A1863 Association between cardiovascular factors and outdoor temperature in the elderly

Monday, March 19, 2012
Ground Floor (Cancun Center)
Chungwon Kang, Occupational Safety & Health Research Institute, Korea Occupational Safety And Health Agency, Incheon, South Korea
Yun-chul Hong, Department of Preventive Medicine, Seoul National University, Seoul, South Korea
Soo-hun Cho, Department of Preventive Medicine, Seoul National University, Seoul, South Korea
Introduction
Seasonal variations have been evaluated by some studies in terms of cardiovascular system. Because the elderly has been known as a susceptible population to climate change, we are to investigate the relationship between some cardiovascular factors including blood pressure, corrected QT interval and outdoor temperature

Methods
A total of 484 elderly panel aged over 60 years in Seongbukgu, Seoul, Korea were enrolled from August 2008 through August 2010. We repeatedly visited them and evaluated their health status and environmental conditions in different seasons. We measured blood pressure and other cardiovascular factors such as vital signs, obesity, electrocardiogram, blood chemistry and heart rate variability up to five times. We obtained weather data such as ambient temperature, apparent temperature, wind speed, humidity and amount of sunshine for each visit. Other individual characteristics such as age, sex, smoking, alcohol drinking history and past medical history were obtained by interviewers with questionnaires. A mixed linear regression model was used to evaluate the association between cardiovascular factors and outdoor temperature.

Results
Mean ages of subjects were 70.60 (SD 5.22, n=484). Both systolic and diastolic blood pressure had an inverse association with outdoor temperature. One degree Celsius decrease in the mean of ambient temperature was associated with increase of 0.31mmHg (p<0.001) in systolic blood pressure and 0.23mmHg (p<0.001) in diastolic blood pressure after adjusting for age, sex, BMI, smoking, alcohol drinking, cardiovascular disease and humidity. Apparent temperature had the same relationship with blood pressure, but effect size was smaller than for ambient temperature. Other factors such as corrected QT interval, platelet and cholesterol have significantrelationships with outdoor temperature, but with gender difference.

Discussion
These results suggest that outdoor temperature is associated with cardiovascular factors including blood pressure in the elderly. 

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