https://www.selleckchem.com/products/mli-2.html Present shift work has been associated with coronary heart disease (CHD) among employed workers, but it remains unclear whether shift work in the past is still associated with CHD in retired workers. We recruited 21,802 retired workers in Shiyan, China in 2008-2010 and 2013, and followed them up for CHD events to December 31, 2018. Retired workers with longer duration of past shift work had higher CHD risks (hazard ratios for those with ≤5.0, 5.25 to 10.0, 10.5 to 20.0, and >20.0 years of past shift work were 1.05 (95% confidence interval 0.94, 1.16), 1.08 (0.94, 1.25), 1.23 (1.07, 1.42), and 1.28 (1.08, 1.51)). The association was substantially higher among services or sales workers than among manufacturing or manual labor workers (hazard ratio for every 5-year increase in past shift work, 1.11 (95% confidence interval 1.05, 1.16) versus 1.02 (0.98, 1.06)). Moreover, the risk was lower among those who were physically active than their inactive counterparts (P for interaction, 0.019). Longer duration of past shift work was associated with higher risk of incident CHD among retired workers, especially those from services or sales sectors. Physical exercise might be beneficial in reducing the excess risk.The test-negative design is often used to estimate vaccine effectiveness in influenza studies, but has also been proposed in the context of other infectious diseases, such as cholera, dengue or Ebola. It was introduced as a variation of the case-control design, in an attempt to reduce confounding bias due to healthcare-seeking behaviour, and has quickly gained popularity due to its logistic advantages. However, examining the directed acyclic graphs that describe the test-negative design reveals that, without strong assumptions, the estimated odds ratio under this sampling mechanism is not collapsible over the selection variable, such that the results obtained for the sampled individuals cannot be generalised to the whole