Liver functions in silica-exposed workers in Egypt: possible role of matrix remodeling and immunological factors

Background: Brick manufacturing constitutes an important industrial sector in Egypt with considerable exposure to silica. Objectives: We aimed for evaluating hepatic functions in silica-exposed workers in the clay brick industry, and the possible role of matrix remodeling and immunological factors. Methods: A case-control study, 87 workers as exposed and 45 as control subjects. Questionnaire, clinical examination, and laboratory investigations: liver functions, matrix metalloproteinase-9, immunoglobulins G and E, and anti-liver kidney microsomal antibody. Results: In the exposed workers, mean levels of liver functions, matrix metalloproteinase-9 (MMP-9), and IgG and IgE were significantly higher. In the silicotic subgroup the mean level of GGT was almost twice the level in the non-silicotic subjects. Logistic regression showed that abnormal GGT and ALT were associated with production workers. Conclusion: Workers in the clay brick industry showed evidence of liver disease that could be related to matrix remodeling.