ObjectivesPatients with chronic obstructive pulmonary disease (COPD) are at increased risk of cerebrovascular disease, which might be associated with decreases in cerebral blood flow. Since studies examining cerebral blood flow in COPD remain scarce and are limited by sample size, we aimed to study cerebral blood flow in participants with and without COPD.DesignObservational cohort study.SettingPopulation-based Rotterdam Study.Participants4177 participants (age 68.0±8.5 years; 53% females) with and without COPD.Predictor variableSpirometry and pulmonary diffusing capacity.Outcome measuresCerebral blood flow by two-dimensional phase-contrast cerebral MRI.ResultsCompared with subjects with normal spirometry (forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) ≥0.7 and FEV₁≥80%), multivariable adjusted cerebral blood flow (mL/min) was preserved in subjects with COPD Global initiative for Chronic Obstructive Lung Disease (GOLD1) (FEV₁/FVC <0.7 and FEV₁≥80%), but significantly lower in subjects with COPD GOLD2-3 (FEV₁/FVC <0.7 and FEV₁<80%), even after adjustment for cardiovascular comorbidities. In sex-stratified analyses, this difference in cerebral blood flow was statistically significant in women but not in men. Cerebral blood flow was lowest in subjects with FEV₁, FVC and diffusion lung capacity for carbon monoxide % predicted values in the lowest quintile, even after adjustment for cardiovascular comorbidities and cardiac function.ConclusionWe observed a lowered cerebral blood flow in subjects with COPD GOLD2-3.