Overweight Among Students in Grades K--12 --- Arkansas, 2003--04 and 2004--05 School Years
Prevalence of overweight among children nearly doubled from 1976--1980 to 1999--2002 in the United States (1). During 1999--2002, approximately 65% of adults aged >20 years were overweight or obese, according to the National Health and Nutrition Examination Survey (NHANES) (1). Among persons aged 6--19 years during the same period, 31% were overweight or at risk for overweight (1). In 2003, the Youth Risk Behavior Surveillance (YRBS) survey indicated that 27% of high school students were overweight or at risk for overweight (2). Among adolescents with a body mass index (BMI) at or above the 95th percentile, approximately 50% will become obese adults (3), and 70% will become obese or overweight adults (4). Although NHANES and YRBS provide population-based, cross-sectional state and national samples, no studies reflect a national or statewide longitudinal cohort assessment of childhood and adolescent obesity. The American Academy of Pediatrics (AAP) (5) and the Institute of Medicine (6) recommend annual assessments of BMI as a strategy for preventing and combating childhood obesity. In 2003, Arkansas implemented a multifaceted statewide initiative to reduce and prevent overweight among children. A key aspect of this initiative (Act 1220*) is the mandated annual statewide BMI assessments of all Arkansas public school students with confidential reporting of results to parents. This report describes the results of this large-scale population screening, which indicated that, during the 2003--04 and 2004--05 school years, 38% of Arkansas students were overweight or at risk for overweight. This finding suggests a more severe problem than that reported for other states. Because rates of childhood and adolescent obesity in certain areas might be higher than anticipated, health policy decisions that address health outcomes and cost of care should be based on state-specific, population-based data.
Demographic data on public school students were provided to the Arkansas Center for Health Improvement (ACHI) by the Arkansas Department of Education (ADE). Schools conducted height and weight assessments during the academic year with standardized instruments (e.g., Tanita HD 314 digital scales and 7-foot board-mounted metal stadiometers) and measurement protocols developed by ACHI that ensured accuracy and maintained confidentiality. Schools reported individual students' height and weight on standardized assessment forms prepopulated by ACHI with a unique student identifier, grade, birth date, sex, race/ethnicity, and name. If a student could not be assessed, the reason for nonassessment was noted. Assessment forms were sent to ACHI for data entry, and BMI was calculated as weight in pounds/height in inches squared × 703. On the basis of sex- and age-specific classifications for BMI percentiles, students were categorized as underweight (BMI <5th percentile), normal weight (BMI 5th percentile to <85th percentile), at risk for overweight (BMI 85th percentile to <95th percentile), or overweight (BMI >95th percentile) (7). Results of the BMI assessments of public school students during 2003--04 (Year 1) were sent in summer 2004 as confidential child health reports to parents along with information on the health risks associated with overweight and AAP recommendations for action. Distribution of 2004--05 (Year 2) reports to parents was the responsibility of individual schools; ACHI is evaluating how and when schools accomplished this required reporting.
After schools performed BMI measurements, data forms were submitted for 94% (423,263 of 449,485) of public school students (grades K--12) in Year 1 and 97% (440,572 of 454,464) in Year 2. Of the 423,263 data forms submitted in Year 1, approximately 82% had valid data for analyses, 1% had invalid data, and the remaining 17% were for students who were not assessed for BMI. Of the 440,572 data forms submitted in Year 2, approximately 84% had valid data for analysis, 1% had invalid data, and the remaining 16% were for students who were not assessed. The most common reason that students were not assessed for BMI was absence from school (6% in Year 1; 8% in Year 2). Parent or student refusal accounted for <6% of nonassessments in both years; other reasons, accounting for up to 5% of nonassessments, included a disability that prohibited measurement, student pregnancy, student was not attending that school, or "other" reason.
On the basis of assessments resulting in valid BMIs for 347,250 students in Year 1 and 367,879 in Year 2, nearly 21% of students were classified as overweight, 17% as at risk for overweight, 60% as normal weight, and 2% as underweight in both years. Prevalence of overweight and at risk for overweight was calculated by sex, three grade groups (K--4, 5--8, and 9--12), and race/ethnicity (Table). Among the students with valid BMI assessments, 332,288 in Year 1 and 364,173 in Year 2 had data that included sex, grade, and race/ethnicity. When examined by grade level, the highest prevalence for females was among 6th-grade blacks (49% in Year 1; 50% in Year 2); among males, the highest prevalence was among 4th-grade Hispanics (59%) in Year 1 and 5th-grade Hispanics (58%) in Year 2.
Males consistently had a slightly higher prevalence of overweight and at risk for overweight than females. The differences in prevalence across grades were similar for males and females during the elementary and early middle-school years, with rates highest during the 6th grade. During the high-school years, however, prevalence for females was 32%--33%, and prevalence for males was 37% by the 12th grade.
