Significant Association Between Gallstone Disease and Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Association between nonalcoholic fatty liver disease and gallstone risk in nonobese and lean individuals

PURPOSE

The association between nonobese/lean nonalcoholic fatty liver disease (NAFLD) and gallstone formation remains unclear. We aimed to assess whether NAFLD is an independent risk factor for gallstones, even in nonobese or lean individuals.

METHODS

We analyzed 265 353 asymptomatic adults who underwent abdominal ultrasonography. The risk of gallstone was assessed on the basis of obesity and NAFLD status.

RESULTS

The overall prevalence rates of NAFLD and gallstones were 27.1% and 2.6%, respectively. The prevalence rates of NAFLD among the 195 204 nonobese and 136 194 lean participants were 14.7% and 7.4%, respectively. Individuals with NAFLD had a significantly increased risk of gallstones (adjusted odds ratio [OR], 1.23; 95% confidence interval [CI], 1.14-1.32). Moreover, NAFLD significantly increased the risk of gallstone (adjusted OR, 1.29; 95% CI, 1.17-1.41) among nonobese individuals. Lean individuals with NAFLD also exhibited a significantly increased risk of gallstones (adjusted OR, 1.20; 95% CI, 1.03-1.40). Furthermore, these findings remained consistent even in nonobese and lean individuals without insulin resistance.

CONCLUSION

Nonobese/lean NAFLD is an independent risk factor for gallstone formation, suggesting its role in gallstone pathogenesis, regardless of obesity status. Therefore, when hepatic steatosis is detected on abdominal ultrasonography, a more thorough evaluation of the gallstones may be necessary, even in nonobese or lean individuals.

Resolution of the Expert Forum "New therapeutic horizons of NAFLD"

Aim. To present the materials of the Expert Forum "New therapeutic horizons of NAFLD," held on December 19, 2023, on the updated nomenclature of fatty liver disease (FLD), its main issues of diagnosis and treatment, the burden of cardiovascular risk in FLD patients. Executive Summary of the Resolution. It is recommended that the latest update of the FLD nomenclature be considered for adaptation to the clinical practice of doctors of all therapeutic specialties. Due to the high prevalence of a combination of non-alcoholic fatty liver disease (NAFLD) and an alcoholic component in the Russian Federation, it is essential to distinguish this subgroup of patients. Numerous clinical conditions associated with NAFLD include cardiovascular disease, pre-diabetes/type 2 diabetes mellitus, polycystic ovary syndrome, obstructive sleep apnea, sarcopenic obesity, cholelithiasis, and chronic kidney disease. Once a diagnosis of NAFLD has been made, further examination of patients should be aimed at detecting the presence of fibrosis using non-invasive methods such as transient liver elastography, FibroTest, and calculation of the FIB-4 fibrosis index. The original ademethionine can be considered a universal drug in treating NAFLD due to reducing oxidative stress and correcting concomitant fatigue and asthenia.

Causal effects from nonalcoholic fatty liver disease on cholelithiasis: A mendelian randomization study

Background and Aims

Both nonalcoholic fatty liver disease (NAFLD) and cholelithiasis are highly prevalent hepatobiliary diseases with risk of progression into severe outcomes. Considering the close relationship between liver and gallbladder in anatomy and physiology, a potential causal relationship between NAFLD and cholelithiasis has been speculated.

Methods

Mendelian randomization (MR) was employed using genome-wide association study (GWAS) summary statistics in Million Veteran Program (MVP) for NAFLD, and statistics in UK biobank for cholelithiasis.

Results

Our results demonstrate that NAFLD has a causal effect on cholelithiasis risk (OR, 1.003; 95%CI, 1.000-1.006; p = 0.03). We also performed the sensitivity analysis and heterogeneity test to ensure the accuracy of outcome and avoid the reverse causality.

Conclusion

NAFLD should be regarded as a potential pathogenic factor in pathogenesis study of cholelithiasis, and be considered in assessment and treatment of cholelithiasis.

