研究稱空氣污染可能加速大腦衰老大綱

Exposure to air pollution may hasten brain aging, a new study has found.
一項新研究發現，暴露在空氣污染中可能會加速大腦衰老。

Researchers studied 1,403 women without dementia who were initially enrolled in a large health study from 1996 to 1998. They measured their brain volume with magnetic resonance imaging scans in 2005 and 2006, when the women were 71 to 89.
這項研究的對象爲1403名未患癡呆症的女性，她們曾在1996年至1998年間參與過另一項大型健康研究。在2005年和2006年，研究人員用磁共振成像掃描的方式，測量了這些年紀在71歲至89歲之間的女性的腦容量。

Using residential histories and air pollution data, they estimated their exposure to air pollution from 1999 to 2006. They used data recorded at monitoring sites on exposure to PM 2.5 — tiny particulate matter that easily penetrates the lungs.
研究人員利用居住記錄和空氣污染數據，對她們從1999年到2006年暴露在空氣污染中的情況進行了估算。他們使用了監測PM 2.5的站點記錄的數據。PM 2.5是一種容易進入肺中的微粒物。

Each increase of 3.49 micrograms per cubic centimeter cumulative exposure to pollutants was associated with a 6.23 cubic centimeter decrease in white matter, the equivalent of one to two years of brain aging. The association remained after adjusting for many variables.
每立方厘米中累積污染物每增加3.49微克，腦白質就會減少6.23立方厘米，相當於大腦衰老一到兩年。根據多個變量進行了調整後，這種相關性依然存在。

Previous studies have shown that air pollution can cause inflammation and damage to the vascular system, but this study, in The Annals of Neurology, showed damage to the brain itself.
之前的研究表明，空氣污染可能會導致血管系統發炎受損，而發表在《神經學年報》(The Annals of Neurology)上的這項研究表明，空氣污染會導致大腦受損。

“This tells us that the damage air pollution can impart goes beyond the circulatory system,” said the lead author, Dr. Jiu-Chiuan Chen, an associate professor of preventive medicine at the Keck School of Medicine at the University of Southern California. “Particles in the ambient air are an environmental neurotoxin to the aging brain.”
“這告訴我們，空氣污染帶來的危害不僅限於循環系統，”文章的第一作者、南加州大學凱克醫學院(Keck School of Medicine at the University of Southern California)預防醫學副教授陳居泉(Jiu-Chiuan Chen)博士說。“對日漸衰老的大腦來說，周圍空氣中的顆粒物是自然環境中的神經毒素。”