TABLE 4.

DETERMINANTS OF ANNUALIZED 5-YEAR CHANGES IN FEV₁ (ml/yr) OVER 20 YEARS OF FOLLOW-UP FOR COTTON WORKERS

	Estimate (95% CI)	P Value*
Age, yr	−0.48 (−1.34 to 0.38)	0.27
Height, cm	−0.53 (−1.24 to 0.17)	0.13
Male sex	−2.11 (−12.48 to 16.69)	0.78
Smoking	−6.79 (−4.29 to 17.87)	0.23
Years of retirement	0.05 (−1.42 to 1.51)	0.94
Exposure to endotoxin, EU/m3	−0.04 (−0.02 to 0.01)	0.58
Exposure to dust, mg/m3	2.92 (−6.91 to 12.76)	0.56
ΔFEV1 drop, 10 ml	−1.52 (−2.01 to −1.04)	<0.0001

Definition of abbreviations: CI = confidence interval; ΔFEV₁: cross-shift change in FEV₁.

A generalized estimating equation model was used, in which all variables but sex and exposure status are time dependent.

^*Tests for whether coefficients are different from zero.