Smoking

My dad told me he was trying to quit smoking. I really think that it is a good idea. But nature of this week said that gene expression changes would remain decades after quit smoking.

Nature:

Gene expression changes brought on by heavy smoking may persist long after the smoker has kicked the habit, researchers have found. The results could provide a molecular explanation for the continued increased risk of lung cancer and other pulmonary ailments among former smokers.

When smokers quit, their bodies gradually begin to undo the damage cigarettes have wrought. But contrary to popular belief, not all of the body's systems make a full recovery. Although the risk of heart disease, for example, eventually returns to that of a nonsmoker, the risk of getting lung cancer and emphysema — a progressive lung condition that leaves sufferers struggling for breath — remains elevated even if the patient hasn't smoked a cigarette in decades.

"You are reducing the risk of disease by quitting," says Raj Chari, a cancer biologist at the British Columbia Cancer Research Centre in Vancouver, Canada, "but it isn't going back to zero."