Relation of Season and Temperature to Endothelium-Dependent Flow-Mediated Vasodilation in Subjects Without Clinical Evidence of Cardiovascular Disease (from the Framingham Heart Study)†

摘要: Multiple studies have documented an increased incidence of cardiovascular events in the winter, but pathophysiologic mechanisms remain incompletely understood. It was hypothesized that brachial flow and flow-mediated dilation (FMD) would vary by season temperature. Season temperature were related to ultrasonic artery endothelium-dependent FMD% (n = 2,587), baseline velocity, maximal reactive hyperemia 1,973) Framingham Offspring Cohort (mean age 61 ± 10 years, 53% women). Outdoor temperatures obtained from National Climate Data Center records for Bedford, Massachusetts (about 14 miles testing site), examination room measured. In multivariate models, highest summer lowest winter (3.01 0.09% vs 2.56 0.10%, respectively, p 0.02 differences across all 4 seasons). warmest coldest outdoor-temperature quartiles. stepwise models adjusting risk factors selecting among season, outdoor temperature, associated with (p 0.02); did not enter model. contrast, hyperemic velocity significantly lower cooler higher warmer overall); each retained a model <0.0001, 0.02, respectively). conclusion, significant association observed between FMD%. Microvascular vasodilator function, as reflected more strongly than season. Endothelial dysfunction may be 1 influencing seasonal variation events.