Introduction: Previous studies show a robust association of low lung function with increased risk of atherosclerotic cardiovascular disease (ASCVD) and genetic studies indicate that this association may be causal. However, importance of low lung function compared to established cardiovascular risk factors remains unexplored.

Objective: To test the hypothesis that low lung function is comparable to diabetes in importance as a risk factor for ASCVD.

Methods: In 100 356 adults without ASCVD from the Copenhagen General Population Study, we defined low lung function as forced vital capacity (FVC) < 80 % predicted. Risk of future ASCVD was investigated in survival analyses adjusted for age, sex, hyperlipidemia, blood pressure, kidney function, smoking status, cumulative smoking, family history of ASCVD, and diabetes.

Results: During a median follow-up of 9 years, we recorded 6917 ASCVD events (1273 events in 9135 individuals with low lung function).  Hazard ratio for ASCVD was 1.37 (95% CI: 1.28-1.46) for those with low lung function versus those without and 1.36 (1.24-1.49) for diabetes. Low lung function and diabetes increased explained variation in survival time (R2) by 1.4% and 0.7%, respectively.  At 10 years of follow-up, absolute risk difference was 2.4% (1.9%-2.9%) for those with low lung function versus those without and 2.4% (1.6%-3.2%) for diabetes. Lastly, population attributable fractions for ASCVD were 4.2% for low lung function and 2.0% for diabetes.

Conclusion: Low lung function is robustly associated with ASCVD and seems as important as diabetes for explaining risk of ASCVD in the general population. Since diabetes by default indicates high risk of ASCVD clinically, so should low lung function.