Given the suggestion of a positive association between FABP-4 and CRC risk in women from both the biomarker and MR analysis, we performed a causal mediation analysis for the association between waist circumference and CRC risk (BMI was not statistically significantly associated with CRC risk in women) with FABP-4 as a potential mediator using the EPIC nested case–control study data, assuming no interaction between waist circumference and FABP-4 (because there was no indication for such interaction). Here, FABP4 is linked to colorectal carcinoma.