Pediatric obesity remains an important public health concern (1-3). School-based body mass index (BMI) screening has been recommended to address pediatric obesity (4), and recent reports suggest that approximately 25% of states require BMI measurement in schools (5,6). States may also be screening for BMI or, more generally, body composition through comprehensive fitness assessments. Many national fitness assessments include a measure of body composition such as BMI or skinfold measurements to assess students' weight-related cardiovascular risk (7-9). The Institute of Medicine suggests that body composition screenings can increase parents' awareness of their child's weight-related risks, which may lead to lifestyle changes and improvements in pediatric obesity (4).

Although recent reports have identified states that require BMI screening (5,6), data are not available on states that recommend BMI screening or require BMI screening as part of a comprehensive fitness assessment. Thus, existing reports on BMI and fitness screening likely underestimate the extent of and number of students exposed to such screening. Further, not all fitness assessments include a measure of body composition, and available reports do not indicate which states' fitness assessments include BMI or body composition. To explore the effect of school-based BMI and body composition screening on obesity, it would be useful to identify states that require or recommend such screening, either alone or through comprehensive fitness assessments, and to determine whether obesity prevalence at the state level is associated with screening practices. Knowing states' varying policies related to BMI and body composition assessment would also support comparisons of the effects of different screening approaches. In this study, we sought to present a comprehensive picture of state requirements and recommendations for BMI and body composition screening and to determine whether pediatric obesity prevalence is associated with state screening policies.

Telephone interviews revealed that 20 (40%) states require BMI or body composition screenings; 13 states require BMI screening, and 7 states require a complete fitness assessment that includes BMI or body composition (Table 1). Of these 20 states, 4 require and 3 recommend use of Fitnessgram; no other assessment tools were mentioned. Alabama required the President's Challenge through the 2009-2010 school year; a new state-developed assessment tool that includes BMI was piloted during 2010-2011 and will be implemented beginning in 2011-2012. Nine of the 20 states requiring BMI or body composition screening also require parent notification (Table 1), and all states require assessments at least annually. In 2 states, contacts did not report that BMI screening was required or recommended, but the Shape of the Nation report suggested that BMI screening was required. Telephone calls with the contact in the Shape of the Nation report (which was the initial telephone interviewee in 1 case) revealed that in both states, height and weight assessments were required but BMI was not calculated (Table 1). Three additional states (Delaware, Missouri, and Virginia) require complete fitness assessments but have opted to make body composition measurement optional.

Among states not requiring screening, New Hampshire recommends BMI screening and Hawaii recommends the use of a fitness assessment that includes body composition. The PE content standards of an additional 7 states promote use of a fitness assessment that includes body composition. Hawaii and the additional 7 states that include body composition in their content standards all suggest use of Fitnessgram, 2 also suggest use of Brockport, and 1 suggests use of APEAS as an option (Table 2).

Compared with states without requirements, the 20 states that require BMI screening or fitness assessments with body composition were more populous (median public school enrollment 900,000 vs 500,000 students, P = .007) and were 3.1 percentage points higher in adolescent obesity (16.7% vs 13.6%, P = .001), adjusting for public school enrollment. The 7 states requiring BMI as part of a fitness assessment were 4.9% percentage points higher in obesity than states that did not require assessment (P = .001), and the 13 states requiring BMI screening alone were 1.7 percentage points higher in obesity than states that did not require assessment (P = .10). States recommending BMI or fitness assessment had no greater enrollment or rates of obesity than states neither requiring nor recommending screenings.

North Carolina and Maryland neither require nor recommend screening or fitness assessment, but state contacts reported that more than 75% of school districts statewide are using a fitness assessment that includes body composition. Contacts in 3 additional states, Oklahoma, Wisconsin, and Kansas, reported that they were conducting pilot studies of Fitnessgram and planned to increase use in coming years.

