The Association between Exposure to Second-Hand Smoke and Disease in the Chinese Population: A Systematic Review and...

To analyze the association between exposure to second-hand smoke (SHS) and 23 diseases, categorized into four classifications, among the Chinese population.

We searched the literature up to June 30, 2021, and eligible studies were identified according to the PECOS format: Participants and Competitors (Chinese population), Exposure (SHS), Outcomes (Disease or Death), and Study design (Case-control or Cohort).

In total, 53 studies were selected. The odds ratio (OR) for all types of cancer was 1.79 (1.56-2.05), and for individual cancers was 1.92 (1.42-2.59) for lung cancer, 1.57 (1.40-1.76) for breast cancer, 1.52 (1.12-2.05) for bladder cancer, and 1.37 (1.08-1.73) for liver cancer. The OR for circulatory system diseases was 1.92 (1.29-2.85), with a value of 2.29 (1.26-4.159) for stroke. The OR of respiratory system diseases was 1.76 (1.13-2.74), with a value of 1.82 (1.07-3.11) for childhood asthma. The original ORs were also shown for other diseases. Subgroup analyses were performed for lung and breast cancer. The ORs varied according to time period and were significant during exposure in the household; For lung cancer, the OR was significant in women.

The effect of SHS exposure in China was similar to that in Western countries, but its definition and characterization require further clarification. Studies on the association between SHS exposure and certain diseases with high incidence rates are insufficient.