Int. J. Environ. Res. Public Health 2009, 6, 209-224; doi:10.3390/ijerph6010209 OPEN ACCESS International Journal of Environmental Research and Public Health ISSN 1660-4601 www.mdpi.com/journal/ijerph Review Smoking and Chronic Obstructive Pulmonary Disease (COPD). Parallel Epidemics of the 21st Century Rafael Laniado-Laborín Facultad de Medicina, Universidad Autónoma de Baja Califonia, Mexico E-Mail: rafaellaniado@gmail.com; Tel.: 011-52-(664) 686-5626 Received: 15 December 2008 / Accepted: 7 January 2009 / Published; 9 January 2009 Abstract: One hundred million deaths were caused by tobacco in the 20th century, and it is estimated that there will be up to one billion deaths attributed to tobacco use in the 21st century. Chronic obstructive pulmonary disease (COPD) is rapidly becoming a global public health crisis with smoking being recognized as its most important causative factor. The most effective available treatment for COPD is smoking cessation. There is mounting evidence that the rate of progression of COPD can be reduced when patients at risk of developing the disease stop smoking, while lifelong smokers have a 50% probability of developing COPD during their lifetime. More significantly, there is also evidence that the risk of developing COPD falls by about half with smoking cessation. Several pharmacological interventions now exist to aid smokers in cessation; these include nicotine replacement therapy, bupropion, and varenicline. All pharmacotherapies for smoking cessation are more efficacious than placebo, with odds ratios of about 2. Pharmacologic therapy should be combined with nonpharmacologic (behavioral) therapy. Unfortunately, despite the documented efficacy of these agents, the absolute number of patients who are abstinent from smoking at 12 months of follow-up is low. Keywords: Tobacco; smoking; COPD; smoking cessation. 1. Introduction According to the World Health Organization (WHO), one hundred million deaths were caused by tobacco in the 20th century, and if current trends continue, there will be up to one billion deaths attributed to tobacco use in the 21st century. There are more than one billion smokers in the world, and