Topic: Methods & Modeling

State-Specific Prevalence of Severe Obesity Among Adults in the United States Using Bias Correction of Self-Reported Body Mass Index

This study examines severe obesity prevalence among US adults by sociodemographic characteristics and by state after adjusting for self-report bias. 

Zhao L, Park S, Ward ZJ, Cradock AL, Gortmaker SL, Blanck HM. State-Specific Prevalence of Severe Obesity Among Adults in the US Using Bias Correction of Self-Reported Body Mass Index. Prev Chronic Dis. 2023 Jul;20. doi:10.5888/pcd20.230005

Abstract

Introduction

Adults with severe obesity are at increased risk for poor metabolic health and may need more intensive clinical and community supports. The prevalence of severe obesity is underestimated from self-reported weight and height data. We examined severe obesity prevalence among US adults by sociodemographic characteristics and by state after adjusting for self-report bias.

Methods

Using a validated bias-correction method, we adjusted self-reported body mass index (BMI) data from the 2020 Behavioral Risk Factor Surveillance System (BRFSS) by using measured data from the National Health and Nutrition Examination Survey. We compared bias-corrected prevalence of severe obesity (BMI ≥40) with self-reported estimates by sociodemographic characteristics and state.

Results

Self-reported BRFSS data significantly underestimated the prevalence of severe obesity compared with bias-corrected estimates. In 2020, 8.8% of adults had severe obesity based on the bias-corrected estimates, whereas 5.3% of adults had severe obesity based on self-reported data. Women had a significantly higher prevalence of bias-corrected severe obesity (11.1%) than men (6.5%). State-level prevalence of bias-corrected severe obesity ranged from 5.5% (Massachusetts) to 13.2% (West Virginia). Based on bias-corrected estimates, 16 states had a prevalence of severe obesity greater than 10%, a level not seen in the self-reported estimates.

Conclusion

Self-reported BRFSS data underestimated the overall prevalence of severe obesity by 40% (5.3% vs 8.8%). Accurate state-level estimates of severe obesity can help public health and health care decision makers prioritize and plan to implement effective prevention and treatment strategies for people who are at high risk for poor metabolic health.


Funding

The work of Drs Ward, Cradock, and Gortmaker was supported in part by grants from The JPB Foundation, the National Institutes of Health (R01HL146625), and CDC (U48DP006376). The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of CDC or other funders. No copyrighted materials were used in this research.

The Societal Costs and Health Impacts on Obesity of BMI Report Cards in US Schools

This study aims to estimate the 10-year cost-effectiveness of school-based BMI report cards, a commonly implemented program for childhood obesity prevention in the US.

Poole MK, Gortmaker SL, Barrett JL, McCulloch SM, Rimm EB, Emmons KM, Ward ZJ, Kenney EL. The Societal Costs and Health Impacts on Obesity of BMI Report Cards in US Schools. Obesity (Silver Spring). 2023 Aug;31(8):2110-2118. doi: 10.1002/oby.23788. Epub 2023 Jul 3.

Abstract

Objective: This study aimed to estimate the 10-year cost-effectiveness of school-based BMI report cards, a commonly implemented program for childhood obesity prevention in the US where student BMI is reported to parents/guardians by letter with nutrition and physical activity resources, for students in grades 3 to 7.

Methods: A microsimulation model, using data inputs from evidence reviews on health impacts and costs, estimated: how many students would be reached if the 15 states currently measuring student BMI (but not reporting to parents/guardians) implemented BMI report cards from 2023 to 2032; how many cases of childhood obesity would be prevented; expected changes in childhood obesity prevalence; and costs to society.

Results: BMI report cards were projected to reach 8.3 million children with overweight or obesity (95% uncertainty interval [UI]: 7.7-8.9 million) but were not projected to prevent any cases of childhood obesity or significantly decrease childhood obesity prevalence. Ten-year costs totaled $210 million (95% UI: $30.5-$408 million) or $3.33 per child per year with overweight or obesity (95% UI: $3.11-$3.68).

Conclusions: School-based BMI report cards are not cost-effective childhood obesity interventions. Deimplementation should be considered to free up resources for implementing effective programs.


