, 2009). In brief, smokers wanting to quit were recruited in a Midwestern university community from 1998 through 2004. Exclusion criteria included smoking fewer than 7 cigarettes/day for the past 2 years, use of psychoactive drugs or medications other than alcohol and caffeine, alcohol use in excess of 28 alcoholic drinks per week, age less than 18 or greater than 50 years, and uncorrected download the handbook visual impairment. Upon completion of the baseline phase of the study, 80% of the participants were randomly assigned to the quit group and the rest were assigned to the group that continued to smoke. Those in the quit group were assigned (50:50 chance) to the nicotine (NP) or placebo (PP) patch group in a double blind manner. Completion of the study resulted in earning $500 minus any penalties for smoking.

Penalties for the first to the third cigarette were $10, $25, and $50, respectively, with a maximum total of $85 for three or four cigarettes. Participants were excluded from the study without payment for smoking more than four cigarettes total over the abstinence period. Financial incentive resulted in a high percentage of individuals that completed the study. Among them, 73 (81%) in the NP group and 68 (84%) in the PP group maintained abstinent status, defined as smoking four or fewer cigarettes total across the 45-day period. The number of cigarettes smoked during the quit period was estimated by a combination of self-report, carbon monoxide concentration (8+ parts per million), plasma or salivary cotinine (20+ ng/ml), and plasma nicotine (1.5+ ng/ml).

If self-report and biochemical indicators differed, the indicator suggesting that the greater number of cigarettes was taken as the number of cigarettes smoked. Of the 38 assigned to the smoke group, 33 (87%) fulfilled the requirements, including continuing to smoke. To avoid ethnic admixture, only the data from the Caucasian subjects (N = 160) were analyzed in this report. Table 1 summarized basic demographic, smoking characteristics, genotype, and group assignment status. There were no significant differences in gender, age, nicotine dependence, and group assignment ratios between subjects with and without TaqIA A1 allele. Table 1. Descriptives of subjects with and without TaqIA A1 allele Genotyping The TaqIA polymorphism was assessed by restriction fragment length polymorphism as described by Gilbert et al.

(2005). For statistical purposes, the genotypes were classified as either A1 allele carriers (A1/A2 and A1/A1) or non-A1 (homozygous A2/A2 alleles) carriers. The allele frequencies (63 [39.4%] A2/A2, 94 [58.8%] A1/A2, and 3 [1.9%] A1/A1) for the gene deviated somewhat from the Hardy�CWeinberg equilibrium, ��2(1, N = 160) = 4.305, p = .035. Brefeldin_A This deviation was verified by conducting blinded reanalysis of the samples.