Whether high cardiovascular fitness is associated with reduced risk of venous thromboembolism (VTE) is unknown. The present study aims to determine whether high cardiovascular fitness reduces the risk of VTE.
A Swedish cohort of male conscripts (n?=?773,925) born in 1954-1970 with no history of previous VTE were followed from enlistment (1972-1990) until 2010. Data on cardiovascular fitness using a cycle ergonometric test (maximal aerobic workload in Watt [Wmax]) at conscription were linked with national hospital register data and the Multi-Generation Register. We identified all full-siblings and first-cousin pairs discordant for maximal aerobic workload. This co-relative design allows for adjustment for familial resemblance.
In total, 3005 (0.39%) males were affected by VTE. Cardiovascular fitness estimated with Wmax was not associated with VTE risk when adjusted for body mass index (BMI). However, cardiovascular fitness estimated with Wmax/kg and adjusted for BMI was associated with reduced risk for VTE (Hazard ratio (HR) 0.81, 95% confidence interval (CI) 0.78-0.85 per standard deviation compared with mean Wmax/kg). The association was weaker over time and also when examining discordant first cousins and full-sibling pairs.
These results suggest that there is a relationship between cardiovascular fitness and weight that is important for future VTE risk. Key messages Whether high cardiovascular fitness is associated with reduced risk of venous thromboembolism (VTE) is unknown. A Swedish cohort of male conscripts (n = 773,925) tested with a cycle ergometric test with no history of previous VTE were followed from enlistment (1972-1990) until 2010. Cardiovascular fitness estimated with Wmax/kg and adjusted for BMI was associated with reduced risk for VTE (HR 0.81, 95% CI 0.78-0.85). These results suggest that there is a relationship between cardiovascular fitness and weight that is important for future VTE risk.