Table 1. The prevalence of pleural plaque and lung fibrosis according to sex, smoking history, age groups and duration of exposure.

Parameters	Lung fibrosis (%)	P value*	Pleural plaque (%)	P value*
Total (n = 35)	27 (77.1)		33 (94.3)
Sex
Male (n = 17)	14 (82.4)		17 (100)
Female (n = 18)	13 (72.2)	0.482	16 (88.9)	0.163
Smoking
Yes (n = 15)	14 (93.3)		15 (100)
No (n = 20)	13 (65)	0.052	18 (90)	0.214
Age (yr)
40-49 (n = 2)	0 (0)		2 (100)
50-59 (n = 4)	3 (75)		4 (100)
60-69 (n = 11)	10 (90.9)		9 (81.8)
70-79 (n = 17)	13 (76.5)		17 (100)
> 80 (n = 1)	1 (100)	0.129†	1 (100)	0.623†
Duration of exposure (yr)
10-19 (n = 1)	1 (100)		1 (100)
20-29 (n = 3)	2 (66.7)		3 (100)
30-39 (n = 8)	3 (37.5)		6 (75)
40-49 (n = 7)	6 (85.7)		7 (100)
50-59 (n = 8)	8 (100)		8 (100)
60-69 (n = 8)	7 (87.5)	0.084†	8 (100)	0.251†

Data are presented as number (%). ^*Comparison was done by chi-square test; ^†By Linear-by-linear association test.