Who were the participants in CARET?
The study had two groups: 14,254 current and former smokers with a long history of smoking and 4,060 asbestos-exposed individuals. The smokers and former smokers included 14,254 men and women ages 50 to 69 who are current smokers or are smokers who had quit within six years of enrolling in the study. Smokers and former smokers must have had a smoking history of at least 20 pack years (one pack per day for 20 years or two packs for 10 years, etc). These participants are 56 percent male (7,965) and 44 percent female (6,289) and had an average of 50 pack years of smoking. About 34 percent were former smokers when they joined the study. All participants were counseled to quit smoking at their visits to the study centers. The asbestos-exposed participants were 4,060 men ages 45 to 69 years who had been exposed to asbestos while at work. These participants had to have extensive occupational asbestos exposure beginning at least 15 years prior to enrollment, determined by either a chest X-ray
