Clinical peculiarities of patients with scleroderma exposed to silica: A systematic review of the literature

Objective: There are few data regarding the existence of clinical differences between patients with systemic sclerosis (scleroderma) exposed to silica (SSc-si) and "idiopathic" cases (SSc-id). Our goal is to describe the clinical characteristics of patients with SSc-si and see if they differ from the SSc-id cases.

Methods: We performed a systematic review of the literature by searching the MEDLINE, EMBASE and Web of Science databases. We also included our own series of patients diagnosed with SSc-si and SSc-id controls at the "Complejo Hospitalario Universitario de Vigo (CHUVI)" from 1985 to January 2013.

Results: The review of the literature disclosed 32 published series, with clinical data of 254 SSc-si patients (96% males). SSc-si represented 37.5-86% of the scleroderma males and 0-2.7% of the scleroderma females. Globally, more than expected proportion of diffuse forms (61%) and interstitial lung disease (81%) were observed in exposed patients. In the present series, the diagnosis of SSc exposure to silica was recorded in nine patients (9.5%), showing predominance of the diffuse form (77%, p = 0.001), positivity for anti-Scl70 (55%, p = 0.001), presence of ILD (78%, p = 0.048) and lower survival (9.2 versus 15.1, p = 0.023). Diffuse variant remained more prevalent analysing exposed versus non-exposed women (50% versus 8%, p = 0,000) and exposed versus non-exposed men (85.8% versus 50%, p = 0,000).

Conclusion: Silica exposure is a predominant risk factor in male SSc populations. The review of the literature is consistent with an association of SSc-si and diffuse scleroderma. A trend toward lower survival was observed in our series in SSc-si group.