Non-Alcoholic Fatty Liver Disease in the South Asian Region: A Systematic Review and Meta-Analysis

Objectives We estimated the prevalence and effect sizes of associations for NAFLD, the commonest chronic liver disease worldwide, among South-Asian adults.Design We searched the PubMed database, using search terms “Prevalence of NAFLD (Non-Alcoholic Fatty Liver Disease)” AND “South Asia” AND South Asian countries (“Afghanistan”, “Bangladesh”, “Bhutan”, “India”, “Maldives”, “Nepal”, “Pakistan” and “Sri Lanka”). We included descriptive, epidemiological studies with satisfactory methodology, reporting the prevalence of NAFLD with a valid diagnostic method (ultrasound/CT imaging, biochemistry, histology). The quality of the studies was assessed using Joanna Briggs Institute Critical Appraisal Checklist for Prevalence Studies. Two authors screened and extracted data independently. A random-effects meta-analysis of prevalence and effect sizes of associations of NAFLD was performed. Gender, urban/rural setting, general population and individuals with metabolic diseases (MetD) stratified the analysis.Results Thirty-two articles were included in the systematic review, and 21 publications were included in the meta-analysis after quality assurance. The pooled overall prevalence of NAFLD in the general population was 25.2% [95%CI 20.3-30.5%] with high heterogeneity (k=9; Q=251.6, DF=8, P<0.0001, I2=96.8%). The prevalence was similar among men and women (Q=0.10, DF=1, P=0.746). The NAFLD prevalence in the rural communities were 26.0% (95%CI: 18.2–34.5%) and it was 26.6% (95%CI: 20.5-33.1%) in urban communities without significant differences in the prevalence (Q=0.01, DF=1, P= 0.916). The pooled overall prevalence of NAFLD in patients with MetD was 55.1% [95%CI 47.4-62.8%] with high heterogeneity (k=8; Q=53.8, DF=7, P<0.0001, I2=85.2%).The pooled overall prevalence of NAFLD in the non-obese population was 11.7% \[95%CI 7.0-17.3%\] (k=6; Q=170.1, DF=5, P<0.0001; I2=97.1%). The pooled prevalence of non-obese NAFLD in the NAFLD population was 43.4% \[95%CI 28.1-59.4%\] \[k=6; Q=181.1; P<0.0001; I2=97.2%\]. Meta-analysis of binary outcomes showed presence of NAFLD in South Asian population was associated with diabetes mellitus [RR-2.03 (1.56-2.63)], hypertension [RR-1.37 (1.03-1.84)], dyslipidaemia [RR-1.68 (1.51-1.88)], general obesity [RR-2.56 (1.86-3.51)], central obesity [RR-2.51 (1.69-3.72)] and metabolic syndrome [RR-2.86 (1.79-4.57)]. Gender was not associated with NAFLD.Conclusions The overall prevalence of NAFLD among adults in South Asia is high, especially those with metabolic abnormalities, and a considerable proportion are non-obese. In the South Asian population, NAFLD was associated with MetD.Strengths and limitations ### Competing Interest StatementThe authors have declared no competing interest.### Funding StatementThe author(s) received no specific funding for this work.### Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.Not ApplicableThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Systematic review and metanalysis of already published data therefore IRB approval not obtainedI confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.Not ApplicableI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).Not ApplicableI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.Not ApplicableAll relevant data are within the manuscript and its Supporting Information files.* BMI : Body Mass Index CI : Confidence Interval HDL : High-density lipoproteins MetD : Metabolic disease NAFLD : Non-alcoholic fatty liver disease NASH : Non-alcoholic steatohepatitis PRISMA : Preferred reporting items for systematic reviews and meta-analysis RR : Relative Risk TG : Triglyceride WC : Waist circumference