Occupational exposure to mineral fibers and incidence of recurrent chest infections in insulators

Abstract

<b>Background:</b> Mineral fibers are common insulating materials. Although exposure to mineral fibers is a known risk factor for mesothelioma, whether long-term occupational exposure to mineral fibers causes recurrent chest infection is unknown. <b>Methods:</b> In this cohort study, 272 insulators without any chest infection at baseline visit were followed up at 3-8 years. Demographic information including work history was obtained at baseline using a structured questionnaire. Information on recurrent chest infections (frequency of chest infections in the past 3 years) was obtained at follow-up. Neutrophil to lymphocyte (N/L) ratio was calculated from hematological tests. Associations between exposure to mineral fibers and episodes of recurrent chest infection were assessed by Poisson regression, adjusting for potential confounders (age, sex, ethnicity, BMI, and marital status, and smoking pack-years). The mediation effect of the N/L ratio was also tested. <b>Results:</b> The incidence of chest infection at follow-up was two times higher among participants who were exposed to mineral fibers (34%) at the baseline visit than those who were not (15%), with a median (range) of 2 (1-18) episodes of chest infection in the past 3 years. Mean (SD) N/L ratio was 2.3 (1.5). After adjusting for confounders, exposure to mineral fibers was associated with increased episodes of chest infections (regression coefficient [β]: 2.4; 95% confidence interval [CI]: 0.5-4.4), albeit no mediating effect of N/L ratio in the association between mineral fiber exposure and recurrent chest infection was observed. <b>Measurements and Main Results:</b> Insulators occupationally exposed to mineral fibers are at a higher risk of recurrent chest infections.