fd852a0f-0271-4b09-bbd5-68193cfd245a
title
Association between polymorphism of the  dopamine transporter  gene and early smoking onset: an interaction risk on nicotine dependence.
2332937c-dbe1-48d9-857c-e51928add904
abstract
Previous studies suggested that a polymorphism in the  dopamine transporter gene (SLC6A3)  is associated with nicotine dependence and age of smoking onset, but the conclusion was controversial. To detect the association of a G-->A polymorphism (NCBI dbSNP cluster ID:  rs27072 ) in 3'-untranslated region of the SLC6A3 with nicotine dependence and early smoking onset, we recruited 253 sibships including 668 nicotine-dependent siblings from a rural district of China. The sibship disequilibrium tests (SDT) showed that the  rs27072-A allele  is significantly associated with smoking onset < or =18 years (kappa2=9.78, p=0.003 in severely nicotine-dependent smokers, and kappa2=4.24, p=0.058 in total smokers), but not significantly associated with severe nicotine dependence. Conditional logistic regression showed that the risk of early smoking onset by the  rs27072-A allele  was almost three times greater in severely nicotine-dependent smokers [Odds ratio (OR)=11.3, 95% confidence interval (CI)=1.5-85.6] than that in total smokers. Linear regression showed that  rs27072-A allele  also increased the risk of nicotine dependence by early smoking onset compared with homozygous  rs27072-G genotype . Although these findings are preliminary and need validation, the results suggest that a polymorphism in the SLC6A3 may play important roles in smoking onset, and there may be an interactive effect between the SLC6A3 and early smoking onset on modulating the susceptibility of nicotine dependence.