Multifactorially adjusted HRs of lung cancer were 2.19 (1.24–3.87) for individuals with CRP ⩾1.7 mg l−1 and YKL-40 <154 μg l−1, 1.08 (0.25–4.72) for individuals with CRP <1.7 mg l−1 and YKL-40 ⩾154 μg l−1, and 2.58 (1.23–5.41) for individuals with CRP ⩾1.7 mg l−1 and YKL-40 ⩾154 μg l−1 compared to individuals with CRP <1.7 mg l−1 and YKL-40 <154 μg l−1 (Figure 3). Here, CHI3L1 is linked to lung cancer.