Short-term Effects of Ambient Temperature on Blood Pressure: A Systematic Review and Meta-analysis

Abstract

Background: Hypertension is a major worldwide public health problem. Previous studies have indicated that ambient temperature is associated with blood pressure, but the nature of this association remains unclear. Objective: The objective of this meta-analysis was to investigate the relationship between ambient temperature and blood pressure. Methods: We performed a systematic search of the literature indexed in PubMed, Web of Science, and Science Direct between 1980 and 2016. The pooled effect sizes for exposure to low/moderate temperatures, as well as high temperature exposure, were calculated using a random effects model. Results: Fifteen studies were included in this meta-analysis. Twelve of these reported the effects of low/ moderate temperature exposure, two reported the effects of high temperature exposure, and one reported the effects of both low/moderate and high temperature exposure. For low/moderate temperature exposure, a 1°C decrease in temperature was associated with a 0.40 mmHg (95% CI: 0.34–0.46) increase in systolic blood pressure and a 0.13 mmHg (95% CI: 0.08–0.18) increase in diastolic blood pressure. For high temperature exposure, the relationship between BP and temperature was not statistically signi cant. Conclusion: For low/moderate temperature exposure, a decrease in temperature was associated with an increase in blood pressure. In contrast, the relationship between high temperature exposure and blood pressure was not statistically signi cant.