According to a study published by BMJ, smokers who were told their lung age were significantly more likely to quit than those who did not receive the information.

Usually, when patients go to the doctor to have their lungs checked, they receive complex lung data. The idea of a lung age was developed to help patients better understand these data and to demonstrate that smoking has a premature aging effect on the lungs. Lung age can be thought of as the age of the average healthy person with similar lung function to the individual.

There is no current evidence indicating that telling people their lung age increases their propensity to quit, and so researcher Gary Parkes and colleagues decided to test this idea. Their working hypothesis is that telling smokers their lung age would lead to quitting and the knowledge would be especially effective in patients with the most lung damage.

A sample of 561 current smokers – older than 35 years of age and from five general practices in Hertfordshire – participated in the study. The researchers initially collected information on age, smoking history, and medical conditions.

A spirometer was used to test lung function before the researchers randomly assigned the participants to two groups. Spirometers record the volume and rate at which a patient exhales air from the lungs.

After the spirometer reading, the intervention group received more detailed results about lung age and a diagram that explained how smoking ages the lungs. They were also told that the rate of lung deterioration could be reduced if they quit smoking. The control group received the raw data results of the spirometer and no further explanation -just a number for forced expiratory volume in one second (FEV1).

Both the intervention and the control groups were encouraged to quit smoking and were offered referral to local NHS services designed to help people quit. In addition, the researchers told both groups that they would receive another lung function assessment after 12 months time.

Upon follow-up, 98% of participants received breath and saliva tests. Results showed that 13.6% of patients in the intervention group and 6.4% of patients in the control group had successfully quit smoking. That is, patients who were told their lung age 12 months prior were about twice as likely to have quit smoking than those who were not given that piece of information.

Contrary to their original hypothesis, the researchers found in both the intervention and control groups, people with worse spirometric lung age results were no more likely to have quit than those with normal lung age results. This is rather unexpected, and it indicates that simply knowing what one’s lung age is helps a smoker quit, regardless of the actual lung age. Additional research is necessary in order to shed light on the psychological reasons behind this finding.

Since smoking cessation rates can be increased if primary care physicians provide spirometry and lung age information to patients, the authors suggest that it may be wise to screen smokers over 35 years of age in order to reduce smoking and improve early diagnosis of chronic lung disease. Parkes and colleagues also acknowledge that a formal economic evaluation should be conducted to estimate the cost effectiveness of this new and simple intervention.

An editorial in the same journal adds that the best way to communicate the lung age results of spirometry is with a graphic display.

Effect on smoking quit rate of telling patients their lung age: the Step2quit randomised controlled trial
Gary Parkes, Trisha Greenhalgh, Mark Griffin, and Richard Dent
BMJ (March 2008). 336:598-600.
doi:10.1136/bmj.39503.582396.25
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Written by: Peter M Crosta