Wednesday, August 10, 2016

How Does Air Pollution Cause Hypertension and Heart Attacks?

English: Main complications of persistent high...
English: Main complications of persistent high blood pressure. Sources are found in main article: Wikipedia:Hypertension#Complications. To discuss image, please see Template_talk:Häggström diagrams. To edit, please use the svg version, convert to png and update both versions online. (Photo credit: Wikipedia)
Associations of Short-Term and Long-Term Exposure to Ambient Air Pollutants With Hypertension A Systematic Review and Meta-Analysis (16 page pdf, Yuanyuan Cai, Bo Zhang, Weixia Ke, Baixiang Feng, Hualiang Lin, Jianpeng Xiao, Weilin Zeng, Xing Li, Jun Tao, Zuyao Yang, Wenjun Ma, Tao Liu, Hypertension, Jun. 1, 2016) 

Today we review a meta-analysis of the links between high blood pressure and hypertension which lead to the number one cause of death in the world, cardiovascular disease, with air pollutants for both short and long term exposure. Results indicate short term exposure ot particulate matter (PM2.5 and PM10) and sulphur dioxide (associated with diesel vehicle emissions and coal burning) as well as long term exposure to nitrogen dioxide and PM10 (associated with vehicle emissions) are linked to a higher risk of hypertension. The mechanisms that lead to hypertension include inflammation and oxidative stress from exposure to air pollutants as well as imbalance of the nervous system from particulates.

Key Quotes: 

 “Cardiovascular disease is the leading cause of death in the world. It is responsible for ≈30% of all deaths or ≈17.5 million people in 2012” “We observed that short-term exposure to SO2, PM2.5, and PM10 and long-term exposure to NO2 and PM10 were associated with an increase in hypertension risk.”

 “Both short- and long-term exposure to some air pollutants commonly associated with coal burning, vehicle exhaust, airborne dust and dirt are associated with the development of high blood pressure” 

"People should limit their exposure on days with higher air pollution levels, especially for those with high blood pressure, even very short-term exposure can aggravate their conditions."

 “The mechanisms by which air pollution exposure could contribute to the development of hypertension might include systemic inflammation and oxidative stress, which may cause increased sympathetic tone and potentially lead to arterial remodeling.”

 “PM may also elevate blood pressure by inducing autonomic nervous system imbalance and vasoconstriction. In addition, PM exposure can also reduce daytime sodium excretion and blunt the normal nocturnal reduction in blood pressure. If this happens repeatedly, the impaired renal handling of excess sodium may partly contribute to elevated blood pressure

 “Compared with PM10, PM2.5 can remain suspended for a longer time in the air and be inhaled into the respiratory tract and directly into the pulmonary alveoli.”

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