New research from pediatricians at the University of Michigan Health System takes a closer look at the influence nutrient intake and activity levels, especially among children in low-income families, has on a child's growth by age 4.
After analyzing data on ethnically and economically diverse children, the study revealed that children from low-income families, at or below the poverty level, had lower birth weights and were measurably shorter by age one than children from higher-income families, based on average growth rates of children.
Those findings, from the U-M Department of Pediatrics and Communicable Diseases, will be presented this week at the Pediatric Academic Societies annual Meeting in Seattle.
Normal growth, a measurement formula based on a child's age used by pediatricians, is one of the best indicators of good health and nutrition for children. However, a family's income level can greatly influence a child's physical development, a fact that many Americans may not be aware of, says the study's lead investigator, Sheila Gahagan, M.D.
"It's important to recognize that nutrient intake among poor and non-poor American children are not the same," says Gahagan, a clinical associate professor in the U-M Medical School. "It's a problem not just in developing countries. Right here in our own back yard, we have children who are underweight, iron deficient and are not at adequate height levels for their age – often because their families are unable to financially provide them with all of the proper nutrients and immunizations they need by age 5."
To determine the factors that may influence children's growth, the study closely looked at the nutrition and activity levels of young children by income level.
By interviewing 242 parents during their children's one-year doctor visit or at 3- to 4-year-old preschool health maintenance visit, the study evaluated feeding practices, activity levels, parental concerns about the child's eating, demographics, income level, and height measurements of children and their parents.
Of the lower-income children in the study, 26 percent were shorter in stature than the standard growth range for an average one-year-old child. Normal height for a one-year-old girl is between 26 ½ in. and 30 ½ in.; for a one-year-old boy normal height ranges between 27 ½ in. and 32 in.
Several factors, however, were shown to predispose lower income children to stunted growth, Gahagan says, including low birth weight and early feeding habits.
About 40 percent of children with stunted growth at age 1 were also low birth weight babies, which is often seen among low-income mothers-to-be who may not have access to prenatal care and lack proper nutrition. Overall, higher-income children had greater birth weights and were taller by age 1 than children from lower-income families.
In addition, children from higher-income families were more likely to be breast-fed during their first year of life, with some baby food intake by the time they are six months-old.
However, many lower-income parents began their children on baby food earlier than recommended – an eating habit with no nutritional benefit that may further hinder a child's growth, according to Gahagan. For the best nutritional value, Gahagan recommends that parents begin slowly integrating solid food into their children's diets between the time they are four to six months old.
"Breast milk is certainly the best nutrition for babies for their first year of life," says Gahagan. "It provides them with protection against certain infectious diseases like diarrhea and ear infections, which is extremely important since babies tend to have slower periods of growth when they are ill."
Beyond proper nutrition through breast milk, higher-income children consumed more servings of fruit and were more likely to graze, or eat small amounts of food throughout the day.
Still, the study found no apparent differences between income and children's sleeping habits, quantity of vegetable servings or amount of television they watched each day.
And although lower-income one-year-old children were found to be at an increased risk for short stature, the 3- and 4-year-old low-income children were not at increased risk for short stature.
But stunted growth early in life may pose possible health risks in adulthood, Gahagan notes, including an increased risk for cardiovascular disease as a result of poor nutrition during peak childhood growing years.
For more information about proper nutrition for children, visit www.med.umich.edu/1libr/yourchild/feed.htm.
To learn more about normal growth, including height and weight visit www.med.umich.edu/1libr/pa/pa_normalgr_hhg.htm.