Adherence to a healthy Nordic diet and risk of type 2 diabetes among men: the Kuopio Ischaemic Heart Disease Risk Factor Study

PURPOSE: To investigate the association between healthy Nordic diet and risk of type 2 diabetes (T2D) in middle-aged and older men from eastern Finland. METHODS: A total of 2332 men aged 42–60 years and free of T2D at baseline in 1984–1989 were included. Diet was assessed with 4-day food records at baseline and the healthy Nordic diet score was calculated based on a modified Baltic Sea Diet Score. T2D diagnosis was based on self-administered questionnaires, fasting and 2-h oral glucose tolerance test blood glucose measurements, or by record linkage to national health registries. Cox proportional hazards regression and analysis of covariance were used for analyses. RESULTS: During the mean follow-up of 19.3 years, 432 men (18.5%) were diagnosed with T2D. The multivariable-adjusted hazard ratio for T2D in the lowest vs. the highest quartile of the healthy Nordic diet score was 1.35 (95% CI 1.03–1.76) (P trend across quartiles 0.028). Lower adherence to healthy Nordic diet was also associated with higher plasma glucose and insulin concentrations. CONCLUSIONS: In this prospective population-based cohort study among middle-aged and older men from eastern Finland, lower adherence to healthy Nordic diet was associated with higher risk of T2D and higher plasma glucose and serum insulin concentrations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00394-021-02569-1.