Undiagnosed lung disease in millions of smokers

New Delhi: A new study has revealed that more than half of long-term smokers and ex-smokers who are believed to be disease-free after successfully passing lung function tests could actually be in the early stages of chronic obstructive pulmonary disease (COPD).

COPD is the name given to a collection of lung diseases, such as emphysema and chronic bronchitis. Symptoms of these include breathlessness when active, a persistent cough with phlegm and frequent chest infections.

The main cause of COPD is smoking, with NHS figures estimating that more than three million people in the UK are living with the disease, of which only about 900,000 cases have been diagnosed.

Researchers at National Jewish Health set out to investigate the relationship between cigarette smoking and COPD diagnosis.

For the study, they recruited 8,872 people aged between 45 and 80, who had smoked at least ten cigarettes a day for ten years. Most of the participants had smoked between 30 and 50 cigarettes each day during the same period.

Based on the results of lung-function tests about half of the participants were considered disease-free.

After taking factors such as use of respiratory medication, physical function, respiratory symptoms and CT scans into consideration, the researchers found that 55 per cent of the participants believed to be disease-free actually had some form of respiratory-related impairment.

They also had a significantly worse quality of life than those who had never smoked.

Elizabeth Regan, lead researcher of the study, said: 'Smokers who have 'normal' lung-function tests often have significant respiratory disease. Many of those smokers likely have the early stages of chronic obstructive pulmonary disease.

'We hope these findings will help debunk the myth of the healthy smoker and highlight the importance of smoking prevention and cessation to prevent lung disease and other long-term effects of smoking.'

The study has been published in the journal JAMA Internal Medicine.