Prevalence of Underweight Among Adults Aged 20 and Over: United States, 1960–1962 Through 2017–2018

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by Cheryl D. Fryar, M.S.P.H., Margaret D. Carroll, M.S.P.H., and Joseph Afful, M.S., Division of Health and Nutrition Examination Surveys

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Poor nutrition or underlying health conditions can result in adults being underweight. Results from the 2017–2018 National Health and Nutrition Examination Survey (NHANES), using measured heights and weights, indicate that an estimated 1.6% of U.S. adults aged 20 and over are underweight. Body mass index (BMI), expressed as weight in kilograms divided by height in meters squared (kg/m2), is used commonly to classify underweight (BMI less than 18.5) among adults aged 20 and over.

The prevalence of underweight among adults aged 20 and over by age and sex from 1988–1994 through 2017–2018 is shown in Table 1. Because surveys before 1988 did not include persons over age 74, Table 2 shows the prevalence of underweight for adults aged 20–74 by age and sex for all survey periods dating to 1960. The total and sex-specific estimates for both tables are age adjusted.

NHANES, conducted by the National Center for Health Statistics, is a multistage probability sample of the civilian noninstitutionalized population of the United States. A household interview and a physical examination are conducted for each survey participant. During the physical examination, conducted in a mobile examination center, height and weight are measured as part of a more comprehensive set of body measurements. These measurements are taken by trained health technicians, using standardized measuring procedures and equipment. Observations for pregnant women and for persons missing a valid height or weight measurement are not included in the data analysis.

For additional information on NHANES methods, visit: https://wwwn.cdc.gov/nchs/nhanes/analyticguidelines.aspx.

This Health E-Stat supersedes the earlier version, “Prevalence of Underweight Among Adults Aged 20 and Over: United States, 1960–1962 Through 2015–2016”.

Suggested citation

Fryar CD, Carroll MD, Afful J. Prevalence of underweight among adults aged 20 and over: United States, 1960–1962 through 2017–2018. NCHS Health E-Stats. 2020.

Tables

Table 1. Prevalence of underweight among adults aged 20 and over, by age and sex: United States, 1988–1994 through 2017–2018
Survey period Sample size (n)
Total1
20–39 40–59 60 and over Men1 Women1
                                                                                                                               Percent (standard error)
1988–1994 16,235 2.3 (0.2) 3.0 (0.4) 1.7 (0.3) 2.3 (0.2) 1.1 (0.2) 3.5 (0.3)
1999–2000 4,117 2.0 (0.2) 2.9 (0.4) 1.3 (0.2) 1.4 (0.4) 1.1 (0.2) 2.7 (0.5)
2001–2002 4,413 1.9 (0.2) 2.9 (0.5) 0.9 (0.2) 1.6 (0.3) 1.0 (0.3) 2.7 (0.3)
2003–2004 4,431 1.7 (0.2) 2.8 (0.3) 1.0 (0.4) 0.8 (0.2) 1.4 (0.3) 2.0 (0.4)
2005–2006 4,356 1.9 (0.3) 2.4 (0.6) 1.4 (0.4) 1.6 (0.3) 1.2 (0.4) 2.5 (0.4)
2007–2008 5,550 1.6 (0.3) 1.9 (0.5) 1.5 (0.5) 1.1 (0.2) 1.0 (0.3) 2.2 (0.4)
2009–2010 5,926 1.8 (0.3) 2.0 (0.3) 2.1 (0.5) 1.3 (0.2) 1.0 (0.2) 2.6 (0.5)
2011–2012 5,181 1.7 (0.2) 2.5 (0.3) 0.9 (0.2) 1.6 (0.4) 0.7 (0.1) 2.6 (0.4)
2013–2014 5,455 1.4 (0.2) 1.9 (0.4) 0.8 (0.3) 1.6 (0.4) 1.3 (0.3) 1.6 (0.2)
2015–2016 5,337 1.5 (0.2) 2.5 (0.4) 0.8 (0.3) 0.9 (0.3) 1.2 (0.2) 1.8 (0.4)
2017–2018 5,120 1.6 (0.2) 2.4 (0.5) 1.6 (0.4) 0.5 (0.2) 1.3 (0.3) 2.0 (0.4)

