Researchers have analyzed genetic material of more than 32,000 African-American smokers and non-smokers to see if certain genes predicted when they began smoking, how many cigarettes they smoked and how easily they were able to quit

According to the new study, a variant in a nicotine receptor gene predicts about one extra cigarette smoked per day. This same general location has been implicated in smoking behavior among white Europeans. Among African-Americans, the new genetic marker appears on a different spot on the same gene. Smoking behaviors differ among ethnic groups. For example, African-Americans typically start smoking at later ages than their counterparts of European descent and smoke fewer cigarettes each day. But they have a higher risk for lung cancer and are less likely to quit smoking.