Association between glucose tolerance level and cancer death in a general Japanese population: the Hisayama Study

The authors examined the associations of glucose tolerance status and fasting and 2-hour postload glucose levels with the risk of cancer death in a 19-year follow-up study of 2,438 Japanese subjects aged 40-79 years who underwent a 75-g oral glucose tolerance test (1988-2007). During follow-up, 229 subjects died of cancer. The risk of cancer death was significantly higher in subjects with fasting plasma glucose levels of ≥5.6 mmol/L or 2-hour postload glucose levels of ≥11.1 mmol/L than in those with the lowest fasting or 2-hour postload glucose levels, after adjustment for potentially confounding factors. According to glucose tolerance status, not only diabetes but also impaired fasting glycemia and impaired glucose tolerance were significant risk factors for cancer death (for impaired fasting glycemia, multivariable-adjusted hazard ratio (HR) = 1.49 (95% confidence interval (CI): 1.05, 2.11); for impaired glucose tolerance, HR = 1.52 (95% CI: 1.05, 2.22); and for diabetes, HR = 2.10 (95% CI: 1.41, 3.12)). With regard to site-specific cancers, elevated fasting or 2-hour postload glucose levels were associated with the risks of death from stomach, liver, and lung cancer. These findings suggest that both prediabetic hyperglycemia and diabetes are significant risk factors for cancer death in the general Japanese population.