The effect of smoking on Sjögren's disease development and severity: a comprehensive literature review

Unlike other autoimmune diseases, little is known about the environmental risk factors for Sjögren's disease (SjD). Smoking is an important risk factor for rheumatoid arthritis but the relationship between smoking and SjD is more complex to understand. Current smoking seems to be negatively linked to SjD, whereas there is mixed data on past smoking. Smoking also seems to impact SjD outcomes, influencing comorbidities like hypertension or associated immune-mediated diseases, and, less clearly, extraglandular involvement, particularly pulmonary disease. Minor salivary gland biopsy findings indicate a lower frequency of positivity associated with smoking, with a potential dose-response relationship. However, smoking's uncertain effect on dryness symptoms complicates interpretation of data with reverse causation remaining a possibility. This review underscores the complexity of the smoking-SjD connection, raising questions about causality and potential protective effects on either SjD's development and/or classification criteria. Understanding these nuances may help unravel SjD pathogenesis and inform future therapeutic strategies.