Environmental tobacco smoke exposure and lung cancer: A systematic review

Table 7 Adjusted/corrected analyses: Per 10 cigs smoked by husband¹

Studies	n	Unadjusted for confoundingUncorrected for misclassificationRR (95%CI)	Adjusted for confounding2Uncorrected for misclassificationRR (95%CI)	Adjusted for confounding2Corrected for misclassification3RR (95%CI)
All	93	1.102 (1.065-1.140)	1.062 (1.027-1.099)	1.032 (0.994-1.071)
North America	29	1.037 (0.977-1.101)	1.006 (0.946-1.070)	0.957 (0.896-1.022)
Europe and New Zealand	20	1.060 (0.995-1.128)	1.020 (0.956-1.088)	1.003 (0.938-1.073)
China (including Hong Kong and study LIM)	27	1.169 (1.082-1.263)	1.127 (1.041-1.219)	1.094 (1.006-1.191)
Rest of Asia (including study ILCCO)	17	1.142 (1.095-1.191)	1.094 (1.050-1.141)	1.079 (1.033-1.127)
North America, Europe and New Zealand	49	1.046 (1.001-1.094)	1.012 (0.967-1.059)	0.974 (0.928-1.023)
Asia	44	1.158 (1.104-1.216)	1.113 (1.060-1.170)	1.089 (1.033-1.147)
Published in 1980s	26	1.148 (1.092-1.207)	1.105 (1.052-1.162)	1.075 (1.019-1.134)
Published in 1990s	27	1.063 (1.004-1.125)	1.025 (0.967-1.087)	0.988 (0.926-1.053)
Published in 2000s	26	1.123 (1.056-1.194)	1.085 (1.020-1.155)	1.061 (0.995-1.132)
Published in 2010s	14	1.073 (0.970-1.188)	1.032 (0.932-1.143)	1.014 (0.912-1.128)
< 100 cases	49	1.143 (1.077-1.213)	1.101 (1.036-1.169)	1.072 (1.005-1.144)
100-199 cases	22	1.062 (0.993-1.137)	1.025 (0.957-1.098)	0.994 (0.926-1.066)
200-399 cases	13	1.176 (1.097-1.261)	1.134 (1.058-1.216)	1.111 (1.027-1.202)
400+ cases	9	1.041 (0.976-1.111)	1.002 (0.938-1.070)	0.966 (0.895-1.042)
With dose-response data4	24	1.123 (1.072-1.176)	1.082 (1.032-1.134)	1.053 (1.005-1.103)
Without dose-response data	69	1.091 (1.044-1.139)	1.053 (1.007-1.100)	1.021 (0.973-1.071)
With age adjustment5	75	1.084 (1.046-1.123)	1.044 (1.008-1.082)	1.015 (0.976-1.056)
Without age adjustment	18	1.211 (1.101-1.331)	1.168 (1.061-1.285)	1.131 (1.018-1.256)
Case-control studies	77	1.106 (1.064-1.150)	1.066 (1.025-1.109)	1.034 (0.991-1.080)
Prospective studies	16	1.081 (1.021-1.145)	1.043 (0.985-1.105)	1.018 (0.957-1.083)

¹All analyses use random-effects models;

²Adjusted for confounding by fruit, vegetables and dietary fat consumption and by education;

³Using the Lee and Forey method[22] with an additive model and assuming a concordance ratio of 3 and misclassification rates of 2.5% for studies in North America and Europe and 10% for studies in Asia;

⁴Specifically for smoking by the husband;

⁵Or matching (within nonsmokers).