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

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

Impact of Smoke-Free Legislation on Acute Myocardial Infarction and Subtypes of Stroke Incidence in Shenzhen,China,2012-2016:An Interrupted Time Series Analysis

Objective This study assesses the impact of smoke-free legislation on the incidence rate for acute myocardial infarction(AMI)and stroke in Shenzhen.Methods Data on ischemic(n=72,945)and hemorrhagic(n=18,659)stroke and AMI(n=17,431)incidence covering about 12 million people in Shenzhen from 2012 to 2016 were used.Immediate and gradual changes in incidence rates were analyzed using segmented Poisson regression.Results Following the smoke-free legislation,a 9%(95%CI:3%-15%)immediate reduction was observed in AMI incidence,especially in men(8%,95%CI:1%-14%)and in those aged 65 years and older(17%,95%CI:9%-25%).The gradual annual benefits were observed only in hemorrhagic and ischemic stroke incidence,with a 7%(95%CI:2%-11%)and 6%(95%CI:4%-8%)decrease per year,respectively.This health effect extended gradually to the 50-64 age group.In addition,neither the immediate nor gradual decrease in stroke and AMI incidence rates did not show statistical significance among the 35-49 age group(P>0.05).Conclusion Smoke-free legislation was enforced well in Shenzhen,which would generate good experiences for other cities to enact and enforce smoke-free laws.This study also provided more evidence of the health benefits of smoke-free laws on stroke and AMI.

Lung Cancer Risk Attributable to Active Smoking in China:A Systematic Review and Meta-Analysis

Objective No consensus exists on the relative risk(RR)of lung cancer(LC)attributable to active smoking in China.This study aimed to evaluate the unified RR of LC attributable to active smoking among the Chinese population.Methods A systematic literature search of seven databases was conducted to identify studies reporting active smoking among smokers versus nonsmokers in China.Primary articles on LC providing risk estimates with their 95%confidence intervals(CIs)for“ever”“former”or“current”smokers from China were selected.Meta-analysis was used to estimate the pooled RR of active smoking.Results Forty-four unique studies were included.Compared with that of nonsmokers,the pooled RR(95%CI)for“ever”“former”and“current”smokers were 3.26(2.79–3.82),2.95(1.71–5.08),and 5.16(2.58–10.34)among men,3.18(2.78–3.63),2.70(2.08–3.51),and 4.27(3.61–5.06)among women,and2.71(2.12–3.46),2.66(2.45–2.88),and 4.21(3.25–5.45)in both sexes combined,respectively.Conclusion The RR of LC has remained relatively stable(range,2–6)over the past four decades in China.Early quitting of smoking could reduce the RR to some extent;however,completely refraining from smoking is the best way to avoid its adverse effects.

Evaluating the Quality of Case-control Studies involving the Association between Tobacco Exposure and Diseases in a Chinese Population based on the Newcastle-Ottawa Scale and Post-hoc Power

According to the 2017 Global Burden of Disease Study,smoking is among the four leading risk factors contributing to deaths and disability-adjusted life years(DALYs)in China.In the past 20 years,there has been a substantial increase in the number of studies focusing on the association between tobacco exposure and disease.