Cigarettes Hit Sick Smokers Hardest

Smokers beware: Scientists in Sydney have uncovered a deadly new link between cigarettes and lung disease.

Researchers at Woolcock Institute of Medical Research have been investigating why some smokers develop smoking-related lung diseases, with surprising results.

"We discovered that lung cells from people with Chronic Obstructive Pulmonary Disease, or COPD, have a heightened response to cigarette smoke," says co-author, Woolcock cell biologist Brian Oliver.

"That is worrying because it indicates that the lungs of these already-ill individuals are programmed to be even more heavily affected by cigarette smoke than those who don't have the disease."

The researchers say their work, published this week in the European Respiratory Journal, adds even more weight the argument to quit smoking.

"We knew smoking was bad but here we've been able to show that it's especially bad for those with pre-existing lung disease," Dr Oliver says. "The sooner you give up, the better."

Smoking rates are declining in Australia, but still 20 per cent of men and 16 per cent of women aged 18 and over smoked in 2011-12, according to the Australian Bureau of Statistics. 

About 6000 Australians, mostly smokers, die each year from COPD, a lung disease that destroys the lungs and makes it difficult to breathe. The condition is responsible for about 60,000 hospitalizations annually.

Keen to better understand the link between smoking and COPD, the research team studied the behaviour of airway smooth muscle cells, a cell type which is known to be increased in the airways of people with COPD, but its role in the disease had not been fully identified.

"We found that cigarette smoke triggered both inflammation and fibrosis in the lungs, two processes which are intimately linked with the development of COPD," Dr Oliver says.

He was surprised to discover the response was stronger in cells from people who already had the disease in comparison to those who smoke but were not yet sick.

The results in the petri dish could also be seen in real lungs.

The team had more bad news for smokers with COPD. "We also found that wound repair was inhibited in response to cigarette smoke in the COPD group only."

Dr Oliver said genetics was likely playing a crucial role in the response.

"The big question is why the COPD cells respond this way, and all evidence points towards altered genes," he said.

"We don’t know if a person is born predisposed to developing COPD or if chronic smoking causes these changes, or maybe both are true."

He says understanding the mechanisms which cause the diseased cells to come hyper responsive will give scientists valuable information about how the disease occurs in the first place.

The paper is entitled Effects Of Cigarette Smoke Extract On Human Airway Smooth Muscle Cells From COPD. The study also involved researchers from Chongqing University and Changzhou University, China, University of Groningen, The Netherlands, and Imperial College, London.

COPD in Australia

  • 5878 people died of COPD in 2011-12
  • There were 59,265 hospitalisations for COPD in 2011–12 among Australians aged 55 and over
  • Males are almost twice as likely than females to die from COPD
  • $929 million was spent on COPD in 2008–09. That's 1.3 per cent of all direct expenditure on diseases