Sarcoidosis and silica dust exposure among men in Sweden: a case–control study

OBJECTIVE: To determine whether occupational exposure to silica dust is associated with an increased risk of developing sarcoidosis. DESIGN: Case–control study of all individuals between 20 and 65 years of age diagnosed with sarcoidosis (D86) in Sweden between 2007 and 2016. Controls were matched to cases (2:1) based on age, sex and county at the time of diagnosis. A Job Exposure Matrix was used to estimate the occupational silica exposure of all cases and controls. SETTING: Medical and occupational data from the National Outpatient Register were used to implement a case–control analysis, while the two controls used for each case were selected from the National Register of the Total Population. Information about occupation and time of employment were collected from the Swedish Occupational Register. PARTICIPANTS: All men and women aged 20–65 years old who were diagnosed sarcoidosis (D86) from 2007 to 2016 were included and assigned two controls. MAIN OUTCOMES: Silica dust exposure correlates with an increased risk of developing sarcoidosis in men. RESULTS: The prevalence of silica exposure at work was statistically significantly higher among male cases than controls (OR 1.27, 95% CI 1.13 to 1.43). For men of an age of 35 years or younger the correlation seems to be stronger (OR 1.48, 95% CI 1.1 to 1.87) than in older men (OR 1.21, 95% CI 1.05 to 1.39). For men older than 35 with exposure to silica the prevalence of sarcoidosis increased with the exposure time, with an OR of 1.44 (95% CI 1.04 to 2.00) for exposure of more than 10 years. CONCLUSIONS: Occupational exposure to silica dust seems to increase the risk of sarcoidosis among men between 20 and 65 years of age. The risk is higher among exposed men 35 years or younger and older men with longer exposure (>6 years).