Are cleaning activities a source of exposure to crystalline silica in women with rheumatoid arthritis? A case-control study.

INTRODUCTION: Inhalation of crystalline silica (silicon dioxide, SiO2) is associated with a wide range of acute and chronic diseases, including rheumatoid arthritis (RA). The objectives of this work were to identify the main sources of exposure to SiO2 in a series of patients with RA not selected on the basis of their professional activity, compared with a representative sample of the French general population, and to assess the association between silica exposure and disease features. METHODS: The Dust Exposure Life-Course Questionnaire (DELCQ) is a tool that enables retrospective quantification of both occupational and non-occupational lifetime exposure to SiO2. DELCQ-previously validated in a large representative sample of the French general population-was administered to 97 consecutive RA patients, and exposure scores were compared between cases and age, gender and smoking status-matched controls (1:4). The main sources of SiO2 exposure were identified in cases and controls, and source-specific exposure levels were compared. The association between DELCQ scores and disease variables in cases was tested via univariable and multivariable analyses. RESULTS: In women with RA, the main sources of SiO2 exposure were cleaning activities and dusty clothes laundry, with higher exposure levels from these sources versus the general population (p<0.005). Across the whole series of RA patients, high SiO2 exposure was independently associated with mediastinal lymphadenopathy (OR 6.3, 95% CI 1.4 to 27.7). CONCLUSION: Cleaning activities and dusty clothes laundry may be underestimated sources of SiO2 exposure in women with RA.

Crystalline silica exposure in patients with rheumatoid arthritis and systemic sclerosis: a nationwide cross-sectional survey.

OBJECTIVES: Develop and validate a thorough exposure questionnaire to comprehensively explore crystalline silica (SiO2) exposure in the general population (gender-specific, occupational and non-occupational) and in patients with autoimmune diseases (rheumatoid arthritis (RA), systemic sclerosis (SSc)). METHODS: Lifetime exposures to SiO2 in occupational and non-occupational settings were assessed using a thorough exposure questionnaire. The questionnaire was applied to a general population panel (n = 2911) sampled from the French rolling census, and to unselected patients with SSc (n = 100) and RA (n = 97). Global (GES), occupational (OES) and non-occupational (NOES) exposure scores were assessed in SSc and RA patients, and compared with up to four controls from the general population, matched by age group, sex and tobacco consumption. RESULTS: Patients had higher GES than their matched controls (SSc: P = 0.001; RA: P < 0.0001) due to higher OES (P < 0.0001 for SSc and RA). Men had higher GES than women (SSc: P < 0.0001; RA: P = 0.002) due to higher OES (P < 0.0001 for SSc and RA). The NOES did not differ between men and women. In SSc patients: Men had higher GES than controls (P < 0.0001). Men and women with SSc had higher OES than controls (P < 0.0001). In RA patients: GES and OES were higher in both men (P = 0.00521; P < 0.0001) and women (P < 0.0001; P < 0.0001) than in their respective controls. Women had higher NOES than controls (P = 0.045). CONCLUSION: The lifetime SiO2 exposure gap between RA and SSc patients and controls was substantially due to occupational exposure. In both diseases, men had higher exposure scores than women.

Exposure to inorganic particles in paediatric sarcoidosis: the PEDIASARC study.

Inorganic antigens may contribute to paediatric sarcoidosis. Thirty-six patients matched with 36 healthy controls as well as a group of 21 sickle-cell disease (SCD) controls answered an environmental questionnaire. Patients' indirect exposure to inorganic particles, through coresidents' occupations, was higher than in healthy and SCD controls (median score: 2.5 (0.5-7) vs 0.5 (0-2), p=0.003 and 1 (0-2), p=0.012, respectively), especially for construction, exposures to metal dust, talc, abrasive reagents and scouring products. Wood or fossil energies heating were also linked to paediatric sarcoidosis. This study supports a link between mineral environmental exposure due to adult coresident occupations and paediatric sarcoidosis.

Paediatric sarcoidosis.

Paediatric sarcoidosis is an extremely rare disease characterized by a granulomatous inflammation. The estimated incidence is 0.6-1.02/100,000 children, but in the absence of international registers, the disease is probably under-reported. Its pathophysiologic basis is not clearly understood but the current hypothesis is a combination of a genetic predisposition and an environmental exposure that could be either organic or mineral. Contrary to adult forms of the disease, general symptoms are often at the forefront at diagnosis. In its most frequent form, paediatric sarcoidosis is a multi-organ disorder affecting preferentially the lungs, the lymphatic system and the liver, but all organs can be affected. This review aims to provide an overview of current knowledge on sarcoidosis in children, providing a summary of the data available from cohort studies on the presentation, the management and the evolution of the disease in this specific population.