Non-alcoholic Fatty Liver Disease in South Asians: A Review of the Literature

Abstract

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are national and global epidemics. The disease is characterized by a spectrum of liver steatosis (fat deposition), inflammation (in NASH) and fibrosis. NAFLD and specifically NASH can lead to cirrhosis, which carry risks of progression to portal hypertension and hepatocellular carcinoma (HCC). NASH is also associated with higher mortality from cardiovascular causes. Most of the data for NAFLD has been obtained from the perspective of developed nations, although the disease is increasing and threatening to reach epidemic proportions across the world. Emerging data is notable for high prevalence of NAFLD in South Asian populations, presumably resulting from a combination of underlying genetic polymorphisms and changes in socio-economic status. It is also notable that an 'Asian Paradox' has been defined for NAFLD based upon the observation of lower than predefined body mass index (BMI), otherwise termed as "lean NAFLD", among this population. Yet, data remains limited in regards to the characteristics of NAFLD/NASH in this population. In this article, we present a review of the literature and discuss the prevalence, associated risk factors and burden of HCC in South Asians with NAFLD. Citation of this article: Singh S, Kuftinec GN, Sarkar S. Nonalcoholic fatty liver disease in South Asians: a review of the literature.

Difference in lifestyle and metabolic profile of non-alcoholic fatty liver disease with raised alanine amino-transferases between obese and non-overweight subjects

“…In our study, the percentage of NAFLD with raised ALT who were non-overweight based on BMI was 6.6%; and in this subgroup, 69.4% had persistently elevated ALT of more than twice the upper limit of normal for at least three months. The results of our study show a lower prevalence when compared to other studies from the Asia–pacific region, which have reported prevalence between 5 and 40% 17 – 19 . However, due to the absence of a national database, the exact prevalence of NAFLD in either non-overweight, overweight or obese patients is not clear.…”

“…There is also a lack of consensus regarding the cut-off BMI to be taken for defining non-obese NAFLD. Studies from the West consider people with BMI < 25 kg/m 2 as non-obese as opposed to BMI < 23 kg/m 2 in Asian population 6 , 7 , 17 . A study from India has raised a pertinent question as to whether people with normal BMI or those with lower BMI < 19 kg/m 2 should be the actual lean NAFLD 17 .…”

rs2267531, a promoter SNP within glypican-3 gene in the X chromosome, is associated with hepatocellular carcinoma in Egyptians

“…The current study revealed for the first time the association of GPC3 rs2267531, a new locus on chromosome Xq26, with HCC risk. Our findings are in accordance with the notion that a mutation in GPC3 gene may contribute to X-linked recessive inheritance causing the phenotype HCC to be more expressed in males than in females 25 . Mutated GPC3 in Simpson-Golabi-Behmel syndrome results in tissue overgrowth and an increased risk of embryonic malignancies in males, while female carriers may have mild manifestations 26 .…”

Prevalence and predictors of nonalcoholic fatty liver disease in South Asian women with polycystic ovary syndrome

“…It has been shown that South Asians have a higher proportion of visceral fat distribution and are more likely to have dyslipidemia than Western patients (33). However, South Asian patients with NAFLD have an overall lower BMI compared to Caucasians (34). Other factors contributing to NAFLD in this ethnic group may include genetic variants of the patatin-like phospholipase domain-containing 3 (PNPLA3) protein, physical inactivity, reduced disease awareness, late diagnosis, as well as sociocultural factors in comparison with Western patient populations (33).…”