Effects of coffee consumption on glucose tolerance, serum glucose and insulin levels - A cross-sectional analysis

Objective: Coffee has several metabolic effects that could reduce the risk of type 2 diabetes. Our objective was to examine the effects of coffee consumption on glucose tolerance, glucose and insulin levels. Research design and methods: A subsample of subjects aged 45 to 64 years in 1987 and in 1992 from the population-based FINRISK study (12 287 individuals) was invited to receive the standard oral glucose tolerance test at baseline. Plasma samples were taken after an overnight fast, and a two-hour oral glucose tolerance test was administered. Fasting and two-hour plasma glucose and insulin were measured in 2434 subjects with data on coffee use and potential confounders. Results: After adjustment for potential confounding factors (age, body mass index, systolic blood pressure, occupational, commuting and leisure time physical activity, alcohol and tea drinking, smoking), coffee consumption was significantly and inversely associated with fasting glucose, two-hour plasma glucose, and fasting insulin in both men and women. Coffee consumption was significantly and inversely associated with impaired fasting glucose, impaired glucose regulation, and hyperinsulinemia among both men and women and with isolated impaired glucose tolerance among women. Conclusions: In this cross-sectional analysis, coffee showed positive effects on several glycemia markers.