Associations between serum 25-hydroxyvitamin D3 concentrations and liver histology in patients with non-alcoholic fatty liver disease.

BACKGROUND AND AIM: To explore associations between serum 25-hydroxyvitamin D(3) [25(OH)D] concentrations and liver histology in patients with non-alcoholic fatty liver disease (NAFLD). METHODS AND RESULTS: We studied 60 consecutive patients with biopsy-proven NAFLD, and 60 healthy controls of comparable age, sex and body mass index (BMI). NAFLD patients had a marked decrease in winter serum 25(OH)D concentrations (51.0+/-22 vs. 74.5+/-15 nmol/L, P<0.001) compared with controls. Metabolic syndrome (MetS; as defined by the Adult Treatment Panel III criteria) and its individual components occurred more frequently among NAFLD patients. The marked differences in 25(OH)D concentrations observed between the groups were little affected by adjustment for age, sex, BMI, creatinine, calcium, homeostasis model assessment (HOMA)-insulin resistance, and the presence of the MetS. Interestingly, among NAFLD patients, decreased 25(OH)D concentrations were closely associated with the histological severity of hepatic steatosis, necroinflammation and fibrosis (P<0.001 for all) independent of age, sex, BMI, creatinine, calcium, HOMA-insulin resistance, and presence of the MetS. CONCLUSIONS: Compared with controls, NAFLD patients have a marked decrease in serum 25(OH)D concentrations, which is closely associated with histopathological features of NAFLD. Further investigation into whether vitamin D(3) may play a role in the development and progression of NAFLD appears to be warranted.

Relations between carotid artery wall thickness and liver histology in subjects with nonalcoholic fatty liver disease.

OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) is closely associated with several metabolic syndrome features. We assessed whether NAFLD is associated with carotid artery intima-media thickness (IMT) as a marker of subclinical atherosclerosis and whether such an association is independent of classical risk factors, insulin resistance, and metabolic syndrome features. RESEARCH DESIGN AND METHODS: We compared carotid IMT, as assessed by ultrasonography, in 85 consecutive patients with biopsy-proven NAFLD and 160 age-, sex-, and BMI-matched healthy control subjects. RESULTS: NAFLD patients had a markedly greater carotid IMT (1.14 +/- 0.20 vs. 0.82 +/- 0.12 mm; P < 0.001) than control subjects. The metabolic syndrome (according to Adult Treatment Panel III criteria) and its individual components were more frequent in those with NAFLD (P < 0.001). The marked differences in carotid IMT observed between the groups were only slightly weakened after adjustment for age, sex, BMI, smoking history, LDL cholesterol, insulin resistance (by homeostasis model assessment), and metabolic syndrome components. Notably, carotid IMT was strongly associated with degree of hepatic steatosis, necroinflammation, and fibrosis among NAFLD patients (P < 0.001 for all). Similarly, by logistic regression analysis, the severity of histological features of NAFLD independently predicted carotid IMT (P < 0.001) after adjustment for all potential confounders. CONCLUSIONS: These results suggest that the severity of liver histopathology among NAFLD patients is strongly associated with early carotid atherosclerosis, independent of classical risk factors, insulin resistance, and the presence of metabolic syndrome.

Associations between plasma adiponectin concentrations and liver histology in patients with nonalcoholic fatty liver disease.

OBJECTIVES: To explore associations between plasma adiponectin concentrations and liver histology in patients with nonalcoholic fatty liver disease (NAFLD). DESIGN AND PATIENTS: In a cross-sectional study, we enrolled 60 consecutive NAFLD patients and 60 age-, sex- and body mass index (BMI)-matched healthy controls. MEASUREMENTS: NAFLD (by liver biopsy), plasma adiponectin concentrations, insulin resistance (by homeostasis model assessment, HOMA-IR) and metabolic syndrome (MetS) features. RESULTS: NAFLD patients had a marked decrease in plasma adiponectin concentration (6.1 +/- 2.8 vs. 13.6 +/- 3.8 microg/ml, P < 0.001) compared with matched controls. MetS, as defined by the Adult Treatment Panel III (ATP III) criteria, and its individual components were more frequent among NAFLD patients. The marked differences in adiponectin concentrations that were observed between the groups were little affected by adjustment for age, sex, BMI, HOMA-IR score and MetS components. Notably, decreased adiponectin levels were closely associated with the degree of hepatic steatosis, necroinflammation and fibrosis (P < 0.001 for all) among NAFLD patients. By logistic regression analysis, low adiponectin levels independently predicted hepatic steatosis [odds ratio (OR) 2.3, 95% confidence interval (CI) 1.5-5.8, P < 0.001] and necroinflammation (OR 3.1, 95% CI 1.9-7, P < 0.001), but not fibrosis (P = 0.07), after adjustment for age, sex, BMI, HOMA-IR and MetS components. CONCLUSIONS: NAFLD patients have markedly lower plasma adiponectin concentrations than control subjects. Low adiponectin levels are strongly associated with the severity of liver histology, thus further supporting the hypothesis that adiponectin might be involved in the development of NAFLD.

Associations between liver histology and cortisol secretion in subjects with nonalcoholic fatty liver disease.

