Title: Non-Alcoholic Fatty Liver Disease among Hispanics in the United States
Authors: Cynthia Acevedo, MAMSc; Maricarmen Garcia Peña, MAMSc; Lenett Trueblood, MAMSc
Introduction
Nonalcoholic Fatty Liver Disease (NAFLD) is a hepatic manifestation of metabolic syndrome that affects both children and adults. Metabolic syndrome is characterized by a cluster of conditions that occur together increasing the risk for heart disease, stroke, and type 2 diabetes. NAFLD is the most common cause of liver disease in the United States, but its prevalence varies across different ethnicities. The rates among Hispanic groups are higher than the rates among non-Hispanic whites and African Americans. Risk factors associated with nonalcoholic fatty liver disease include lifestyle, genetic, socioeconomic, and environmental factors. Furthermore, factors such as increased visceral fat and the diagnosis of type 2 diabetes increase the risk of developing NAFLD. The purpose of this paper is to conduct a narrative literature review on NAFLD among the Hispanic population in the United States with a focus on prevention, treatment, and contributing factors.
Methods
A narrative literature review was conducted, and relevant articles were identified from: PubMed, ClinicalKey, Medline Complete, TripPro, Cochrane Library, and CINAHL. Exact search terms included: NAFLD in Different Ethnicities, NAFLD Differences between Hispanic Groups, NAFLD Mexican Americans vs Mexican NAFLD rates, NAFLD Genetic Risk Factors, NAFLD prevalence in Hispanic/Latinos. Inclusion criteria consisted of: over 18 years old and written in English. This resulted in 24 articles.
Results
We found that genetic polymorphisms on the gene PNPLA3 (specifically the I148M polymorphism in the PLPLA3rs738409 gene) play a role in lipid metabolism that influences the varying prevalence of NAFLD across different ethnicities. The PNPLA3 polymorphisms can lead to elevation of hepatic fat, triglycerides and inflammation. In addition, reduction of 5% body weight through caloric deficits has been found to be effective in reducing liver fat, AST & ALT levels, and has potential to reverse NAFLD.
Discussion
Given the limited research on NAFLD and the high prevalence of NAFLD among Hispanic subgroups, more studies are necessary to assess the most effective and culturally tailored treatment options, contributing factors, and preventative measures for NAFLD among Hispanic groups. Additionally, future research focusing specifically on NAFLD among Mexican Americans is also necessary considering that Mexican Americans are the highest risk group for NAFLD in comparison to other Hispanics. This review examines the current literature available on NAFLD and discusses implications for further research regarding Hispanics with NAFLD.
This is an interesting and important topic. As one of the judges for your poster, I was wanting a bit more information on the articles you reviewed. Your abstract lists 24 articles while your presentation states this as 64. How many articles did you actually review and how were these broken down on your three main areas of prevention, treatments, and contributing factors? Thanks!
Thank you, Dr. Rhodes, for your question. Originally, we had 24 articles, however we decided to expand our search to the method described in the video. The method used resulted in 64 articles, which we’ve further narrowed down to 51 articles, as some were done outside of the U.S or were not applicable to our project.
Thanks for this presentation, I am one of your judges. In your literature search, I’m wondering if you came across any studies correlating the number of SNPs with more prevalent or advanced disease.
Thank you, Dr. Mapes, for your question. The studies we reviewed largely focused on a few genes at a time. Only one study had a comprehensive list of NAFLD-associated genetic SNPs in relation to liver phenotypes in different Hispanic groups, and this study was published in 2019. This study did not correlate the total number of SNPs with prevalence or advanced disease, but multiple studies suggested that PNPLA3 rs738409 was associated with more advanced NAFLD. One study mentioned that the HSD17B13 rs72613567: TA variant could be protective and decrease PNPLA3 mRNA expression and reduce the amount of liver injury associated with PNPLA3 rs738409.
Certain polymorphisms have also been linked more with specific races/ethnicities, as one study found that PNPLA3, NCAN, GCKR, and PPP1R3B variants were associated with the non-Hispanic white population, while PNPLA3 was associated with Mexican Americans.
Thank you for your presentation. I am one of the judges evaluating your poster. Did the literature address the prevalence of PLPLA3 polymorphisms across populations?
Thank you, Dr. Smith, for your question. Some of the literature reviewed mentioned that PNPLA3 SNP rs738409:G allele is more common in Hispanics/Latinos than in European- and African-ancestry populations. One study that we reviewed suggested this SNP has a frequency of 40% in Hispanics/Latinos and 19% in African Americans, while another study that we reviewed suggested the frequency of the allele was 49% in Hispanics, 23% in European Americans, and 17% in African-Americans. Within the Hispanic group, PNPLA3 G was more prevalent in the Mexican (52%), Central American (48%), and South American (51%) groups compared to Dominican (23%), Puerto Rican (35%), and Cuban (28%) groups. One study suggested the differences between groups may have to do with ancestry, as the Dominican group (which had the lowest % allele frequency for rs738409) had the highest proportion of African ancestry.
In contrast, PNPLA3 variant rs6006460 (S453I), which is associated with lower hepatic fat content, has been found in higher frequencies in the African American population (10%), but was rare in European American (0.3%) and Hispanic (0.8%) populations. The articles suggest this may be the reason for differences in NAFLD prevalence between the populations, but other genes and contributing factors must be considered as well.