When smokers kick the habit, they may gain about 20 pounds, according to a new analysis -  quite a bit more than the commonly cited 5 pounds to 15 pounds.

“The findings highlight the need to provide effective dietary and physical activity counseling along with smoking cessation programs,” say study authors Daniel Eisenberg of the University of Michigan and Brian Quinn of the University of California, Berkeley.

The authors are quick to emphasize that this finding in no way changes the bottom line that the net health benefit of quitting is substantial. The study appears in the latest issue of Health Services Research.

The authors suggest that earlier studies overlooked key personality differences between quitters and smokers -  such as general concern for health or ability to focus on long-term goals -  that could influence the likelihood of gaining weight.

They reanalyzed data from the Lung Health Study, in which 5,887 American smokers were randomly assigned to either a smoking cessation program or usual care and then followed for five years. The authors of the 1998 study had estimated that quitters gained nearly 12 pounds.

Using a complex statistical method that allowed them to compare “apples to apples” in the two groups, Eisenberg and Quinn found that average weight gain actually topped 21 pounds. They recommend that future trials incorporate the new analytical approach when appropriate.

The authors said that the Lung Health Study excluded morbidly obese smokers and did not report racial and ethnic information. Thus the results should be applied with caution to broad population groups.

The larger-than-expected weight gain among ex-smokers is not just a cosmetic issue, said Robert Klesges at the University of Tennessee Health Science Center in Memphis and St. Jude Children’s Research Hospital. “We’re talking about a population of U.S. adults that is already overweight and obese. Incorporating weight control strategies is important to prevent future medical problems.”

Klesges called for more studies on methods to reduce weight gain following smoking cessation, especially those that combine behavioral and pharmacological approaches. Some new drugs on the horizon may help with both smoking cessation and weight loss, he said.

Health Services Research is the official journal of the AcademyHealth and is published by Blackwell Publishing on behalf of the Health Research and Educational Trust.

Health Behavior News Service