Table 2.
Association of trihalomethanes (THMs) in residential tap water and nitrate waterborne ingestion with chronic lymphocytic leukemia (CLL).
| Exposure | Controls | Cases | OR (95% CI) Multivariable adjusteda | OR (95% CI) Multivariable adjustedb | OR (95% CI) Multivariable adjustedc |
|---|---|---|---|---|---|
| Total THMs in residential tap water (μg/L), N = 1374 | |||||
| Tertile 1 (<52.2) | 411 | 31 | Ref. [1] | Ref. [1] | Ref. [1] |
| Tertile 2 (52.2–83.2) | 409 | 23 | 0.48 (0.20, 1.19) | 0.49 (0.19, 1.25) | 0.57 (0.22, 1.48) |
| Tertile 3 (>83.2) | 410 | 90 | 2.11 (0.91, 4.89) | 2.13 (0.89, 5.14) | 2.22 (0.90, 5.48) |
| P-trend | 1230 | 144 | <0.001 | <0.001 | <0.001 |
| Per 10 μg /L | 1230 | 144 | 1.24 (1.16, 1.32) | 1.23 (1.15, 1.32) | 1.24 (1.16, 1.34) |
| Brominated THMs in residential tap water (μg/ L), N = 1374 | |||||
| Tertile 1 (<30.0) | 411 | 31 | Ref. [1] | Ref. [1] | Ref. [1] |
| Tertile 2 (30.0–60.8) | 409 | 23 | 0.50 (0.21, 1.22) | 0.52 (0.21, 1.29) | 0.85 (0.31, 2.36) |
| Tertile 3 (>60.8) | 410 | 90 | 2.16 (0.94, 4.94) | 2.23 (0.95, 5.26) | 2.32 (0.91, 5.91) |
| P-trend | 1230 | 144 | <0.001 | <0.001 | <0.001 |
| Per 10 μg/L | 1230 | 144 | 1.25 (1.17, 1.33) | 1.24 (1.17, 1.3) | 1.22 (1.14, 1.31) |
| Chloroform in residential tap water (μg/L), N = 1374 | |||||
| Tertile 1 (<17.3) | 410 | 54 | Ref. [1] | Ref. [1] | Ref. [1] |
| Tertile 2 (17.3– 22.3) | 410 | 62 | 0.69 (0.45, 1.06) | 0.70 (0.45, 1.08) | 0.81 (0.50, 1.31) |
| Tertile 3 (>22.3) | 410 | 28 | 0.23 (0.13, 0.40) | 0.23 (0.13, 0.41) | 0.42 (0.22, 0.82) |
| P-trend | 1230 | 144 | <0.001 | <0.001 | 0.02 |
| Per 10 μg/L | 1230 | 144 | 0.44 (0.32, 0.61) | 0.44 (0.31, 0.61) | 0.54 (0.34, 0.87) |
| Nitrate waterborne ingestion (mg/day), N = 1245 | |||||
| Tertile 1 (<8.6) | 372 | 34 | Ref. [1] | Ref. [1] | Ref. [1] |
| Tertile 2 (8.6–16.8) | 371 | 57 | 1.54 (0.91, 2.61) | 1.57 (0.92, 2.68) | 1.52 (0.87, 2.64) |
| Tertile 3 (>16.8) | 371 | 40 | 0.94 (0.53, 1.66) | 1.00 (0.56, 1.79) | 1.04 (0.57, 1.89) |
| P-trend | 1114 | 131 | 0.36 | 0.51 | 0.64 |
| Per 5 mg/day | 1114 | 131 | 0.93 (0.83, 1.04) | 0.95 (0.84, 1.06) | 0.91 (0.80, 1.04) |
Odds ratios (OR) and 95% confidence intervals (CI) were calculated using mixed models with residential area (Barcelona, Asturias, Cantabria) as random effect.
Brominated THMs includes bromodichloromethane, dibromochloromethane, and bromoform.
Total THMs includes chloroform, bromodichloromethane, dibromochloromethane, and bromoform.
ORs Odds ratios, 95% CIs 95% confidence intervals.
aModel adjusted for age, sex, and educational level.
bModel further adjusted for family history of hematologic malignancy, body mass index, smoking, physical activity, ever worked in farming or agriculture and alcohol consumption.
cModel further mutually adjusted for the other corresponding components, i.e., total THMs (nitrate model), nitrate (THMs model), chloroform and nitrate (brominated THMs model), brominated THMs and nitrate (chloroform model).