Association between air temperature and Cardiovascular risk Biomarkers

Background: Climatic conditions, especially changes in temperature are associated with cardiovascular (CV) events but underlying mechanisms are not well understood. We investigated association between air temperature and CV biomarkers such hemoglobin (Hb), fasting plasma glucose (FPG), and C-reactive protein (CRP), in type 2 diabetes patients. Methods: The subjects were (943 men and 757 women) resident of Pune city and suburbs. The relationships between air temperature and biomarker concentration were analyzed using robust regression models. Result: Mean daily air temperature during study period varied between 15 degrees C to 34 degrees C. A 5 degrees C decrease in the air temperature was associated with significant increase in arithmetic mean of Hb concentration ranging from 1.59% to 3.74%, for lag period up to 5 days before blood collection and of 3.19% and 3.80% for average last 3 and 7 days respectively. Correspondingly, increase in geometric mean of FPG concentration was observed for the same lag time and multi-day average (4.64% to 7.76% for lags days and 6.94% and 9.67% for multi- days) whereas, CRP showed an increase of 15.26% in geometric mean (95% CI = 4.42 to 24.88) with a lag of 1-day. Conclusion: This study suggests that temperature decrease is associated with change in several CV risk biomarkers. We need to investigate physiological and environmental mediators of this association to help improve CV risk.