Table 3– Prevalence of chest radiograph findings by age and exposure categories
Exposure categorySubjects nPrevalence %
Profusion ≥1/0PlaqueDPT and/or CAO
Grace worker
 25–40 yrs of age200205
 41–50 yrs of age80026.25
 51–60 yrs of age633.234.93.2
 61–90 yrs of age8111.145.78.6
Other vermiculite occupation
 25–40 yrs of age1220.80.80
 41–50 yrs of age1920.57.81
 51–60 yrs of age1600.613.70.6
 61–90 yrs of age1650.624.88.5
Other dusty occupation
 25–40 yrs of age23703.80.4
 41–50 yrs of age21302.80.9
 51–60 yrs of age1750.612.60
 61–90 yrs of age1831.121.93.3
Household
 25–40 yrs of age22402.20
 41–50 yrs of age234011.10.4
 51–60 yrs of age194120.11.5
 61–90 yrs of age2092.438.35.7
Environmental
 25–40 yrs of age47200.40
 41–50 yrs of age46801.90.2
 51–60 yrs of age44207.70.9
 61–90 yrs of age4631.312.72.2
  • DPT: diffuse pleural thickening; CAO: costophrenic angle obliteration.