Supplementary Table 1: Excess relative risk for death from lung cancer per unit of cumulative exposure to radon in WLM
in the 1960+ sub-cohort of miners hired 1960 or later
Study / model
n
Deaths
Person-years
ERR/WLM
95% CI
Total
26,766
334
846,809
0.013
0.007; 0.021
Separate adjustment for
Smoking status a
External gamma radiation b
Long-lived radionuclides b
Silica dust c
26,766
26,766
26,766
26,715
334
334
334
333
846,809
846,809
846,809
845,443
0.011
0.011
0.014
0.014
0.005; 0.018
0.004; 0.019
0.007; 0.022
0.007; 0.022
Person-year restriction to d
<100 WLM
<50 WLM
26,766
26,766
306
245
834,090
794,923
0.016
0.013
0.008; 0.028
0.001; 0.029
16,964
243
570,104
0.019
0.011; 0.032
6,364
8,702
11,700
23
149
162
192,991
269,859
383,959
0.015
0.011
0.009
<0 e; 0.091
0.004; 0.023
0.002; 0.020
Sub-cohorts by
Duration of employment > 5 ys
Smoking status
Non-/light smokers
Moderate/heavy smokers
Unknown
ERR/WLM: excess relative risk per WLM, CI: confidence interval, WLM: working level months
a: Multiplicative adjustment (Walsh et al. 2015)
b: Additive adjustment (Walsh et al. 2015)
c: Additive adjustment with silica dust in three categories: [0-0.5), [0.5-2), [2-16) dust-years (Walsh et al. 2015), for 51 cohort members data on silica dust are missing
d: Restriction of grouped dataset to categories (not workers) with radon exposures <100 / 50 WLM,
e: Lower bound out of parameter range for ERR
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Supplementary Table 2: Sensitivity analyses (Inclusion of effect modifiers and choice of model) on the excess relative risk for death from lung
cancer per unit of cumulative exposure to radon in WLM in the 1960+ sub-cohort of miners hired 1960 or later
Model
Parameter description
Parameter
Estimates (95% CI)
Deviance d
ß
0.013 (0.007; 0.021)
4320.4
Models with effect-modifying variables a
Linear
ERR/WLM
Linear with one
effect-modifying variable
ERR/WLM b
Time since median exposure
ß
exp(10ε)
0.016 (0.008; 0.026)
0.71 (0.44; 1.15)
4319.0
Linear with three
effect-modifying variables
ERR/WLM c
Time since median exposure
Age at median exposure
Exposure rate
ß
exp(10ε)
exp(10α)
exp(ψw)
0.016 (0.006; 0.031)
0.72 (0.40; 1.30)
1.04 (0.51; 2.12)
1.03 (0.39; 2.75)
4318.9
Non-linear models
Log-linear
Quadratic
Linear-quadratic
RR(w) = exp(ß w)
RR(w) = 1 + ß w2
RR(w) = 1 + ß1 w + ß2 w2
ß
ß
ß1
ß2
0.006 (0.004; 0.008)
0.00007 (0.00003; 0.00012)
0.016 (0.005; 0.029)
-0.00002 (-0.00008; 0.00005)
4324.0
4329.6
4320.1
ERR/WLM: excess relative risk per working level month, CI: confidence interval, RR(w): Relative risk for cumulative radon exposure w.
ERR/WLM are statistically significant if their CI does not contain zero. Effect-modifying variables are statistically significant if their CI does not contain one.
a: Notation and estimation of statistical models with effect-modifying variables are identical to those in Walsh et al. (2010) and Tomasek et al (2008a).
b: ERR/WLM at time since median exposure 20 years.
c: ERR/WLM at time since median exposure 20 years, age at median exposure 30 years and exposure rate 0.3 WL.
d: When comparing two models with the same number of parameters, the model with the smaller deviance is considered to be better. In case that model B has one additional
parameter compared to model A, model B is considered to be an improvement over model A with 95% probability if the deviance is reduced by 3.84 points (Walsh, 2007, Radiat
Environ Biophys).
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Supplementary Table 3: Mortality from lung cancer by cumulative radon exposure at low doses or dose rates from published studies in miners
Study (publication)
Deaths
Sex
Mean cumulative
exposure to radon
ERR/WLM
95% CI
Miner cohorts
BEIR VI joint miner cohort
(NRC, 1999)
677
468
m
m
<100 WLM
<50 WLM
0.008
0.012
0.003; 0.014
0.002; 0.025
French/ Czech pooled miner cohort
(Tomasek et al, 2008a)
574
m
47 WLM
0.042a
0.024; 0.072
Euopean pooled miner case-control studies
(Hunter et al, 2013)
742
m
< 300 WLM
0.017
0.009; 0.035
Port Hope male uranium processor cohort
(Zablotska et al, 2013)
78
m
10 WLM
0.004
<-0.012; 0.045
French miner sub-cohort 1956+
(Rage et al, 2014)
94
m
18 WLM
0.024
0.009; 0.051
159
m
8 WLM
0.034
-0.0001; 0.068
334
m
17 WLM
0.013
0.007; 0.021
m+f
m
-
0.012b
0.019b
0.004; 0.023
0.007; 0.037
German miller cohort
(Kreuzer et al, 2014)
German miner sub-cohort 1960+
present analyses
Residential radon study
European pooled case-control study
(Darby et al, 2005)
7,148
5,521
ERR/WLM: Excess Relative Risk per WLM in a linear model, CI: confidence interval
a: ERR/WLM at age at median exposure 30 years, time since median exposure 20 years and related only to measured exposure
b: Conversion from a radon concentration of 100 Bq/m 3 over 30 years assuming 7,000 hours spent at home per year (Hunter et al, 2013)
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