1. Introduction
The World Health Organization estimates that tobacco causes approximately 5 million deaths annually worldwide,
and this number is expected to double by 2025. The reason for that high number is that Tobacco use is a major
cause of many of the world’s top killer diseases including cardiovascular disease, chronic lung disease and lung
cancer. Smoking is often the hidden cause of many killing diseases. In Saudi Arabia, the prevalence of current
smoking ranges from 2.4-52.3% (median = 17.5%) depending on the age group. The results of a Saudi modern
study predicted an increase of smokers number in the country to 10 million smokers by 2020. The current number
of smokers in Saudi Arabia is approximately 6 million, and they spend around 21 billion Saudi Riyal on smoking
annually. Clearly smoking is a prevalent problem among Saudis that requires intervention for eradication. Persistent
education of the health hazards related to smoking is recommended particularly at early ages in order to prevent
initiation of smoking [1, 2]. Tobacco use is considered a disease that can spread through social contact in a way
very similar to the spread of infectious diseases.
Like many infectious diseases, mathematical models can be used to understand the spread of smoking and to
predict the impact of smokers on the community in order to help reducing the number of smokers. Castillo-Garsow
et al. [3] presented a general epidemiological model to describe the dynamics of Tobacco use and they considered
the effect of peer presure, relapse, counselling and treetment. In their model the population was devided into nonsmokers,
smokers and smokers who quit smoking. Later, this mathematical model was refined by Sharomi and Gumel
[4], they introduced a new class of smokers who temporarily quit smoking. They concluded that the smokingfree
equilibrium is globally-asymptotically stable whenever a certain threshold, known as the smokers-generation
number, is less than unity, and unstable if this threshold is greater than unity. The public health implication of this
result is that the number of smokers in the community will be effectively controlled (or eliminated) at equilibrium