The association between metabolic syndrome and colorectal neoplasm: systemic review and meta-analysis

There has been constant speculation about the association between metabolic syndrome (MetS) and colorectal neoplasia (CN); however, the published results are conflicting. The aims of this study are to conduct a systematic search, and assess the literature to determine the available evidence on the association between these two conditions.

Meta-analysis was conducted based on relevant studies identified through a systematic literature review from PubMed, OvidSP, and Cochrane database during January 1980 to July 2011. A combined analysis was performed, followed by a subgroup analyses stratified by the study design, type of colorectal lesions, and sex. Publication bias was assessed using the Begg and Egger tests and visual inspection of funnel plot.

Eighteen studies were included in the final analysis. Overall, MetS was associated with 34% increase in the risk of CN [summary relative risk (RR), 1.34; 95% confidence interval (CI), 1.24-1.44]. The association between MetS and CN was found to be statistically significant in separate analysis for both case-control studies (summary RR, 1.58; 95% CI, 1.44-1.73) and cohort studies (summary RR, 1.21; 95% CI, 1.13-1.29). The association remained significant when analyses were restricted by type of colorectal lesions (colorectal cancer: RR, 1.30; 95% CI, 1.18-1.43; colorectal adenoma: RR, 1.37; 95% CI, 1.26-1.49). Further subgroup analysis by sex showed significant association between MetS and CN in both male and female population.

Our meta-analysis showed significant association between presence of MetS and CN. These results may help in identifying high-risk individuals at early stage, who might benefit from targeted colorectal cancer screening intervention.