The prevalence and incidence of NAFLD worldwide: a systematic review and meta-analysis.
Level 2 - randomized trial
Systematic review and meta-analysis of observational studies
PubMed 35798021 · doi:10.1016/S2468-1253(22)00165-0
What was done
Researchers conducted a systematic review and random-effects meta-analysis of observational studies (searching MEDLINE, EMBASE, Scopus, and Web of Science up to May 25, 2021) to assess the global prevalence, incidence, and temporal trends of non-alcoholic fatty liver disease (NAFLD). Inclusion was limited to general adult populations (aged ≥18 years) diagnosed using imaging, excluding individuals with excessive alcohol intake, viral hepatitis, or high-risk subpopulations.
What was found
Across 72 publications (1,030,160 individuals, 17 countries) for prevalence and 16 publications (381,765 individuals, 5 countries) for incidence: - Overall global NAFLD prevalence was 32.4% (95% CI 29.9–34.9). - Prevalence increased significantly over time from 25.5% (95% CI 20.1–31.0) in or before 2005 to 37.8% (95% CI 32.4–43.3) in 2016 or later (p = 0.013). - NAFLD prevalence was higher in men than women: 39.7% (95% CI 36.6–42.8) vs 25.6% (95% CI 22.3–28.8; p < 0.0001). - Overall global incidence was 46.9 cases per 1,000 person-years (95% CI 36.4–57.5), higher in men (70.8 per 1,000 person-years, 95% CI 48.7–92.8) than women (29.6 per 1,000 person-years, 95% CI 20.2–38.9; p < 0.0001). - Heterogeneity across studies was extreme for both prevalence (I² = 99.9%) and incidence (I² = 99.9%).
Why it matters
This review updates the global burden of NAFLD, showing that nearly one in three adults is affected worldwide, with rising temporal trends and higher rates in men. It emphasizes the need for public health strategies and cost-effective risk stratification.
Limits
Between-study statistical heterogeneity was exceptionally high (I² = 99.9%). Geographic representation was restricted to 17 countries for prevalence and 5 for incidence. Diagnoses were based on imaging rather than liver biopsy, and pediatric populations were excluded.
Cited by
- supports One-third of the global population has non-alcoholic steatohepatitis or fatty liver disease.