Table 3.
Characteristics of the study population (N = 396,049) according to the categories of exposure, Taiwan, 2001–2003.
| Characteristic | TTHMs (0–4 μg/L) Reference N (%) | TTHMs (5–9 μg/L) Low N (%) | TTHMs (10–19 μg/L) Medium N (%) | TTHMs (20+ μg/L) High N (%) | Total N (%) |
| Total | 181,985 (100%) | 55,950 (100%) | 82,797 (100%) | 75,317 (100%) | 396,049 (100%) |
| Gender of infant | |||||
| Male | 95,027 (52.2%) | 29,128 (52.1%) | 43,155 (52.1%) | 39,413 (52.3%) | 206,723(52.2%) |
| Female | 86,958 (47.8%) | 26,822 (47.9%) | 39,642 (47.9%) | 35,904 (47.7%) | 189,326 (47.8%) |
| Maternal age | |||||
| <20 years | 6,419 (3.5%) | 1,838 (3.3%) | 3,499 (4.2%) | 3,461 (4.6%) | 15,217 (3.8%) |
| 20–34 | 156,087 (85.8%) | 46,871 (83.8%) | 72,402 (87.4%) | 65,947 (87.6%) | 341,307 (86.2%) |
| 35- | 19,476 (10.7%) | 7,241 (12.9%) | 6,893 (8.3%) | 5,909 (7.8%) | 39,519 (10.0%) |
| Maternal diabetes mellitus | |||||
| Yes | 418 (0.2%) | 189 (0.3%) | 179 (0.2%) | 144 (0.2%) | 930 (0.2%) |
| No | 181,567 (99.8%) | 55,761 (99.7%) | 82,618 (99.8%) | 75,173 (99.8%) | 395,119 (99.8%) |
| Plurality | |||||
| Singleton | 176,791 (97.1%) | 54,383 (97.2%) | 80,755 (97.5%) | 73,442 (97.5%) | 385,371 (97.3%) |
| Multiple birth | 5,194 (2.9%) | 1,567 (2.8 %) | 2,042 (2.5%) | 1,875 (2.5%) | 10,678 (2.7%) |
| Population density (no of people/km2)* | |||||
| <1000 | 29,881 (16.4%) | 6,697 (12.0%) | 20,387 (24.6%) | 26,392 (35.2%) | 83,357 (21.1%) |
| 1000–5000 | 71,005 (39.0%) | 27,257 (48.7%) | 23,569 (28.5%) | 31,823 (42.5%) | 153,654 (38.8%) |
| >5000 | 81,099 (44.6%) | 21,996 (39.3%) | 38,841 (46.9%) | 16,738 (22.3%) | 158,674 (40.1%) |