Funding

The JPB Foundation; National Cancer Institute, Grant/Award Number: 3P50CA244433; National Institute of Diabetes and Digestive and Kidney Diseases, Grant/Award Number:DK 007703-22; Robert Wood Johnson Foundation, Grant/Award Number: 2833590; National Heart, Lung, and Blood Institute, Grant/Award Number: 1F31HL162250-01A1.

Use of Evidence-Based Interventions to Promote Healthy Weight, Nutrition, and Physical Activity in Community Health Improvement Plans from Large Local Health Departments

This study identifies evidence-based healthy weight, nutrition, and physical activity strategies related to obesity prevention in large local health department Community Health Improvement Plans.

Dupuis R, Reiner JF, Silver S, Barrett JL, Daly JG, Lee RM, Gortmaker SL, Cradock AL. Use of Evidence-Based Interventions to Promote Healthy Weight, Nutrition, and Physical Activity in Community Health Improvement Plans from Large Local Health Departments. J Public Health Manag Pract. 2023 Sep-Oct 01;29(5):640-645. doi: 10.1097/PHH.0000000000001778. Epub 2023 Jun 20.

Abstract

We sought to identify evidence-based healthy weight, nutrition, and physical activity strategies related to obesity prevention in large local health department (LHD) Community Health Improvement Plans (CHIPs). We analyzed the content of the most recent, publicly available plans from 72 accredited LHDs serving a population of at least 500 000 people. We matched CHIP strategies to the County Health Rankings and Roadmaps’ What Works for Health (WWFH) database of interventions. We identified 739 strategies across 55 plans, 62.5% of which matched a “WWFH intervention” rated for effectiveness on diet and exercise outcomes. Among the 20 most commonly identified WWFH interventions in CHIPs, 10 had the highest evidence for effectiveness while 4 were rated as likely to decrease health disparities according to WWFH. Future prioritization of strategies by health agencies could focus on strategies with the strongest evidence for promoting healthy weight, nutrition, and physical activity outcomes and reducing health disparities.


Funding

This study was supported by The JPB Foundation and the Centers for Disease Control and Prevention (U48DP001946 and U48DP006376). The findings and conclusions are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or The JPB Foundation.

Study Design Decision Tree

This decision tree can be used when reviewing evidence to determine the type of study design used and evaluate the quality of the evidence.

Excess mortality associated with elevated body weight in the USA by state and demographic subgroup: A modelling study

A CHOICES study estimates excess mortality associated with elevated body weight nationally and by US state and subgroup.

Ward ZJ, Willett WC, Hu FB, Pacheco LS, Long MW, Gortmaker SL. Excess mortality associated with elevated body weight in the USA by state and demographic subgroup: A modelling study. eClinicalMedicine. 2022 Apr;48. doi:10.1016/j.eclinm.2022.101429

The obesity epidemic in the U.S. continues to grow. Excess weight-related mortality has been estimated for the general population, however, less is known about how it varies by state and demographic subgroup within the U.S. Estimating the health consequences of obesity can improve understanding of the implications of the obesity epidemic, as excess weight is associated with increased incidence and mortality of many health conditions.

Although no comprehensive data on this topic exist in any one study or dataset, mathematical modelling is an approach that can analyze information from multiple sources and make estimates for relevant outcomes of interest. This study estimated state-level trends in excess deaths and life expectancy loss due to excess weight between 1999 and 2016 by population subgroup using a microsimulation model.

The researchers developed a computational approach to stimulate a nationally representative virtual population of U.S. adults, estimating annual all-cause mortality rates for each person according to their demographic characteristics, body mass index (BMI), and smoking history.

Using this microsimulation model, the team found that excess weight was responsible for more than:

  • 1,300 excess deaths per day (nearly 500,000 per year)
  • Loss in life expectancy of nearly 2.4 years in 2016

Relative excess mortality rates were nearly twice as high for women compared to men in 2016 and were higher for Black non-Hispanic adults. By state, overall excess weight-related life expectancy loss ranged from 1.75 years in Colorado to 3.18 years in Mississippi.

