Aspirin use was ascertained by asking the
respondents "How often do you take aspirin? Examples of aspirin include Bufferin, Anacin,
enteric-coated aspirin, Ecotrin, and Excedrin (Do not include acetaminophen, Tylenol,
Ibuprofen, Advil): never, less than one per week, one per week, 2–5 per week, and 6+ per
week