A Severely Dilated Gallbladder With Multiple Gallstones After Concomitant Laparoscopic Sleeve Gastrectomy and Childbirth in a Hispanic Woman

Independent studies have associated laparoscopic sleeve gastrectomy (LSG) and pregnancy with a higher incidence of gallstones, especially in Hispanic populations. However, the synergistic impact of these risk factors is currently unknown. We present the case of a 42-year-old Hispanic woman who initially identified intermittent upper right abdominal pain, which worsened over the last four days before the presentation. Abdominal ultrasound indicated hepatic steatosis, hepatomegaly, and cholelithiasis. A hydropic gallbladder with numerous gallstones, surrounding pericholecystic inflammatory changes, and mild intra-abdominal and pelvic ascites was confirmed by computed tomography. The patient underwent an uneventful robotic-assisted cholecystectomy. A gross examination of the gall bladder measuring 15.5 x 6 x 5.5 cm revealed multiple stones measuring 1.0-1.5 cm in the lumen, the largest of which was impacted in the neck. This case underscores the importance of considering ethnicity and pregnancy history while assessing the post-LSG risk of incident cholelithiasis.

Hepatic, Extra-hepatic Outcomes and Causes of Mortality in NAFLD - An Umbrella Overview of Systematic Review of Meta-Analysis

Background

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease globally. While the prevalence, impact, and causes of mortality have been described in various meta-analyses, a systematic all-encompassing umbrella review has yet to be conducted to consolidate the evidence on outcomes associated with NAFLD.

Methods

Search was conducted on Medline and Embase for meta-analysis investigating associated complications and causes of mortality in NAFLD patients. Summary estimates were presented with original units, sample size, and I2 for heterogeneity. The Assessment of Multiple Systematic Reviews 2 was employed for article selection.

Results

25 meta-analyses were included in the present review. NAFLD increased the risks of systemic complications, including cardiovascular diseases, systemic malignancies, diabetes, and chronic kidney disease. Regarding hepatic outcomes, the incidence of hepatocellular carcinoma in NAFLD was 2.39 per 100 person years (CI: 1.40 to 4.08). Individuals with NAFLD were also found to have an increased likelihood of cholangiocarcinoma (OR: 1.88, CI: 1.25 to 2.83) and gallstone disease (OR: 1.55, CI: 1.31 to 1.82) compared to individuals without NAFLD. NAFLD was associated with a higher risk of fatal and non-fatal CVD events (HR: 1.45, CI: 1.31 to 1.61) compared to individuals without NAFLD. Coronary heart disease and subclinical and clinical coronary heart disease were also significantly elevated in NAFLD individuals compared to individuals without NAFLD. Additionally, NAFLD was associated with an increased risk of all-cause mortality (HR: 1.34, CI: 1.17 to 1.54) and cardiovascular (HR: 1.30, CI: 1.08 to 1.56) but not cancer-related mortality.

Conclusion

The study summarizes high-level evidence from published meta-analyses to provide a much-needed update on the outcomes in patients with NAFLD. The significant systemic burden associated with NAFLD and impending fatty liver epidemic requires prompt action from multidisciplinary providers, policy providers, and stakeholders to reduce the burden of NAFLD.

Bidirectional association between NAFLD and gallstone disease: a systematic review and meta-analysis of observational studies

BACKGROUND

Growing evidence indicates an association between NAFLD and gallstone disease (GD), while some does not support this. The aim of this meta-analysis was to evaluate the bidirectional association between NAFLD and GD.

RESEARCH DESIGN AND METHODS

Five electronic databases were searched from inception to May 2022. The association was analyzed based on the odds ratio (OR) and 95% confidence interval (CI) with Reviewer Manager 5.3.

RESULTS

Ten studies involving 284,512 participants met the criteria for GD predicting the onset of NAFLD. GD patients had a higher incidence of NAFLD (OR:1.48, CI:1.32-1.65, p < 0.00001), especially the incidence of moderate-to-severe NAFLD (OR:1.63; CI:1.40-1.79), with females at a higher risk (OR: 1.84; CI: 1.48-2.29). The inverse association was explored in eight studies involving 326,922 participants. The GD incidence in NAFLD patients was higher (OR:1.71, CI:1.63-1.79, p < 0.00001) and may increase due to female sex (OR: 4.18; CI: 1.21-14.37) and high BMI (OR: 1.80; CI: 1.36-2.56), compared with the non-NAFLD group. Besides, this bidirectional association was also confirmed in the Chinese population.

