Group CS Group FS
Mean (SD) Median
(min; max) 		Pa Mean (SD) Median
(min; max) 		Pb
Age Cigarettes
(n = 63) 		39.34 (12.1)c 40 (21; 69)c 0.017* Cigarettes
(n = 37) 		42.78 (11.93) 42 (25; 63) 0.19
Hookah
(n = 5) 		24.4 (3.13) 25 (19; 27) Hookah
(n = 3) 		32.67 (11.85) 39 (19; 40)
Cigar and pipe
(n = 2) 		28 (4.24) 28 (25; 31) Cigar and pipe
(n = 0) 		N/A N/A
Time of
consumption 		Cigarettes
(n = 63) 		16.32 (9.79) 15.5 (1; 38) 0.06 Cigarettes
(n = 37) 		17.14 (9.48) 15.5 (4.5; 35) 0.589
Hookah
(n = 5) 		6.4 (1.82) 7 (4; 8) Hookah
(n = 3) 		13.67 (8.39) 18 (4; 19)
Cigar and pipe
(n = 2) 		10 (0) 10 (10; 10) Cigar and pipe
(n = 0) 		N/A N/A
Daily
consumption 		Cigarettes
(n = 63) 		14.71 (9.79) 12.5 (0.25; 50) 0.141 Cigarettes
(n = 37) 		5.19 (5.26) 4 (1; 27) 0.185
Hookah
(n = 5) 		6.26 (9.02) 0.1 (0.1; 20) Hookah
(n = 3) 		2.33 (1.53) 2 (1; 4)
Cigar and pipe
(n = 2) 		11.3 (15.84) 11.3 (0.1; 22.5) Cigar and pipe
(n = 0) 		N/A N/A
HMI score Cigarettes
(n = 63) 		1.89 (1.08) 2 (0; 4) 0.179 Cigarettes
(n = 37) 		0.19 (0.4) 0 (0; 1) 0.413
Hookah
(n = 5) 		1.2 (0.45) 1 (1; 2) Hookah
(n = 3) 		0 (0) 0 (0; 1)
Cigar and pipe
(n = 2) 		1 (1.41) 1 (0; 2) Cigar and pipe
(n = 0) 		N/A N/A

aKruskal-Wallis test; bMann-Whitney U test; cMann-Whitney U test with Bonferroni correction.
*Statistically significant at level P < 0.05.
n = number; HMI = Hedin's melanin index; SD = standard deviation; CS = current smokers; FS = former smokers.