Prevalence of Underweight Among Children and Adolescents: United States, 2003-2006
by Cheryl D. Fryar, M.S.P.H., and Cynthia L. Ogden, Ph.D., Division of Health and Nutrition Examination Surveys
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Underlying health conditions can result in underweight. In addition, among children underweight can reflect acute malnutrition. Results from the 2003-2006 National Health and Nutrition Examination Survey (NHANES), using measured heights and weights, indicate that an estimated 3.3% of children and adolescents aged 2-19 years are underweight (see table). Trends from 1971-1974 to 2003-2006 show that there has been an overall significant decrease in underweight among children and adolescents from 5.1% to 3.3%. Underweight significantly decreased from 5.8% to 2.8% among 2-5 year olds and from 5.3% to 2.7% among 6-11 year olds between 1971-1974 and 2003-2006. Among adolescents aged 12-19, underweight decreased although not significantly from 4.7% to 3.8% during the same time period. Surveys before 1971 did not include children 2-5 years.
Body mass index (BMI), expressed as weight/height2 (BMI;kg/m2) is commonly used to classify weight status among adults, and is also recommended to identify children’s weight status. Cutoff criteria are based on the sex specific 2000 CDC BMI-for-age growth charts for the United States. Based on current recommendations of expert committees, children with BMI values below the 5th percentile of the sex specific BMI-for-age growth charts are categorized as underweight.
NHANES used a stratified multistage probability sample of the U.S. civilian noninstitutionalized population. A household interview and a physical examination were conducted for each survey participant. During the physical examination (conducted in mobile examination centers), height and weight were measured as part of a more comprehensive set of body measurements. These measurements were taken by trained health technicians using standardized measuring procedures and equipment. Observations for persons missing a valid height or weight measurement were not included in the data analysis.
| Age (in years)1 | NHANES (1963-1965 and 1966-1970)2 | NHANES (1971-1974) | NHANES (1976-1980) | NHANES (1988-1994) | NHANES (1999-2002) | NHANES (2003-2006) |
|---|---|---|---|---|---|---|
| Total | – | 5.1 | 4.5 | 4.0 | 3.7 | 3.3 |
| 2-5 | – | 5.8 | 5.3 | 4.3 | 3.8 | 2.8 |
| 6-11 | 5.8 | 5.3 | 4.2 | 3.9 | 3.8 | 2.7 |
| 12-19 | 4.6 | 4.7 | 4.4 | 3.9 | 3.7 | 3.8 |
– Quantity zero.
1 Excludes pregnant girls starting with 1971-1974. Pregnancy status not available for 1963-1965 and 1966-1970.
2 Data for 1963-1965 are for children 6-11 years of age; data for 1966-1970 are for adolescents 12-17 years of age, not 12-19 years.
NOTE: NHANES is National Health and Nutrition Examination Survey.