Filter ventilation and the risk associated with cigarette smoking

It has long been clear that cigarette smoking is causally linked to many diseases, particularly lung cancer, chronic obstructive pulmonary disease and various forms of cardiovascular disease. For lung cancer, for example, a meta-analysis my colleagues and I conducted, based on epidemiological evidence published in the 1900s [1], estimated that current smoker/never smoker relative risks, were around 10 in North America and Europe, though lower (around three) in Asia. They were higher for squamous cell carcinoma than for adenocarcinoma, were very strongly related to amount smoked, and declined with increasing years of cessation of smoking.