Body Mass Index (BMI) Measurement in Schools

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Overview

There are two types of BMI measurement programs and each serves a specific purpose.

  1. Surveillance: To identify the percent of students in the school or school district who are underweight, healthy weight, overweight or obese. These data are typically anonymous and can be used to identify trends over time or monitor the outcomes of a school policy or practice aimed to improve student health. This is not to inform parents of their child’s weight status.
  2. Screening: To provide parents with information on whether their child is underweight, healthy weight, overweight or obese.

CDC does not make a recommendation for or against BMI measurement programs in schools.1 However, it does recommend that a school have the following in place before it launches a BMI measurement program:

  • A safe and supportive environment for students of all body sizes.
  • A comprehensive set of strategies to prevent and reduce obesity. The CDC’s School Health Guidelines to Promote Healthy Eating and Physical Activity can serve as the foundation for developing, implementing, and evaluating school-based healthy eating and physical activity policies and practices for students.
  • A series of safeguards that address the primary concerns raised about such programs.

Key Resources

Body Mass Index Measurement in Schools (Article) [PDF - 239KB]

This article describes the purpose of school-based BMI measurement programs, summarizes the research, and recommends safeguards for schools choosing to engage in this practice.

BMI Measurement in Schools Executive Summary [PDF - 2 MB]BMI Executive Summary Cover

This executive summary covers key points from the research article. 

What evidence is available on the effectiveness of school BMI measurement programs?

To date, there is not enough evidence for scientists to conclude whether school-based BMI measurement programs are effective at preventing or reducing childhood obesity or whether they cause harm, by either increasing the stigma attached to obesity or increasing pressures to engage in unsafe weight control behaviors 1-3 To minimize the risk for potential negative consequences, screening programs should follow safeguards. 1-3

Many-researchers and public health professionals believe that efforts to measure BMI in schools have potential benefits and should be studied more closely because

  • Obesity is highly prevalent and has a significant impact on health.4
  • BMI is an acceptable measure of weight status.5
  • Many school districts already require health screenings for other conditions.6
  • The majority of school-aged youth in the US are enrolled in schools.7

Before implementing these programs, decision makers need to consider the costs involved, potential negative consequences for students, and existing school-based strategies to support healthy weight-related behaviors and prevent weight-based bullying.

Safeguards

Safeguards are an essential part of a BMI measurement program. They help to ensure respect for student privacy and confidentiality, protect students from potential harm, and increase the likelihood that the program will have a positive impact on promoting a healthy weight. Safeguards 1–8 are relevant to both screening and surveillance programs. In schools that screen students’ BMI, additional safeguards (Safeguards 9 and 10) are needed to ensure that parents have what they need to make informed decisions and take follow-up actions.

All of the safeguards are from the same source: Nihiser AJ, Lee SM, Wechsler H, McKenna M, Odom E, Reinold C, Thompson D, Grummer-Strawn L. Body Mass Index Measurement in Schools. Journal of School Health. 2007; 77:651–671.

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