Table 3A: GEE model (Approach 1): Effect estimates for longitudinal change of lung function parameter sin relationship with cumulative exposure of coal mine dust (in mg/m3-years) and co. variables. No. of subjects = 1343.

VCmax (liters) FEV1(liters) FEV1/VCmax(%)
Estimate Std.Err P > |z| P > |z| Estimate Std.Err P > |z| Estimate Std.Err P > |z|
Approach 1
Cumulative coal mine dust* -0.002 0.001 0.074 -0.001 0.001 0.505 0.010 0.011 0.389
Height (in cm) 0.063 0.002 < 0.001 0.049 0.002 < 0.001 -0.056 0.025 0.023
Weight (in kg) -0.005 0.001 < 0.001 -0.005 0.001 < 0.001 -0.006 0.010 0.532
Age ≤ 25 -0.035 0.004 < 0.001 -0.034 0.003 < 0.001 -0.127 0.039 0.001
Age > 25 -0.029 0.004 < 0.001 -0.032 0.003 < 0.001 -0.195 0.037 < 0.001
Non-German nationality*** -0.161 0.045 < 0.001 -0.184 0.042 < 0.001 -1.277 0.494 0.010
Active smoker*** -0.145 0.022 < 0.001 -0.090 0.021 < 0.001 0.184 0.255 0.471
Former smoker*** -0.109 0.031 < 0.001 -0.021 0.028 0.458 0.908 0.346 0.009
Cumulative pack years -0.004 0.001 0.004 -0.008 0.001 < 0.001 -0.096 0.016 < 0.001
Coking coal*** 0.271 0.032 < 0.001 0.087 0.030 0.004 -2.461 0.355 < 0.001
Custovit*** 0.128 0.012 < 0.001 -0.025 0.011 0.026 -2.480 0.170 < 0.001
Vitalograph*** 0.358 0.023 < 0.001 0.390 0.023 < 0.001 1.173 0.314 < 0.001
Year of measurements 0.014 0.004 < 0.001 0.023 0.004 < 0.001 0.233 0.042 < 0.001

Statistics: Hazard ratio with standard error, Wald test: z-value, two-sided p-value; *unit: In mg/m3-years; **Reference: German nationality; gas and flaming coal; non-smoker; body plethysmograph.