968 Lead (Pb) Exposure and Risk of Non-Alcoholic Fatty Liver Disease and Advanced Fibrosis: An Association Modified by Race/Ethnicity and Gender in NHANES 2011-2016

Abstract

INTRODUCTION: NAFLD and NASH are most commonly associated with risk factors such as metabolic syndrome and obesity. Increasing evidence support that environmental toxicants may also play a role. Common sources of Lead (Pb) include paint, dust, waterpipes, and gasoline. In this study we aim to investigate the association of Lead toxicity with NAFLD and advanced fibrosis. METHODS: A population of 5,590 non-pregnant individuals age 18–74 were included in this secondary analysis of NHANES 2011-2016. Exclusion criteria: AST/ALT > 500 IU/L, alcohol > 10 drinks/week (females)/ >20 drinks/week (males), transferrin saturation > 50%, positive hepatitis B and C serology. NAFLD was defined by Fatty Liver Index score > 60. Advanced fibrosis was defined by National Fibrosis Score > 0.676. Student’s T-test was used for continuous and Rao-Scott Chi-Square test for categorical variables. Comparison across quartiles were done with simple linear regression for continuous, Rao-Scott Chi-Square test for categorical variables. Demographics and patient confounders were adjusted using multivariate logistic regression (SAS 9.4) for odds of NAFLD/Advanced Fibrosis with respect to Lead quartile. RESULTS: Increasing exposure to blood Lead levels is significantly associated with increasing age, male gender, longer education, lower BMI, and increasing Mercury levels (see Table 1). After multivariate adjustment for confounding factors, risk of Advanced Fibrosis significantly increased with Lead exposure, (Quartile 4 OR 5.63, 95% CI 3.17–9.99). Upon stratification analysis, this increased risk was highest in males (Q4 OR 16.67, 95% CI 3.96–70.09), African Americans (Q4 OR 9.96, 95% CI 4.45–22.33), and significant trends were positively correlated across all racial groups. Increased exposure to Lead after the median also showed a positive trend for risk of NAFLD (Q4 OR 1.11, 95% CI 0.64–1.92). This positive association was seen in males and whites, however a negative trend was seen in African Americans (see Table 3). CONCLUSION: Our findings show a strong association for Advanced Fibrosis and elevated Lead levels, particularly for African Americans and males. NAFLD is also positively associated with Lead exposure. This study can help identify populations in need of aggressive screening. Further studies are needed.