Association between serotonin transporter gene polymorphism and smoking among Japanese males

The serotoninergic system may be involved in smoking behavior because nicot ine increases brain serotonin secretion, nicotine withdrawal decreases sero tonin levels, and a selective serotonin reuptake inhibitor antagonizes the response to nicotine. Compared with the L allele, the S allele of the polym orphism in the upstream regulatory region of the serotonin transporter gene is associated with decreased transcription efficiency of the 5-HTT gene pr omoter. We examined this polymorphism in a Japanese population consisting o f 387 males from two different areas in Japan. The L allele was observed si gnificantly more often in smokers (21%) than in nonsmokers (lifetime nonsmo kers + ex-smokers, 14%; P = 0.005), The presence of the L allele (the L/L L/S genotypes) was also significantly increased in smokers 37%) compared w ith that in nonsmokers (24%; P = 0.003, The present study suggests that ind ividuals with the S/S genotype are less inclined to smoke and/or can more e asily stop smoking than others, supporting a role of the serotoninergic sys tem in smoking behavior.