Association of dietary protein consumption with incident silent cerebral infarcts and stroke: The Atherosclerosis Risk in Communities (ARIC) study

Background and Purpose - The effect of dietary protein on the risk of stroke has shown inconsistent results. We aimed to evaluate the relationship of dietary protein sources with the risk of stroke and silent cerebral infarcts in a large community-based cohort. Methods - We studied 11601 adults (age, 45-64 years at baseline in 1987-1989) enrolled in the Atherosclerosis Risk in Communities (ARIC) Study, free of diabetes mellitus and cardiovascular disease. Dietary protein intake was assessed with validated food frequency questionnaires at baseline and after 6 years of follow-up. Incident stroke events were identified through hospital discharge codes and stroke deaths and physician-adjudicated through December 31, 2011. A subset of participants (n=653) underwent brain magnetic resonance imaging in 1993 to 1995 and in 2004 to 2006. Cox proportional hazard models and logistic regression were used for statistical analyses. Results - During a median follow-up of 22.7 years, there were 699 stroke events. In multivariable analyses, total, animal, and vegetable protein consumption was not associated with risk of stroke. Red meat consumption was associated with increased stroke risk, particularly ischemic events. The hazard ratios (95% confidence interval) for risk of ischemic stroke across ascending quintiles of red meat consumption were 1 (ref), 1.13 (0.85-1.49), 1.44 (1.09-1.90), 1.33 (0.99-1.79), and 1.47 (1.06-2.05); P_trend=0.01. No association of major dietary protein sources with silent cerebral infarcts was detected. Conclusions - This study supports the notion that consumption of red meat may increase the risk of ischemic stroke. No association between dietary protein intake and silent cerebral infarcts was found.