Data from: Associations between changes in city and address specific temperature and QT interval - the VA Normative Aging Study

Background: The underlying mechanisms of the association between ambient
temperature and cardiovascular morbidity and mortality are not well
understood, particularly for daily temperature variability. We evaluated
if daily mean temperature and standard deviation of temperature was
associated with heart rate-corrected QT interval (QTc) duration, a marker
of ventricular repolarization in a prospective cohort of older men.
Methods: This longitudinal analysis included 487 older men participating
in the VA Normative Aging Study with up to three visits between 2000–2008
(n = 743). We analyzed associations between QTc and moving averages (1–7,
14, 21, and 28 days) of the 24-hour mean and standard deviation of
temperature as measured from a local weather monitor, and the 24-hour mean
temperature estimated from a spatiotemporal prediction model, in
time-varying linear mixed-effect regression. Effect modification by
season, diabetes, coronary heart disease, obesity, and age was also
evaluated. Results: Higher mean temperature as measured from the local
monitor, and estimated from the prediction model, was associated with
longer QTc at moving averages of 21 and 28 days. Increased 24-hr standard
deviation of temperature was associated with longer QTc at moving averages
from 4 and up to 28 days; a 1.9°C interquartile range increase in 4-day
moving average standard deviation of temperature was associated with a 2.8
msec (95%CI: 0.4, 5.2) longer QTc. Associations between 24-hr standard
deviation of temperature and QTc were stronger in colder months, and in
participants with diabetes and coronary heart disease.
Conclusion/Significance: In this sample of older men, elevated mean
temperature was associated with longer QTc, and increased variability of
temperature was associated with longer QTc, particularly during colder
months and among individuals with diabetes and coronary heart disease.
These findings may offer insight of an important underlying mechanism of
temperature-related cardiovascular morbidity and mortality in an older
population.