Fewer seventh- and eighth-grade students in North Dakota are drinking alcohol at an early age or smoking cigarettes, but more are refraining from regular physical activity and are overweight, a new survey shows.

The 2005 Middle School Youth Risk Behavior Survey released Wednesday by the state Departments of Health and Public Instruction polled 1,239 students in 64 North Dakota schools last spring.

It found that the percentage of students who smoked cigarettes on one or more of the 30 days prior to the survey dropped from 20 in 1995 to 9 last year, and the percentage of students who had their first drink of alcohol before age 11 decreased from 18 in 1999 to 14 in 2005.

The survey also found that the percentage of students who never or rarely wore a seat belt went from 25 in 1995 to 11 last year.

"The results … show some positive changes in behavior by our young people," said State Health Officer Terry Dwelle. "While these trends are very encouraging, other behaviors have not improved. We know we still have work to do."

The survey found that the percentage of students who were overweight increased from 10 in 1999 to 13 in 2005, and the percentage of students who participated in regular, vigorous physical activity decreased from 80 in 1999 to 73 in 2005.

The percentage of students who have tried marijuana for the first time before age 11 has remained at about 3 from 1999 to 2005.

The Youth Risk Behavior Survey was developed in 1990 by the Centers for Disease Control and Prevention to monitor behaviors that contribute to the leading causes of death, disability and social problems. North Dakota has participated since 1995. The survey is done every two years.

Kim Senn, director of the Health Department's Division of Family Health, said some data comparisons are made to 1999 and not 1995 because the questions were not asked until 1999.

"We try to look at the trend over time," she said. "Sometimes you don't see significant changes in a two-year period of time.

"Habits are really one of the most difficult things to change. It takes a very long time," she said.

First lady Mikey Hoeven, a spokeswoman for Healthy North Dakota, a statewide initiative to promote healthy behavior, said she was encouraged by the data on seat belt, cigarette and alcohol use.

"But we need to keep working so that all of our children develop lifelong healthy habits," she said.

State School Superintendent Wayne Sanstead said the information in the survey will be used to guide development of health and educational programs.

"Our goal is healthy and safe students," he said.

(On the Web: The 2005 survey: dpi.state.nd.us/health/YRBS/index.shtm.)