IFNA1 and scleroderma: Conversely, when considering deaths attributed to scleroderma (n = 16), after adjusting for age, IFN score had a significant positive association with SSc mortality in its linear component (HR 2.83, 95% CI 1.18–6.75; P = 0.019), whereas the nonlinear component did not reach statistical significance (P = 0.230).