Background Although systemic sclerosis is a rare disease, incidence rates h
ave increased recently in the United States. This study investigated the as
sociation between systemic sclerosis and exposure to solvents.
Methods A Medline search of articles published between 1966 and 2000 dealin
g with solvent exposure and systemic sclerosis identified eight studies tha
t met inclusion criteria of the meta-analysis. The studies included seven c
ase-control studies and one cohort study published between 1989 and 1998. A
series of meta-analyses of studies on systemic sclerosis and solvent expos
ure were performed for all studies and for case-control studies. A random e
ffect model was used to calculate a combined estimator of relative risk.
Results The combined estimator of relative risk for all studies was 2.91, w
ith a 95% confidence interval (CI) of 1.60 to 5.30. The combined estimator
of relative risk for the seven case-control studies was 3.14 (95% CI, 1.56-
6.33).
Conclusion A statistically significant increased relative risk for all stud
ies and for case-control studies suggests that exposure to organic solvent
may be a risk factor for developing systemic sclerosis. Further studies usi
ng other study designs and better control of confounders are needed. (C) 20
01 Wiley-Liss, Inc.