Table 1 Characteristics of Skin-Lesion Cases and Population-Based Controls in Pabna, Bangladesh

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