CHAPEL HILL -- Childhood obesity is a worldwide problem, not just one for U.S. youth, according the lead investigator of research appearing in the December Journal of Nutrition and released today (Dec.11).
Using four large, representative surveys of Russian, Brazilian, South African and Chinese children, investigators showed that the prevalence of overweight children ranged from 10.5 percent of groups sampled to 25.6 percent. In the United States, it was 22 percent, according to the National Health and Nutrition Examination Survey.
"What we clearly know is that childhood obesity is biologically and behaviorally related to adult obesity and that serious health consequences for the child can result from being obese," said Dr. Barry M. Popkin, professor of nutrition at the University of North Carolina at Chapel Hill schools of public health and medicine. "That is the frightening aspect. Although we do not understand fully the biological mechanisms, being overweight as a child is associated with cardiovascular disease, diabetes and other problems in adulthood."
Critical periods for weight gain are the third trimester of pregnancy, early infancy, ages 5 to 7 and during the adolescent growth spurt.
Popkin conducted the study with graduate student Marie Richards and Dr. Carlos A. Montiero of the University of Sao Paulo in Brazil for the journal published by the American Society for Nutritional Sciences.
Their goal was to analyze large samples of children to examine the relative risk of being overweight among stunted children. The results, Popkin said, revealed a significant association between stunting and overweight in children of all countries.
In infancy or childhood stunting occurs when a youngster's height is below the bottom 2.5 percent of those for his or her same age and sex group based on US standards of the National Center for Health Statistics, which are accepted and used worldwide. Similarly, when children's weight for their height is above the top 2.5 percent of the distribution, they are classified as overweight.
"Stunting remains a major problem in most low-income countries," Popkin said. "The major cause of stunting is a combination of inadequate breast feeding and inappropriate weaning, followed by the feeding of nutritionally inadequate, low-protein foods such as rice, bananas, potatoes and water during the first 5 to 8 months of life.
"Stunting is mainly a problem of infant feeding," he said. "If you give a child in any low-income country a middle-class diet and a healthy environment, he or she will grow like an American child."
In the U.S., according to the Centers for Disease Control and Prevention Pediatric Surveillance System, about 6 percent of low-income children under age 5 are stunted.
For Russia, investigators used 1994-95 Russian Longitudinal Monitoring Survey data on a sample of the 1,106 3- to 9-year-olds. More than 9 percent were stunted. Of those children, 45 percent were overweight.
"In Russia, stunting is a relatively new phenomenon," Popkin said. "Only in the last half decade, most likely linked with the decline in public health services, including provision of free or very inexpensive breast milk substitutes, has stunting emerged as a new nutrition problem."
For China, researchers used 1991 and 1993 China Health and Nutrition Survey data. They examined samples of 1,755 and 1,637 3-to 9-year-olds. For the two surveys, 30 percent and 26 percent were stunted, respectively. Of those, more than a fifth were overweight.
For South Africa, they used 1994 Living Standards Measurement Survey data and measured 2,467 3-to 6-year olds. More than 28 percent were stunted, with 13 percent of those overweight.
Investigators used a 1989 random national nutrition survey conducted by a Brazilian statistical agency to examine youngsters in that country. Of the 11,109 3- to 9-year olds, 15 percent were stunted and 3.5 percent of those were overweight.
- 30 -
Note: Popkin can be reached at (919) 966-1732
Journal Contact: Jim Augustine (703) 644-6824
News Services Contact: David Williamson