Subjects were
defined as current smokers, former smokers, pipe or cigar
smokers, or never smokers based on their responses to a
series of questions. Current pipe or cigar smokers were
considered ‘‘current smokers’’. Subjects had to have smoked
at least 100 cigarettes, 50 cigars, or 3 ounces of pipe tobacco
to qualify as a former or current smoker. Data from the
reported smoking history were used to calculate pack years of
cigarettes smoked and, for former smokers, years since they
stopped smoking. Subjects were asked what occupation they
had worked in for the longest period of time and this was
classified into one of six categories: agriculture, mining/
manufacturing, transportation, service, other/unemployed,
and retail. Subjects reported their average monthly intake of
dairy products, vegetables, fruits, meats, and grains