’‘tis bitter cold and I am sick at heart’a: establishing the relationship between outdoor temperature, blood pressure, and cardiovascular mortality

This editorial refers to ‘Outdoor temperature, blood pressure, and cardiovascular disease mortality among 23 000 individuals with diagnosed cardiovascular diseases from China’[†][1], by L. Yang et al. on page 1178. In this issue of the journal, Yang and co-authors explored the relationship between outdoor temperature, blood pressure (BP) values, and cardiovascular (CV) mortality in the China Kadoorie Biobank cohort, a large cohort including ∼500 000 adults from both rural and urban regions prospectively followed up for ∼7 years.1 The analysis presented in this article considered ∼23 000 individuals with previous CV events. The main finding was a strong relationship between monthly outdoor temperature and office BP: mean systolic BP was 9 mmHg higher in winter than in summer, and, at an outdoor temperature above 5 ° C, systolic BP was 6.2 mmHg higher for each 10 ° C decrease in temperature. Since BP was associated with increased CV mortality and there was a 41% increase in CV mortality during winter, the authors suggested that cold outdoor temperature might favour CV mortality at least in part by increasing BP values. … [1]: #fn-2