Table 2.
Mean proportions (standard deviations) of each arsenic species.
| Variable | N | % | %iAs | %MMA | %DMA |
|---|---|---|---|---|---|
| All | 558 | 100 | 9.6 (6.3) | 10.8 (4.8) | 80.0 (8.3) |
| Cancer status | |||||
| Controls | 347 | 62 | 10.4 (6.6) | 10.2 (4.3) | 79.4 (8.4) |
| Lung cancera | 94 | 17 | 10.0 (5.9) | 12.6 (5.4) | 77.4 (8.6) |
| p=0.58 | p<0.001 | p=0.05 | |||
| Bladder cancera | 117 | 21 | 6.9 (5.0) | 11.2 (5.3) | 81.9 (7.3) |
| p<0.001 | p=0.04 | p=0.005 | |||
| Genderb | |||||
| Women | 162 | 31 | 9.0 (5.9) | 9.8 (4.5) | 81.2 (7.9) |
| Men | 396 | 69 | 9.8 (6.5) | 11.2 (4.8) | 78.9 (8.4) |
| p=0.18 | p=0.001 | p=0.004 | |||
| Smokingb | |||||
| Ever | 390 | 70 | 9.3 (6.1) | 11.1 (4.9) | 79.5 (8.3) |
| Never | 168 | 30 | 10.1 (6.9) | 10.1 (4.6) | 79.8 (8.5) |
| p=0.19 | p=0.02 | p=0.75 | |||
| Age (years)c | |||||
| <60 | 166 | 32 | 10.8 (6.1) | 10.3 (4.5) | 78.9 (8.1) |
| 60–70 | 198 | 35 | 8.9 (6.4) | 11.0 (5.2) | 80.1 (8.9) |
| >70 | 194 | 33 | 9.2 (6.4) | 11.1 (4.6) | 79.7 (8.0) |
| R = − 0.15 | R=0.08 | R=0.05 | |||
| p< 0 .001 | p=0.08 | p=0.16 | |||
| Urinary arsenicc,d | |||||
| Low tertile | 183 | 33 | 8.9 (6.7) | 11.0 (4.9) | 80.2 (8.2) |
| Medium tertile | 191 | 34 | 9.9 (5.9) | 11.0 (4.7) | 79.1 (8.1) |
| High tertile | 184 | 33 | 9.9 (6.4) | 10.5 (4.8) | 79.6 (8.8) |
| R=0.10 | R=−0.05 | R=−0.02 | |||
| p=0.02 | p=0.20 | p=0.61 |
a
p-values comparing cancer cases to controls calculated using the Wilcoxon rank-sum test.
b
p-values comparing men to women or ever to never smokers calculated using the Wilcoxon rank-sum test.
c
Spearman correlation coefficients (R) and their p-values.
d
Sum of urinary concentrations of iAs, MMA, and DMA. The tertile cutoff points are 14.5 and 28.5 μg/L.