The revised by-law was challenged in court and the case focused on what degree waterpipes and second-hand smoke from waterpipes constitutes a public health threat and whether the by-law infringes on the Canadian Charter of Rights and Freedoms. [...] The conceptual model is presented in Appendix B. 4 Literature Review Question The research question addressed in this review is: What are the health effects for the general population of using and being exposed to tobacco and non-tobacco waterpipes? [...] Limitations in study methodologies for the other health outcomes included factors such as no standardized measurement tool to account for variables in waterpipe smoking such as the quantity and type of tobacco smoked, use of other substances, frequency and length of waterpipe. [...] The type of tobacco used in waterpipes in India and China is typically unprocessed and heated directly by coal, as opposed to the more widespread use of processed tobacco and indirect heat. [...] The study reported an OR for association of waterpipe tobacco smoking with dysplasia of the oral mucosa on the chewing side to be 8.33 (95% CI 0.78 - 9.47).