Table 7.

Association of obstructive pattern with exposure duration and smoking habit.

Variable	Agricultural workers (n = 75)	P-value*	Office workers (n = 75)	P-value*
Workplace exposure ≥ 16 yrs with obstructive pattern	9/42 (21.4%)	0.147	-	-
Workplace exposure ≤ 15 yrs with obstructive pattern	3/33 (9.1%)
Daily smokers with obstructive pattern	5/12 (41.7%)	0.283	3/5 (60.0%)	0.118
Daily smokers without obstructive pattern	15/63 (23.8%)		19/70 (27.1%)
Passive smokers with obstructive pattern	3/12 (25.0%)	0.394	2/5 (40.0%)	0.153
Passive smokers without obstructive pattern	9/63 (14.3%)		9/70 (12.9%)

Data are expressed as number and percentage of examinees with certain variable with and without obstructive pattern. Yrs: years.

^*Tested by Chi-square test.