It's also quite possible that these doctors were smokers. Chinese doctors smoke at least as much as the general chinese population, which already suffers the h

It's also quite possible that these doctors were smokers. Chinese doctors smoke at least as much as the general chinese population, which already suffers the highest per capita smoking rates in the world. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3519549/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3519549/ - Tobacco smoking among doctors in mainland China: a study from Shandong province and review of the literature