Insulin resistance/hyperinsulinemia and cancer mortality: the Cremona study at the 15th year of follow-up

Type 2 diabetes is associated with risk of cancer. Hyperinsulinemia and insulin resistance may be the link with cancer, but whether this is independent of the diabetes status, obesity/visceral obesity and metabolic syndrome is uncertain and the present study wanted to address this issue. Fifteen-year all-cause, CVD and cancer mortality data were obtained through the Regional Health Registry in 2,011 out of 2,074 Caucasian middle-aged individuals of the Cremona Study, a population study on the prevalence of diabetes mellitus in Italy in which anthropometric and metabolic characteristics were collected. During the 15-year observation period, 495 deaths were registered: 221 CVD related and 180 cancer related. Age and sex were independently associated with all-cause, cancer and CVD mortality rates. Age- and sex-adjusted analysis showed that HOMA-IR, cigarette smoking and diabetes were independently associated with all-cause mortality; HOMA-IR, systolic blood pressure and fibrinogen were independently associated with CVD mortality; HOMA-IR and smoking habit were independently associated with cancer mortality. Individuals in the highest quintile of serum insulin had a 62% higher risk of cancer mortality (HR = 1.62 95% CI: 1.19-2.20; P < 0.0022) and 161% higher risk of gastrointestinal cancer mortality (HR = 2.61 95% CI: 1.73-3.94; P < 0.0001). Age- and sex-adjusted analysis showed that hyperinsulinemia/insulin resistance is associated with cancer mortality independently of diabetes, obesity/visceral obesity and the metabolic syndrome.