Lan Q, Wu S, Wang Y, et al. - Given that nonalcoholic fatty liver disease (NAFLD) is common and may differ in prevalence and prognosis according to sex, researchers conducted this case-control study to explore the connection between blood copper and NAFLD according to sex. This investigation was performed in Tangshan, China, from January 1, 2016 to December 31, 2017, based on the Kailuan cohort. The sample consisted of 1,816 cases of NAFLD and 1,111 sex- and age-matched control cases. In men, blood copper concentration was lower in the NAFLD group vs the control group. The odds ratio of NAFLD at the highest quartile of copper vs the lowest quartile after adjustment for possible confounders was 0.57; the protective effect of higher blood copper was increased with the severity of NAFLD. In male subjects with metabolic syndrome, lower copper concentration was a significant additional factor that contributed to higher risk of NAFLD, as seen in the stratified analysis. Other then a NAFLD fibrosis score <-1.455 and moderate hepatic steatosis, no significant link was seen between copper and NAFLD in women with various features. According to results, higher levels of copper have a major protective impact against NAFLD in men, but not women.