S. population (Hays et al., 2003). The present sample includes the 90,849 (97%) of baseline AZD9291 structure participants who provided sufficient data on the measures used here. At baseline, the participants in the present sample were an average age of 63.6 years (SD = 7.36). The sample was predominantly White, not of Hispanic origin (83.9%), with the remainder of the sample being American Indian/Alaskan Native (0.4%), Asian/Pacific Islander (2.9%), Black (8.0%), Hispanic (3.7%), and unknown (1.1%). Five percent of participants had less than a high school education, 16% had a high school education, 37% had some education beyond high school but had not completed college, and 42% had completed college. Measures Smoking status, history of smoking, and sociodemographic factors were assessed at baseline.
Quality of life was assessed at baseline and at a 3-year follow-up. Mortality was assessed across an approximately 10-year follow-up period. Sociodemographic Factors Sociodemographic factors used as control variables included age (in years), educational level, and ethnic group membership. Educational level was operationalized as less than a high school (or vocational school) education, high school (or vocational school) education, some education beyond high school but not having completed college, and completed college. Smoking Status Smoking status at baseline (never-smoker, former smoker, light smoker, heavier smoker) was indexed in several steps. First, participants were asked, ��During your entire life, have you smoked at least 100 cigarettes?�� Participants who responded ��no�� were coded as never-smokers.
Next, participants who reported having smoked at least 100 cigarettes in their entire life were asked, ��Do you smoke cigarettes now?�� Those who reported that they did not currently smoke cigarettes were coded as former smokers. Those who reported that they currently smoked cigarettes were coded as either light or heavier smokers based on their response to a question that asked, ��On an average, how many cigarettes do you usually smoke each day?�� Response choices were as follows: less than 1, 1�C4, 5�C14, 15�C24, 25�C34, 35�C44, and 45 or more. Following definitions of light smoking used in other studies (Falba, Jofre-Bonet, Busch, Duchovny, & Sindelar, 2004; Godtfredsen, Prescott, & Osler, 2005; Godtfredsen, Prescott, Vestbo, & Osler, 2006; Hatsukami et al., 2006; Wilson et al., 1999), light smoking was operationalized as less than 15 cigarettes/day. Heavier smoking was operationalized as 15 or more cigarettes/day (Hatsukami et al., Brefeldin_A 2006). Years of Smoking Among former smokers, years of regular smoking was indexed by a question that asked, ��How many years were you a regular smoker? Do not count the times you stayed off cigarettes.