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Table 9 Generalized estimating equation analysis of ≥ 2 repeated measurements of pulmonary function over 4 years

From: Longitudinal follow-up of health effects among workers handling engineered nanomaterials: a panel study

 ControlRisk Level 1Risk Level 2GEE analysis coefficient B (SE)
Model 1Model 2
VariablesaNMean ± SDNMean ± SDNMean ± SDRL1*TimeRL2*TimeRL1*Time
FEF25(%) 1st3498.9 ± 24.6253103.5 ± 17.424697.52 ± 17.931.269 (0.966)1.337 (1.091)0.717 (0.548)
FEF25(%) 2nd74103.91 ± 22.5781104.78 ± 18.8868105.08 ± 25.18
FEF25(%) 3rd7396.11 ± 18.6674105.06 ± 18.8872101.56 ± 20.59
FEF25(%) 4th7895.01 ± 19.8767104.29 ± 17.036497.66 ± 20.74
FEF25(%) 5th6597.02 ± 18.3152101.71 ± 17.885798.54 ± 23
FEF50(%) 1st3482.84 ± 25.15387.64 ± 21.84685.24 ± 21.661.002 (1.064)0.549 (1.029)0.305 (0.519)
FEF50(%) 2nd7490.64 ± 26.628188.68 ± 20.196891.92 ± 27.01
FEF50(%) 3rd7383.09 ± 23.967484.68 ± 19.417287.51 ± 22.3
FEF50(%) 4th7881.97 ± 21.326784.03 ± 19.026482.5 ± 22.02
FEF50(%) 5th6580.15 ± 21.845282.11 ± 21.415781.84 ± 20.57
FEF75(%) 1st3458.53 ± 26.865364.07 ± 22.694660.24 ± 25.06-0.16 (1.230)-0.04 (1.224)-0.048 (0.613)
FEF75(%) 2nd7464.91 ± 22.948161.12 ± 20.746866.05 ± 25.75
FEF75(%) 3rd7356.92 ± 19.787457.15 ± 21.077260.79 ± 17.83
FEF75(%) 4th7756.91 ± 22.456753.76 ± 17.946451.62 ± 19.02
FEF75(%) 5th6558.15 ± 24.745051.74 ± 15.325755.31 ± 23.12
  1. a.times of measurements (1st: at baseline; 2nd: at 6 months later; 3rd: at 18 months later; 4th: at 30 months later; 5th: at 42 months later)
  2. Analytical Model (Dependent variable: FEF25 (%)) includes main effects of sex, smoking, chronic bronchitis, and angina pectoris.
  3. Analytical Model (Dependent variable: FEF50 (%)) includes main effects of sex, smoking, and chronic bronchitis.
  4. Analytical Model (Dependent variable: FEF75 (%)) includes main effects of age, sex, smoking, asthma, and arrhythmia.