The researchers in the study include Gary Parkes (The Limes Surgery), Trisha Greenhalgh and Mark Griffin (both from the Department of Primary Care and Population Sciences, University College London), and Mark Griffin (Queen Elizabeth II Hospital).

According to the abstract to their paper, the objective of the study was: “To evaluate the impact of telling patients their estimated spirometric lung age as an incentive to quit smoking.”

They used a randomized controlled trial with 561 regular smokers that were over 35 years of age. They were all patients within five general medical practices in Hertfordshire, England.

All subjects were given a spirometric assessment of lung function. The “Lung Age” test (or pulmonary function test) provides the age of a person based on spirometry, or the measurement of lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled through the mouth from the lungs.

Both groups were advised to quit smoking and offered referral to local smoking cessation services.

Then, half of the smokers (the intervention group) were told their “lung age” and showed a chart that compared their lung function with the “lung age” of the average nonsmoker with the same age. Generally, smokers have lung ages that are older than their true ages.

The other half of the subjects (the control group) were not told of their lung age, but only given raw numeric values, which were difficult to understand.

One year later, 89% of the subjects returned with their results.

What was the finding of the study? Please read on.