The list of benefits for smokers who quit has just been extended: a new study shows they might also have improved cholesterol profiles.
If confirmed in future research, the finding could shed light on the strong, yet somewhat mysterious relationship between smoking and heart health. Up to 20% of heart disease deaths are currently blamed on smoking, but researchers haven't yet had a clear understanding of what underlies the effect. Lowered oxygen levels are at least partly to blame.
Some small studies have also shown that smoking lowers HDL cholesterol and raises LDL cholesterol, lead researcher Dr Adam Gepner of the University of Wisconsin School of Medicine and Public Health, in Madison, said.
To test the impact of smoking on cholesterol levels more rigorously, and in a realistic setting, Dr Gepner and his colleagues recruited more than 1,500 smokers representative of the current US population, including its high proportion of overweight and obese individuals.
At baseline, the average participant smoked about 21 cigarettes per day. After a year on one of five smoking cessation programs, 334 (36%) had been able to stop smoking.
Those who stopped smoking had an average rise in HDL cholesterol of about 5%, or 2.4 mg/dL, the researchers report in the American Heart Journal. They also had an increase in large HDL particles.
The effects were somewhat stronger in women. However, it did not seem to matter how many cigarettes people smoked per day at baseline: heavy smokers enjoyed the same HDL benefit as lighter smokers after quitting.
One downside of smoking cessation can be weight gain. Sure enough, the group that quit gained an average of about 10 pounds compared to one or two pounds in the group that relapsed to smoking.
Many participants were already overweight at the start of the study, with an average body mass index of 29.6. The researchers think the weight gain might have offset some of the beneficial effects seen in the abstainers.
"Further benefits on cholesterol levels may have been actually masked by the weight gain seen after quitting," Dr Gepner said.
"It is important to counsel quitters about weight gain and the need for a healthy diet and regular exercise during the quitting period," he added.
(Reuters Health, Lynne Peeples, December 2010)