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.