Table 1 Selected characteristics of the study population at baseline
Characteristics | Non-Cases (n = 79,880) | Cases (n = 164) | P-Valve |
|---|---|---|---|
Age | 57.02 ± 14.22 | 68.07 ± 10.85 | <.001 |
PM2.5 (μg/m3) | 12.88 ± 3.72 | 13.11 ± 3.98 | <.001 |
Ozone 24 h (ppb) | 26.88 ± 3.89 | 27.07 ± 4.22 | <.001 |
Gender | Â | Â | 0.730 |
 Females | 52,067 (65.2%) | 109 (66.5%) |  |
 Males | 27,813 (34.8%) | 55 (33.5%) |  |
Smoking Status | Â | Â | <.001 |
 Never Smokers | 64,817 (81.1%) | 89 (54.3%) |  |
 Past smokers | 15,063 (18.9%) | 75 (45.7%) |  |
Race | Â | Â | 0.599 |
 Blacks | 57,461 (71.9%) | 121 (73.8%) |  |
 Non-Blacks | 22,419 (28.1%) | 43 (26.2%) |  |
Education | Â | Â | <.001 |
 High school or less | 21,820 (27.3%) | 77 (47.0%) |  |
 Trade school/ associate degree/ some college | 27,112 (33.9%) | 52 (31.7%) |  |
 Bachelor degree+ | 30,948 (38.7%) | 35 (21.3%) |  |
Family Income | Â | Â | <.001 |
 Less than $31,000 | 41,247(51.6%) | 110 (67.1%) |  |
 $31,000–$75,000 | 23,534 (29.5%) | 41 (25.0%) |  |
 $75,000 or more | 15,099 (18.9%) | 13 (7.9%) |  |
Body Mass Index (kg/m2)a | Â | Â | 0.280 |
 Less than 25 | 30,411 (39.3%) | 54 (34.4%) |  |
 25–29.99 | 27,034 (34.9%) | 64 (40.8%) |  |
 30 or more | 19,993 (25.8%) | 39 (24.8%) |  |
Physical Activity | Â | Â | 0.290 |
 Low | 31,401 (39.3%) | 74 (45.1%) |  |
 Medium | 33,472 (41.9%) | 64 (39.0%) |  |
 High | 15,007 (18.8%) | 26 (15.9%) |  |
Hours Per Day Spent Outdoors | Â | Â | 0.003 |
 Less than 1 h/day | 19,508 (24.4%) | 39 (23.8%) |  |
 1–3.5 h/day | 45,156 (56.5%) | 77 (47.0%) |  |
 More than 3.5 h/day | 15,216 (19.1%) | 48 (29.3%) |  |
Alcohol Statusa | Â | Â | <.001 |
 Never | 46,935 (59.1%) | 73 (44.8%) |  |
 Ever | 32,537 (40.9%) | 90 (55.2%) |  |
Residence Lengthb | Â | Â | <.001 |
 Less than 5 years | 19,924 (25.0%) | 29 (17.7%) |  |
 5 ≤ years <12 | 20,583 (25.8%) | 32 (19.5%) |  |
 12 ≤ years <24 | 19,713 (24.7%) | 43 (26.2%) |  |
 More than 24 years | 19,660 (24.6%) | 60 (36.6%) |  |
Moving Distancec | Â | Â | 0.649 |
 0 KM | 48,865 (61.2%) | 95 (57.9%) |  |
 0 < KM ≤30 | 15,054 (18.9%) | 32 (19.5%) |  |
 More than 30 KM | 15,961 (20.0%) | 37 (22.6%) |  |
Years Since Quit Smoking (7 levels) | Â | Â | <.001 |
 Never smokers | 64,817 (81.1%) | 89 (54.3%) |  |
 Quit ≥30 | 4738 (5.9%) | 19 (11.6%) |  |
 Quit 20–29.9 years | 3601 (4.5%) | 15 (9.2%) |  |
 Quit 10–19.9 years | 3170 (4.0%) | 17 (10.4%) |  |
 Quit 5–9.9 years | 1394 (1.8%) | 7 (4.3%) |  |
 Quit 1–4.9 years | 1199 (1.5%) | 8 (4.9%) |  |
 Quit <1 year | 961 (1.2%) | 9 (5.5%) |  |
Average Number of Cigarettes Per Day | Â | Â | <.001 |
 None | 64,906 (81.1%) | 89 (54.3%) |  |
 Less than 8.5 | 7677 (9.6%) | 27 (16.5%) |  |
 Greater or equal to 8.5 | 7461 (9.3%) | 48 (29.3%) |  |
Non-Melanoma Skin Cancer | Â | Â | <.001 |
 No | 74,529 (93.3%) | 142 (86.6%) |  |
 Yes | 5351 (6.7%) | 22 (13.4%) |  |