Association between neuropeptide Y receptor 2 polymorphism and the smoking behavior of elderly Japanese.

Molecular heterogeneity of neuropeptide Y (NPY) and its three receptors (1, 2 and 5) has recently been discovered. NPY2R polymorphisms have been shown to be related to cocaine and alcohol dependence in European Americans. To test our hypothesis that these polymorphisms influence the smoking behavior of Japanese population, we investigated the prevalence of the rs4425326 and rs6857715 polymorphisms, which have been suggested to be related to alcohol dependence in European Americans, in 2517 Japanese elderly subjects for whom information on smoking behaviors was available. The prevalence of current smokers was greater among Japanese men having the rs4425326 C allele than ex-smokers. Among the ever-smokers, the Fagerström Test for Nicotine Dependence scores were higher in men having the rs4425326 homozygous T allelotype, and the numbers of cigarettes smoked per day were also significantly higher in the male smokers having the TT genotype. No correlations between the Tobacco Dependence Screener scores and any genotypes were detected. These results suggest that rs4425326 polymorphism may be related to smoking behavior in the Japanese elderly population. This study for the first time suggests NPY2R genotype as a possible genetic factor in nicotine dependence.