Independent association between occupational exposure and decline of forced vital capacity in systemic sclerosis (SSc): a multicenter recruitment retrospective cohort study

Published:November 15, 2021DOI:
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      Although male sex is associated with poor prognosis in Systemic Sclerosis (SSc), it is unclear whether this association is independent of confounding factors such as occupational exposure to toxicants.

      Research Question

      What is the respective impact of sex and occupational exposure on SSc patients’ characteristics with a focus on lung function decline?

      Study Design and Methods

      Patients with SSc (n=210, 55 males) underwent standardized quantitative assessment of occupational exposure through a cumulative exposure score (CES) in a multicenter recruitment retrospective cohort. Association of the CES with patients’ characteristics was assessed. Mixed linear, logistic and Cox regression models were used to identify predictors of time variation of forced vital capacity (FVC) and the hemoglobin-corrected transfer coefficient for carbon monoxide in the lung (DLCOc).


      Male sex was strongly associated with occupational exposure (OR=10.3, p<.0001). The CES was inversely correlated (r= -.20) and independently associated with decline in FVC over time and with occurrence of FVC decline ≥10% from baseline (p<.05). By contrast, the CES was not associated with decline in DLCOc or DLCOc decline ≥15%. There was no independent association between sex and decline in FVC or DLCOc. The prevalence of interstitial lung disease was similar across sex or occupational exposure.


      Occupational exposure to toxicants appears to independently predict decline of FVC in SSc patients, regardless of sex. Assessment of occupational exposure may be useful for SSc prognostication.



      SSc (Systemic sclerosis), FVC (forced vital capacity), SSc-ILD (SSc-related interstitial lung disease), DLCO (diffusing capacity of the lungs for carbon dioxide), HRCT (high-resolution computed tomography scan), PAH (pulmonary arterial hypertension), dcSSc (diffuse cutaneous form), PFT (pulmonary function test), mRSS (modified Rodnan skin score), DLCOc (diffusing capacity of the lungs for carbon dioxide corrected for hemoglobin), CES (cumulative exposure score), IQR (interquartile range), SD (standard deviation), OR (odds ratio), CI (Confidence Interval)
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