Lung cancer. Heart disease. Stroke. Premature infants. Just when you think the news about smoking and health can’t get any worse, it gets a little worse.
Researchers in Denmark have found that the lifetime risk of developing a chronic obstructive pulmonary disease, such as bronchitis or emphysema, is significantly higher than was previously thought. Through the Copenhagen City Heart Study, which began in 1976 and is ongoing, researchers have been studying more than 8,000 men and women between the ages of 30 and 60, focusing mainly on cardiovascular and pulmonary risk factors. No other study has looked at lung function in smokers for that long.
“Our study shows a lifetime risk of at least 25%. One in four smokers develops COPD,” says Dr. Peter Lange of the department of cardiology and respiratory medicine at Hvidovre Hospital in Denmark and an author of the study published last week in the online journal Thorax. “Previously, we thought that the absolute risk was about 15%.” People who have never smoked have a less than 5% risk of COPD, according to the study. Add up all the disease risks quantified so far, and about half of continual smokers will die of a smoking-related illness, losing an average of six to 10 years of their life spans, Lange says.
The study doesn’t differentiate between heavy and light smokers. Researchers divided people according to the date they quit within a 25-year period. The longer a person had not smoked, the lower his or her risk.
But quitting even after many years has immediate benefits. “There is a cessation of symptoms like cough and phlegm production and a lower risk of chest infections,” Lange says.
But there’s no getting back what has been lost. “If the lung function is reduced at the time of quitting, it will not return to normal,” Lange says. Still, when a smoker stops, the lungs begin to age naturally from that point on.
One of the first studies to examine the effect of smoking cessation programs on mortality, published in the Annals of Internal Medicine on Feb. 15, 2005, followed 5,887 middle-aged people for more than 14 years. Those who quit reduced significantly their risks of lung cancer, heart disease and respiratory disease.
“Stopping smoking means the damage to the lungs stops,” Lange says.
As the Denmark study continues to monitor the lungs of people who keep smoking -- and keep living -- it appears that respiratory failure gets more likely over time, according to an accompanying editorial by Dr. Nicholas Anthonisen of the University of Manitoba Respiratory Hospital, and author of the 2005 mortality study. He writes: “An argument can be made that many (perhaps most) smokers are ‘susceptible’ to COPD if they live long enough.”