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Who is at risk for a specific health problem?

Surveillance data are analyzed by person characteristic to determine who is at risk of a health problem. The Health Indicator by Demographic Variables tables can be used to examine age, race/ethnicity, and education specific prevalence to identify groups that have a high prevalence for each health indicator.


Health indicators can vary by age. In the PedNSS and PNSS tables, age groups or categories were selected to be narrow enough to detect age-related patterns for a specific health indicator.

Age Categories in PedNSS and PNSS


Age Categories for Anemia

  • Anemia is reported at 6 month intervals for children less than 2 years of age to capture the time period of highest prevalence which is usually 12 to 18 months of age and at wider intervals for children greater than 2 years of age. The age categories used for the anemia analyses are 6–11 months, 12–17 months, 18–23 months, 24–35 months, and 36–59 months.

Age Categories for Growth Indicators

  • Growth indicators including short stature, underweight, overweight, and obesity are reported at one year intervals for all children.
  • In the United States childhood obesity is a major health problem. Obesity in children over the age of two is associated with adolescent or adult obesity. Clinical guidelines and the American Academy of Pediatrics recommend that children over the age of two have their BMI-for-age monitored annually and receive related medical care as needed. Therefore, in addition to the one year interval groupings, overweight is reported for all children 2 years and older to determine the overall prevalence of obesity using BMI-for-age.


Age Categories for Pregnant Teens

  • Teens (<15 years and 15–17 years) and older women (> 40 years of age) are the age groups at greatest risk of poor birth outcomes. Teens are less likely than older women to begin prenatal care in the first trimester. Older women have a higher prevalence of overweight and are more likely to gain more weight during pregnancy than younger women. Both young teens and older women are at higher risk of having a low birthweight infant.


Race/ethnicity data are analyzed because differences that are observed in racial and ethnic groups may reflect

  • differences in their susceptibility or exposure to disease or a health problem or
  • the persistence of that disease or problem.

For example, a particular race/ethnic group may be of low socioeconomic status and have poor access to health care that may increase their susceptibility to a health problem. Additionally, race/ethnicity and age are often analyzed at the same time to see if the prevalence of a health indicator differs by age within racial and ethnic groups.


  1. National PedNSS data have shown that the highest prevalence of anemia is among black children of all age groups and the highest prevalence of overweight is among Hispanic and American Indian/Alaska Native children 2 to 5 years of age.
  2. The race/ethnic groups with the best or highest prevalence of ever breastfeeding and breastfeeding at least 6 and 12 months were also Hispanic and American Indian/Alaska Native infants.
  3. For women, PNSS data show that black women have the highest prevalence of anemia during their 3rd trimester of pregnancy.


Education is often used as a proxy measure for socioeconomic status. In other words, education is an indirect measure.


  1. The risk of low birthweight declines sharply among mothers with at least 12 years of education. This relationship between education and low birthweight is independent of maternal age and race/ethnicity.
  2. Education is associated with breastfeeding. The prevalence of breastfeeding is lowest among women with less than a high school education.

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Page last reviewed: October 29, 2009
Page last updated: October 29, 2009
Content Source: Division of Nutrition, Physical Activity and Obesity, National Center for Chronic Disease Prevention and Health Promotion



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