Table 1.

Results of studies on exposure to secondhand smoke and risk of lung cancer among never smokers

StudyDesign/populationExposure groupReference groupRisk estimate (95% CI)Adjustment variables
Hackshaw et al. (98)Meta-analysis:39 studies (5 cohort, 34 case-control) of “lifelong nonsmokers”;5005 total lung cancer cases; Study locations: United States, Europe, Asia; Publication dates: 1981-1997Spousal exposure:Age only, when possible
Women (37 studies, 4,626 cases):
Husband currently smoked vs.Husband never smoked1.24 (1.13–1.36)
Men (9 studies, 274 cases):
Wife currently smoked vs.Wife never smoked1.34 (0.97–1.84)
Men and women (39 studies, 5,005 cases):
Spouse currently smoked vs.Spouse never smoked1.23 (1.13–1.34)
Zhong et al. (41)Meta-analysis: 40 studies (5 cohort, 35 case-control) of “lifetime nonsmoking” subjects; 5,140 total lung cancer cases; Study locations: United States, Europe, Asia; Publication dates: 1981-1999Spousal exposure:Age and demographic characteristics, when possible
Women (40 studies, no. cases not stated):
Husband ever smoked vs.Husband never smoked1.20 (1.12–1.29)
Men (11 studies, 443 cases):
Wife ever smoked vs.Wife never smoked1.48 (1.13–1.92)
Workplace exposure:
Women (14 studies, 2,594 cases):
Workplace SHS exposure vs.No workplace SHS exposure1.15 (1.04–1.28)
Men (5 studies, 254 cases):
Workplace SHS exposure vs.No workplace SHS exposure1.29 (0.93–1.78)
Men and women (19 studies, 2,848 cases):
Workplace SHS exposure vs.No workplace SHS exposure1.16 (1.05–1.28)
Childhood exposure:
Women (18 studies, 3,584 cases):
Ever exposed to SHS during childhood vs.Never exposed to SHS during childhood0.91 (0.83–1.00)
Surgeon General Report (81)Meta-analysis: 52 studies (8 cohort, 44 case-control) of “lifetime nonsmokers”; Total number of cases not stated; Study locations: North America, Europe, Asia; Publication dates: 1981–2002Spousal exposure:Not stated
Women (no. studies and cases not stated):
Smoking husband vs.Nonsmoking husband1.22 (1.10–1.35)
Men (no. studies and cases not stated):
Smoking wife vs.Nonsmoking wife1.37 (1.05–1.79)
Workplace exposure:
Women (25 studies, no. cases not stated):
Workplace SHS exposure vs.No workplace SHS exposure1.22 (1.10–1.35)
Men (11 studies, no. cases not stated):
Workplace SHS exposure vs.No workplace SHS exposure1.12 (0.86–1.50)
Men and Women (25 studies, no. cases not stated):
Workplace SHS exposure vs.No workplace SHS exposure1.22 (1.13–1.33)
Childhood Exposure:
Women (no. studies and cases not stated):
Mother smoked during childhood vs.Mother did not smoke during childhood1.28 (0.93–1.78)
Father smoked during childhood vs.Father did not smoke during childhood1.17 (0.91–1.50)
Men and women (no. studies and cases not stated):
Mother smoked during childhood vs.Mother did not smoke during childhood1.15 (0.86–1.52)
Father smoked during childhood vs.Father did not smoke during childhood1.10 (0.89–1.36)
Either parent smoked during childhood vs.Neither parent smoked during childhood1.11 (0.94–1.31)