Prevalence of Overweight and Obesity in the United States, 2007-2012

Overweight and obesity are associated with various chronic conditions.’ These conditions are considerable health care and societal burdens, yet could potentially be averted by prevent­ing weight gain and obesity. In a prior analysis, now almost 20 years old, Must et ale used a nationally representative data set from 1988 through 1994 and reported the US chronic disease burden associated with body mass index (BMI), thus inform­ing clinical practice and the priorities for cost-effective pre­vention strategies. Using the most recent data in the National Health and Nutrition Examination Survey (NHANES, 2007­2012), we updated the prevalence of overweight and obesity by sex, age, and race/ethnicity and compared the values with those of the earlier study.²

Methods I The NHANES was designed to provide cross-sectional estimates of the prevalence of major diseases, nu­tritional disorders, and potential risk factors among the US population.³ We aggregated data from 2007-2008, 20 09- 2010, and 2011-2012 and included only adults who were 25 years

or older (n = 15 208), excluding those who were pregnant at the time of examination (n = 125) or provided insufficient data re­garding weight and height (n = 827). The NHANES obtained ap­proval from the National Center for Health Statistics Re­search Ethics Review Board and participants provided written consent.

Weight and height were measured during the physical ex­amination using standard procedures. Patients’ BMIs (calcu­lated as weight in kilograms divided by height in meters squared) were classified according to the following catego­ries: underweight (<18.5), normal weight (18.5-24.9), over­weight (25.0-29.9), obesity class 1 (30.0-34.9), obesity class 2 (35.0-39.9), and obesity class 3 (?.40).²

Data regarding patients’ age, sex, and race/ethnicity were collected. Age was classified as 25 to 54 years or 55 or more years. Self-reported race/ethnicity were categorized as Mexi­can American, non-Hispanic black, non-Hispanic white, or other.

We stratified the analyses by sex and calculated the weighted proportion estimates in each BMI category by race or ethnic group and age group. All statistical analyses were con­ducted in Stata, version. 12.0 (StataCorp LP), using survey analy­sis procedures to account for the complex sampling design.

Results I Of the sample population, 39.96% (weighted n = 36 325 297) of men and 29.74% (weighted n = 28 894 630) of women were overweight and 35.04% (weighted n = 31 847198) of men and 36.84% (weighted n 35 792 733) of women were obese. The weight status distribution was similar for both sexes across racial groups (Table), except for the proportion of non-Hispanic white women, which was higher in the normal-weight than the overweight category. Compared with 20 years ago, the greatest increase in the proportion of patients in the obesity class 3 category was among non-Hispanic black women.

Discussion I Compared with 1988 4994,² the distribution of the population’s weight status has increased in the past 20 years. The rising trends in overweight and obesity warrant timely at­tention from health-policy and health care-system decision makers. Clinical practice for the prevention and treatment of chronic conditions has mainly focused on screening high-risk populations. As a result, people in higher-weight catego­ries are more likely to be diagnosed with the chronic diseases associated with excess weight² because of more frequent mea­surements, compared with people in the normal-weight cat­egory. This approach may ignore individuals with normal weight and their weight gain, which puts them at risk.

Population-based strategies helping to reduce modifiable risk factors such as physical environment interventions, enhancing primary care efforts to prevent and treat obesity, and altering so­cietal norms of behavior are required.⁴ In 2012, the Institute of Medicine identified population-based obesity-prevention strat­egies that target physical activity, healthy diet, and models of healthy social norms and provided recommendations on set­ting specific implementations of those policy and environmen­tal strategies to combat ob esity.⁵ The Institute of Medicine⁶ also summarized specific key metrics to evaluate the progress of obe­sity-prevention strategies toward sustainable implementation. Delivering these strategies is a priority to counter the burden of obesity on contemporary and future generations

Author Affiliations: Department of Surgery, Division of Public Health Sciences, Siteman Cancer Center, Washington University School of Medicine, St Louis, Missouri.

Corresponding Author: Graham A. Colditz, MD, DrPH, Department of Surgery, Division of Public Health Sciences, Washington University School of Medicine, 660 5 Euclid Ave, Campus Box 8109, St Louis, MO 63110 ([email protected]).

Published Online: June 22, 2015. doi;10.1001/jamainternmed.2015.2405,

Author Contributions: Drs Colditz and Yang had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: All authors.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: All authors.

Critical revision of the manuscript for important intellectual content: Colditz. Statistical analysis: All authors.

Study supervision: Colditz.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported by grant U54 CA155496 from the Washington University School of Medicine Transdisciplinary Research on Energetics and Cancer Center (Drs Colditz and Yang), which is funded by the National Cancer Institute, National Institutes of Health, and the Siteman Cancer Center; the Foundation for Barnes-Jewish Hospital (Drs Colditz and Yang); and the Breast Cancer Research Foundation (Dr Colditz).

Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

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3. Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey. http://www.cdc.govinchsinhanes.htm. Accessed February 10, 2015.
4. Doyle YG, Furey A, Flowers J. Sick individuals and sick populations: 20 years later. J Epidemiol Community Health. 2006;60(5):396-398.
5. Committee on Accelerating Progress in Obesity Prevention, Food and Nutrition Board, Institute of Medicine. In: Glickman D, Parker L, Sim U, et al, Accelerating Progress in Obesity Prevention: Solving the Weight of the Nation. Washington, DC: National Academies Press; 2012.
6. Committee on Evaluating Progress of Obesity Prevention Effort, Food and Nutrition Board, Institute of Medicine. In: Green LW, Sim L, Breiner H, eds. Evaluating Obesity Prevention Efforts: A Plan for Measuring Progress. Washington, DC: National Academies Press; 2013.

Lin Yang, PhD
Graham A. Colditz, MD, DrPH