Metabolic syndrome and risk of ovarian and fallopian tube cancer in the United States: An analysis of linked SEER–Medicare data

Objective: To clarify associations between metabolic syndrome, its components, and ovarian cancer risk. Methods: Using a case-control study within the U.S.-based Surveillance, Epidemiology and End Results (SEER)–Medicare linked database, we examined metabolic syndrome, its components (obesity, impaired fasting glucose, hypertension, HDL cholesterol, triglycerides), and ovarian/fallopian tube cancer risk. Cases (n = 16,850) were diagnosed with cancer between age 68–89 from 1994 through 2013. Controls (n = 281,878) were Medicare enrollees without these cancers living in registry areas. We estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) with logistic regression. Results: Women with metabolic syndrome had reduced ovarian cancer risk compared to women not meeting the diagnostic criteria (OR 0.86, CI 0.82–0.89). Having one or two syndrome components was associated with increased risk, but having ≥3 was not, when compared to women without any components. Impaired fasting glucose, which was highly prevalent among those with metabolic syndrome, was associated with reduced risk (OR 0.90, CI 0.87–0.93). Hypertension and high triglycerides, the most prevalent components among women without metabolic syndrome, were associated with increased risks (OR 1.08, CI 1.04–1.12; OR 1.05, CI 1.01–1.08, respectively). Conclusions: Specific metabolic syndrome components may have modest associations with ovarian cancer. These associations varied in direction and the prevalence of the components influenced the overall association between metabolic syndrome and ovarian cancer. Evaluating metabolic syndrome as a composite exposure could be misleading in ovarian cancer research, but further study of the syndrome components is warranted.