For Immediate Release: 18 May 1998

Contact: David L. Williamson
University of North Carolina at Chapel Hill

New Study Shows Second Generation Immigrant Children Gaining Weight

UNC-CH News Services

CHAPEL HILL - Adolescent obesity increases significantly among second- and third-generation immigrants to the United States, according to a new University of North Carolina at Chapel Hill study. Why is not known, scientists say, but less physical activity and a higher-fat, more plentiful diet probably are responsible.

Researchers at the UNC-CH schools of public health and medicine conducted the study, the most comprehensive investigation of its kind. A report on the findings appears in the May issue of the Journal of Nutrition. Authors are Drs. Barry M. Popkin, professor of nutrition, and Richard Udry, Kenan professor of maternal and child health and professor of sociology. Both are fellows at the Carolina Population Center.

"Childhood obesity is a major public health problem affecting nearly 25 percent of all North American children," the authors wrote. "Its effects on health during childhood and adulthood and its related social and economic consequences are becoming clearer. What is less clear is the way in which patterns of adolescent obesity vary by race, age and sex."

The researchers studied information from a nationally representative sample of 13,783 adolescents gathered through the National Longitudinal Study of Adolescent Health, a major UNC-CH survey also called Add Health.

All Asian immigrant groups, except Chinese and Filipinos, doubled their proportion of obese children during the transition from first-generation to second-generation residency, the study showed. That is, those born overseas were half as likely to be overweight as those born in the United States. The level of increase between first- and second-generation Hispanics was almost as great.

"These results tell us that the power of the process of adapting to the American lifestyle of diet and activity is far greater and occurs more rapidly than we thought," Popkin said.

The new study has important implications for Americans, he said.

"We know that the risk of hypertension and diabetes among adolescents is increasing rapidly, and both those diseases are strongly associated with being overweight," the researcher said. "Adolescent obesity often leads to adult obesity, and a large number of health problems are linked with adult obesity."

For the total sample, 26.5 percent of the children were obese, he said. Individual obesity rates by group were: white non-Hispanics, 24.2 percent; black non-Hispanics, 30.9 percent; all Hispanics, 30.4 percent; and all Asian-Americans, 20.6 percent.

Chinese and Filipino adolescents showed significantly lower obesity than non-Hispanic whites -- 15.3 percent and 18.5 percent, respectively. All groups showed more obesity among males than females except for blacks, whose rates were 27.4 percent for boys and 34 percent for girls.

"We know that obesity among U.S. adolescents has been increasing, particularly over the last decade," Popkin said. "We also are aware that the highest levels of obesity have been among Hispanic males and females and black females.

"Our new results indicate that we must focus our concern much more on Hispanic and Asian immigrants, two major groups of new Americans. These are the largest and fastest growing ethnic groups in the United States, and so the results portend increases in U.S. obesity over the next several decades unless we actively address this problem."

The Add Health study made national news last September when Udry, the principal investigator, and others reported their first findings. Strong and supportive ties between parents and children were found to help protect adolescents against a variety of risky behaviors, including substance abuse, early sexual activity, pregnancy, emotional distress and violence.

Feeling connected with one's school and, in some cases, one's religion also helps adolescents avoid some pitfalls of youth, the study showed.

Add Health is unique in the size of its adolescent sample and in its ability to provide large representative samples of Anglo, Black, Hispanic and Asian-American adolescents.

Several other studies have confirmed that overweight children tend to become overweight adults. Still others have shown obesity often results in lower income, reduced chances of marriage and discrimination. The proportion of overweight U.S. children held constant through the 1960s and 1970s, but since then the percentage of adolescents above the 95th percentile in weight more than doubled.

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Note: Popkin's number is (919) 966-1732, Udry's is 966-2829.
Contact: David Williamson, 962-8596.