Researchers at the University of Colorado at Denver and the Health Sciences Center compared the age of first-time drug users across the nation to the age of first-time drug users on and near two different American Indian reservations.

American Indian adolescents were found to be at higher risk for trying marijuana than their peers across the country, according to the study published in the July issue of the American Journal of Public Health, online under First Look.

For the population born before 1960, the potential risk for drug use peaked at age 18, with a greater risk in the overall national population group. After 1960, the risk for trying marijuana was highest at age 16 and is now higher among reservation-dwelling youth than the general population, according to Nancy Whitesell, of the University of Colorado at Denver School of Medicine.

"The numbers show the Native American samples are catching up and even surpassing the national population samples for the youngest populations that are at risk for drug use," Whitesell said in a statement.