Table 4.

Association of respiratory symptoms with exposure duration and smoking habit.

Variable	Agricultural workers (n = 75)	P-value*	Office workers (n = 75)	P-valuee*
Workplace exposure ≥ 16 yrs with respiratory symptoms	17/42 (40.5%)	0.043	-	-
Workplace exposure ≤ 15 yrs with respiratory symptoms	5/33 (15.2%)
Daily smokers with respiratory symptoms	12/22 (54.5%)	0.001	12/16 (75.0%)	0.001
Daily smokers without respiratory symptoms	8/53 (15.1%)		10/59 (16.9%)
Passive smokers with respiratory symptoms	5/22 (22.7%)	0.318	4/16 (25.0%)	0.233
Passive smokers without respiratory symptoms	7/53 (13.2%)		7/59 (11.8%)

Data are expressed as number and percentage of examinees with certain variable with and without chronic respiratory symptoms. Yrs: years.

^*Tested by Chi-square test.