OBJECTIVES: To assess associations between the activity of hypothalamo-pituitary-adrenal (HPA) axis and liver histology in patients with nonalcoholic fatty liver disease (NAFLD). DESIGN AND PATIENTS: In a cross-sectional study, we enrolled 50 consecutive, overweight, NAFLD patients and 40 control subjects who were comparable for age, sex and body mass index (BMI). MEASUREMENTS: NAFLD (by liver biopsy), HPA axis activity (by 24-hour urinary free cortisol [UFC] excretion and serum cortisol levels after 1 mg dexamethasone), insulin resistance (by homeostasis model assessment: HOMA-IR), and metabolic syndrome (MetS) features. RESULTS: NAFLD patients had markedly higher (P < 0.001) 24-h UFC (149 +/- 24 vs. 90 +/- 16 nmol/day) and postdex suppression cortisol concentrations (32 +/- 10 vs. 16 +/- 7 nmol/l) than controls. The MetS and its individual components were more frequent among NAFLD patients. The marked differences in urinary/serum cortisol concentrations that were observed between the groups were little affected by adjustment for age, sex, BMI, waist circumference, systolic blood pressure, triglycerides, homeostasis model assessment for insulin resistance score and presence of diabetes. Importantly, 24-h UFC and postdex cortisol concentrations strongly correlated to hepatic necroinflammatory grade (P < 0.01) and fibrosis stage (P < 0.001) among NAFLD patients. By logistic regression analysis, 24-h UFC (odds ratio (OR) 1.80, 95%CI 1.3-2.8) or postdex cortisol concentrations (OR 1.95, 95%CI 1.4-3.1) independently predicted the severity of hepatic fibrosis, but not necroinflammation, after adjustment for potential confounders. CONCLUSIONS: These results suggest that NAFLD patients have a subtle, chronic overactivity in the HPA axis (that is closely associated with the severity of liver histopathology) leading to subclinical hypercortisolism that might be implicated in the development of NAFLD.

Nonalcoholic fatty liver disease and risk of future cardiovascular events among type 2 diabetic patients.

Nonalcoholic fatty liver disease (NAFLD) is closely correlated to several metabolic syndrome features. We assessed prospectively whether NAFLD predicts future cardiovascular disease (CVD) events among type 2 diabetic individuals, independent of metabolic syndrome features and other classical risk factors. We carried out a prospective nested case-control study in 2,103 type 2 diabetic patients who were free of diagnosed CVD at baseline. During 5 years of follow-up, 248 participants (case subjects) subsequently developed nonfatal coronary heart disease (myocardial infarction and coronary revascularization procedures), ischemic stroke, or cardiovascular death. Using risk-set sampling, 496 patients (control subjects) among those who remained free of diagnosed CVD during follow-up were randomly selected in a 2:1 ratio, matched for age and sex to the case subjects. After adjustment for age, sex, smoking history, diabetes duration, HbA1c, LDL cholesterol, liver enzymes, and use of medications, the presence of NAFLD was significantly associated with an increased CVD risk (odds ratio 1.84, 95% CI 1.4-2.1, P < 0.001). Additional adjustment for the metabolic syndrome (as defined by National Cholesterol Education Program Adult Treatment Panel III criteria) appreciably attenuated, but did not abolish, this association (1.53, 1.1-1.7, P = 0.02). In conclusion, NAFLD is significantly associated with a moderately increased CVD risk among type 2 diabetic individuals. This relationship is independent of classical risk factors and is only partly explained by occurrence of metabolic syndrome.

Decreased plasma adiponectin concentrations are closely associated with nonalcoholic hepatic steatosis in obese individuals.

OBJECTIVES: To evaluate whether subjects with nonalcoholic hepatic steatosis (HS) differed in their circulating adiponectin levels compared with those in subjects without HS and, if so, to examine to what extent such differences are mediated by the adverse pattern of the metabolic syndrome variables, typically observed in these subjects. DESIGN AND PATIENTS: In a cross-sectional study, we analysed 68 healthy, mildly obese individuals with a negative or negligible daily alcohol consumption. MEASUREMENTS: HS (by ultrasonography), glucose tolerance status (by oral glucose load), insulin resistance [by homeostasis model assessment (HOMA)], and plasma adiponectin concentration [by enzyme-linked immunosorbent assay (ELISA)] were measured. RESULTS: Subjects with nonalcoholic HS (n = 43) had markedly lower plasma adiponectin concentrations than those without HS (n = 25) (5.6 +/- 3 vs. 10.8 +/- 4 microg/ml; P < 0.001). In addition, the former had significantly higher values for body mass index (BMI), waist/hip ratio (WHR), HOMA-insulin resistance score, plasma insulin (at fasting and after glucose load), plasma triglyceride and liver enzyme concentrations [such as alanine aminotransferase (ALT) and gamma-glutamyltranspeptidase (GGT)], and tended to have lower high density lipoprotein (HDL) cholesterol concentration. The significant differences in plasma adiponectin levels that were observed between the groups were little affected by adjustment for potential confounding variables, such as age, sex, BMI, WHR, lipids and HOMA-insulin resistance score. Similarly, in multivariate regression analyses, hypoadiponectinaemia significantly predicted the presence of HS (P < 0.001) and the increased levels of GGT and ALT (P < 0.05), independently of potential confounders. CONCLUSIONS: These results show that decreased plasma adiponectin concentrations are closely correlated with nonalcoholic HS in healthy obese individuals.