Montana & Mesothelioma - Table 1
Montana & Mesothelioma - Table 1
Table 1. Distribution and characteristics of participants
in the Libby medical screening program.
Variable No. (%)
Age
10-17 600 (8.2)
18-44 2,519 (34.5)
45-64 3,031 (41.5)
[greater than or equal to] 65 1,157 (15.8)
Sex
Male 3,601 (49.3)
Female 3,706 (50.7)
Smoking history
Never 3,711 (50.8)
Ex-smoker 2,156 (29.5)
Current 1,438 (19.7)
Years lived in Libby
0.5-13 1,864 (25.7)
14-21 1,892 (26.1)
22-33 1,761 (24.2)
[greater than or equal to] 34 1,747 (24.1)
BMI
0-18 234 (3.2)
19-24 2,185 (30.2)
25-29 2,529 (34.9)
[greater than or equal to] 30 2,292 (31.7)
Table 2. Number (percent) of participants reporting
each exposure pathway. (a)
Exposure pathway No. (%)
Ever work for WRG 370 (5.1)
Secondary contractor work 465 (6.4)
Dust exposure at non-WRG jobs 2,396 (32.8)
Vermiculite exposure at 1,103 (15.2)
non-WRG jobs
Worked non-WRG job
As a pipe fitter or steam fitter 164 (2.2)
As a plumber 168 (2.3)
As a brake repair person 249 (3.4)
As an insulator 240 (3.3)
As a dry wall finisher 221 (3.0)
As a carpenter 568 (7.8)
As a roofer 362 (5.0)
As an electrician 187 (2.6)
As a welder 467 (6.4)
Mixing, cutting, or spraying asbestos 144 (2.0)
In a shipyard or performed ship 129 (1.8)
construction or repair
Exposed to asbestos 851 (11.8)
Worked around anyone performing 804 (11.0)
non-WRG jobs (listed above)
Asbestos exposure in the military 182 (2.7)
Lived with WRG workers 1,418 (19.5)
Vermiculite insulation in Lincoln 3,017 (45.8)
County homes
Asbestos products in Lincoln County 1,155 (17.4)
homes
Used vermiculite for gardening 3,702 (51.9)
Used vermiculite around the home 638 (8.8)
Handled vermiculite insulation 3,635 (50.5)
Recreational activities along Rainey 4,898 (67.4)
Creek Road
Played at ball field near expansion plant 4,772 (65.5)
Played in vermiculite piles 2,442 (33.7)
Popped vermiculite 2,797 (38.4)
Other contact with vermiculite 2,232 (31.0)
(a) Participants may have answered "yes" to more than one category.
Table 3. Number (percent) of pleural and interstitial
abnormalities by exposure pathways.
Intersti-
Pleural, atial, P-
Exposure pathway views A view
All participants [greater than or equal to]
18 years of age (n = 6,668) 1,186 (17.8) 54 (0.8)
Ever worked for WRG (n = 365) 186 (51.0) 14 (3.8)
Secondary contractor work (n = 463) 161 (34.8) 8 (1.7)
Dust exposure at non-WRG jobs (n = 2,390) 527 (22.1) 21 (0.9)
Vermiculite exposure at non-WRG jobs
(n = 1,100) 254 (23.1) 8 (0.7)
Worked non-WRG job
As a pipe or steam fitter (n = 164) 54 (32.9) 2 (1.2)
As a plumber (n = 168) 50 (29.8) 3 (1.8)
As a brake repair person (n = 247) 68 (27.5) 2 (0.8)
As an insulator (n = 240) 44 (18.3) 1 (0.4)
As a dry wall finisher (n = 221) 41 (18.6) 0 (0.0)
As a carpenter (n = 566) 129 (22.8) 2 (0.4)
As a roofer (n = 361) 79 (21.9) 2 (0.6)
As an electrician (n = 187) 48 (25.7) 3 (1.6)
As a welder (n = 465) 122 (26.2) 5 (1.1)
Mixing, cutting, or spraying asbestos
(n = 143) 47 (32.9) 2 (1.4)
In a shipyard or performed ship
construction or repair (n = 129) 45 (34.9) 4 (3.1)
Exposed to asbestos (n = 849) 208 (24.5) 7 (0.8)
