Tobacco smoking and sarcoidosis revisited-Evidence, mechanisms, and clinical implications: a narrative review.

Abstract

Sarcoidosis is a multisystem inflammatory disease with unclear etiology, influenced by genetic predisposition and environmental exposures. Smoking has been widely studied for its potential role in sarcoidosis, with conflicting evidence regarding its impact on disease risk, severity, and treatment response. While some epidemiologic studies suggest that smoking is associated with a lower risk of sarcoidosis, others highlight variations based on geography, ethnicity, and smoking history. Assessing the effects of smoking is particularly challenging because of the complex composition of tobacco smoke, which contains thousands of chemicals with diverse biologic effects. Nicotine, a major component of tobacco, has demonstrated both pro- and anti-inflammatory properties, further complicating its role in sarcoidosis. This narrative review explored the complex relationship between smoking and sarcoidosis by examining smoking's effects on immune modulation, disease presentation and prognosis, and response to immunosuppressive therapy. By summarizing current evidence, this paper aimed to clarify the impact of smoking and nicotine on sarcoidosis and identify key areas for future research, particularly in understanding the mechanisms underlying smoking-related immune modulation and treatment outcomes.