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Table 6 Effect of genetic polymorphisms and smoking histories of participants on nicotine dependence in current smokers: Regression analysis of the effect of combinations of genetic polymorphisms on nicotine dependence

From: Genetic influence of dopamine receptor, dopamine transporter, and nicotine metabolism on smoking cessation and nicotine dependence in a Japanese population

Genes R 2 AIC P -value
SLC6A3 0.054, 0.048 77.940, 72.719 0.025, 0.040
SLC6A3 + ANKK1/DRD2 0.057, 0.260 78.660, 74.262 0.045, 0.098
SLC6A3 + CYP2A6 0.098, 0.087 75.327*, 70.761 0.009, 0.018
  1. Each analysis was performed for the whole cohort (the left side) and the male subgroup only (the right side). Forward-selection regression began with the effect of the SLC6A3 polymorphism alone. Variables were added one at a time to the model until no remaining variable produced a significant result. SLC6A3: input 1 or 0 for the 10r/10r or other genotype, respectively; ANKK1/DRD2: input 1 for the A2/A2 genotype, 0 for the A1/A2 or A1/A1 genotypes; CYP2A6: input 1 for the *1/*1 genotype, 0 for genotypes including the *4 allele. R2, squared multiple correlation coefficient adjusted for degrees of freedom; AIC, Akaike’s information criterion. *The appropriate model was selected on the basis of minimising AIC.