As found by the University of Minnesota study, the past thirty years have witnessed decline in the smoking rates among adults, which has been contributed by the increase in the income and education level.

The study that was sponsored by the U-S National Institutes of Health, the Heart and Stroke Foundation of Canada, and the Quebec Foundation for Health Research involved adults aged 25-to-74 in the Minneapolis and St. Paul area and analyzed their smoking trends from 1980 to 2009.

It was discovered that there was a 50% reduction in the number of current smokers. In men, those who were smoking diminished to 15.5% from 33%, while women smokers reduced to around 12% from about 33%. Also, those who were smoking currently burnt less number of cigarettes. In men, the age-adjusted average number of cigarettes smoked per day plummeted to 13 from 23 and the figures came down to 10 from 21 in women.

Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City stated that it was good that there had been a reduction in the smoking rates, but still decreasing the number of cigarettes could pose the risk of heart disease by three times.

The findings of the study were presented at the American Heart Association's annual meeting in Chicago.