Solid Fuel, Secondhand Smoke, and Lung Cancer Mortality: A Prospective Cohort of 323,794 Chinese Never-Smokers.

In a recent meta-analysis of 41 studies of nonsmoking women in Asia, Europe, and North America, Ni and colleagues (2018) found a significant association between SHS and lung cancer in 34 case-control studies (pooled OR, 1.35; 95% CI, 1.17–1.56), but the association did not reach statistical significance in the seven cohort studies (pooled RR, 1.17; 95% CI, 0.94–1.44) ( 40 ).

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Subgroup analyses in Figure 3 also found consistent results, though only a borderline significant difference between those who self-reported their health as “poor” and “not poor” ( P heterogeneity = 0.047).

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