The association between tobacco smoking and the onset of psoriasis was recently reviewed in a study, “Psoriasis and smoking: links and risks,” published in Psoriasis: Targets and Therapy.
Tobacco smoke is a complex mixture containing more than 7,000 chemicals, of which over 100 are known to be toxic. Exposure to these toxic components is of public health concern as it induces or contributes to the development of many diseases, including several types of cancer, and cardiovascular and pulmonary diseases. World Health Organization estimates indicate that tobacco killed around 100 million people over the 20th century.
Psoriasis, an autoimmune disease characterized by red, scaly, itchy patches of abnormal skin, is also among the diseases associated with smoking.
“Incident psoriasis has been linked with smoking habits in both case-control and cohort studies. Ideally, assessment of risks should be done separately for each clinical variant. This has been rarely done,” the author wrote.
In this paper, the author reviewed published data from various sources in an effort to establish a link between tobacco smoking and psoriasis. His findings revealed a strong relationship between tobacco smoking and the development psoriasis. The odds ratio, a measure of association between exposure to tobacco and development of psoriasis, estimated from pooled analysis of 25 case-control studies was 1.78 for smokers.
Furthermore, results from pooled analyses of three particular cohort studies indicated that the risk of developing psoriasis among smokers increases from 1.81 in those smoking 1 to 14 cigarettes per day to 2.29 in those smoking more than 25 cigarettes per day.
Other findings suggest that smoking not only affects the onset of psoriasis, but also disease severity and response to treatment. Also, a number of comorbidities linked to psoriasis were connected to smoking, including inflammatory bowel disease, cardiovascular disease, and several cancers related to the respiratory tract. Finally, the association between smoking and psoriatic arthritis was found less consistent than psoriasis.
The influence of smoking on the onset and development of psoriasis could be explained through a number of pathophysiological mechanisms, the author found. This includes the oxidative stress, vascular effects, and interaction of chemicals found in smoke with the signaling pathways that activates the development of psoriasis.
“Psoriasis is just one of the many diseases associated with smoking, but it is visible and disabling. Dermatologists could play a major role in reducing the health burden of smoking by influencing the patients to change their behavior,” concluded the author.