Clinical phenotyping strategies in selection of tobacco smokers for future genotyping studies.

Various behavioral and chemical measures were studied as potential simplified phenotyping techniques in overnight abstinent tobacco smokers. Irrespective of the machine-rated nicotine delivery (yield) of the cigarette used, there was a statistically significant correlation between the number of cigarettes consumed per day and overnight abstinence plasma cotinine concentration (r=.88) and its calculated nicotine dose per day (r=.88). Exhaled carbon monoxide (CO) levels correlated well with the number of cigarettes smoked (r=.83) and the Fagerström dependence scores (r=.85). The greater the Fagerström scores, the greater the daily cigarette consumption and plasma cotinine concentrations. After overnight abstinence, the baseline mean+/-S.D. heart rate was 62.9+/-10.0/min, the systolic blood pressure was 115.6+/-13.3 mm Hg and the diastolic blood pressure was 67.1+/-10.9 mm Hg. There were no statistically significant gender differences. Persons who were outliers on any measure are potential candidates for future genotyping studies. Preliminary guidelines of what is needed are described.