The prevalence and incidence of NAFLD worldwide: a systematic review and meta-analysis

doi:10.1016/S2468-1253(22)00165-0

The Lancet Gastroenterology & Hepatology

Volume 7, Issue 9, September 2022, Pages 851-861

https://doi.org/10.1016/S2468-1253(22)00165-0 Get rights and content

Summary

Background

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and the leading cause of liver-related morbidity and mortality. We aimed to predict the burden of NAFLD by examining and estimating the temporal trends of its worldwide prevalence and incidence.

Methods

In this systematic review and meta-analysis, we searched MEDLINE, EMBASE, Scopus, and Web of Science without language restrictions for reports published between date of database inception and May 25, 2021. We included observational cross-sectional or longitudinal studies done in study populations representative of the general adult population, in whom NAFLD was diagnosed using an imaging method in the absence of excessive alcohol consumption and viral hepatitis. Studies were excluded if conducted in paediatric populations (aged <18 years) or subgroups of the general population. Summary estimates were extracted from included reports by KR and independently verified by HA using the population, intervention, comparison, and outcomes framework. Primary outcomes were the prevalence and incidence of NAFLD. A random-effects meta-analysis was used to calculate overall and sex-specific pooled effect estimates and 95% CIs.

Findings

The search identified 28 557 records, of which 13 577 records were screened; 299 records were also identified via other methods. In total, 72 publications with a sample population of 1 030 160 individuals from 17 countries were included in the prevalence analysis, and 16 publications with a sample population of 381 765 individuals from five countries were included in the incidence analysis. The overall prevalence of NAFLD worldwide was estimated to be 32·4% (95% CI 29·9–34·9). Prevalence increased significantly over time, from 25·5% (20·1–31·0) in or before 2005 to 37·8% (32·4–43·3) in 2016 or later (p=0·013). Overall prevalence of NAFLD was significantly higher in men than in women (39·7% [36·6–42·8] vs 25·6% [22·3–28·8]; p<0·0001). The overall incidence of NAFLD was estimated to be 46·9 cases per 1000 person-years (36·4–57·5); 70·8 cases per 1000 person-years (48·7–92·8) in men and 29·6 cases per 1000 person-years (20·2–38·9) in women (p<0·0001). There was considerable heterogeneity between studies of both NAFLD prevalence (I²=99·9%) and NAFLD incidence (I²=99·9%).

Interpretation

Worldwide prevalence of NAFLD is considerably higher than previously estimated and is continuing to increase at an alarming rate. Incidence and prevalence of NAFLD are significantly higher among men than among women. Greater awareness of NAFLD and the development of cost-effective risk stratification strategies are warranted to address the growing burden of NAFLD.

Funding

Canadian Institutes of Health.

Introduction

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and the leading cause of liver-related morbidity and mortality.1, 2, 3, 4 The prevalence of NAFLD has been rising and varies globally, usually paralleling the prevalence of obesity and type 2 diabetes.² Due to its asymptomatic presentation, high prevalence, and potential hepatic and extra-hepatic outcomes, NAFLD is a global health problem.4, 5, 6, 7

Few meta-analyses have evaluated the epidemiology of NAFLD. Only two meta-analyses have assessed the worldwide burden of NAFLD, while others have been limited to particular geographical areas, such as Asia.2, 8, 9, 10, 11 Updated epidemiological data on NAFLD will help stakeholders to better understand the disease, predict growth trends, and develop strategies to increase awareness and interventions to decrease its burden. Therefore, we conducted a systematic review and meta-analysis with the aim of predicting the burden of NAFLD by examining and estimating the temporal trends of its worldwide prevalence and incidence.

Section snippets

Search strategy and selection criteria

We reported this systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.¹² On May 25, 2021, we did a literature search of four databases—MEDLINE and EMBASE using the Ovid search platform, Scopus, and Web of Science—without language restrictions for reports published between date of database inception and May 25, 2021. A full list of search terms is provided in the appendix (p 1). After excluding duplicates, citations

Results

The search identified 28 557 records, of which 66 publications were eligible for prevalence calculations and 14 were eligible for incidence calculations (figure 1). The reference review from existing systematic reviews on NAFLD prevalence and incidence retrieved six additional references for the prevalence analysis and two additional references for the incidence analysis. Therefore, ultimately, we included 72 publications in the prevalence analysis and 16 in the incidence analysis (figure 1).

Discussion

In this systematic review and meta-analysis, we found a significant increase in the prevalence of NAFLD worldwide. Specifically, we observed an increase in prevalence of NAFLD over time, steadily increasing from 25·5% in or before 2005 to an alarming 37·8% in 2016 or later. The trend observed in our study is in line with previous reports. The study by Younossi and colleagues² reported an increase from 20·1% to 26·8% between 2000 and 2015,² and the report by Le and colleagues⁸ showed a rise from

Declaration of interests

MGS declares receiving research grants from Gilead, Intercept, CymaBay, Genkyotex, GlaxoSmithKline, Genfit, Novartis, Pfizer, Galectin Therapeutics, Celgene, Astra Zeneca, Novo Nordisk, and AbbVie; and honoraria from Abbott, Gilead Roche, Intercept, Gilead, Abbott, and Novo Nordisk. SEC declares receiving research grants from Gilead, Boehringer Ingelheim, Genfit, Allergan, and Axcella Health; and honoraria from Interceot and AstraZeneca. A-AS declares receiving research grants from Gilead and

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ArticlesThe prevalence and incidence of NAFLD worldwide: a systematic review and meta-analysis

Summary

Background

Methods

Findings

Interpretation

Funding

Introduction

Section snippets

Search strategy and selection criteria

Results

Discussion

Declaration of interests

J Hepatol

Lancet Gastroenterol Hepatol

Mayo Clin Proc

Clin Microbiol Infect

J Clin Epidemiol

Prev Med

Prim Care Diabetes

Arab J Gastroenterol

Am J Med Sci

The diagnosis and management of nonalcoholic fatty liver disease: practice guidance from the American Association for the Study of Liver Diseases

Hepatology

Global epidemiology of nonalcoholic fatty liver disease-meta-analytic assessment of prevalence, incidence, and outcomes

Hepatology

Nonalcoholic fatty liver disease and liver transplantation - where do we stand?

World J Gastroenterol

Dietary patterns and components in nonalcoholic fatty liver disease (NAFLD): what key messages can health care providers offer?

Nutrients

Case-finding strategies in non-alcoholic fatty liver disease

JHEP Rep

Clinical epidemiology and disease burden of nonalcoholic fatty liver disease

World J Gastroenterol

2019 Global NAFLD prevalence: a systematic review and meta-analysis

Clin Gastroenterol Hepatol

Unexpected rapid increase in the burden of NAFLD in China from 2008 to 2018: a systematic review and meta-analysis

Hepatology

Epidemiology of nonalcoholic fatty liver disease in Europe: a systematic review and meta-analysis

Ann Gastroenterol

The PRISMA 2020 statement: an updated guideline for reporting systematic reviews

BMJ

Governmental standard drink definitions and low-risk alcohol consumption guidelines in 37 countries

Addiction

Methodological guidance for systematic reviews of observational epidemiological studies reporting prevalence and cumulative incidence data

Int J Evid-Based Healthc

The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomized studies in meta-analyses

Articles
The prevalence and incidence of NAFLD worldwide: a systematic review and meta-analysis