Table 1.
Demographic characteristics of participants and nonparticipants at the last survey in 2006.
| Characteristica | Participants | Nonparticipants |
|---|---|---|
| Subjects (n) | 317 | 130 |
| Men [n (%)] | 140 (44.2) | 73 (56.2) |
| Baseline age (year) | 36.5 ± 10.0* | 41.1 ± 11.4 |
| Baseline FEV1 | 2959.6 ± 707.6 | 2816.2 ± 760.3 |
| Baseline ever smoking status [n (%)] | 121 (38.2) | 37 (28.5) |
| Years since cessation of exposureb | 12.7 ± 5.3** | 17.7 ± 4.3 |
| Cumulative endotoxin exposure (EU/m3-years)c | 52,820 ± 45,507 | 61,451 ± 58,626 |
| Intensity of endotoxin (EU/m3)d | ||
| 1981 | 2,086 (677–3,779) | 3,003 (681–3,638) |
| 1986 | 1,078 (696–5,072) | 3,584 (849–5,883) |
| 1992 | 1,289 (646–5,021) | 1,082 (117–2,259) |
| 1996 | 98 (0–878) | 797 (0–1,594) |
| Annualized changes in FEV1 over the first 20 years (mL/year)c | −31.8 ± 16.5# | −41.3 ± 21.7 |
a
Valus are mean ± SD, unless otherwise stated.
b
Comparison made only among retired participants at the 2001 survey.
c
Comparison made only among participants at the 2001 survey.
d
Median (interquartile range) of work area concentration for cotton workers.
*
Significant difference between participants and nonparticipants, p < 0.0001.
**
Calculated among retired workers only, difference between participants and nonparticipants, p = 0.07.
#
Significant difference between participants and nonparticipants, p < 0.01.