No such thing as safe smoking

Even individuals who are long-term, low-intensity smokers and consume 10 or fewer cigarettes per day over their lifetime have a higher risk of death than those who never smoke, compared with those who never smoke, according to results from the National Institutes of Health—AARP Diet and Health Study, published online by JAMA Internal Medicine. The bottom line is that there is no such thing as a safe level of smoking.

Researchers from the National Cancer Institute (NCI), Rockville, MD, and the Center for Tobacco Products of the US Food and Drug Administration, Silver Spring, MD, assessed the possible association between the risk of death and long-term smoking of 1 to 10 cigarettes per day in 290,215 older adults aged 59 to 82 years who completed a questionnaire for the National Institutes of Health—AARP Diet and Health Study in 2004-2005. Included were 22,337 current smokers (7.7%), 156,405 former smokers (53.9%), and 111,473 never smokers (38.4%). In these subjects, researchers led by Maki Inoue-Choi, PhD, MD, of the NCI, measured smoking intensity during periods when subjects were less than 15 years old, to over 70 years old via questionnaire.

They found a higher risk of all-cause mortality in those who were low-intensity smokers of 10 or less cigarettes per day compared with never smokers. Associations with smoking-related causes of death were also higher and similar in both men and women, and notably included lung cancer mortality (HR: 9.12; 95% CI, 2.92-28.47, and HR: 11.61; 95% CI, 8.25-16.35 for < 1 and 1-10 cigarettes per day, respectively).

But the good news was that the younger a person was when he/she quit, the progressively lower the risk of death became. For example, the hazard ratio for consistent smokers of less than 1 and 1 to 10 cigarettes per day who quit at 50 years or older were 1.44 (95% CI: 1.12-1.85) and 1.42 (95% CI: 1.27-1.59), respectively.

“These findings provide further evidence that there is no safe level of cigarette smoking. All smokers should be targeted for smoking cessation, regardless of how few cigarettes they smoke per day. Further studies are needed to examine the health risks of low-intensity cigarette smoking in combination with electronic nicotine delivery systems and other tobacco products,” concluded Dr. Inoue-Choi and fellow researchers.