Table 5: Average values of spirometric parameters distributed on occupational group, age group and smoking status.

	≤ 49 years				≥ 50 years
	Demolition workers N = 108	Insulators N = 63	Carpenters N= 203	Hospital porters N = 153	Demolition workers N = 33	Insulators N = 87	Carpenters N = 93	Hospital porters N = 160
Never smokers	n = 20	n = 11	n = 96	n = 58	n = 4	n = 28	n = 39	n = 42
Measured FEV1 (litres)	4.11	4.13	4.18	3.91	3.01	3.80	3.83	3.69
Measured FVC (litres)	5.31	5.31	5.35	4.98	4.03	4.85	5.00	4.79
FEV1/FVC	0.78	0.78	0.78	0.79	0.74	0.79	0.77	0.77
Measured FEV1/expected FEV1	98.93	102.33	101.81	96.41	87.32	102.24	104.03	98.55
Measured FVC/expected FVC	104.45	107.73	106.67	99.71	93.15	103.82	107.90	101.71
Former smokers	n = 22	n = 20	n = 58	n = 44	n = 15	n = 34	n = 34	n = 66
Measured FEV1 (litres)	3.89	3.82	4.14	3.87	3.29	3.37	3.65	3.51
Measured FVC (litres)	5.06	4.93	5.37	5.13	4.40	4.47	4.90	4.70
FEV1/FVC	0.77	0.78	0.77	0.76	0.74	0.75	0.75	0.74
Measured FEV1/expected FEV1	94.83	96.66	99.28	95.70	89.18	94.01	98.61	94.49
Measured FVC/expected FVC	100.90	101.48	104.83	103.32	94.94	99.25	105.18	100.80
Current smokers	n = 65	n = 31	n = 45	n = 51	n = 14	n = 25	n = 19	n = 49
Measured FEV1 (litres)	3.81	3.81	4.04	3.76	3.11	3.29	3.17	3.35
Measured FVC (litres)	5.18	5.21	5.39	5.02	4.32	4.67	4.43	4.63
FEV1/FVC	0.74	0.73	0.75	0.75	0.72	0.71	0.72	0.72
Measured FEV1/expected FEV1	92.53	94.23	97.43	91.32	85.28	91.82	88.67	91.09
Measured FVC/expected FVC	102.84	104.97	106.12	99.69	94.44	103.41	98.35	100.24

N = All in age and workgroup.

n = total in smoking sub-group.