classified as early nicotine users if they reported smoking at least 100 cigarettes lifetime before age 18. Using this criterion, 28% of respondents were early regular smokers (46% of those who had smoked 100+ cigarettes lifetime). In the 1987 self-report questionnaire, respondents were asked whether they had been stationed in Southeast Asia during their Vietnam-era military service. Thirty-seven percent of the respondents served in Southeast Asia, 59% were stationed elsewhere, and 4% were of unknown status because of missing data in the 1987 questionnaire.
