Table 1.

Characteristics of Skin-Lesion Cases and Population-Based Controls in Pabna, Bangladesh

		Controls		Cases
Diffuse Melanosis				n = 377
Leukomelanosis				n = 342
Spotted Melanosis				n = 145
Diffuse Keratosis				n = 117
Spotted Keratosis				n = 73
Hyperkeratosis				n = 40
Mean Age in yrs (SD)		33.7 (12.6)	n = 597	33.9 (12.7)	n = 592	P = 0.58
Mean Body Mass Index (kg/m2) (SD)		20.4 (3.1)	n = 597	20.1 (3.1)	n- = 592	P = 0.70
% Male		60.3%	n = 360	60.3%	n = 357	P = 0.91
Mean Duration of Present well use(yrs) (SD)		10.1 (9.0)	n = 592	8.0 (7.2)	n = 592	P = 0.02
% Reported a Previous Well		2.84%	n = 17	7.77%	n = 45	P < 0.0001
Mean As concentration of current well (μg/l) (SD)		66.2 (149.6)	n = 595	232.8 (315.7)	n = 592	P < 0.0001
Mean Daily Total Water/Liquid consumption (L) (SD)		3.8 (1.2)	n = 595	3.7 (1.1)	n = 592	P = 0.84
% Ever used Betel nuts		24.3%	n = 145	27.7%	n = 164	P = 0.007
Mean Years of Betel nut Use (SD)		10.8 (8.9)	n = 143	11.0 (9.5)	n = 160	P = 0.78
Mean Number of Betel nuts chewed per day (SD)		5.6 (3.6)	n = 158	5.7 (3.8)	n = 149	P = 0.53
% Chew tobacco leaves		16.4%	n = 587	17.1%	n = 590	P < 0.0001
Mean Years of Tobacco leaves chewed (SD)		9.9 (9.1)	n = 95	10.9 (9.4)	n = 95	P = 1.0
% Smokes Cigarettes Currently		30.5%	n = 597	26.7%	n = 592	P = 0.03
% Ever Smoked		31.0%	n = 597	28.7%	n = 592	P = 0.0007
Education Level		n = 597		N = 592		P = 0.80
% Illiterate		17.4%	n = 104	22.9%	n = 136
% Literate (incomplete Primary Education)		23.8%	n = 142	29.4%	n = 174
%Completed Primary Education		11.7%	n = 79	11.8%	n = 70
% Completed Middle School Education		31.9%	n = 191	23.5%	n = 139
%Completed Secondary Education or More		13.6%	n = 81	26.0%	n = 154
Polymorphims:
GSTT1						P = 0.07
Null	17.9%	18.9%	n = 112	16.9%	n = 100
Wildtpe	82.1%	81.1%	n = 482	83.1%	n = 492
GSTM1						P = 0.72
Null	41.1%	41.1%	n = 244	41.0%	n = 243
Wildtype	58.9%	58.9%	n = 350	59.0%	n = 349
GSTP1						P = 0.07
AA	53.8%	53.5%	n = 313	54.1%	n = 318
AG	38.7%	40.3%	n = 236	37.1%	n = 218
GG	7.5%	6.2%	N = 36	8.8%	n = 52