NorwayTo cite this article: Lerstad G, Brodin EE, Enga KF, Jorde R, Schirmer H, Njølstad I, Svartberg J, Braekkan SK, Hansen J-B. Hyperglycemia, assessed according to HbA 1c , and future risk of venous thromboembolism: the Tromsø study. J Thromb Haemost 2014; 12: 313-9.Summary. Background: HbA 1c , a marker of average plasma glucose level during the previous 8-12 weeks, is associated with the future risk of cardiovascular disease and all-cause mortality. Objectives: To examine the association between hyperglycemia, assessed according to HbA 1c , and the future risk of venous thromboembolism (VTE) in a population-based cohort. Methods: HbA 1c was measured in 16 156 unique subjects (25-87 years) who participated in one or more surveys of the Tromsø study (Tromsø 4, 1994(Tromsø 4, -1995 Tromsø 5, 2001 Tromsø 5, -2002 and Tromsø 6, 2007-2008). All subjects were followed, and incident VTE events were recorded up to 31 December 2010. Results: There were 333 validated first VTE events, of which 137 were unprovoked, during a median followup of 7.1 years. HbA 1c was not associated with the future risk of VTE in analyses treating HbA 1c as a continuous variable, or in categorized analyses. The risk of VTE increased by 5% per one standard deviation (0.7%) increase in HbA 1c (multivariable-adjusted hazard ratio [HR] 1.05; 95% confidence interval [CI] 0.97-1.14), and subjects with HbA 1c ≥ 6.5% had a 27% higher risk than those with HbA 1c < 5.7% (multivariable-adjusted HR 1.27; 95% CI 0.72-2.26). There was no significant linear trend for an increased risk of VTE across categories of HbA 1c (P = 0.27). Conclusions: Serum levels of HbA1c were not associated with the future risk of VTE in multivariable analysis. Our findings suggest that hyperglycemia does not play an important role in the pathogenesis of VTE.