The study findings suggest that relying on reports of required school-based BMI screening greatly underestimates the number of students who have BMI or body composition screened. This study extends data in the Shape of the Nation report, which neither assessed recommendations for screening nor distinguished between fitness assessments that did and did not include body composition (6). According to the Shape of the Nation report, the percentage (26%) of states that specifically required BMI screening in 2010 increased only slightly from the 22% reported in the 2006 School Health Policies and Programs Study (SHPPS) (5,6). However, we found that an additional 14% of states require comprehensive fitness assessment that includes body composition, and 18% recommend BMI or fitness assessment; neither were collected in SHPPS. Thus, we found that BMI or body composition screening, either alone or as part of a comprehensive fitness assessment, was required by 20 states, representing nearly 30 million school-aged children (14), and was recommended by another 9 states, representing almost 4 million children.

Recommendations for screening likely helped to increase BMI screenings, as data from SHPPS indicated that only 22% of states required BMI screening but more than 40% of schools enacted the practice (6). Although the SHPPS data may in part reflect that states requiring screening are more populous than other states (as our data indicate), clearly screening also occurs voluntarily. In our study, contacts from 5 states without requirements or recommendations for screening reported widespread use or pilot testing of comprehensive fitness assessments that include body composition. Additionally, screening policies may not be enforced and, even in states with required screening, actual prevalence of screening is unknown. Studies that gather data at the school level will be informative, particularly studies with questions about comprehensive fitness assessments that include BMI or body composition screening as well as BMI screening in isolation.

To our knowledge, this is the first study to examine the relationship between state policies related to body composition screening and obesity prevalence. We found that the prevalence of obesity is higher in states that require screening than in those that do not. It is possible that states with the greatest prevalence of obesity have instituted screening policies to improve the health of their children, although this cross-sectional study cannot assess causality. Reporting results to parents might help improve child health, yet only 8 states require that parents be notified of screening results. Nonetheless, it is likely that parent reporting occurs frequently even when not required. In California, where annual body composition testing is required but reporting results to parents is optional, half of school districts elect to notify parents (15).

Given that states require or recommend Fitnessgram more than other assessment tools, future evaluations of body composition screening and reporting should include Fitnessgram. Specific attention should be given to reporting methods, as results from a study in California suggest that current methods of body composition reporting do not alter pediatric obesity at the population level (15). One area for research is comparing the effectiveness of reporting BMI versus percent body fat results to parents to promote family lifestyle changes. Although the Fitnessgram specifically recommends using skinfolds to assess body composition, in the nonresearch setting, skinfolds may be less accurate than height and weight and may not be better in predicting body fat than using a BMI cutoff at or above the 95th percentile (16). Whether BMI or skinfold assessments are used, future research should also compare the effect of reporting body composition alone versus multiple results from a comprehensive fitness screening on child health. In our study, states with the highest prevalence of obesity were more likely to require the comprehensive fitness assessments than BMI screening alone. Further, to assist states in resource allocation decisions related to child health, the equipment and software required for some comprehensive fitness assessments should be considered in cost-effectiveness analyses.

The 9 states that recommend BMI screening or fitness assessment offer an opportunity for research on the frequency of such assessments in the absence of a specific policy. Studying variation in the adoption of recommendations and adherence to PE content standards among states may shed light on how to most effectively implement policies addressing pediatric obesity.

This study had several limitations. Contacts may not have provided accurate information, and information at the state level may not reflect what happens locally. Thus, estimates of screening prevalence may be too high or too low. Information on obesity prevalence came from parents' reports, which may be inaccurate and subject to bias. However, even if estimates of obesity prevalence at the state level are biased, it is difficult to determine how this would affect the demonstrated associations between obesity prevalence and screening policies.

School-based BMI and body composition screening policies are widespread. Further studies examining the effect of school-based screening practices on obesity are needed. Our study, which documents the prevalence of BMI and body composition screening across the United States, will allow those researching obesity-related policy to target states at various stages of screening implementation.