Table 2

Characteristics of smokers according to serotonin transporter genotypes

S/S (n = 127) Mean (SD)S/L (n = 66) Mean (SD)L/L (n = 9) Mean (SD)ANCOVA F(P)a
Age at smoking initiationb21.1(2.5)19.6(2.3)19.7(0.5)0.5(0.50)
Cigarettes/day in the last week27.4(10.6)34.0(14.5)33.3(10.0)15.0(0.0002)
Total days of quit attempts516(1575)254(414)16(22)3.6(0.06)
Number of quit attempts lasting 24 h1.6(3.7)1.1(2.0)0.7(0.5)2.9(0.09)
  • a P for L/L+L/S versus S/S, adjusted by age and average weight of absolute ethanol consumed/week.

  • b Age at smoking initiation may be underreported because smoking by persons under age 20 is prohibited by law in Japan.