A new study shows that smokers who quit have healthier arteries a year later and probably will have less risk of heart disease as a result.

Doctors say the improvement came even though people who kicked the habit gained an average of 9 pounds. The study at the University of Wisconsin in Madison involved 1,500 smokers who were given one of five methods, such as nicotine patches or lozenges, to help them quit.

About one-third were successful, regardless of which method they used. Ultrasound tests were used to measure the health of their arteries before and after the study.

Results were reported Monday at a cardiology conference in Atlanta.