CONCLUSIONS

The findings supported positive concurrent and bidirectional relationships between NAFLD and GD. Therefore, clinicians may alert the possibility of NAFLD in patients with GD and vice versa.

Complex impacts of gallstone disease on metabolic syndrome and nonalcoholic fatty liver disease

Background

Patients with gallstone disease (GSD) often have highly co-occurrence with metabolic syndrome (MetS) and Nonalcoholic fatty liver disease (NAFLD) both associated with insulin resistance (IR). Meanwhile, highly prevalence of NAFLD was found in patients who received cholecystectomy. However, the associations of GSD with MetS, NAFLD is inconsistent in the published literature. And risk of cholecystectomy on NAFLD is unclear.

Methods

We searched the Medline EMBASE and WOS databases for literature that met our study topic. To be specific, studies with focus on associations between GSD and MetS/NAFLD, and risk evaluation on cholecystectomy and NAFLD incidence were enrolled for further analysis. The random effect model was used to calculate the combined relative ratio (RR) and odds ratio (OR)and 95% confidence interval (CI).

Results

Seven and six papers with focus on connections between GSD and NAFLD/MetS prevalence. Correspondingly, seven papers with focus on risk of cholecystectomy on NAFLD occurrence were also enrolled into meta-analysis. After pooling the results from individual study, patients with GSD had higher risk of MetS (OR:1.45, 95%CI: 1.23-1.67, I2 = 41.1%, P=0.165). Risk of GSD was increased by 52% in NAFLD patients (pooled OR:1.52, 95%CI:1.24-1.80). And about 32% of increment on NAFLD prevalence was observed in patients with GSD (pooled OR: 1.32, 95%CI:1.14-1.50). With regard to individual MetS components, patients with higher systolic blood pressure were more prone to develop GSD, with combined SMD of 0.29 (96%CI: 0.24-0.34, P<0.05). Dose-response analysis found the GSD incidence was significantly associated with increased body mass index (BMI) (pooled OR: 1.02, 95%CI:1.01-1.03) in linear trends. Patients who received cholecystectomy had a higher risk of post-operative NAFLD (OR:2.14, 95%CI: 1.43-2.85), P<0.05). And this impact was amplified in obese patients (OR: 2.51, 95%CI: 1.95-3.06, P<0.05).

Conclusion

Our results confirmed that controls on weight and blood pressure might be candidate therapeutic strategy for GSD prevention. And concerns should be raised on de-novo NAFLD after cholecystectomy.

Hepatobiliary Thyroid Hormone Deficiency Impacts Bile Acid Hydrophilicity and Aquaporins in Cholestatic C57BL/6J Mice

Women are more prone to develop either hypothyroidism or cholesterol gallstones than men. However, a male predominance in cholesterol gallstones under hypothyroidism was reported. Recently, a novel pathogenic link between thyroid hormone (TH) deficiency and cholesterol gallstones has been described in male mice. Here, we investigate if TH deficiency impacts cholesterol gallstone formation in females by the same mechanism. Three-month-old C57BL/6J mice were randomly divided into a control, a TH deficient, a lithogenic, and a lithogenic + TH deficient group and diet-treated for two, four, and six weeks. Gallstone prevalence, liver function tests, bile composition, hepatic gene expression, and gallbladder aquaporin expression and localization were investigated. Cholesterol gallstones were observed in lithogenic + TH deficient but not lithogenic only female mice. Diminished hydrophilicity of primary bile acids due to decreased gene expression of hepatic detoxification phase II enzymes was observed. A sex-specific expression and localization of hepatobiliary aquaporins involved in transcellular water and glycerol permeability was observed under TH deficient and lithogenic conditions. TH deficiency promotes cholesterol gallstone formation in female C57BL/6J mice by the same mechanism as observed in males. However, cholesterol gallstone prevalence was lower in female than male C57BL/6J mice. Interestingly, the sex-specific expression and localization of hepatobiliary aquaporins could protect female C57BL/6J mice to cholestasis and could reduce biliary water transport in male C57BL/6J mice possibly contributing to the sex-dependent cholesterol gallstone prevalence under TH deficiency.

