The Complicated Relationship Between Metabolic Syndrome and Cancer

Since the 1990s, clinicians have been increasing concerned with the metabolic syndrome (MetS)—the constellation that includes 5 distinct components: obesity, raised triglycerides, lowered HDL-C, insulin resistance, hypertension. Lately, it seems like the pendulum is swinging in research, and studies are trying to tease out each component’s contribution to specific diseases.

Such is the case in a study published in the May 2015 issue of Diabetes & Metabolism. Conducted in Australia, the study examined MetS as a risk factor for cancer. It specifically examined whether MetS confers a greater cancer risk than the sum of its individual components and component associations, and whether MetS is a useful predictor for future cancer risk.

These researchers looked at 20,648 patients for whom data on MetS component was available and linked patients to national cancer registries. Over approximately 8.5 years, these patients developed 2827 cancers of any kind (overall cancers), of which 468, 651 and 549 cancers were colorectal, prostate and breast cancer, respectively.

MetS seems to be protective for prostate cancer. Men with MetS were 15% to 25% less likely to develop prostate cancer than matched controls. Elevated waist circumference and triglycerides were inversely associated with prostate cancer.

The researchers found no association between a MetS diagnosis and overall cancer, colorectal or breast cancers.

A subgroup, patients with 5 positive MetS components, was twice as likely to develop colorectal cancer as patients with no positive MetS components. This association seems to be driven by waist circumference and hypertension. Greater waist circumference and elevated blood pressure increased risk of colorectal cancer by 38% and 29% respectively.

The MetS is a useful tool for predicting risk of cardiovascular disease and type 2 diabetes, and many researchers wonder if it might predict other late-life health conditions. The MetS only predicted cancer risk moderately, and appeared to have no clinical value as a predictor for cancer. The authors indicate that the implications for clinical practice are to focus on waist circumference and blood pressure reduction.