Prevalence of NAFLD, NASH High in Overweight, Obese Population

The risk of developing a number of liver diseases, including non-alcoholic fatty liver disease (NAFLD) is higher for individuals who are overweight or obese.

A team, led by Jingxuan Quek, Yong Loo Lin School of Medicine, National University of Singapore, identified the prevalence of NAFLD, non-alcoholic fatty liver (NAFL), and non-alcoholic steatohepatitis (NASH) in individuals who are overweight or obese.

The Global Prevalence

The global prevalence of NAFLD is increasing globally along a parallel line with the global increase of obesity rates.

While the status of overweight or obese individuals could be an effective indicator for NAFLD screening, the exact prevalence of NAFLD within this population is not currently known.

In the systematic review and meta-analysis, the investigators searched various databases from inception until March 6, 2022 and identified cross-sectional and longitudinal observational studies published after 2000 including an adult population. They identified 7389 articles, with 151 studies meeting the inclusion criteria. The pooled analysis included 101,028 individuals.

Outcomes

The investigators sought a primary outcome of the prevalence of NAFLD, NAFL, and NASH in individuals who are overweight or obese, as well as the prevalence of fibrosis in individuals who were overweight or obese and who had NAFLD.

The investigators developed a meta-analysis of proportions with the generalized linear mixed model.

The results show the prevalence of NAFLD in individuals who were overweight was 69.99% (95% CI, 65.40–74.21; I²=99·10%), the prevalence of NAFL was 42.49% (95% CI, 32.55–53.08; I² = 96.40%), and the prevalence of NASH was 33.50% (95% CI, 28.38–39.04; I² = 95·60%).

There were similar prevalence estimates found in the obese population. The estimated prevalence of NAFLD in this population was (95% CI, 70.90–79.18; I² = 98·50%), while the prevalence estimates for NAFL was 43.05% (95% CI, 32.78-53.97; I² = 96.30%) and for NASH was 33.67% (95% CI, 28.45–39.31; I² = 95.60%).

The investigators also looked at regions.

The prevalence of NAFLD in the Americas in the overweight population was 75.34% (95% CI, 67.31–81.93; I² = 99.00%).

The results also show that clinically significant fibrosis was present in 20.27% (95% CI, 11.32–33.62; I² = 93.00%) of overweight individuals with NAFLD and in 21.60% (95% CI, 11.47–36.92; I² = 95.00%) of obese patients with NAFLD.

On the other hand, 6.65% (95% CI, 4.35–10.01; I² = 58.00%) of overweight individuals with NAFLD and 6.85% (95% CI, 3.85–11.90; I² = 90·00%) of obese individuals with NAFLD had advanced fibrosis.

“This study summarizes the estimated global prevalence of NAFLD, NAFL, and NASH in overweight and obese individuals; these findings are important for improving the understanding of the global NAFLD burden and supporting disease management in the at-risk overweight and obese population,” the authors wrote.

The study, “Global prevalence of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in the overweight and obese population: a systematic review and meta-analysis,” was published online in The Lancet Gastroenterology & Hepatology.