Cholecystectomy reduces the risk of myocardial and cerebral infarction in patients with gallstone-related infection

We compared the risk of myocardial infarction (MI) or cerebral infarction (CI) in patients with or without-gallstone-related infection (GSI) and change in the risk following cholecystectomy. GSI (n = 84,467) and non-GSI (n = 406,800) patients with age- and sex-matched controls (n = 4,912,670) were identified from Korean population based data. The adjusted hazard ratios (aHRs) of MI or CI were analyzed in both groups treated with or without cholecystectomy. Subgroup analysis was performed for both sexes and different ages. The risk of MI or CI was higher in the GSI group than in the non-GSI group (aHR for MI; 1.32 vs. 1.07, aHR for CI; 1.24 vs. 1.06, respectively). The risk reduction rate of MI following cholecystectomy was 11.4% in the GSI group, whereas it was 0% in the non-GSI group. The risk of CI after cholecystectomy was more reduced in the GSI group than in the non-GSI group (16.1% and 4.7%, respectively). The original risk of MI or CI in patients with gallstones and risk reduction rates following cholecystectomy were higher in females and younger patients than in males and older patients. Increased risk of MI or CI and greater risk reduction following cholecystectomy were seen in patients with GSI.

Causal associations between changes in lipid profiles and risk of gallstone disease: a two-sample Mendelian randomization study

Background

Nonalcoholic fatty liver disease (NAFLD) has been linked to gallstone disease (GSD) in observational studies; however, the relationships between certain lipid profiles and GSD remain unclear.

Methods

We adopted a two-sample Mendelian randomization (MR) framework by applying different statistical methods to assess causalities between lipid profiles and GSD. We identified single-nucleotide polymorphisms (SNPs) for blood lipids and NAFLD from separate previous genome-wide association studies (GWASs).

Results

We retrieved GSD SNPs attributed to 10,520 cases and 361,194 controls and validated our estimates using GWAS summary data from UK Biobank. We also performed sex-stratified analyses. Based on the summary estimates of 41, 59, 35, and 2 SNPs for low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), triglycerides (TGs), and NAFLD, respectively, we found no evidence of a causal relationship between genetically-predicted lipid profiles and GSD. The odds ratios were 0.995 for LDLC [95% confidence interval (CI): 0.994-0.998] per 0.98 mmol/L, 0.999 for HDLC (95% CI: 0.996-1.003) per 0.41 mmol/L, 0.997 for TGs (95% CI: 0.994-1.001) per 1 mmol/L, and 0.993 for NAFLD (95% CI: 0.984-1.003). No evidence of associations between lipid profile s and GSD in validation MR analyses or the sex-stratification analyses was noted.

Conclusions

Genetically predicted hyperlipidemia or NAFLD is not causally associated with GSD.

Metabolically associated fatty liver disease – a disease of the 21st century: A review

Metabolically associated fatty liver disease (MAFLD) is a widespread chronic disease characterized by increased accumulation of fat in the liver, which is based on metabolic dysfunction. The incidence of MAFLD is well over 20% in most regions of the world and is on an increasing trend. Current thinking considers the etiology and pathogenesis of MAFLD under the concept of "multiple parallel blows". According to this model, the development and progression of the disease are due to the interaction of multiple genetic, environmental and adaptive factors, which include specific genetic polymorphisms (e.g., the PNPLA3 gene) and epigenetic modifications, dietary patterns (e.g. high saturated fat and fructose intake), sedentary activity, obesity, insulin resistance, dysregulation of adipokines, lipotoxicity, oxidative stress, and gut microbiota dysbiosis (small intestinal bacterial overgrowth syndrome). The basis for the diagnosis of MAFLD is the presence of proven hepatic steatosis in combination with one of the following criteria: overweight/obesity, presence of type 2 diabetes mellitus, signs of metabolic dysregulation. Nonmedicamental therapies recommended for patients with MAFLD include weight loss (if overweight or obese), reduction of saturated fatty acid and fructose intake, and inclusion of adequate amounts of omega-3 polyunsaturated fatty acids and dietary fibre (psyllium) in the diet. Pharmacotherapy of MAFLD should be aimed at correcting insulin resistance, improving liver function and reducing the risk of associated diseases.

