NBC News reported that information based on a study of 16,000 people. The patterns are made in a process called methylation, which is an alteration of DNA that can inactivate a gene or change how it functions — often causing cancer and other diseases, researchers said.
Heart disease and cancer are caused by genetic damage — some of it inherited, but most of it caused by day-to-day living. Smoking is one of the biggest causes, researchers said.
The research team examined blood samples given by 16,000 people taking part in various studies since 1971. In all of the studies, people have given blood samples and filled out questionnaires about smoking, diet, lifestyle and their health histories.
They found smokers had a pattern of methylation changes affecting more than 7,000 genes, or one-third of known human genes. Many of the genes had known links to heart disease and cancers known to be caused by smoking.