With each generation in the United States, adolescents from Asian immigrant families improved their health habits, while their Latino counterparts either showed no improvement or developed worse habits, according to a Rand Corp. study released Tuesday.
The study, which looked at diet, exercise, television viewing and other practices among at least three generations of youths aged 12 to 17, could help explain rising rates of obesity and diabetes among Latinos.
Upon arrival in the United States, Asian and Latino immigrants started out drinking fewer sodas and eating more fruits and vegetables than whites, according to the study, which was based on a survey of nearly 6,000 adolescents in 2001.
After two generations, Asian youths caught up with or surpassed whites in other measures, including more hours exercising and fewer watching television.
Meanwhile, similar Latino adolescents had poorer diets than their Asian and white peers and were less likely to use seat belts, bicycle helmets or sunscreen, according to the study, published on the online edition of the American Journal of Public Health.
Previous research has suggested that Latino immigrants overall tend to enjoy relatively good health despite low incomes, a phenomenon known as the "Latino paradox." But these findings suggest that the effect could diminish with each generation.
"If the trend we're seeing here, at least for Latino teens, is true," the case that Latinos are doing better than expected "is probably not going to hold out over generations," said Dr. Michele L. Allen, the study's lead author.
Allen is assistant professor of family medicine and investigator in the Program in Health Disparities Research at the University of Minnesota.
Income alone did not account for the disparity between Latinos and the others, Allen said, because the findings held true across economic groups. (The one exception was physical activity; more affluent Latino youths exercised as much as whites.) It will be up to future studies to explain the differences across generations and among Asians, Latinos and whites.
She acknowledged, however, that poverty plays a role in Latinos' health.
"We know that Latinos are much more likely to be uninsured than other groups," Allen said. "There is the possibility that they're not hearing the health messages because they don't have access to a regular source of healthcare."
The study looked at Latinos and Asians because they are the nation's largest immigrant groups. One in five children in the United States is an immigrant or born to immigrants. Although other studies have examined risk behaviors of Latino teenagers, this was the first major study to examine preventive behaviors and one of few studies of Asian health, Allen said.
"I hope this will encourage more research on Asians so that we can understand why these health behaviors improve over time," said Dr. Mark Schuster, a UCLA pediatrician, director of health promotion at Rand and one of the authors of the study.
The researchers were interested in adolescents because "that's a time when habits are formed that can last for years to come -- eating habits, exercise habits," Schuster said.