Brief Reports

By Matthew E. Fink, MD, Professor and Chairman, Department of Neurology, Weill Cornell Medical College, and Neurologist-in-Chief, New York Presbyterian Hospital. Dr. Fink is a retained consultant for MAQUET.

The articles originally appeared in the April 2013 issue of Neurology Alert.

Mediterranean Diet Can Reduce Risk for Stroke

Source: Estruch R, et al, for the PREDIMED Study Investigators. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013; Feb. 25. DOI: 10.1056/NEJMoa1200303. [Epub ahead of print.]

The PREDIMED investigators from Barcelona, Spain, reported the results of their multicenter, randomized dietary treatment trial of the effects of three different diets on cardiovascular events — a Mediterranean diet supplemented with extra virgin olive oil, a Mediterranean diet supplemented with mixed nuts, or a control diet that included advice to reduce dietary fat. The Mediterranean diet is characterized by a high intake of olive oil, fruit, nuts, vegetables, and cereals; a moderate intake of fish and poultry; a low intake of dairy products, red meat, processed meats, and sweets; and wine in moderation consumed with meals. A number of observational cohort studies suggested that this diet, over many years, might confer a reduced risk of cardiovascular disease, but this was the first large-scale, randomized study that directly compared diets. The primary endpoint was the rate of major cardiovascular diseases (myocardial infarction, stroke, death from cardiovascular causes), and the trial was stopped early (median follow-up of 4.8 years) when an interim analysis showed a significant difference in outcomes, based on which diet was instituted.

The enrolled subjects were free of cardiovascular disease, but had risk factors for disease — type 2 diabetes mellitus, or at least three of the following other risk factors: smoking, hypertension, elevated LDL, low HDL, obesity, or family history of premature coronary heart disease. A total of 7447 patients were enrolled (ages 55 to 80 years); 57% were women, and they were followed for a mean time of 4.8 years before the study was terminated. In a multivariable-adjusted analysis, the hazard ratios were 0.70 (95% confidence interval [CI], 0.54-0.92) for the Mediterranean diet with extra olive oil, and 0.72 (95% CI, 0.54-0.96) for the group assigned to the Mediterranean diet with nuts, vs the control group. For stroke alone, the hazard ratios for the two Mediterranean diets were 0.67 (olive oil) and 0.54 (nuts). Adherence to the Mediterranean diet results in a clinically and statistically significant reduction in cardiovascular events, especially stroke.


Low Levels of Light Exposure Associated with Higher Stroke Incidence

Source: Kent ST, et al. Short- and long-term sunlight radiation and stroke incidence. Ann Neurol 2013;73:32-37.

This investigation was a subset observational cohort of the REGARDS trial, which looked at a variety of risk exposures to African American and white patients living in the Southeastern Stroke Belt as well as the Southwest United States. Sunlight exposure was determined by using the North American Land Data Assimilation System dataset with calculation made for different regions over periods of 15-, 10-, 5-, 2-, and 1-year exposures. A cohort of 16,606 stroke and coronary artery disease-free black and white participants > 45 years were analyzed for these defined time periods, and compared for stroke risk using the lowest and highest quartiles of exposure to sunlight. After adjustment for other covariates, the previous year’s monthly average insolation exposure that was below the median gave a hazard ratio of 1.61 (95% CI, 1.15-2.26) and the previous year’s highest monthly average temperature exposure gave an HR of 1.92 (95% CI, 1.27-2.92).

The results of this study suggest that low light exposure increases stroke risk and that high temperature exposure increases stroke risk. The physiologic mechanisms related to these observations are unknown and require further investigation.