Objective To systematically evaluate the risk of lung cancer in non-smoking women with passive smoking based on prospective cohort studies.

Methods Medline, Embase, Web of Science, CNKI, Wanfang Data, and SinoMed databases were searched for prospective cohort studies on the association between passive smoking and lung cancer published up to August, 2021. Newcastle-Ottawa Scale was used for quality assessment, and Stata 14.0 and R 3.6.1 were used for meta-analysis.

Results A total of 14 cohort studies on lung cancer in women were included in this study, among which 8 were set the onset of lung cancer as study outcome (number of individuals followed up/number of lung cancer cases: 424 374/832) and 6 were set death due to lung cancer as study outcome (number of individuals followed up/number of lung cancer cases: 372 204/866). The meta-analysis showed that passive smoking in non-smoking women was associated with an increased risk of the onset of lung cancer (pooled relative risk RR=1.23, 95% CI: 1.04-1.45) and death due to lung cancer (pooled RR=1.16, 95% CI: 1.04-1.28).The pooled relative risk of the onset of lung cancer due to adulthood family exposure was 1.34 (95% CI: 1.06-1.69), and the pooled relative risk of death due to lung cancer for adulthood family exposure was 1.19 (95%CI: 1.01-1.40).The pooled relative risk of lung cancer caused by passive smoking due to family exposure was 1.23 (95% CI: 1.08-1.41), and the pooled relative risk of lung cancer due to workplace exposure was 1.34 (95% CI: 1.02-1.76).

Conclusion Passive smoking may increase the risk of the onset of lung cancer and the risk of death due to lung cancer in non-smoking women.