我們太習(xí)慣于把健康問題歸罪于肥胖了

A few years ago, Mercedes Carnethon, a diabetes researcher at the Feinberg School of Medicine at Northwestern University, found herself pondering a conundrum. Obesity is the primary risk factor for Type 2 diabetes, yet sizable numbers of normal-weight people also develop the disease. Why?

幾年前，美國西北大學(xué)(Northwestern University)芬堡醫(yī)學(xué)院(Feinberg School of Medicine)的研究人員梅賽德絲·卡尼索恩(Mercedes Carnethon)遇到了一個難解之謎：肥胖是II型糖尿病最主要的風(fēng)險因素，然而相當(dāng)數(shù)量體重正常的人也罹患這種疾病。這是為什么?

In research conducted to answer that question, Dr. Carnethon discovered something even more puzzling: Diabetes patients of normal weight are twice as likely to die as those who are overweight or obese. That finding makes diabetes the latest example of a medical phenomenon that mystifies scientists. They call it the obesity paradox.

為了回答這個問題，卡尼索恩博士進(jìn)行了研究，然而在這些研究中，她發(fā)現(xiàn)了更令人費解的事情：正常體重的糖尿病患者的死亡率有可能是那些超重或者肥胖的糖尿病患者的兩倍。這一發(fā)現(xiàn)結(jié)果使得糖尿病成為令科學(xué)家們困惑不解的醫(yī)學(xué)現(xiàn)象的最新例證。他們稱這種奇怪的現(xiàn)象為肥胖悖論。

In study after study, overweight and moderately obese patients with certain chronic diseases often live longer and fare better than normal-weight patients with the same ailments. The accumulation of evidence is inspiring some experts to re-examine long-held assumptions about the association between body fat and disease.

一項又一項研究發(fā)現(xiàn)，患有同樣慢性疾病的超重和中度肥胖病人一般都比有同樣疾病的正常體重的病人活得更長久、質(zhì)量也更高。越來越多的證據(jù)激發(fā)了一些專家對體脂和疾病之間的關(guān)系進(jìn)行重新研究，長期以來人們假設(shè)體脂是很多疾病的原因。

Dr. Carl Lavie, medical director of cardiac rehabilitation and prevention at the John Ochsner Heart and Vascular Institute in New Orleans, was one of the first researchers to document the obesity paradox, among patients with heart failure in 2002. He spent more than a year trying to get a journal to publish his findings.

新奧爾良約翰·奧克斯納心血管研究所(John Ochsner Heart and Vascular Institute)負(fù)責(zé)心血管康復(fù)和預(yù)防的醫(yī)務(wù)主任卡爾·拉維(Carl Lavie)博士是第一批記錄肥胖悖論的研究人員之一，2002年，他在心臟衰竭的病人中發(fā)現(xiàn)了這一現(xiàn)象。拉維花費了一年多的時間來說服一份期刊發(fā)表自己的研究結(jié)果。

“People thought there was something wrong with the data,” he recalled. “They said, ‘If obesity is bad for heart disease, how could this possibly be true?’ ”

“人們以為那些數(shù)據(jù)有問題，”他回憶說：“他們說，‘如果肥胖對心臟病不利，這些數(shù)據(jù)又怎么可能是正確的?’”

But there were hints everywhere. One study found that heavier dialysis patients had a lower chance of dying than those whose were of normal weight or underweight. Overweight patients with coronary disease fared better than those who were thinner in another study; mild to severe obesity posed no additional mortality risks.

但是，到處都能找到這條悖論的蛛絲馬跡。一項研究發(fā)現(xiàn)，超重的透析患者的死亡概率要低于體重正?；蛘唧w重過輕的病人。而在另一項研究中，超重的冠狀動脈疾病病人比那些瘦弱的病人生存率更高;輕度到重度肥胖都沒有帶來額外的死亡風(fēng)險。

In 2007, a study of 11,000 Canadians over more than a decade found that those who were overweight had the lowest chance of dying from any cause.

2007年，一項持續(xù)超過10年、以1.1萬加拿大人為研究對象的研究發(fā)現(xiàn)，不管死于任何疾病，肥胖人士的死亡率都是最低的。

To date, scientists have documented these findings in patients with heart failure, heart disease, stroke, kidney disease, high blood pressure — and now diabetes.

迄今為止，科學(xué)家們已經(jīng)將心臟衰竭、心臟病、腦中風(fēng)、腎臟疾病、高血壓患者的研究結(jié)果記錄在案——現(xiàn)在是糖尿病了。

Experts are searching for explanations. One idea is that once a chronic disease develops, the body becomes catabolic, meaning it needs higher energy and caloric reserves than usual. If patients do not have those reserves, they may become malnourished even though their weight is normal, said Dr. Gregg Fonarow, one of the directors of the preventive cardiology program at the University of California, Los Angeles.

