研究：上夜班會造成DNA損傷並引發癌症

上夜班不光會讓你長痘，新研究發現，上夜班的人身體會停止自動修復日常的DNA損傷，從而可能導致基因突變和癌症。

Night shift work may stop the body repairing daily damage to DNA and raise the risk of mutations which lead to cancer, a new study suggests.
一項新研究顯示，上夜班會阻止身體修復日常的DNA損傷，令基因突變風險增大進而引發癌症。

The link between working at night and poor health has been known for several years, with those who work after dark more likely to suffer diabetes, obesity, poor fertility, heart attacks and tumors.
人們多年前就已經知道上夜班和健康不良之間的聯繫。那些上夜班的人更容易患上糖尿病、肥胖、生育困難、心臟病和腫瘤。

Scientists believed that disruption to the body’s natural body clock was responsible for the increased risk of chronic illness, but could never pinpoint the mechanism.
科學家認爲，擾亂人體自然的生物鐘會增加慢性病的風險，但卻無法確定其原理。

Now US researchers have discovered that when people work nights they produce 80 percent less of a chemical which is a by-product of DNA tissue repair. They say it indicates that the body is not carrying out the crucial restoration to cells which should happen naturally overnight.
如今美國研究人員發現，人們上夜班時，體內分泌的一種化學物質將減少80%，這種化學物質是修復DNA組織的副產品。研究人員稱，這表明人體沒有對受損的細胞進行關鍵的修復，這種修復本應在夜間自然地完成。

They believe the effect could be caused by a lack of melatonin, the sleep hormone, which is far lower among people who sleep in the daytime.
科學家認爲，這種效應可能是由褪黑激素（睡眠荷爾蒙）的缺乏引發的，在白天睡覺的人羣當中，這種激素水平要低得多。

Dr Parveen Bhatti, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA, said if awake at night the body has ‘reduced capacity to repair and clear oxidative DNA damage.’
美國華盛頓州西雅圖的福瑞德哈金森腫瘤研究中心的帕爾文•巴提博士說，如果夜裏醒着，身體就會“降低修復和清除DNA氧化損傷的能力。”

“Over time, this accumulation would likely increase the risk of cancer across multiple sites as has been observed among shift workers,” she added.
她補充道：“長此以往，累積的損傷就會增加身體多處的癌症風險，這些都是在倒班工人身上觀察到的。”

The study tested 50 night shift workers for levels of 8-OH-dG - a chemical which is produced when DNA is repaired. They then tested them again when they were working days, and found levels jumped by 300 percent.
該研究檢測了50個夜班工人體內的8-OH-dG——人體修復DNA損傷時產生的化學物質。然後研究人員又在這些工人上白班時給他們做了檢測，發現這種化學物質的分泌量增加了300%。

They believe that shift workers may need to take sleep hormone supplements to allow DNA to carry out repairs as they sleep in the day.
科學家認爲，倒班工人也許需要攝入睡眠荷爾蒙補充劑，讓他們在白天睡覺時DNA也可以正常地自我修復。

“If such effects are confirmed, melatonin supplementation should be explored as an intervention to reduce the occurrence of potentially carcinogenic DNA damage among shift workers,” added Dr Bhatti.
巴提博士補充道：“如果效果得到證實，應該探討用褪黑激素補充劑進行干預，來減少倒班工人具有潛在致癌性的DNA損傷。”

The research was published in the journal Occupational & Environmental Medicine.
該研究報告發表在《職業與環境醫學》雜誌上。