Survey of potential toxic exposure in patients with systemic sclerosinin rescle registry. A preliminary study

Abstract

Background Systemic sclerosis (SSc) is a systemic autoimmune disease with extremely heterogeneous clinical features and unknown etiology, although numerous studies suggest a relationship with environmental and occupational factors. So far there is little information on whether toxic substances can play a relevant role in its phenotypic expression (1).

Objectives To analyze in a cohort of patients with SSc the proportion of patients exposed to toxic and their correlation with epidemiologic, clinical and serological data.

Methods A survey was conducted aimed at the knowledge of the working life of patients from six centers belonging to the Spanish Scleroderma Registry (RESCLE), categorizing them in six groups: no potential exposure to toxic substances, potential exposure to silica, to hydrocarbons, to organic solvents, to mixed toxics (silica and/or hydrocarbons and/or organic solvents) and to another toxics. In all patients 87 epidemiological, clinical and analytical variables included in the registry were analyzed, carrying out a comparative study between groups.

Results 225 SSc patients were selected. Of these, 81 patients (36%) had worked in professions with potential risk of toxic exposure, 64 women out of the 227 included (28%) and 17 men out of the 28 included (60%). The toxic agent most frequently involved was silica in 29 patients (35.8%), followed by hydrocarbons in 21 (25.9%), mixture of toxic substances in 21 other patients (25.9%), organic solvents in 4 patients (4.9%) and other toxic in 6 cases (7.4%). Toxic exposure was associated with a lower risk of being female (OR 0.15, p <0.001), having been exposed to tobacco (OR 0.4, p 0.037) and digital ulcers (OR 0.43, p 0.016) and with a greater likelihood of hepatic involvement (OR 3.63, p 0.021), musculoskeletal involvement (OR 2.13, p 0.017) and the slow capillary pattern of Maricq (OR 1.8, p 0.063). Analyzing the exposure groups separately, patients exposed to silica had a lower probability of Raynaud’s phenomenon (OR 0.25, p 0.005) and a higher probability of diagnosis at older ages (OR: 1.04, p 0.005), presence of Topoisomerase I antibody (OR 3.71, p 0.023) and slow capillary pattern of Maricq (OR 4.15, p 0.008). Patients exposed to hydrocarbons had an increased risk of liver involvement (OR 5.34, p 0.029).

Conclusion In our cohort of 225 patients with SSc, 60% of male patients and 28% of women worked in a profession with a potential risk of toxic exposure. In this preliminary study, important differences were observed in the probability of a different phenotypic expression of the SSc according to the history of occupational exposure to toxins. Studies with a larger number of patients are needed to establish these associations in a solid way.