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

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

	Control		Risk Level 1		Risk Level 2		GEE analysis coefficient B (SE)
	Control		Risk Level 1		Risk Level 2		Model 1		Model 2
Variables^a	N	Mean ± SD	N	Mean ± SD	N	Mean ± SD	RL1*Time	RL2*Time	RL1*Time
FEF25(%) 1st	34	98.9 ± 24.62	53	103.5 ± 17.42	46	97.52 ± 17.93	1.269 (0.966)	1.337 (1.091)	0.717 (0.548)
FEF25(%) 2nd	74	103.91 ± 22.57	81	104.78 ± 18.88	68	105.08 ± 25.18
FEF25(%) 3rd	73	96.11 ± 18.66	74	105.06 ± 18.88	72	101.56 ± 20.59
FEF25(%) 4th	78	95.01 ± 19.87	67	104.29 ± 17.03	64	97.66 ± 20.74
FEF25(%) 5th	65	97.02 ± 18.31	52	101.71 ± 17.88	57	98.54 ± 23
FEF50(%) 1st	34	82.84 ± 25.1	53	87.64 ± 21.8	46	85.24 ± 21.66	1.002 (1.064)	0.549 (1.029)	0.305 (0.519)
FEF50(%) 2nd	74	90.64 ± 26.62	81	88.68 ± 20.19	68	91.92 ± 27.01
FEF50(%) 3rd	73	83.09 ± 23.96	74	84.68 ± 19.41	72	87.51 ± 22.3
FEF50(%) 4th	78	81.97 ± 21.32	67	84.03 ± 19.02	64	82.5 ± 22.02
FEF50(%) 5th	65	80.15 ± 21.84	52	82.11 ± 21.41	57	81.84 ± 20.57
FEF75(%) 1st	34	58.53 ± 26.86	53	64.07 ± 22.69	46	60.24 ± 25.06	-0.16 (1.230)	-0.04 (1.224)	-0.048 (0.613)
FEF75(%) 2nd	74	64.91 ± 22.94	81	61.12 ± 20.74	68	66.05 ± 25.75
FEF75(%) 3rd	73	56.92 ± 19.78	74	57.15 ± 21.07	72	60.79 ± 17.83
FEF75(%) 4th	77	56.91 ± 22.45	67	53.76 ± 17.94	64	51.62 ± 19.02
FEF75(%) 5th	65	58.15 ± 24.74	50	51.74 ± 15.32	57	55.31 ± 23.12

^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)
Analytical Model (Dependent variable: FEF25 (%)) includes main effects of sex, smoking, chronic bronchitis, and angina pectoris.
Analytical Model (Dependent variable: FEF50 (%)) includes main effects of sex, smoking, and chronic bronchitis.
Analytical Model (Dependent variable: FEF75 (%)) includes main effects of age, sex, smoking, asthma, and arrhythmia.

ISSN: 1476-069X