WEDNESDAY, Feb. 25, 2009 (HealthDay News) -- Being obese at age 18 increases the risk of premature death in adulthood as much as smoking more than 10 cigarettes a day, according to Swedish researchers.
Dr. Martin Neovius of the Karolinska Institute and colleagues analyzed data from more than 45,000 18-year-olds who underwent military conscription tests in which their body mass index (BMI) and smoking status were recorded. The men were followed for an average of 38 years.
During the follow-up period, 2,897 of the men died. The incidence of death was highest among obese men and lowest among those of normal weight. Compared with those who had a normal weight at age 18, those who had been overweight were about a third more likely to die early, whereas those who were obese were more than twice as likely to die prematurely.
Being underweight did not increase the risk, but being seriously underweight (BMI of less than 17) increased the risk of premature death as much as being overweight did. The study also found that heavy smokers were more than twice as likely as nonsmokers to die prematurely and that heavy smokers who were obese were almost five times more likely to die early than were normal weight nonsmokers.
However, the researchers did not find a statistically significant interaction between heavy smoking and obesity, which they said means that being overweight at age 18 increases the risk of premature death, regardless of smoking status.
The study was published online Feb. 25 in BMJ.
In many countries, increasing numbers of adolescents smoke and are overweight or obese. The researchers concluded that "overweight, obesity and smoking among adolescents remain important targets for intensified public health initiatives."
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about the health risks of being overweight.