Table 1.
Age-standardized characteristics of the 111,769 study participants at baseline in 1990 with respect to categories of PM 10
| PM 10 | ||||
|---|---|---|---|---|
| Pollution category | Q1* | Q2 | Q3 | Q4 |
| Median PMa | 19.0 | 22.6 | 26.0 | 31.8 |
| Age, mean (sd) | 58.2 (7.2) | 58.2 (7.2) | 58.1 (7.2) | 58.2 (7.2) |
| Never Smoker (%) | 48.0 | 46.5 | 45.9 | 42.3 |
| Pack years, mean (sd) | 12.8 (19.3) | 13.1 (19.4) | 13.0 (19.1) | 13.9 (19.5) |
| Caffeine mg/day, mean (sd) | 284.2 | |||
| (239.5) | 284.6 | |||
| (238.1) | 280.2 | |||
| (234.1) | 274.8 | |||
| (228.2) | ||||
| Ibuprofen ever user (%) | 28.7 | 28.4 | 28.7 | 26.8 |
| Census tract incomeb, USD, mean (sd) | 51602.9 | |||
| (16926) | 58044.3 | |||
| (22510.2) | 66772.3 | |||
| (26322.7) | 66,772.3 | |||
| (26322.7) | ||||
| (Population density)b, (persons/tract), mean, (sd) | 1436.3 | |||
| (2184.5) | 2139.3 | |||
| (3216.8) | 1922.6 | |||
| (3088.5) | 4449.4 | |||
| (9575.1) | ||||
| Region of US | ||||
| ‘Northeast Region | 12.2 | 18.5 | 41.8 | 61.2 |
| ‘Midwest region’, % | 31.8 | 26.2 | 27.2 | 14.7 |
| ‘West region’, % | 7.0 | 3.5 | 6.7 | 15.9 |
| ‘South region’, % | 49.0 | 51.8 | 24.3 | 8.2 |
*Q (1,2,3,4) - quartiles – categories (C1, C2, C3 and C4) for distance to road as shown in Table 3.
g/day: grams/day.
aμg/m3 (PM).
btract-level variable based on the 2000 US Census.