Table 1.
Characteristics of the populations included in the drinking water and dietary nitrate analyses in the New England Bladder Cancer Study
| Population included in main drinking water analysesa | Population included in dietary analysesb | |||
|---|---|---|---|---|
| Cases | Controls | Cases | Controls | |
| Characteristic | ||||
| State, n (%) | ||||
| Maine | 487 (49) | 614 (52) | 522 (49) | 665 (52) |
| Vermont | 179 (18) | 202 (17) | 187 (18) | 226 (18) |
| New Hampshire | 321 (33) | 364 (31) | 356 (33) | 376 (30) |
| Age (years), n (%) | ||||
| 30-54 | 157 (16) | 204 (17) | 158 (15) | 195 (15) |
| 55-64 | 257 (26) | 279 (24) | 273 (26) | 306 (24) |
| 65-74 | 370 (37) | 456 (39) | 403 (38) | 504 (40) |
| 75 and older | 203 (21) | 241 (20) | 231 (22) | 262 (21) |
| Sex, n (%) | ||||
| Male | 750 (76) | 863 (73) | 809 (76) | 928 (73) |
| Female | 237 (24) | 317 (27) | 256 (24) | 339 (27) |
| Race, n (%) | ||||
| White | 931 (94) | 1111 (94) | 1007 (95) | 1198 (95) |
| Other | 55 (6) | 67 (6) | 58 (5) | 67 (5) |
| Don't know | 1 | 1 | 0 | 1 |
| Refused | 0 | 1 | 0 | 1 |
| Hispanic status, n (%) | ||||
| Yes | 20 (2) | 21 (2) | 20 (2) | 20 (2) |
| No | 967 (98) | 1158 (98) | 1045 (98) | 1244 (98) |
| Don't know | 0 | 1 | 0 | 3 |
| Education, n (%) | ||||
| Less than high school | 222 (22) | 205 (17) | 220 (21) | 199 (16) |
| High School graduate | 325 (33) | 361 (31) | 337 (32) | 376 (30) |
| Vocational | 80 (8) | 90 (8) | 79 (7) | 98 (8) |
| Some college | 134 (14) | 193 (16) | 157 (15) | 197 (16) |
| College graduate | 118 (12) | 162 (14) | 146 (14) | 200 (16) |
| Post-graduate | 108 (11) | 169 (14) | 126 (12) | 197 (16) |
| Smoking status, n (%) | ||||
| Non-smoker | 149 (15) | 405 (34) | 162 (15) | 425 (34) |
| Former | 508 (52) | 571 (48) | 564 (53) | 631 (50) |
| Occasional | 17 (2) | 35 (3) | 18 (2) | 39 (3) |
| Current | 312 (32) | 169 (14) | 320 (30) | 171 (14) |
| Don't know | 1 | 0 | 1 | 1 |
| High-risk occupation, n (%) | ||||
| Yes | 534 (55) | 365 (31) | 585 (55) | 406 (32) |
| No | 444 (45) | 808 (69) | 474 (45) | 852 (68) |
| Missing | 9 | 7 | 6 | 9 |
| Average TTHM concentration, n (%) | ||||
| 0-15.7 | 474 (49) | 575 (50) | 503 (49) | 611 (50) |
| >15.7-26.8 | 234 (24) | 285 (25) | 258 (25) | 299 (25) |
| >26.8-37.1 | 150 (16) | 176 (15) | 156 (15) | 185 (15) |
| >37.1-45.7 | 52 (5) | 59 (5) | 51 (5) | 63 (5) |
| >45.7 | 61 (6) | 65 (6) | 59 (6) | 61 (5) |
| Missing | 16 | 20 | 38 | 48 |
| Red meat intake (g/d), n (%) | ||||
| 0-31 | 360 (46) | 467 (50) | 441 (47) | 562 (50) |
| >31 | 417 (54) | 473 (50) | 495 (53) | 561 (50) |
| Missing | 210 | 240 | 129 | 144 |
| Total energy intake (kcal/d) | 1922 ± 936 | 1812 ± 842 | 1877 ± 780 | 1797 ± 679 |
| Dietary vitamin C intake (mg), mean (sd) | 71 ± 45 | 70 ± 38 | 72 ± 48 | 71 ± 39 |
| Dietary vitamin B12 intake (mcg), mean (sd) | 2.5 ± 1.0 | 2.6 ± 1.0 | 2.5 ± 1.0 | 2.5 ± 1.0 |
| Total water intake (L/d) | 2.0 ± 1.2 | 1.8 ± 1.1 | 2.0 ± 1.3 | 1.8 ± 1.1 |
a
Included participants with a drinking water nitrate estimate for >=70% exposure-years from 1970 to diagnosis/reference date from residential and workplace public water supplies and measured and modeled private wells; those with missing water intake were excluded
b
Included participants that completed the Diet History Questionnaire (DHQ); those with total energy in the 1st or 99th percentiles were excluded
sd indicates standard deviation.