Excess weight has significant impacts on mortality in the U.S. with large disparities by state and subgroup. As the obesity epidemic continues to grow, premature mortality due to excess weight is likely to rise. This highlights the need for cost-effective interventions to promote healthy weight across the life course.

“Overall, we found that excess weight contributed to more than 1,300 excess deaths per day (nearly 500,000 per year) in the USA in 2016, increasing the total mortality rate by nearly 18% and resulting in nearly 2.4 years of life expectancy loss. On the basis of these findings, it is vital to invest in cost-effective policies and programs that can make a difference.” – Zach Ward, lead author.


Funding

The JPB Foundation, NIH, CDC

 

Intro to Economic Evaluation: How the CHOICES Framework Can Advance Chronic Disease Prevention & Address Health Equity

This is a recording of a training led by Dr. Michael Long and Dr. Stephen Resch. This introductory training looks at how economic evaluation and cost-effectiveness analysis can advance chronic disease prevention and health equity. This training is intended for anyone working in public health with an interest in learning about the key concepts of cost-effectiveness analysis to advance their work.

View the slides from this training.

Reducing risk of childhood obesity in the wake of COVID-19

Kids eating healthy food at lunch time

A study shows that the COVID-19 pandemic has worsened the risk factors for the development and progression of childhood obesity.

Chung A, Tully L, Czernin S, Thompson R, Mansoor A, Gortmaker S. Reducing risk of childhood obesity in the wake of covid-19. The BMJ. 2021;374:n1716. doi:10.1136/bmj.n1716

Key Takeaways: 1. The public health response to covid-19 has exacerbated risk factors for the development and progression of childhood obesity; 2. An opportunity exists to leverage the global attention brought about by covid-19 for public health action to improve population health; 3. Action to reduce childhood obesity must be equitable, evidence based, and government led; 4. Priorities include promotion of healthy school food and physical activity environments, reducing exposure to unhealthy food marketing, and taxation of sugar-sweetened beveragesAn international team of researchers has found that the swift and necessary public health response to the COVID-19 pandemic has had detrimental consequences for the prevention and management of childhood obesity. As societies build back from the pandemic, they recommend a focus on reducing childhood obesity risk factors through equitable, evidence-based, and government led action.

Priorities for action in reducing this risk and improving population health and health equity include promoting healthy school food and physical activity environments, reducing children’s exposure to unhealthy food marketing, and imposing taxes on sugar-sweetened beverages. These actions are proven to be successful, cost-effective, can improve health equity, and comprise a comprehensive approach to preventing childhood obesity.

During the pandemic, schools were closed for long periods of time and as a result, many children learned from home, which reduced opportunities for physical activity. School closures also reduced the availability of nutritious foods for children who rely on school meals.

The COVID-19 pandemic has also increased reliance on digital platforms for children’s learning and communication and in turn increased exposure to unhealthy food and beverage marketing, which can impair their dietary choices and consumption. The study team found that there is a need to restrict and regulate marketing of unhealthy food and beverages.

Many households were increasingly reliant on low-cost foods that are calorie dense and processed, due to the economic effects of the pandemic. The study team found that a tax on sugar-sweetened beverages is an effective public health intervention that can reduce consumption of sugar-sweetened beverages and can reduce obesity.

The researchers conclude that governments must focus on childhood obesity risk factors that were increased by the COVID-19 pandemic and take public health action to promote population health and health equity.


Watch a video summary of this paper

Limiting Television to Reduce Childhood Obesity: Cost-Effectiveness of Five Population Strategies

A CHOICES study finds that strategies to reduce television exposure could help reduce childhood obesity at a relatively low cost.

Kenney EL, Mozaffarian RS, Long MW, Barrett JL, Cradock AL, Giles CM, Ward ZJ, Gortmaker SL. Limiting Television to Reduce Childhood Obesity: Cost-Effectiveness of Five Population Strategies. Child Obes. 2021 May 10. doi: 10.1089/chi.2021.0016. Epub ahead of print. PMID: 33970695.

The study’s research team, led by Erica Kenney, found that strategies to reduce television exposure could help reduce childhood obesity on a population level. Television watching is one of the strongest risk factors for childhood obesity as children are highly influenced by television advertising and are exposed to many advertisements for unhealthy foods and beverages.

