Smoking Cutback Can Aid Eventual Quitting

BURLINGTON, Vt., Dec. 7 -- Cutting down on the number of cigarettes smoked every day can improve the chances of quitting eventually, according to researchers here.

A review of the scientific literature contradicts the idea that quitting cold turkey is the only way to stop, found John Hughes, M.D., of the University of Vermont College of Medicine here, and a co-author, reported in the December issue of Nicotine and Tobacco Research.

"Our review indicates cutting back is often a great way to start changing smoking that can lead to eventual quitting," said Dr. Hughes, along with Matthew Carpenter, Ph.D., of the Medical University of South Carolina in Charleston.

On the other hand, there's no good scientific evidence that smoking less has any health benefit, they noted. Quitting entirely, of course, is a different matter. The researchers cautioned that clinicians should not suggest to smokers that they will have lower risks of tobacco-associated diseases if they cut back.

Instead, they said, doctors should suggest reducing the number of cigarettes smoked as a step on the way to quitting.

The researchers examined 19 studies that examined the link between reduction and subsequent quitting and 10 studies that looked at cutting back and subsequent disease risk. Because the studies differed widely in design and results, a formal meta-analysis wasn't possible, they said.

Among the 19 studies of reduction and quitting, the researchers said, none found that cutting back undermined the chances of successfully getting off tobacco, and 16 found that it increased the chances of quitting.

Among the trials, the two best were randomized controlled studies compared cutting back versus no treatment and compared the chances of being abstinent from cigarettes six months down the road, the researchers found.

In both studies, the reduction group did better than the no-treatment group, 18% and 15% versus 4% and 5%, they said.

"These findings are the strongest evidence that reduction increases future cessation," Drs. Hughes and Carpenter said.

On the other hand, there are no randomized controlled trials looking at the issue of health risks and smoking reduction. (The researchers excluded studies that used biomarkers as an endpoint.)

Case-control and cohort studies, for the most part, give conflicting results, the researchers said, and are often too small to give clear answers.

The only really large study pooled data from three cohorts in the Copenhagen Center Study, which used medical records to measure disease outcomes and had smoking data only at wide intervals.

However, in three analyses that used between 643 and 858 reducers over 14 to 15 years, smokers who had reduced by at least 50% did not have fewer myocardial infarctions, less obstructive lung disease and less mortality than those who didn't cut down.

A fourth analysis, though, reported that reducers had a 27% reduction in lung cancer diagnoses.

No financial conflicts were reported. The study was financed by a grant from the National Institute on Drug Abuse.