Four fifths of people with chronic obstructive pulmonary disease (COPD), a disease associated with lung cancer, have not yet been diagnosed, a study has revealed.
According to Cancer Research UK, nearly four million people in the UK could be unaware that they are suffering from the disease, which is usually caused by smoking and includes bronchitis and emphysema.
This figure is far greater than official data, which reveals that just 600,000 to 900,000 people have been diagnosed with the illness even though a simple screening process picks up the disease.
The study found that over 1,000 of the 8,215 adults investigated were suffering from COPD, although only 20 per cent of these were aware of their condition.
Professor Robert West, director of tobacco studies at Cancer Research UK's health behavioural unit, said many smokers assumed that their symptoms were normal side-effects of their habit and tried to ignore them.
"It is crucial to identify smokers with COPD and take urgent action to support them in stopping smoking because the most effective way of halting the progression of the disease is to stop smoking," the professor insisted.
In addition, the research also revealed that over one third of patients who had been diagnosed with COPD continued to smoke.
"Many smokers feel that they will get away with it and not be affected in a serious way by their habit. For smokers with COPD that doubt is removed. Every day they continue to smoke will make things worse," Professor West said.