Worked around anyone performing previous 12
jobs (n = 801) 184 (23.0) 6 (0.8)
Asbestos exposure in the military (n = 182) 78 (42.9) 2 (1.1)
Lived with WRG workers (n = 1,376) 358 (26.0) 17 (1.2)
Vermiculite insulation in homes (n = 2,819) 600 (21.3) 27 (1.0)
Asbestos products in homes (n = 1,071) 222 (20.7) 9 (0.8)
Used vermiculite for gardening (n = 3,469) 702 (20.2) 29 (0.8)
Used vermiculite around the home (n = 586) 120 (20.5) 1 (0.2)
Handled vermiculite insulation
Sometimes (n = 2,739) 572 (20.9) 25 (0.9)
Frequently (n = 732) 191 (26.1) 9 (1.2)
Recreational activities along Rainey Creek
Sometimes (n = 3,134) 546 (17.4) 21 (0.7)
Frequently (n = 1,433) 307 (21.4) 15 (1.1)
Played at ball field near expansion plant
Sometimes (n = 2,034) 293 (14.4) 10 (0.5)
Frequently (n = 2,290) 432 (18.9) 16 (0.7)
Played in vermiculite piles
Sometimes (n = 1,430) 269 (18.8) 8 (0.6)
Frequently (n = 875) 220 (25.1) 5 (0.6)
Popped vermiculite
Sometimes (n = 2,140) 460 (21.5) 13 (0.6)
Frequently (n = 538) 138 (25.7) 9 (1.7)
Other contact with vermiculite
Sometimes (n = 1,759) 340 (19.3) 14 (0.8)
Frequently (n = 323) 73 (22.6) 5 (1.6)
Table 4. Risk of pleural abnormalities by exposure pathways and
covariates. (a)
Adjusted OR
Variable Level Beta (95% CI)
Intercept -19.46
Workwr Yes 2.08 -- (b)
HHWR Yes 1.29 --
Vermplay Sometimes 0.60 1.82 (1.48-2.25)
Frequently 0.70 2.02 (1.59-2.57)
Sex Male 1.58 --
Resdur (years) 14-21 0.25 1.29 (0.97-1.71)
22-33 0.22 1.25 (0.96-1.62)
[greater than or
equal to] 34 0.75 2.12 (1.66-2.70)
In(Age) 3.86 --
BMI 2nd quartile (24-27) 0.18 1.20 (0.91-1.60)
3rd quartile (28-31) 0.56 1.75 (1.32-2.32)
4th quartile ([greater
than or equal to] 32) 1.14 3.12 (2.37-4.12)
Smoke Ever 0.30 1.35 (1.14-1.59)
Age x Workwr Yes -0.02 --
HHWR x sex Yes x male -0.75 --
Milexp Yes 0.47 1.61 (1.10-2.35)
Age x In(Age) -0.05 --
Abbreviations: HHWR, household contact with WRG worker; Milexp,
asbestos exposure in the military; Resdur, duration of residence in
Libby area; Vermplay, played in vermiculite piles; Workwr, ever worked
for WRG.
(a) Twenty-nine exposure pathways and all covariates were assessed for
their contribution to the risk of pleural abnormalities; final model
fit: Hosmer-Lemeshow goodness-of-fit test, [chi square] = 2.47, degrees
of freedom = 8, p = 0.96. (b) A single value cannot be presented for
adjusted ORs involving interaction terms.
Table 5. Risk of pleural abnormalities for former
WRG workers compared with non-WRG workers at
different ages.
Age (years) OR (95% CI)
30 4.18 (2.20-7.94)
40 3.37 (2.14-5.29)
50 2.71 (2.00-3.67)
60 2.18 (1.66-2.86)
70 1.76 (1.19-2.58)
80 1.41 (0.80-2.48)
90 1.14 (0.53-2.44)
Table 6. Risk of pleural abnormalities by number of
exposure pathways (baseline: no apparent exposure)
controlling for age, sex, BMI, residential duration,
and smoking.
No. of exposure pathways OR (95% CI)
1 1.40 (0.60-3.26)
2-3 1.36 (0.62-2.97)
4-5 1.80 (0.83-3.90)
6-7 2.41 (1.11-5.23)
8-9 3.12 (1.43-6.83)
10-11 3.48 (1.56-7.77)
[greater than or equal to] 12 3.75 (1.65-8.50)
Final model fit: Hosmer-Lemeshow goodness-of-fit test,
[chi square] = 5.45, degrees of freedom = 8, p = 0.71.
