Any amount of cigarette smoke is dangerous to your lungs

20^th August - Even the smallest amount of cigarette smoke in the lungs is harmful, according to research from the US. Researchers from New York-Presbyterian Hospital and Weill Cornell Medical Center have found that cigarette smoke affects a person’s genes.

The study, published in the American Journal of Respiratory and Critical Care Medicine, says that low levels of cigarette smoke, whether by directly smoking or from second-hand smoke, put people at risk for lung cancer and chronic obstructive pulmonary disease (COPD).

"Even at the lowest detectable levels of exposure, we found direct effects on the functioning of genes within the cells lining the airways," says Dr Ronald Crystal, senior author of the study and chief of pulmonary and critical care medicine at the hospital.

Certain genes are turned “on” in regular smokers, but Crystal’s research shows that this same action happens in people with very low exposure to smoke. “The genetic effect is much lower than those who are regular smokers, but this does not mean that there are no health consequences," says Crystal. "Certain genes within the cells lining the airways are very sensitive to tobacco smoke, and changes in the function of these genes are the first evidence of 'biological disease' in the lungs of individuals."

The “canary in a coal mine”

The researchers tested 121 people and classified them as non-smokers, active smokers and low-exposure smokers based on urine levels of nicotine and cotinine, both markers of smoking in the body. The researchers then scanned each person’s genes and found that any level of these markers was associated with genetic abnormalities.

“This means that no level of smoking, or exposure to second-hand smoke, is safe," says Crystal, who compares these genetic changes to a canary in a coal mine. “The canary is chirping for low-level exposure patients, and screaming for active smokers.”

Crystal says these findings are further evidence for a ban on smoking in public places. The UK has had a ban on smoking in public places and research is just now starting to appear that shows health benefits. For example, since the ban, in England there have been 1,200 fewer emergency admissions to hospital for heart attacks, according to research from the June issue of the British Medical Journal.

Lung diseases

The British Lung Foundation (BLF) estimates that there are 3.7 million people in the UK living with COPD. The symptoms can include coughing, tight chest, difficulty breathing and repeated lung and chest infections. Many people dismiss symptoms as “smoker’s cough” and do not seek treatment. The BLF says that there is no cure, but that the symptoms can be treated by stopping smoking, using inhalers and taking other medications such as steroids or antibiotics for infections.

Unfortunately, the early symptoms of lung cancer are similar to those for COPD, but also include unexplained weight loss and coughing up blood. Lung cancer is the second most common cancer (after skin cancer) and 38,000 people are diagnosed with it each year in the UK.

Treatments for lung cancer include surgery to remove diseased sections of lung, chemotherapy and radiotherapy. Several new treatment options are becoming more available and can include heat or cold therapy to kill cancer cells and medications to inhibit cancer cell growth.

Not smoking is the best way to prevent lung cancer, but evidence shows that diet and exercise can play an important role in reducing risk, according to the NHS.

If you smoke and you want to stop, contact your doctor or the NHS stop smoking service on 0800 022 4332.