American Association of Clinical Endocrinology Clinical Practice Guideline for the Diagnosis and Management of Nonalcoholic Fatty Liver Disease in Primary Care and Endocrinology Clinical Settings: Co-Sponsored by the American Association for the Study of Liver Diseases (AASLD)

OBJECTIVE

To provide evidence-based recommendations regarding the diagnosis and management of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) to endocrinologists, primary care clinicians, health care professionals, and other stakeholders.

METHODS

The American Association of Clinical Endocrinology conducted literature searches for relevant articles published from January 1, 2010, to November 15, 2021. A task force of medical experts developed evidence-based guideline recommendations based on a review of clinical evidence, expertise, and informal consensus, according to established American Association of Clinical Endocrinology protocol for guideline development.

RECOMMENDATION SUMMARY

This guideline includes 34 evidence-based clinical practice recommendations for the diagnosis and management of persons with NAFLD and/or NASH and contains 385 citations that inform the evidence base.

CONCLUSION

NAFLD is a major public health problem that will only worsen in the future, as it is closely linked to the epidemics of obesity and type 2 diabetes mellitus. Given this link, endocrinologists and primary care physicians are in an ideal position to identify persons at risk on to prevent the development of cirrhosis and comorbidities. While no U.S. Food and Drug Administration-approved medications to treat NAFLD are currently available, management can include lifestyle changes that promote an energy deficit leading to weight loss; consideration of weight loss medications, particularly glucagon-like peptide-1 receptor agonists; and bariatric surgery, for persons who have obesity, as well as some diabetes medications, such as pioglitazone and glucagon-like peptide-1 receptor agonists, for those with type 2 diabetes mellitus and NASH. Management should also promote cardiometabolic health and reduce the increased cardiovascular risk associated with this complex disease.

Factors Influencing Gallstone Formation: A Review of the Literature

Gallstone disease is a common pathology of the digestive system with nearly a 10–20% incidence rate among adults. The mainstay of treatment is cholecystectomy, which is commonly associated with physical pain and may also seriously affect a patient’s quality of life. Clinical research suggests that cholelithiasis is closely related to the age, gender, body mass index, and other basic physical characteristics of patients. Clinical research further suggests that the occurrence of cholelithiasis is related to obesity, diabetes, non-alcoholic fatty liver, and other diseases. For this reason, we reviewed the following: genetic factors; excessive liver cholesterol secretion (causing cholesterol supersaturation in gallbladder bile); accelerated growth of cholesterol crystals and solid cholesterol crystals; gallbladder motility impairment; and cardiovascular factors. Herein, we summarize and analyze the causes and mechanisms of cholelithiasis, discuss its correlation with the pathogenesis of related diseases, and discuss possible mechanisms.

Insights into modifiable risk factors of cholelithiasis: A Mendelian randomization study

BACKGROUND AND AIMS

The risk factors of cholelithiasis have not been clearly identified, especially for total cholesterol. Here, we try to identify these causal risk factors.

