Metabolic syndrome components correlation with colorectal neoplasms: A systematic review and a meta-analysis

Background: Patients with metabolic syndrome (MetS) have a higher risk of developing colorectal neoplasms (CRN) including colorectal adenoma (CRA) and colorectal cancer (CRC). Nonetheless, the role and implication of each component of the syndrome, i.e. (hyperglycemia, hypertension, dyslipidemia, and visceral obesity) are not well ascertained.  Aims: We conducted a systematic review and a meta-analysis in order to assess the association between MetS components and CRN. Methods and Material: A systematic literature search using the PubMed database was performed with the objective of identifying relevant English studies. Effect estimates were measured. Heterogeneity, subgroup, sensitivity analyses, and publication bias analyses were performed. Results: Thirty-one studies met our inclusion criteria. Generally, subjects with hyperglycemia (RR = 1.33; 95% CI 1.14-1.54), high waist circumference (RR = 1.30; 95% CI 1.19-1.42), high triglycerides (RR = 1.30; 95% CI 1.13-1.49), and hypertension (RR = 1.26; 95% CI 1.17-1.36) showed a stronger positive significant association with CRA formation risk. A similar pattern was found between high fasting blood glucose (RR = 1.35; 95% CI 1.23-1.47) and high blood pressure (RR = 1.28; 95% CI 1.20-1.37) with CRC incidence. A moderate association was found between hypertriglyceridemia and visceral obesity with CRC risk. Conversely, no significant association was found between low high-density lipoprotein-cholesterol (HDL-C) with both outcomes.  Conclusions: Our results indicate that hyperglycemia, hypertension, visceral obesity, and hypertriglyceridemia increases CRA and CRC risk. Low HDL-C has no significant effect on those outcomes.