To investigate the relationship between serum fatty acid (FA) metabolites and vitamin D (VD) levels and colorectal cancer (CRC).

The clinical data of 41 patients with first diagnosis of CRC and 41 healthy subjects from January 2019 to December 2021 were retrospectively analyzed, which were divided into CRC group and healthy group, respectively. Some related short-chain fatty acids and medium-long chain fatty acids were analyzed by liquid chromatography-mass spectrometry. The level of 25-(OH)D in serum was detected by enzyme-linked immunosorbent assay (ELISA). Data were processed by SPSS 22.0. Measurement data such as 25-(OH)D level were represented by () and independent sample t test was performed. Statistical data such as VD distribution were represented by [n (%)] and χ² test was performed. Logistic regression model was used to analyze the risk factors of CRC in fatty acid metabolites. P<0.05 was considered statistically significant.

Among the 20 fatty acids tested, only 4 fatty acids (2-hydroxylaurate, eicosanediate, heptadecic acid and 4-methylnonylcarnitine) in CRC group had significant differences compared with the healthy group (P<0.05). The results of univariate and multivariate analysis showed that the levels of 2-hydroxylaurate and 4-methylnonylcarnitine in FA metabolites were independent risk factors for CRC (P<0.05). There was statistical significance in VD distribution between the two groups (P<0.05). Moreover, the serum 25-hydroxyvitamin D[25-(OH)D] level in CRC group was significantly lower than that in healthy group (P<0.05). The level of serum 25-(OH)D in CRC patients was closely correlated with the degree of differentiation, pTNM stage and lymph node metastasis, and the differences were statistically significant (P<0.05).

Serum fatty acid metabolites 2-hydroxylaurate, 4-methylnonylcarnitine and serum 25-(OH)D are closely related to the occurrence of CRC. Specific FA metabolites and VD levels may be used as serological markers to predict the occurrence of CRC.