We first studied 583 men and women of European, Japanese or Native Hawaiian ancestry who were long-term smokers of >10 cigarettes day. Participants were randomly selected among members of the Multiethnic Cohort Study (88%) or controls of several completed population-based case-control studies (12%) living on Oahu, Hawaii (6-8). Other inclusion criteria included having no previous history of invasive cancer, having both parents of Japanese or European ethnicity, or of any amount of Native Hawaiian ancestry, and smoking at least 10 cigarettes per day. These individuals were re-contacted for this study and instructed on how to record their food consumption for three days, as well as to collect a 12-hour, overnight urine sample at the end of those 3 days. A blood sample was then collected and a short questionnaire (including tobacco use during the previous three days) administered. The overall target sample size for this study was 100 in each sex and ethnic group. A total of 596 participants completed all aspects of the study, corresponding to a participation rate of 64.4%. Eight subjects were excluded for reporting to smoke fewer than the required 10 cigarettes per day during data collection, and 5 were excluded for missing covariate.
