Even though we found associations between YKL-40 levels and lipid levels, and between SNPs of CHI3L1 and YKL-40 levels, we did not find convincing or reproducible associations between SNPs of CHI3L1 and lipid levels, as would be expected if there were a causal link between elevated YKL-40 levels and the development of dyslipidemia. Here, CHI3L1 is linked to metabolic syndrome.