Table 2

Pulmonary function impairment in engineered stone workers with silicosis

OverallAustraliaIsraelSpainUSAP value*
N=169N=14N=125N=20N=10
Pulmonary function testing measurements, mean (SD)
 FEV1, % predicted (n=147)66.4±26.684.6±13.458.4±25.789.8±14.991.6±14.9<0.0001 IA, IS, US
 FVC, % predicted (n=147)70.9±24.687.6±13.163.8±23.591.9±14.993.3±17.3<0.0001 IA, IS, US
 FEV1/FVC, % (n=147)73.6±13.579.4±8.071.7±14.978.2±4.078.6±6.60.0474
 TLC, % predicted (n=129)84.9±23.387.5±15.883.0±23.993.3±4.699.3±22.00.1648
 DLCO, % predicted (n=137)75.0±27.886.1±14.268.1±26.493±20.2108±28.1<0.0001 IU, IS
Abnormal pulmonary function testing, n (%)
 Restrictive‡35/128 (27.3)2/11 (18.2)32/104 (30.8)0/3
(0.0)
1/10 (10.0)0.3861
 Obstructive§33/142 (23.2)1/14 (7.1)31/105 (29.5)0/13 (0.0)1/10 (10.0)0.0206IS
 Mixed¶12/128 (9.4)0/11 (0.0)12/104 (11.5)0/3 (0.0)0/10 (0.0)0.6816
 Normal**62/147 (42.2)11/14 (78.6)30/108 (27.8)13/15 (86.7)8/10 (80.0)<0.0001 IA, IS, IU
 Reduced TLC††50/129 (38.0)2/11 (18.2)47/105 (44.8)0/3 (0.0)1/10 (10.0)0.0287IU
 Reduced DLCO‡‡63/137 (46.0)4/14 (28.6)56/101 (55.5)2/12 (16.7)1/10 (10.0)0.0016 IU, IS
 Hypoxaemia39/166 (23.5)0/14 (0.0)36/122 (29.5)0/20 (0.0)3/10 (30.0)0.0009IA, IS, US
  • *One-way ANOVA for continuous variables and Fisher’s exact test for cross-country comparison of categorical variables; individual comparisons: A=Australia, I=Israel, S=Spain, U=USA.

  • †Pulmonary function tests included measurements of FEV1, FVC, the ratio of FEV1/FVC, TLC, DLCO. Global lung Initiative reference values were used for FEV1, FVC, FEV1/FVC, DLCO and LLN for all parameters.

  • ‡Restrictive defined as FEV1/FVC ratio ≥LLN, FVC <LLN and TLC <LLN.

  • §Obstructive defined as a FEV1/FVC ratio <LLN and FVC ≥LLN; or FEV1/FVC ratio ≥LLN, FVC <LLN and TLC ≥LLN; or FEV1/FVC ratio <LLN, FVC <LLN and TLC ≥LLN.

  • ¶Mixed defined as FEV1/FVC ratio <LLN, FVC <LLN and TLC <LLN.

  • **Normal defined as FEV1/FVC ratio ≥LLN and FVC ≥LLN.

  • ††Reduced TLC defined as a measured TLC value <LLN.

  • ‡‡Reduced DLCO defined as a measured DLCO value <LLN.

  • ANOVA, analysis of variance; DLCO, diffusion capacity of lung for carbon monoxide; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; LLN, lower limits of normal ; TLC, total lung capacity.