APPROACH AND RESULTS

We obtained genetic variants associated with the exposures at the genome-wide significance (p < 5 × 10^-8 ) level from corresponding genome-wide association studies. Summary-level statistical data for cholelithiasis were obtained from FinnGen and UK Biobank (UKB) consortia. Both univariable and multivariable Mendelian randomization (MR) analyses were conducted to identify causal risk factors of cholelithiasis. Results from FinnGen and UKB were combined using the fixed-effect model. In FinnGen, the odds of cholelithiasis increased per 1-SD increase of body mass index (BMI) (OR = 1.631, p = 2.16 × 10^-7 ), together with body fat percentage (OR = 2.108, p = 4.56 × 10^-3 ) and fasting insulin (OR = 2.340, p = 9.09 × 10^-3 ). The odds of cholelithiasis would also increase with lowering of total cholesterol (OR = 0.789, p = 8.34 × 10^-5 ) and low-density lipoprotein-cholesterol (LDL-C) (OR = 0.792, p = 2.45 × 10^-4 ). However, LDL-C was not significant in multivariable MR. In UKB, the results of BMI, body fat percentage, total cholesterol, and LDL-C were replicated. In meta-analysis, the liability to type 2 diabetes mellitus and smoking could also increase the risk of cholelithiasis. Moreover, there were no associations with other predominant risk factors.

CONCLUSIONS

Our MR study corroborated the risk factors of cholelithiasis from previous MR studies. Furthermore, lower total cholesterol level could be an independent risk factor.

Gallstone Disease in Cirrhosis-Pathogenesis and Management

Gallstones are more common in patients with cirrhosis of the liver, and the incidence increases with severity of liver disease. Pigment stones are the most frequent type of gallstones (GSs) in cirrhotics, and majority remain asymptomatic. Hepatitis C virus infection and nonalcoholic fatty liver disease are the underlying etiologies of liver diseases that most often associated with GSs. Multiple altered mechanisms in cirrhosis such as chronic hemolysis due to hypersplenism, reduced bile acid synthesis and transport, decreased cholesterol secretion, decreased apolipoprotein A-I and A-II secretion, gallbladder hypo-motility, autonomic dysfunction, and portal hypertension collectively lead to increased risk of lithogenesis. Asymptomatic GSs should be followed up closely and offered laparoscopic cholecystectomy once symptomatic in Child-Pugh class A and B patients. The model for the end-stage liver disease score is the best predictor of the outcome after cholecystectomy. In patients of Child-Pugh class C, conservative or minimally invasive approaches should be used to treat complications of GSs.

Gallstone disease and nonalcoholic fatty liver disease in patients with type 2 diabetes: a cross-sectional study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and gallstone disease (GSD) often coexist in the general population owing to shared risk factors. This study explored the relationship between NAFLD and GSD in patients with type 2 diabetes.

METHODS

We conducted a retrospective cross-sectional analysis of 4325 patients with type 2 diabetes. GSD and NAFLD were confirmed using ultrasonography. GSD was defined as either asymptomatic gallstones or previous cholecystectomy, and each was analyzed separately.

RESULT

There was no significant difference in the prevalence of GSD between patients with and without NAFLD (23.8% vs. 21.2%, P = 0.15). After case-control matching (1:1) of baseline data such as age, sex, duration of diabetes, and HbA1c between patients with and without NAFLD, there was still no significant difference in the prevalence of GSD (25.5% vs. 23.6%, P = 0.15). The prevalence of NAFLD in patients with asymptomatic gallstones was lower than that of patients without GSD (38.6% vs. 47.3%, P < 0.001), whereas the prevalence in those who had undergone cholecystectomy was much higher (61.2% vs. 47.3%, P < 0.001). The ratio of cholecystectomy to asymptomatic gallstone in patients with or without NAFLD was 1.97 and 0.79, respectively. The rate of cholecystectomy was higher in the patients with NAFLD than in those without NAFLD (15.8% vs. 9.3%, P < 0.001), consistent with the result after case-control matching (17.3% vs. 11.2%, P < 0.001). Multivariate logistic regression analysis, after adjusting for numerous potential confounding factors, revealed that GSD (OR = 1.241, 95%CI: 1.036-1.488, P = 0.002) and cholecystectomy (OR = 1.946, 95%CI: 1.546-2.445, P < 0.001) were both strongly associated with NAFLD. However, asymptomatic gallstone (OR = 0.663, 95%CI: 0.513-0.856, P = 0.002) seemed to be negatively correlated with NAFLD.