After systematically searching for evidence for intervention strategies that could be effective for reducing children’s TV viewing or advertising exposure if implemented at a population level, the study team used the CHOICES microsimulation model to estimate the cost, population reach, and impact on childhood obesity over 10 years (from 2020-2030) of five potential policy strategies. These strategies included: (1) eliminating the tax deductibility of food and beverage advertising; (2) targeting TV reduction during home visiting programs; (3) motivational interviewing to reduce home television time at Women, Infants, and Children (WIC) clinic visits; (4) adoption of a television-reduction curriculum in child care; and (5) limiting noneducational television in licensed child care settings.

They found that, of the five potential strategies, eliminating the tax benefit to companies of advertising unhealthy foods and beverages to children would reach the most children, prevent the most cases of obesity, and save more in future health care costs than it costs to implement. In addition, incorporating counseling to reduce TV viewing into the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) and requiring licensed childcare settings to limit noneducational television were also noted as low-cost, practical intervention strategies. However, these strategies would be limited to young children in those specific settings.

The researchers concluded that strategies to limit television exposure across a range of settings could help contribute to other efforts to prevent childhood obesity in the population at a low cost. Policymakers and public health providers should consider using these kinds of strategies as part of a larger obesity prevention toolkit.

“Policy intervention strategies to reduce exposure to noneducational television time can reduce obesity risk, yet they aren’t widely implemented. This cost-effectiveness modeling study suggests that over 10 years, implementing such strategies could help improve population health at a high value.” – lead author, Erica Kenney

Association of body mass index with health care expenditures in the U.S. by age and sex

Obesity & severe obesity lead to higher annual medical costs. Adults with obesity incur an extra $1861 in annual medical costs per person, and adults with severe obesity incur an extra $3097 annual medical costs per person. Children with obesity incur an extra $116 in annual medical costs per person, and children with severe obesity incur an extra $310 in annual medical costs per person. $170 billion is the total amount spent in the U.S. each year on medical costs due to adult obesity. Policies to promote healthy weight at all ages are needed to both promote health and help reduce excess medical costs related to obesity and severe obesity in the U.S.

A CHOICES study shows that excess body weight is associated with higher health care costs for people across a wide range of body-mass-index (BMI) levels in the U.S.

Ward ZJ, Bleich SN, Long MW, Gortmaker SL. Association of body mass index with health care expenditures in the United States by age and sex. PLoS ONE. 2021 Mar;16(3): e0247307. doi10.1371/journal.pone.0247307.

To address gaps in the literature, the study’s research team, led by Zach Ward, examined the association of weight with health care costs across the entire body mass index (BMI) distribution by age and sex.

The researchers used data for BMI-related health care costs from the Medical Expenditure Panel Survey (MEPS) 2011-2016 for 175,726 participants and adjusted total costs to $US 2019. To correct for self-report bias (which often leads to underestimates of obesity prevalence), the team also adjusted reported BMI data from the MEPS.

The team found that higher health care costs are associated with excess body weight across a broad range of ages and BMI levels, and were especially high for people with severe obesity. In general, the researchers found that among adults, obesity is associated with over $1,800 in extra annual medical costs per person, which accounts for over $170 billion of annual spending in the U.S. This figure rises to over $200 billion if excess costs from overweight (over $600 per person) are included. It was also found that, among children, obesity is associated with over $100 in extra annual medical costs per person, and over $1 billion of excess medical costs in the U.S.

These findings highlight the large economic impact of overweight and obesity in the U.S. and the importance of promoting healthy weight across all BMI levels. These data will provide policymakers and health care providers with better estimates of the health care cost impacts of excess weight.

“Although extra annual medical costs associated with children with obesity are a relatively small contributor to overall excess medical spending (less than 1% of all obesity-related medical expenditures), promoting healthy child weight may help to avert future health care costs, since excess body weight during childhood is a strong predictor of excess weight during adulthood.” – lead author, Zach Ward

The CHOICES Model

Zach Ward describes how the CHOICES microsimulation model is used to look at the future and potential impact of a strategy, and how CHOICES modifies the model to fit a local context.