Meteorological and chronobiological factors and the occurrence of acute aortic dissection

Although a number of studies have demonstrated seasonal variations in acute cardiovascular events, the association between winter and low temperatures and the incidence rate of acute aortic dissection has not been fully elucidated. In this study, we investigated the association between meteorological and chronobiological factors and the occurrence of acute aortic dissection classified by the Stanford type, sex and age. We retrospectively collected 131 patients who had been admitted consecutively to our institution with acute aortic dissection, including 58 type A patients and 73 type B patients, from January 2013 to December 2017. The meteorological data were downloaded from the homepage of the Japan Meteorological Agency. The daily incidence of aortic dissection was higher in winter (10.2%) than in fall (5.3%) (P = 0.04), and a significant winter peak was also observed in the sub-groups of males and type B, while there were no significant differences in the proportions of type A, female, and <= 70- and > 70-year-old patients. The maximum, mean and minimum temperatures on the days with aortic dissection were significantly lower than on the days without aortic dissection. Divided into four seasons, lower temperatures were found only in spring. The most significant and greatest difference was observed between the maximum temperature on the day of aortic dissection and that at 2 days earlier. The multivariate logistic regression analysis showed that the difference in the maximum temperature between the day of and 2 days before the incident (odds ratio 0.91; 95% confidence interval 0.87-0.96; P < 0.01) as well as the maximum temperature (odds ratio 0.97; 95% confidence interval 0.95-0.99; P = 0.02) were significantly associated with the incidence of aortic dissection. Cold weather and a sudden decrease in temperature might trigger aortic dissection, although the influence might differ among sub-groups.