呼吸霧霾會加快動脈硬化引發中風
Breathing particulate-laden (aka smoggy) air may be hardening your arteries faster than normal, according to research published today in PLOS Medicine. While everyones’ arteries harden gradually with age, a team of researchers led by epidemiologist Sara Adar of the University of Michigan School of Public Health discovered that higher concentrations of fine particulate air pollution were linked to a faster thickening of the inner two layers of the carotid artery.
Because the carotid artery feeds blood to the neck, head, and brain, a narrowing or blockage there can trigger strokes. And general atherosclerosis, or hardening of the arteries, is a major risk factor for cardiovascular disease, heart attack, and heart failure.
Past research has demonstrated that the rates of stroke and heart attack are higher in polluted areas, but experts haven’t been able to pinpoint just how polluted air is raising peoples’ risk for heart attack or stroke. This time, Adar’s team, along with Joel Kaufman, professor of environmental and occupational health sciences and medicine at the University of Washington, was able to directly measure carotid artery thickness and link it to air pollution data.
The study involved 5,362 people between the ages of 45 and 84 living in six different cities that are part of the MESA AIR (Multi-Ethnic Study of Atherosclerosis and Air Pollution) research project, led by Joel Kaufman. Each participant underwent two carotid artery ultrasounds three years apart. These measurements were then correlated with data on fine particulate air pollution.
While the artery walls of all participants increased by 14 micrometers per year, the arteries of those who were exposed to higher levels of fine particulate air pollution in their homes thickened faster than their neighbors in other parts of the city.
Interestingly, the researchers also found the reverse effect to be true: reducing fine particulate air pollution levels slowed down atherosclerosis progression. Carotid artery measurements are considered by experts to be an indicator for arterial plaque and hardening throughout the body.根據今日發表在《公共科學圖書館•醫學》雜誌上的研究，呼吸含大量顆粒物的（霧霾）空氣可能會讓你的動脈硬化速度加快。儘管每個人的動脈都會隨着年齡增大而逐漸硬化，但密歇根大學公共衛生學院的流行病學家薩拉•阿達領導的研究團隊發現，空氣中的細微顆粒污染物濃度升高與頸動脈內膜和中膜增厚加快有關。
由於頸動脈要向頸部、頭部和大腦供血，頸動脈變窄或堵塞可能會引發中風。通常動脈硬化是冠心病、心臟病發作和心力衰竭的主要風險因素。
以往的研究已經表明，在受污染地區中風和心臟病發作的機率更高，但專家還未能查明空氣污染是如何提高人們心臟病或中風發作的風險的。這次阿達帶領的團隊和華盛頓大學環境與職業健康科學和醫學專業的教授喬爾•考夫曼聯手合作，已經能夠直接測量頸動脈厚度，並將其和空氣污染數據聯繫起來。
喬爾•考夫曼領導的這一動脈硬化和空氣污染多種族研究項目調查了居住在6個不同城市、年齡在45歲到84歲之間的5362個人。每個參與者隔三年都要做一次頸動脈超聲波檢查。研究人員把這些測量結果和細顆粒物空氣污染的數據聯繫起來。
儘管所有參與者的動脈壁每年都會增厚14微米，但那些家周邊空氣中細顆粒污染物水平更高的人動脈壁比住在同城其他地區的人增厚速度更快。
有趣的是，研究人員還發現反之亦然：降低空氣中的細顆粒污染物水平會減慢動脈硬化的速度。專家認爲頸動脈的測量數據是動脈斑塊和周身硬化的指示標誌。
