal to reduce the prevalence of overweight to no more than 15% among school children by the year 2006. To achieve this goal, the New York State Department of Health is implementing a program-based intervention, "Eat Well Play Hard," through the Special Supplemental Nutrition Program for Women, Infants, and Children, the Child and Adult Care Food Program, and the state's Hunger Prevention and Nutrition Assistance Program. The intervention targets selected dietary behaviors and increasing physical activity beginning in the preschool period. The "Eat Well Play Hard" intervention is guided by an expert advisory panel with representation from major hospitals and academic institutions in NYC. Because these programs deliver most of their services to NYC residents, "Eat Well Play Hard" is designed to have a substantial impact on groups at highest risk for overweight in that part of the state. In addition, the state's Healthy Heart Program is providing nutrition services through four school-based health clinics in NYC. These provide nutrition counseling to overweight students and work with cafeteria and teachers to improve the nutrition environment in the schools. Healthy Heart also funds coalitions in NYC to increase opportunities for physical activity and improved nutrition, one of which is targeting these services to teenagers.

References

1. Dietz WH Jr. Obesity in infants, children, and adolescents in the United States. I. Identification, natural history, and aftereffects. Nutrition Research 1981;1:117-37.

2. Gortmaker SL, Dietz WH Jr, Sobol AM, Wehler CA. Increasing pediatric obesity in the United States. Am J Dis Child 1987;141:535-40.

3. Troiano RP, Flegal KM, Kuczmarski RJ, Campbell SM, Johnson CL. Overweight prevalence and trends for children and adolescents: the National Health and Nutrition Examination surveys, 1963 to 1991. Arch Pediatr Adolesc Med 1995;149:1085-91.

4. CDC. Update: prevalence of overweight among children, adolescents, and adults -- United States, 1988-1994. MMWR 1997;46:199-202.

5. Lohman TG, Roche AF, Martorell R, eds. Anthropometric standardization reference manual. Champaign, Illinois: Human Kinetics Publishers, 1988.

6. Shah BV, Barnwell BG, Hunt PN, Nileen P, LaVange LM. SUDAAN user's manual. Release 5.50. Research Triangle Park, North Carolina: Research Triangle Institute, 1991.

7. McDowell MA, Briefel RR, Alaimo K, et al. Energy and macronutrient intakes of persons ages 2 months and over in the United States: Third National Health and Nutrition Examination Survey, Phase 1, 1988-91. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, National Center for Health Statistics, 1994. (Advance data no. 255).

TABLE 1. Prevalence of overweight,* by grade, sex, and race/ethnicity+ -- New York
City, 1996
==================================================================================================
Characteristic          No.    (%)       (95% CI&)
-----------------------------------------------------
Third grade
 Sex
  Boys                  131   (21.7)   (13.5%-29.9%)
  Girls                 176   (18.2)   (11.5%-24.9%)
 Race/Ethnicity
  Non-Hispanic white     67   (15.3)   ( 6.3%-24.3%)
  Non-Hispanic black    107   (24.9)   (14.7%-35.1%)
  Hispanic              101   (21.1)   (11.7%-30.5%)

 Total                  307   (19.7)   (14.6%-24.8%)

Sixth grade
 Sex
  Boys                  131   (22.7)   (13.3%-32.1%)
  Girls                 206   (20.1)   (12.5%-27.7%)
 Race/Ethnicity
  Non-Hispanic white     76   (18.7)   ( 6.7%-30.7%)
  Non-Hispanic black    106   (22.2)   (11.4%-33.0%)
  Hispanic              105   (19.7)   ( 9.5%-29.7%)

 Total                  337   (21.2)   (15.1%-27.3%)
-----------------------------------------------------
* Body mass index (BMI) (kg/m 2 ) at or above sex- and age-specific 95th BMI percentile calculated
  at 1-year age intervals, derived from the second and third National Health and Nutrition
  Examination surveys.
+ Numbers for racial/ethnic groups other than non-Hispanic white, non-Hispanic black, and
  Hispanic were too small for meaningful analysis. As a result, the numbers to not equal to the
  total.
& Confidence interval.
==================================================================================================

Disclaimer   All MMWR HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices.

Page converted: 01/11/99

HOME  |  ABOUT MMWR  |  MMWR SEARCH  |  DOWNLOADS  |  RSS |  CONTACT POLICY  |  DISCLAIMER  |  ACCESSIBILITY

Morbidity and Mortality Weekly Report Centers for Disease Control and Prevention 1600 Clifton Rd, MailStop E-90, Atlanta, GA 30333, U.S.A Department of Health and Human Services

This page last reviewed 5/2/01