Table 2.

Results of pooled analyses of case-control studies evaluating risks of radon for lung cancer among never smokers

StudyDesign/populationExposure groupReference groupRisk estimate (95% CI)Adjustment variables
Krewski et al. (177)Meta-analysis: 7 case-control studies with 659 lung cancer cases and 2,185 population controls who “never smoked”; Study location: North America;Publication dates: 1992-2000Per 100 Bq/m3 increase in radon exposure during the 5–30 years before index (diagnosis or death) date vs.<25 Bq/m3 radon exposure during the 5–30 years before index (diagnosis or death) date10% increased risk (0.91–42%)Study, gender, age, number of residences, years with a-track measurements
Darby et al. (178)Meta-analysis: 13 case-control studies with 884 lung cancer cases and 5,418 controls that were “lifelong nonsmokers”;Study location: Europe; Publication dates: 1992–2005Per 100 Bq/m3 increase in radon exposure during the 5–30 years before index (diagnosis or death) date vs.<25 Bq/m3 radon exposure during the 5–30 years before index (diagnosis or death) date10.6% increased risk (0.3–28.0%)Not stated
Darby et al. (179)Meta-analysis:13 case-control studies with 884 lung cancer cases and 5,418 controls that were “lifelong nonsmokers”;Study location: Europe; Publication dates: 1992–2005<25 Bq/m3 cumulative radon exposure during 5–30 years before index (diagnosis or death) date vs.0 Bq/m3 cumulative radon exposure during the 5–30 years before index (diagnosis or death) date1.06 (0.78–1.45)Study, age, gender, residence location
25–49 Bq/m3 cumulative radon exposure during 5–30 years before index (diagnosis or death) date vs.0 Bq/m3 cumulative radon exposure during the 5–30 years before index (diagnosis or death) date1.07 (0.90–1.26)Study, age, gender, residence location
50–99 Bq/m3 cumulative radon exposure during 5–30 years before index (diagnosis or death) date vs.0 Bq/m3 cumulative radon exposure during the 5–30 years before index (diagnosis or death) date1.02 (0.90–1.16)Study, age, gender, residence location
100–199 Bq/m3 cumulative radon exposure during 5–30 years before index (diagnosis or death) date vs.0 Bq/m3 cumulative radon exposure during the 5–30 years before index (diagnosis or death) date1.23 (1.02–1.48)Study, age, gender, residence location
200–399 Bq/m3 cumulative radon exposure during 5–30 years before index (diagnosis or death) date vs.0 Bq/m3 cumulative radon exposure during the 5–30 years before index (diagnosis or death) date1.37 (1.00–1.90)Study, age, gender, residence location
≥400 Bq/m3 cumulative radon exposure during 5–30 years before index (diagnosis or death) date vs.0 Bq/m3 cumulative radon exposure during the 5–30 years before index (diagnosis or death) date1.72 (1.04–2.88)Study, age, gender, residence location

Abbreviation: Bq/m3, becquerels per cubic meter.