Decreasing Prevalence of Pleural Calcifications Among Metsovites With Nonoccupational Asbestos Exposure: CXR Evaluation

All CXRs were carefully evaluated for the presence of PCs (Fig 1) by two of us (C.M-S. and S.H.C.), independently and then in joint session. In order to have results that were comparable with those from 1980, only posteroanterior CXRs were evaluated. The prevalence of PCs was calculated as the percentage of the total number of examined CXRs for each group (Table 1).
Statistical Analysis
The x2 test was applied in order to examine the difference in the overall prevalence of PCs between the two studies (ie, from 1978 to 1982 and from 1998 to 2002). The significance of PC prevalence between men and women in the present study also was examined with the x2 test. The x2 test for multiple outcomes was used in order to examine the significance of differences in PCs between the two periods (ie, 1978 to 1982 and from 1998 to 2002) at the same age intervals as well as between males and females in the present study. A Bonferroni correction was used in order to define the source of significance. The level of significance was set at 95% (ie, p < 0.05).
Results
Of the 307 CXRs examined, the evaluation of the two readers differed on 11 occasions (11 of 307 CXRs; 3.6%). In all 11 cases, a consensus was reached in the joint session. The prevalence of PCs in Metsovites from 1978 to 1982 and from 1998 to 2002 according to age group is presented in Table 1, and is graphically depicted in Figure 2. The percentage of PCs in each group according to sex is shown in Table 2. other
Most of the individuals examined (82.7%) came from Metsovo, which is the capital of the area. The same was true in the older study (78.9%).
PCs were slightly more frequent among men than women in all studied age groups, except for those individuals > 70 years of age. This difference was statistically significant only in the group of individuals 60 to 69 years of age (Table 2). A similar male predominance in PCs was observed in our previous work.
Fig1
Figure 1. CXR of an inhabitant of Metsovo with characteristic PCs.
Fig2
Figure 2. The percentage of PCs in Metsovites, according to age group from 1978 to 1982 (black columns) and from 1998 to 2002 (gray columns).

Table 1—Number and Prevalence of PCs in Metsovites

Age Group, yr 1978-1982 1998-2002 p Value
30-39 6/21 (28.6) 0/15 (0.0) < 0.001
40-49 25/56 (44.6) 8/36 (22.2) < 0.01
50-59 38/58 (65.5) 13/49 (26.5) < 0.01
60-69 30/42 (71.4) 71/101 (70.3) > 0.05
> 70 30/37 (81.0) 86/106 (81.1) > 0.05
Total 129/214 (60.3) 178/307 (58.0) > 0.05

Table 2—Individuals With PCs From 1998 to 2002

Age Group, yr Number PCs p Value
Men Women
30-39 15 0/11 (0.0) 0/4 (0.0) > 0.05
40-49 36 5/16(31.2) 3/20 (15.0) > 0.05
50-59 49 6/17 (35.3) 7/32 (22.0) > 0.05
60-69 101 46/59 (78.0) 25/42 (59.5) < 0.05
> 70 106 52/67 (77.6) 34/39 (87.2) > 0.05
Total 307 109/170 (64.1) 69/137 (50.4) 0.01
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