determined quantitatively. The pooled analysis showed a linear increase in risk of about a factor of 3 for smokers over never-smokers. This value is a decrease from the BEIR IV estimate of 10 to I for smokers over never-smokers. A striking feature of the data is the time-since-exposure effect. With three time windows in the model, the joint analysis showed a reduced risk with time, compared with two time windows included in the BEIR IV model, which did not show this effect.

BEIR VI Model

In 1999, the National Research Council published the BEIR VI report (National Research Council 1999), a revision and update of the BEIR IV report. The BEIR VI models to project lung-cancer incidence from 222Rn decay-product exposure produce equations that are identical with that reported by NIH (Lubin

Table 5.6

Parameter Estimates from BEIR VI (National Research Council 1999) Models Based on Original (Lubin and Others 1994) and Updated Pooled (Lubin and Boice 1997) Miner Data

Exposure-Age-Duration Modela

Exposure-Age-Concentration Modela

 

Original Data

Updated Data

 

Original Data

Updated Data

Βb × 100

0.39

0.55

Β × 100

6.11

7.68

Time-since-exposure windows

θ5-14

1.00

1.00

θ5-14

1.00

1.00

θ-24

0.76

0.72

θ15-24

0.81

0.78

θ25+

0.31

0.44

θ25+

0.40

0.51

Attained age

ϕ<55

1.00

1.00

ϕ<55

1.00

1.00

ϕ55-64

0.57

0.52

ϕ55-64

0.65

0.57

ϕ65-74

0.34

0.28

ϕ65-74

0.38

0.29

ϕ75+

0.28

0.13

ϕ75+

0.22

0.09

Duration of exposure

Exposure rate (WL)

γlt;5

1.00

1.00

γlt;0.5

1.00

1.00

γ5-14

3.17

2.78

γ0.5-1.0

0.5 1

0.49

γ15-24

5.27

4.42

γ1.O-3.0

0.32

0.37

γ25-34

9.08

6.62

γ3.0-5.0

0.27

0.32

γ35+

13.6

10.2

γ5.0-15.0

0.13

0.17

 

 

 

γ15.0+

0.10

0.11

a Parameters estimated on the basis of the model RR=1+βw*Φaγz fit using the two-stage method where w*=w5-1415-24w15-2425+w25+. Here the subscript a denotes categories of attained age and the subscript z denotes categories of either exposure duration (in years) or radon concentration in WL.

b Units arc WLM-1.



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