Systemic sclerosis is a rare chronic disease of unknown cause characterized by diffuse fibrosis, degenerative changes, and vascular abnormalities in the skin, joints, and internal organs (especially the esophagus, lower GI tract, lung, heart, and kidney). Common symptoms include Raynaud’s syndrome, polyarthralgia, dysphagia, heartburn, and swelling and eventually skin tightening and contractures of the fingers. Lung, heart, and kidney involvement accounts for most deaths.
Researchers from the University of Toledo (USA) examined the association between systemic sclerosis (SSc) and occupational exposure to silica. They included 16 studies in the analysis and calculated the combined estimator of relative risk (CERR) and 95% confidence interval (CI) using fixed or random effect models. The findings suggest that silica exposure may be a significant risk factor for developing SSc and specifically in males: the overall CERR was 3.20 (95% CI, 1.89–5.43), in females 1.03 (95% CI, 0.74–1.44), in males 3.02 (95% CI, 1.24–7.35).
Occupational silica exposure as a risk factor for scleroderma: a meta-analysis
Zachary D. McCormic, Sura S. Khuder, Bishwa K. Arya1, April L. Ames and Sadik A. Khuder International Archives of Occupational and Environmental Health Online: 3 January 2010
Objectives: Among potential environmental risk factors for systemic sclerosis (SSc), occupational exposures have received some attention. In this meta-analysis, we examined the association between SSc and occupational exposure to silica.
Methods: We searched Medline, Toxline, BIOSIS, and Embase (1949 and November 2009) for original articles published in any language. Sixteen studies are included in the analysis, of which, 3 are cohort studies, 9 case–control and 4 are of other designs. The combined estimator of relative risk (CERR) and 95% confidence interval (CI) were calculated using fixed or random effect models.
Results: Significant heterogeneity was detected (I 2 = 97.2%; P < 0.01), and the CERR was 3.20 (95% CI, 1.89–5.43). The CERR for studies in females was 1.03 (95% CI, 0.74–1.44) and was 3.02 (95% CI, 1.24–7.35) for males. The CERR for case–control studies was 2.24 (95% CI, 1.65–3.31) and was 15.49 (95% CI, 4.54–52.87) for cohort studies.
Conclusions: The findings suggest that silica exposure may be a significant risk factor for developing SSc and specifically in males. Further observational studies examining the role of occupational silica exposure in the context of other risk factors are needed.