All Group CS Group FS P
(n = 110) (n = 70) (n = 40)
Sex Female (n) 47 30 17 0.971
Male (n) 63 40 23
Age
(year) 		Mean (SD) 39.43 (12.3) 37.93 (12.26) 42.03 (12.08) 0.084
Median (min; max) 40 (19; 69) 37 (19; 69) 41.5 (19; 63)
Time of
consumption
(year) 		Mean (SD) 15.95 (9.55) 15.42 (9.69) 16.88 (9.35) 0.41
Median (min; max) 15 (1; 38) 15 (1; 38) 16.25 (4; 35)
HMI score Mean (SD) 1.22 (1.18) 1.81 (1.07) 0.18 (0.39) 0.001a
Median (min; max) 1 (0; 4) 2 (0; 4) 0 (0; 1)

aStatistically significant at level P < 0.05 (Mann-Whitney U test).
n = number; HMI = Hedin's melanin index; SD = standard deviation; CS = current smokers;
FS = former smokers.