编者按：“第七届全国脂肪性肝病学术会议暨2017 CSH-AASLD脂肪性肝病联合学术会议”召开期间，香港中文大学黄炜燊（Vincent W.S. WONG）教授在“流行病学”专题中介绍了瘦者NAFLD的最新知识点，会后本刊邀就相关问题采访了黄教授。

 

《国际肝病》：瘦者NAFLD在脂肪性肝病患者中的估计百分率是多少？

 

黄教授：在过去，我们通常认为非酒精性脂肪性肝病（NAFLD）仅仅是肥胖者的一种疾病。但最近几年，我们已经认识到并非如此。在不同的研究中，约10%～20%的体质量指数相对正常者（BMI<25）仍然有可能罹患NAFLD。

 

Prof.Wong: In the past, we often thought that non-alcoholic fatty liver disease was only a disease of the obese population. But in recent years, we have recognized that this is not the case. In different studies, around 10-20% of people with a relatively normal body mass index (<25) will still have NAFLD.

 

《国际肝病》：在常规临床实践中，如何诊断瘦者NAFLD?

 

黄教授：在常规临床实践中，我们通常首先做简单的检查，包括肝生化和腹部超声检查。脂肪肝患者的超声检查可见肝内回声增强和远场回声衰减，与肥胖症的诊断非常相似。同时，我们也需要排除其他肝脏疾病，如慢性病毒性肝炎。

 

Prof.Wong:In routine clinical practice, we usually do simple investigations first, including liver biochemistry and abdominal ultrasonography. On an ultrasound scan, a patient with a fatty liver would have bright liver echo texture and deep attenuation of the structures, so the diagnosis is quite similar to that of the obese population. At the same time, we also need to rule out other liver diseases, such as chronic viral hepatitis.

 

《国际肝病》：在代谢紊乱方面，瘦者NAFLD与超重或肥胖NAFLD者有什么显著差异?

 

黄教授：瘦者NAFLD尽管BMI相对正常，但这一疾病的形成也是有因可寻的。其中，较为常见的原因是存在其他代谢性因素，如高血糖、血脂异常以及向心性肥胖。此外，我们不应仅看目前的代谢情况，还要看随时间的变化，如很多瘦者NAFLD患者会出现近期体重增加，所以观察这一点也很重要。同时，我们也了解到，一些患者携带危险等位基因（PNPLA3），这是脂肪肝遗传易感性的危险因素，这些患者可能也会罹患脂肪肝，尽管BMI相对正常。

 

Prof.Wong:If a patient develops NAFLD despite a relatively normal BMI, there is usually a reason. That reason is usually the presence of other metabolic factors such as high blood sugar levels, dyslipidemia and also central obesity. Moreover, we should not only look at the metabolic profile at the present but also the changes over time. In many patients with lean NAFLD, they will have shown recent weight gains, so this is important to look into as well. We also know that some patients will carry the at-risk allele, PNPLA3, which is the genetic predisposition for fatty liver. Those patients may also develop fatty liver despite a relatively normal BMI.