1Age adjusted by the direct method to U.S. Census 2000 estimates using the age groups 20–39, 40–59, and 60 and over. Crude estimates (not age adjusted) for 2017–2018 are 1.5% for total, 1.2% for men, and 1.8% for women.
NOTE: Underweight is body mass index less than 18.5 kg/m2. Pregnant women are excluded from the analysis.
SOURCE: National Center for Health Statistics, National Health and Nutrition Examination Surveys, 1988–1994 and 1999–2018.

Table 2. Prevalence of underweight among adults aged 20–74, by age and sex: United States, 1960–1962 through 2017–2018
Survey period Sample size (n)
Total1
20–39 40–59 60–74 Men1 Women1
                                                                                                                                          Percent (standard error)
1960–1962 6,126 4.0 (0.2) 5.7 (0.4) 2.3 (0.3) 3.7 (0.6) 2.2 (0.2) 5.7 (0.4)
1971–1974 12,911 3.6 (0.2) 4.9 (0.3) 2.2 (0.3) 3.8 (0.4) 2.4 (0.3) 4.8 (0.3)
1976–1980 11,765 3.0 (0.1) 4.2 (0.3) 1.9 (0.3) 2.7 (0.4) 1.6 (0.2) 4.4 (0.3)
1988–1994 14,319 2.3 (0.2) 3.0 (0.4) 1.7 (0.3) 1.9 (0.3) 1.1 (0.2) 3.5 (0.3)
1999–2000 3,603 2.0 (0.2) 2.9 (0.4) 1.3 (0.2) 1.1 (0.2) 1.2 (0.2) 2.7 (0.5)
2001–2002 3,916 1.8 (0.2) 2.9 (0.5) 0.9 (0.2) 1.4 (0.4) 1.0 (0.3) 2.6 (0.4)
2003–2004 3,756 1.7 (0.2) 2.8 (0.3) 1.0 (0.4) 0.7 (0.3) 1.4 (0.3) 2.1 (0.4)
2005–2006 3,835 1.8 (0.3) 2.4 (0.6) 1.4 (0.4) 1.1 (0.5) 1.3 (0.4) 2.4 (0.5)
2007–2008 4,876 1.6 (0.3) 1.9 (0.5) 1.5 (0.5) 0.9 (0.2) 0.9 (0.3) 2.3 (0.4)
2009–2010 5,279 1.9 (0.3) 2.0 (0.3) 2.1 (0.5) 1.2 (0.3) 1.0 (0.3) 2.7 (0.5)
2011–2012 4,674 1.7 (0.2) 2.5 (0.3) 0.9 (0.2) 1.2 (0.5) 0.7 (0.1) 2.6 (0.4)
2013–2014 4,940 1.4 (0.2) 1.9 (0.4) 0.8 (0.3) 1.7 (0.5) 1.4 (0.3) 1.5 (0.3)
2015–2016 4,778 1.5 (0.2) 2.5 (0.4) 0.8 (0.3) 0.8 (0.3) 1.2 (0.3) 1.9 (0.4)
2017–2018 4,536 1.7 (0.3) 2.4 (0.5) 1.6 (0.4) 0.4 (0.2) 1.4 (0.3) 2.1 (0.4)

1Age adjusted by the direct method to U.S. Census 2000 estimates using the age groups 20–39, 40–59, and 60–74. The 1960–1962 National Health Examination Survey included adults aged 18–79, and the 1971–1974 and 1976–1980 National Health and Nutrition Examination Surveys did not include individuals over age 74.
NOTE: Underweight is body mass index less than 18.5 kg/m2. Pregnant women are excluded from the analysis.
SOURCES: National Center for Health Statistics, National Health Examination Survey, 1960–1962; and National Health and Nutrition Examination Surveys, 1971–1974, 1976–1980, 1988–1994, and 1999–2018.

Page last reviewed: December 16, 2020
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