Low Thyroid Function in Nonalcoholic Fatty Liver Disease Is an Independent Predictor of All-Cause and Cardiovascular Mortality.

INTRODUCTION: Higher levels of thyroid-stimulating hormone (TSH) in the euthyroid state can negatively affect the metabolic health, including nonalcoholic fatty liver disease (NAFLD). We studied the effect of TSH levels in the setting of normal levels of thyroid hormone on all-cause and cause-specific mortality stratified by NAFLD status. METHODS: The National Health and Nutrition Examination Survey (NHANES) III from 1988 to 1994 and NHANES III-linked mortality data through 2015 were used. NAFLD was defined as ultrasonographically diagnosed hepatic steatosis without coexisting liver diseases. Subclinical hypothyroidism was defined as a TSH level over 4.5 mIU/L and "low-normal" thyroid function as higher TSH level (2.5-4.5 mIU/L) within the euthyroid reference range. The Cox proportional hazard model analyzed the all-cause mortality and cause-specific mortality. RESULTS: In a multivariate logistic regression analysis, individuals with low thyroid function demonstrated an association with NAFLD in a dose-dependent manner. During a median follow-up of 23 years, low thyroid function was associated with increased all-cause mortality only in the univariate model. Low thyroid function was associated with a higher risk for all-cause mortality in individuals with NAFLD and not in those without NAFLD. Furthermore, low thyroid function was associated with a higher risk for cardiovascular mortality in the entire population and among those with NAFLD but demonstrated no association with the non-NAFLD group. DISCUSSION: In this large nationally representative sample of American adults, low thyroid function was associated with NAFLD and a predictor of higher risk for all-cause and cardiovascular mortality in individuals with NAFLD.

Diet quality and its association with nonalcoholic fatty liver disease and all-cause and cause-specific mortality.

BACKGROUND & AIMS: Healthy diet has been recommended for nonalcoholic fatty liver disease (NAFLD), although it is not clear whether improving diet quality can prevent mortality. We aim to assess the impact of quality of diet on NAFLD and mortality in subjects with and without NAFLD. METHODS: We performed cohort study using the Third National Health and Nutrition Examination Survey from 1988 to 1994 and linked mortality data through 2015. We used the Healthy Eating Index (HEI) scores to define diet quality, with higher HEI scores (Q4) indicating better adherence to dietary recommendations. NAFLD was defined as ultrasonographic hepatic steatosis. RESULTS: Multivariate analysis showed that subjects with higher diet quality were inversely associated with NAFLD in a dose-dependent manner. During the median follow-up of 23 years, having a higher diet quality was associated with reduction in risk of all-cause mortality in the age, sex, Race/ethnicity-adjusted hazard ratio (HR) (Q4, HR: 0.60, 95% CI: 0.52-0.68) and the multivariate model (Q4, HR: 0.81, 95% CI: 0.71-0.92). Higher diet quality was associated with a lower risk for all-cause mortality in subjects without NAFLD; however, this protective association with diet quality was not noted in those with NAFLD. Furthermore, a high diet quality was associated with a lower risk for cancer-related mortality in the total population and among those without NAFLD. This association was not noted in those with NAFLD. CONCLUSIONS: High diet quality was inversely associated with NAFLD and was positively associated with a lower risk for cancer-related and all-cause mortality in those without NAFLD.