Table 1.
Population characteristics, including information about the variables included in the adjustment model (n = 920)
| Total population (n = 920) | Population with water [As] < 1 μg/L (n = 707) | Population with water [As] between 1 and 10 μg/L (n = 157) | Population with water [As] > 10 μg/L (n = 56) | |||||
|---|---|---|---|---|---|---|---|---|
| A. Continuous variables |
Mean ± 1SD |
Mean ± 1SD |
Mean ± 1SD |
Mean ± 1SD |
||||
| Toenail arsenic (μg/g) |
0.122 ± 0.136 |
0.102 ± 0.096 |
0.149 ± 0.154 |
0.292 ± 0.297 |
||||
| Water arsenic (μg/L) |
2.711 ± 9.978 |
0.269 ± 0.225 |
3.806 ± 2.498 |
30.467 ± 27.942 |
||||
| Age (years) |
61.0 ± 10.0 |
61.1 ± 10.1 |
60.5 ± 9.9 |
61.7 ± 10.1 |
||||
| Water consumption from household supply (L/d) |
1.11 ± 0.77 |
1.11 ± 0.76 |
1.07 ± 0.75 |
1.17 ± 0.94 |
||||
| Energy intake (kcal/d) |
1919.1 ± 630.1 |
1907.3 ± 633.8 |
1934.8 ± 600.9 |
2024.6 ± 662.1 |
||||
| B. Categorical variables |
n |
% |
n |
% |
n |
% |
n |
% |
| Sex | ||||||||
| Female |
364 |
39.6 |
280 |
39.6 |
66 |
42.0 |
18 |
32.1 |
| Male |
556 |
60.4 |
427 |
60.4 |
91 |
58.0 |
38 |
67.9 |
| Smoking status | ||||||||
| Never smoked |
298 |
32.4 |
224 |
31.7 |
57 |
36.3 |
17 |
30.4 |
| Has smoked |
622 |
67.6 |
483 |
68.3 |
100 |
63.7 |
39 |
69.6 |
| Season in which the toenail sample was collected | ||||||||
| Winter |
186 |
20.2 |
142 |
20.1 |
30 |
19.1 |
14 |
25.0 |
| Spring |
182 |
19.8 |
144 |
20.4 |
32 |
20.4 |
6 |
10.7 |
| Summer |
268 |
29.1 |
191 |
27.0 |
52 |
33.1 |
25 |
44.6 |
| Fall |
284 |
30.9 |
230 |
32.5 |
43 |
27.4 |
11 |
19.6 |
| Case–control Status | ||||||||
| Control |
227 |
24.7 |
179 |
25.3 |
33 |
21.0 |
15 |
26.8 |
| Bladder cancer |
275 |
29.9 |
206 |
29.1 |
45 |
28.7 |
24 |
42.9 |
| Basal cell skin cancer |
214 |
23.3 |
162 |
22.9 |
40 |
25.5 |
12 |
21.4 |
| Squamous cell skin cancer |
204 |
22.2 |
160 |
22.6 |
39 |
24.8 |
5 |
8.9 |
| Body mass index | ||||||||
| Normal (<25 kg/m²) |
164 |
17.8 |
119 |
16.8 |
37 |
23.8 |
8 |
14.3 |
| Overweight (≥25 kg/m² & <30 kg/m²) |
176 |
19.1 |
142 |
20.1 |
28 |
17.8 |
6 |
10.7 |
| Obese (≥30 kg/m²) |
73 |
7.9 |
56 |
7.9 |
14 |
8.9 |
3 |
5.4 |
| Missing | 507 | 55.1 | 390 | 55.2 | 78 | 49.7 | 39 | 69.6 |