When analyzed by sex and grade or by sex, grade, and race/ethnicity, data were similar for subgroups each year. More Hispanic males were overweight in grades K--11 than males of other racial/ethnic populations (Figure). Among females, the prevalence of students overweight and at risk for overweight was similar among blacks and Hispanics. Percentages for these two populations were higher than for whites or those of other race in grades K--12. After the 5th grade, the prevalence for black females tended to stay constant, whereas the prevalence among Hispanic females began to decrease.
Reported by: J Thompson, MD, J Shaw, MPH, P Card-Higginson, R Kahn, MD, Arkansas Center for Health Improvement, Little Rock, Arkansas.
The impact of obesity on society through increased morbidity, mortality, and cost of medical care has been well documented (4--6). Among children and adolescents, overweight or obesity is linked to emotional and social problems and to serious medical conditions, such as type 2 diabetes, hypertension, dyslipidemia, and depression (6).
The goals of Act 1220 in Arkansas are to 1) change the environment in which children go to school and learn health habits every day, 2) engage the community to support parents and build a system that encourages health, and 3) mobilize resources and establish support structures through enhanced awareness of childhood and adolescent obesity (8). Specific requirements of the legislation include 1) elimination of all vending machines in public elementary schools, 2) professional education on nutrition for all cafeteria workers, 3) public disclosure of "pouring contracts" (i.e., contracts between schools and soft drink bottlers reflecting compensation for exclusive rights to sell products on school grounds), 4) creation of school nutrition and physical activity advisory committees in all school districts, 5) formation of a statewide Child Health Advisory Committee (CHAC), and 6) annual statewide assessment and reporting to parents of BMI for all public school students. In this first statewide assessment of overweight in children and adolescents, Arkansas has documented substantially higher proportions of overweight and at risk for overweight children and adolescents than those described in previous national reports (1,2).
In both assessment years, the percentage of childhood and adolescent overweight and at risk for overweight (38%) in Arkansas was approximately 23% higher than that reported in 2002 by NHANES (31%) (1) and 38--39% higher than that reported in 2003 national YRBS results for high school students (27%) (2). These differences might reflect differences between Arkansas and the nation as a whole, sampling variation for NHANES and YRBS, or a continued progression of the epidemic of childhood obesity. The NHANES estimates are from a nationwide sample of children assessed during 1999--2002; the Arkansas results are from serial assessments during school years 2003--04 and 2004--05. Results from the self-reported 2003 YRBS data reveal lower prevalence rates than either NHANES or the Arkansas study, which used actual height and weight measurements to calculate BMI.
The findings in this report are subject to at least two limitations. First, this study reflects the classification of Arkansas public school students by BMI percentile. Although nearly 93% of Arkansas children attend public schools, differences between public- and private/home-schooled students (e.g., socioeconomic or other demographic characteristics) might exist that could be linked to likelihood of obesity. Second, missing data for those students who were absent from school or opted out of the measurement present a potential bias in results, although both of these groups accounted for less than 12%--14% of nonassessments in the years reported. Regardless of these limitations, the consistency in the data for Year 1 and Year 2 indicate that a substantial proportion of Arkansas youth are overweight.
In addition to the statewide BMI assessments, state legislation also required community- and school-based actions described in this report. CHAC, formed in 2003, was charged with developing school nutrition and physical activity standards and recommending policies to the Arkansas Board of Education (ABE) and Board of Health. Evidence-based and "best practice" recommendations made to ABE covered foods sold in cafeterias, access to and offering of competitive foods (non-USDA school lunch program foods), professional development for food service staff, physical education (PE) staff qualifications, and PE/physical activity requirements for students. In September 2005, ABE adopted rules closely matching CHAC recommendations, which will further enhance school and state efforts to prevent and combat childhood obesity (9). Additional support for obesity-prevention and treatment activities is provided by the Arkansas Academy of Pediatrics, the Arkansas Academy of Family Physicians, and the Arkansas Medical Society, which have cooperated in continuing education programs, journal publications, and mailings of guidelines on managing pediatric overweight.
Ongoing data collection for the 2005--06 school year (Year 3) will enable Arkansas to create a large-scale longitudinal dataset examining childhood and adolescent obesity. Annual evaluations of Act 1220 activities are being conducted (10). Reports on the prevalence of students who are overweight and at risk for overweight at the school and district level might enable communities to correlate changes in prevalence with community-based or statewide interventions (8). In addition, by measuring all students, individual reporting can inform parents of their children's potential health risks.
The findings in this report are based, in part, on contributions by the American Diabetes Association; the Robert Wood Johnson Foundation; the Arkansas Center for Health Improvement; and the Division of Health, Arkansas Department of Health and Human Services.
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Date last reviewed: 1/12/2006