Lower serum copper concentrations are associated with higher prevalence of nonalcoholic steatohepatitis: a matched case-control study

Background and aim Copper is an essential trace element involved in oxidative stress reactions and energy metabolism. While nonalcoholic fatty liver disease (NAFLD) is closely related to metabolic dysfunction, the role of copper in the development of simple steatosis (NAFL) and nonalcoholic steatohepatitis (NASH) is still unclear. We aimed to compare serum copper levels between patients with simple steatosis and those with NASH. Methods and results We studied 102 patients with biopsy-proven NASH (cases) and 102 NAFL controls, who were matched for age, sex, and residential city. Multivariable conditional logistic analysis was performed to explore associations between serum copper levels and the presence of NASH. Serum copper levels were significantly lower in patients with NASH than in those with matched NAFL controls (15.53 +/- 2.41 mu mol/l vs. 16.34 +/- 3.23 mu mol/l; P = 0.029). This intergroup difference in serum copper levels was more pronounced in men than in women. The per unit, per SD, and per doubling of serum copper levels were associated, respectively, with an approximately 20, 40, and 90% decrease in risk of having NASH, even after adjustment for potential confounding factors. Conclusion Lower serum copper concentrations are significantly associated with higher prevalence of NASH among biopsied-proven NAFLD patients, particularly in men.