Smoking cigarettes can leave a lasting imprint on human DNA, altering more than 7,000 genes in ways that may contribute to the development of smoking-related diseases, a new study says. Reviewing results from blood samples taken from nearly 16,000 people in 16 prior studies, the researchers also found that for those who stopped smoking, most genes "recovered" within five years of quitting.

Smoking cigarettes can leave a lasting imprint on human DNA, altering more than 7,000 genes in ways that may contribute to the development of smoking-related diseases, a new study says.

Reviewing results from blood samples taken from nearly 16,000 people in 16 prior studies, the researchers also found that for those who stopped smoking, most genes "recovered" within five years of quitting.