Serum Insulin, Glucose, Indices of Insulin Resistance, and Risk of Lung Cancer.
Cancer Epidemiol Biomarkers Prev. 2017 Jul 11. Epub 2017 Jul 11. PMID: 28698186
BACKGROUND: Although insulin may increase risk of some cancers, few studies have examined fasting serum insulin and lung cancer risk.
METHODS: We examined serum insulin, glucose, and indices of insulin resistance (insulin:glucose molar ratio and homeostasis model assessment of insulin resistance [HOMA-IR]) and lung cancer risk using a case-cohort study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Studyof Finnish men. 196 cases and 395 subcohort members were included. Insulin and glucose were measured in fasting serum collected 5-12 years pre-diagnosis. Cox proportional hazards models were utilized to estimate the relative risk of lung cancer.
RESULTS: The average time between blood collection and lung cancer was 9.6 years. Fasting serum insulin levels were 8.7% higher in subcohort members than cases. After multivariable adjustment, men in the fourth quartile of insulin had a significantly higher risk of lung cancer than those in the first quartile (HR=2.10, 95%CI=1.12-3.94). A similar relationship was seen with HOMA-IR (HR=1.83, 95%CI=0.99-3.38). Risk was not strongly associated with glucose or the insulin:glucose molar ratio (Ptrend=0.55 and Ptrend=0.27, respectively).
CONCLUSIONS: Higher fasting serum insulin concentrations, as well as the presence of insulin resistance, appear to be associated with an elevated risk of lung cancer development.
IMPACT: Although insulin is hypothesized to increase risk of some cancers, insulin and lung cancer remains understudied. Higher insulin levels and insulin resistance were associated with increased lung cancer risk. Although smoking cessation is the best method of lung cancer prevention, other lifestyle changes that impact insulin concentrations and sensitivity may reduce lung cancer risk.