專家們在尋求答案。一種觀點是，一旦人體出現(xiàn)了慢性疾病，新陳代謝隨之加快，意味著需要比往常更多的能量和熱量儲備。加州大學(xué)洛杉磯分校(University of California, Los Angeles)心臟病預(yù)防項目主任之一格雷格·佛納羅(Gregg Fonarow)博士介紹說，如果患者沒有這些儲備，即使體重正常，也可能營養(yǎng)不良。

Some researchers suspect genetics: Maybe thin people who develop diabetes, cardiovascular disease and other chronic ailments have gene variants that make them more susceptible to these illnesses and put them at greater risk once they become ill. Heart disease in thin people may represent a different illness from heart disease in heavier people, Dr. Lavie said.

一些研究人員懷疑可能是遺傳學(xué)的原因：也許罹患糖尿病、心血管疾病以及其他慢性疾病的瘦人，他們本身攜帶了易于患病的基因變異，而患病后這些基因變異使他們需要面對更大的風(fēng)險。拉維博士說，瘦人的心臟病和胖人的心臟病有可能是截然不同的兩回事。

It may be that doctors do not treat thin patients as aggressively as they do heavier patients — or that the yardstick itself is to blame. Most researchers assess obesity by measuring body mass index, a simple ratio of height and weight. But B.M.I. does not take into account body fat, lean muscle mass, metabolic abnormalities and other nuances of physical composition.

也許是因為醫(yī)生們在治療瘦患者時不像他們治療胖患者時力度那么大——或者就是測量指數(shù)本身的問題。大多數(shù)研究人員通過測量體重指數(shù)(BMI，是國際統(tǒng)一使用的肥胖分型標(biāo)準(zhǔn)，計算方法是體重(公斤)/身高(米)的平方，男性大于24，女性大于22為超重——譯注)來評估是否肥胖，而BMI就是簡單計算身高和體重的比例，沒有把體脂含量、肌肉比例、代謝異常以及其他身體構(gòu)成的細(xì)微差別考慮進(jìn)去。

Perhaps, some experts say, we are not asking the right question in the first place. Maybe we are so used to framing health issues in terms of obesity that we are overlooking other potential causes of disease.

還有一些專家說，或許我們一開始就沒有發(fā)現(xiàn)真正的問題所在?；蛟S我們太習(xí)慣于把健康問題歸罪于肥胖，從而忽視了其他潛在的致病原因。

Dr. Neil Ruderman, an endocrinologist at Boston University School of Medicine, was the first to identify a condition he called “metabolically obese normal weight,” in 1981. Such people have weights in the normal range on the B.M.I. chart but also have metabolic abnormalities, including high levels of insulin resistance and triglycerides; they tend to carry fat around the middle, which is more apt to affect the heart, liver and other organs than fat in the hips and thighs.

尼爾·魯?shù)聽柭?Neil Ruderman)博士是波士頓大學(xué)醫(yī)學(xué)院(Boston University School of Medicine)的內(nèi)分泌學(xué)專家，1981年他第一次明確了一種現(xiàn)象，他稱之為“正常體重代謝性肥胖”(metabolically obese normal weight)。表現(xiàn)出這種癥狀的病人在BMI圖表上的體重處在正常值范圍內(nèi)，但卻存在著新陳代謝異常，包括高胰島素抗性和高甘油三酯;他們腰間往往像套了個救生圈，相比那些脂肪囤積在臀部和大腿的人來說，這種情況更容易影響心臟、肝臟還有其他器官。

“If we’re open-minded when we look at the data, we often find confounding factors that can explain the disease associations we blame on weight,” said Linda Bacon, a nutrition professor at City College of San Francisco and author of “Health at Every Size: The Surprising Truth About Your Weight.”

“如果在研究這些數(shù)據(jù)時候心態(tài)更加開放，往往會發(fā)現(xiàn)那些被我們歸咎于體重的疾病，是有著其他易于混淆的因素可以解釋的，”舊金山市立學(xué)院(City College of San Francisco)營養(yǎng)學(xué)教授琳達(dá)·培根(Linda Bacon)說。她也是《各種體型的健康：關(guān)于體重的驚人真相》(Health at Every Size: The Surprising Truth About Your Weight)一書的作者。

Fitness is an important, and often unmeasured, confounder, and the growing pile of paradoxical evidence is forcing experts to re-evaluate its importance.

身體體質(zhì)是一個重要的、而且一般不可測量的干擾變量，然而越來越多自相矛盾的證據(jù)迫使專家們?nèi)ブ匦潞饬克闹匾浴?/p>