Assessing causality between second-hand smoking and potentially associated diseases in multiple systems: A two-sample Mendelian randomization study.

This study explored the causality between exposure to SHS in the workplace and potential associated diseases in multiple systems, including MI, AF, stroke, lung cancer, asthma, allergic disease, type 2 diabetes, and depression, using a MR study. The MR study can circumvent the methodological constraints of observational studies and establish a causal relationship. The two-sample MR analysis provides evidence supporting the causal association of frequent workplace SHS with AF and stroke. Individuals exposed to SHS in the workplace may also have a heightened risk of MI, asthma, and depression. However, whether SHS affects other diseases and the causality between them requires further investigation. To our knowledge, this is the first two-sample MR study to determine the causal relationship between SHS and potential diseases. As exposure to SHS in the workplace is a prevalent issue and may contribute to a global disease burden. The reduction of exposure following the introduction of smoke-free laws has led to a decrease in the admission rate for cardiac events and an improvement in health indicators. It is crucial to further advance smoke-free policies and their implementation.