People who smoke an average of less than one cigarette per day over their lifetime have a 64% higher risk of earlier death than never smokers, and those who smoke between one and 10 cigarettes a day have an 87% higher risk, according to a study by researchers at the National Cancer Institute published online today by JAMA Internal Medicine. For those who quit, the risk fell with their age at quitting. The study looked at risk of death from respiratory and cardiovascular disease for more than 290,000 adults in the NIH-AARP Diet and Health Study. Among current smokers, 159 reported smoking less than one cigarette per day consistently throughout the years that they smoked, and about 1,500 reported smoking between one and 10 cigarettes per day. “The results of this study support health warnings that there is no safe level of exposure to tobacco smoke,” said lead author Maki Inoue-Choi.