Telling smokers their lung age significantly improves the likelihood of them quitting, finds a study published on bmj.com today.

The concept of lung age (the age of the average healthy person with similar lung function to the individual) was developed to help patients understand complex lung data and to show how smoking prematurely ages the lungs. But currently there is no evidence that this increases quit rates.

So researchers set out to test the theory that telling smokers their lung age would lead to successful smoking cessation, especially in those with most damage.

The study took place in five general practices in Hertfordshire and involved 561 current smokers aged over 35. Information such as age, smoking history, and medical conditions were recorded.

All participants had a lung function test using a spirometer (this records the volume and rate at which a patient exhales air from the lungs) before being split into two random groups. The intervention group received detailed information about their spirometry results and lung age, given a diagram of how smoking ages the lungs, and told that quitting would slow down the rate of deterioration. The control group were given a raw figure for forced expiratory volume in one second (FEV1) with no further explanation.

Both groups were told that their lung function would be measured again after 12 months to see if there had been any change. They were also strongly encouraged to quit and offered referral to local NHS smoking cessation services.

Twelve months later, breath and saliva tests confirmed that 13.6% of patients in the intervention group and 6.4% of patients in the control group had successfully quit. In other words, patients in the intervention group were around twice as likely to have stopped smoking than those in the control group.

However, people with worse spirometric lung age results were no more likely to have quit than those with normal lung age in either the intervention or the control group.

This unexpected finding suggests that knowing ones lung age helps a smoker to quit whatever the result, explain the authors, and more research is needed to investigate the psychological reasons behind this.

Smoking cessation rates can be improved by spirometry and lung age estimation in primary care, say the authors. This study supports the introduction of screening smokers over 35 years of age to reduce smoking and improve early diagnosis of chronic lung disease. They also suggest that formal economic evaluation of this new and simple intervention should be a research priority.

An accompanying editorial says that providing feedback on lung age with graphic displays seems to be the best option so far for communicating the results of spirometry. This strategy might also be an opportunity for general practitioners to tailor smoking cessation messages to the individual, as recommended in the recent NICE guidance on smoking cessation.

Source: British Medical Journal