Environmental exposures are important risk factors for advanced liver fibrosis in African American adults: NHANES 1999-2018

Background and aims The prevalence and etiology of liver fibrosis vary over time and impact racial/ethnic groups unevenly. This study measured time-trends and identified factors associated with advanced liver fibrosis in the U.S. Methods Standardized methods were used to analyze data on 47,422 participants (≥ 20 years) in the National Health and Nutrition Examination Survey (1999-2018). Advanced liver fibrosis was defined as Fibrosis-4 ≥2.67 and/or Forns Index ≥6.9 and elevated ALT. Results The estimated number of people with advanced liver fibrosis increased from 1.3 million (95% CI, 0.8-1.9) to 3.5 million (95% CI, 2.8-4.2), a nearly 3-fold increase. Prevalence was higher in non-Hispanic Black and Mexican American persons than in non-Hispanic White persons. In multivariable logistic regression analysis, cadmium was an independent risk factor in all racial/ethnic groups. Smoking and current excessive alcohol use were risk factors in most. Importantly, non-Hispanic Black persons had a distinctive set of risk factors compared to non-Hispanic White persons that included poverty (OR = 2.09; 95%CI, 1.44-3.03), and susceptibility to lead exposure (OR = 3.25; 95%CI, 1.95-5.43), but did not include diabetes (OR = 0.88; 95% CI, 0.61-1.27, P =0.52). Non-Hispanic Black persons were more likely to have high exposure to lead, cadmium, polychlorinated biphenyls, and poverty than Non-Hispanic White persons. Conclusions The number of people with advanced liver fibrosis has increased, creating a need to expand the liver care workforce. The risk factors for advanced fibrosis varied by racial/ethnicity. These variations provide useful information for the design of screening programs. Poverty and toxic exposures were associated with the high prevalence of advanced liver fibrosis in non-Hispanic Black persons and need to be addressed. Lay summary Because liver disease often produces few warning signs, simple and inexpensive screening tests that can be performed by non-specialists are needed to allow timely detection and linkage to care. This study shows that non-Hispanic Black persons have a distinctive set of risk factors that need to be taken into account when designing liver disease screening tests. Exposure to exogenous toxins may be especially important risk factors for advanced liver fibrosis in non-Hispanic Black persons. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement National Institute for Occupational Safety and Health (NIOSH): U01 OH01163 ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study used public available NHANES data, which es exempt from IRB review, which were originally located at I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced are available online at * (ALD) : Alcohol-associated liver disease (ALT) : Alanine aminotransferase (AUROC) : Area under the receiver operating curve (BMI) : Body mass index (CI) : Confidence interval (KI) : Fibrosis-4 (FIB-4) : score; Kidney insufficiency (HR) : Hazard ratio (LF) : Liver fibrosis (MA) : Mexican American (NHW) : Non-Hispanic White (NHB) : Non-Hispanic Black (NAFLD) : Non-alcoholic fatty liver disease (NHANES) : National Health and Nutrition Evaluation Survey (NEI) : No exposure identified (PCB) : Polychlorinated biphenyls (Q) : Quartile (VH) : Viral hepatitis