Table 1. Children’s Health Study Population and Exposure Characteristics.
| Characteristic | No. (%) | |
|---|---|---|
| 2010 | 2012 | |
| Sex | 2290 | 1390 |
| Boys | 1141 (50) | 688 (49) |
| Girls | 1149 (50) | 702 (51) |
| Age, mean (SD), y | 13.5 (0.6) | 15.3 (0.6) |
| Height, mean (SD), cm | 159.9 (8.3) | 165.7 (8.7) |
| Weight, mean (SD), kg | 55.9 (15.1) | 65.3 (16.7) |
| Exposed to secondhand smoke | 189 (8.3) | 83 (6.0) |
| Race/ethnicity | ||
| Asian | 108 (5) | 73 (5) |
| African American | 56 (2) | 45 (3) |
| White | 919 (40) | 485 (35) |
| Mixed | 292 (13) | 156 (11) |
| Other | 588 (26) | 396 (28) |
| Unknown or missing | 327 (14) | 235 (17) |
| Hispanic | 1291 (56) | 839 (60) |
| Non-Hispanic | 866 (38) | 463 (33) |
| Unknown or missing | 133 (6) | 88 (6) |
| Trouble initiating sleep | 1239 (54) | NA |
| Trouble staying asleep | 464 (20) | NA |
| Sleep ≥8 h | 1357 (59) | NA |
| Exposures, mean (SD) | ||
| NRP, ppba | ||
| Freeway | 13.2 (16.3) | 12.4 (15.0) |
| Nonfreeway | 4.04 (2.83) | 4.05 (2.63) |
| Noise, dB | 72.3 (7.84) | 73.1 (7.57) |
| ALAN | ||
| VIIRS, nW/cm2/srb | 24.0 (15.80) | 26.3 (17.27) |
| World atlas, mcd/m2c | 4.03 (2.16) | 4.28 (2.53) |
| NDVI | 0.34 (0.08) | 0.32 (0.08) |
| EVI | 0.20 (0.05) | 0.19 (0.04) |
| Communities | ||
| Anaheim | 211 (15) | 211 (15) |
| Glendora | 69 (5) | 69 (5) |
| Long Beach | 178 (13) | 178 (13) |
| Mira Loma | 121 (9) | 121 (9) |
| Riverside | 239 (17) | 239 (17) |
| Santa Barbara | 308 (22) | 308 (22) |
| San Dimas | 126 (9) | 126 (9) |
| Upland | 138 (10) | 138 (10) |
| PSS-4, mean (SD)d | 5.28 (3.29) | 5.35 (3.30) |
Abbreviations: ALAN, artificial light at night; EVI, enhanced vegetation index; mcd/m2, millicandela per meter squared; NA, not applicable; NDVI, normalized difference vegetation index; NRP, near-roadway air pollution; nW/m2 per centimeter, nanowatts per meter squared; ppb, parts per billion; PSS-4, 4-item Perceived Stress Scale; VIIRS, Visible Infrared Imaging Radiometer Suite.
a
Nitrogen oxides.
b
Artificial light at night from the Visible Infrared Imaging Radiometer Suite in nanowatts per centimeter squared per steradian.
c
Artificial light at night from the world atlas of artificial night light.38
d
Score scaled from 0 to 16, with higher scores indicating greater perceived stress.