Comparison of exposure duration in the exposed group between subjects without and with symptoms.

Table 4: Comparison of exposure duration in the exposed group between subjects without and with symptoms.

Respiratory chronic symptoms	Exposure duration (months) in the exposed group (Mean ± SD)		p-Value^*
Respiratory chronic symptoms	Without symptoms	With symptoms	p-Value^*
Asthma	39.92 ± 15.59	45.06 ± 16.27	0.260
Chronic cough	37.68 ± 15.56	46.88 ± 14.74	0.021*
Morning cough with sputum	39.85 ± 16.03	44.42 ± 15.10	0.291
Phlegm	41.11 ± 15.64	42.00 ± 20.78	0.914
Chronic phlegm	41.75 ± 16.76	34.00 ± 16.12	0.295
Wheeze	41.21 ± 15.26	40.88 ± 20.49	0.956
Respiratory problems (asthma, coughing) caused by current work	39.49 ± 15.63	55.29 ± 8.99	0.011^*

T-test: ^*significant at P < 0.05, ^** significant at P < 0.01, ^*** significant at P < 0.001.