Table 1.
Characteristics of the Study Population, California (1997–2007)
| Characteristic | Cases | Controls | |
|---|---|---|---|
| N | 5896 | 23369 | |
| Birth year | 1997–1999 | 2046 (35%) | 8114 (35%) |
| 2000–2002 | 1718 (29%) | 6805 (29%) | |
| 2003–2005 | 1454 (25%) | 5760 (25%) | |
| 2006–2007 | 678 (12%) | 2690 (12%) | |
| Age at diagnosis | 0–1 | 1853 (31%) | NA |
| 2–6 | 3187 (54%) | NA | |
| >6 | 856 (15%) | NA | |
| Sex | Male | 3278 (56%) | 12979 (56%) |
| Female | 2618 (44%) | 10390 (45%) | |
| Age of mother | Mean (SD) | 28.40 (6.4) | 27.96 (6.3) |
| Age of father | Mean (SD) | 31.21 (7.2) | 30.85 (7.1) |
| Median household income ($) | Mean (SD) | 49828.4 (24708) | 48433.53 (24221) |
| Proportion of Adults without a GED (%) | Mean (SD) | 0.29 (0.2) | 0.30 (0.2) |
| Population density (persons/m2) | Mean (SD) | 0.0038 (0.0040) | 0.0040 (0.0041) |
| Race/ethnicity of mother | White, non-Hispanic | 2097 (36%) | 8078 (35%) |
| Hispanic | 2704 (46%) | 10886 (47%) | |
| Black, non-Hispanic | 288 (5%) | 1158 (5%) | |
| Asian & Pacific Islander, non-Hispanic | 578 (10%) | 2339 (10%) | |
| Alaskan & Native American, non-Hispanic | 25 (1%) | 94 (1%) | |
| Other | 204 (4%) | 814 (4%) | |
| Race/ethnicity of father | White, non-Hispanic | 2016 (34%) | 7587 (33%) |
| Hispanic | 2555 (43%) | 10196 (44%) | |
| Black, non-Hispanic | 335 (6%) | 1300 (6%) | |
| Asian & Pacific Islander, non-Hispanic | 485 (8%) | 2095 (9%) | |
| Alaskan & Native American, non-Hispanic | 18 (1%) | 100 (1%) | |
| Other | 487 (8%) | 2091 (9%) |
Abbreviations: GED=general education diploma, SD=standard deviation.