CONCLUSIONS

The prevalence of GSD was similar in patients with type 2 diabetes with and without NAFLD. The higher proportion of cholecystectomy and lower proportion of asymptomatic gallstones in patients with NAFLD suggests that NAFLD may increase the risk of complications of GSD.

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

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Cholecystectomy as a risk factor for metabolic dysfunction-associated fatty liver disease: unveiling the metabolic and chronobiologic clues behind the bile acid enterohepatic circulation

Metabolic dysfunction-associated fatty liver disease (MAFLD) is highly prevalent worldwide. Recent clinical and experimental studies have addressed the association between cholecystectomy and MAFLD, confirming that cholecystectomy is an independent risk factor for MAFLD. In this review, we describe the epidemiologic evidence that links cholecystectomy to MAFLD, and discuss the possible mechanisms behind these connections, in order to unveil the metabolic and chronobiologic signals conveyed by the waves of the bile acid enterohepatic circulation.

The Association Between Cholecystectomy, Metabolic Syndrome, and Nonalcoholic Fatty Liver Disease: A Population-Based Study

Obesity is a risk factor for several phenotypes such as gallstones, metabolic syndrome (MS), and nonalcoholic fatty liver disease (NAFLD). It has been suggested that cholecystectomy is a risk factor for metabolic abnormalities and NAFLD. We aimed to determine whether cholecystectomy is associated with MS or NAFLD in a Dutch population-based study.

Epidemiological survey to determine the prevalence of cholecystolithiasis in Uyghur, Kazakh, and Han Ethnic Groups in the Xinjiang Uyghur Autonomous Region of China: cross-sectional studies

Background

This study was performed to understand the prevalence of and possible risk factors for cholecystolithiasis in Uyghur, Kazakh, Han, and other ethnic groups in the Xinjiang Uyghur autonomous region of China.

Methods

Subjects were enrolled using typical case sampling and multistage stratified random sampling. We collected epidemiological data regarding cholecystolithiasis using a standard questionnaire of risk factors for gallbladder disease in Xinjiang. The subjects completed the questionnaire and underwent an abdominal ultrasound examination of the liver and gallbladder.

Results

This study included 5454 Xinjiang residents aged ≥ 18 years. The prevalence of cholecystolithiasis was 15% (11.3% in men and 17.1% in women), and the sex difference was statistically significant (male-to-female odds ratio [OR] 1.867; p < 0.001). The cholecystolithiasis prevalence was also significantly different among the Han, Uyghur, Kazakh, and other ethnic groups (13.1%, 20.8%, 11.5%, and 16.8%, respectively; p < 0.001). The prevalence of cholecystolithiasis in northern Xinjiang was 13.5% and that in southern Xinjiang was 17.5%; this difference was also statistically significant (OR 1.599; p < 0.001). Across all ethnic groups, the cholecystolithiasis prevalence significantly increased with age (all p < 0.01) and body mass index (BMI) (all p < 0.01). A multivariate logistic regression analysis indicated that cholecystolithiasis prevalence was associated with sex, age, BMI, smoking, diabetes, fatty liver disease, and geographical differences between northern and southern Xinjiang.

Conclusions

The prevalence of cholecystolithiasis was significantly higher in the Uyghur ethnic group than in the Han, Kazakh, and other ethnic groups; in women than in men; in southern Xinjiang than in northern Xinjiang; in patients with fatty liver disease; and increased with age and BMI. Our findings could provide a theoretical basis for the formulation of control measures for cholecystolithiasis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01677-w.

An inverse association of weight and the occurrence of asymptomatic gallbladder stone disease in hypercholesterolemia patients: a case-control study

Background

Despite the fact that the majority of gallstones formed in the gallbladder are mainly composed of cholesterol, as they are formed from cholesterol-supersaturated bile, and hypercholesterolemia is a common metabolic disorder, which is closely related to cardiac, hepatic, renal and other oxidative damage inflammation and necrosis, there is still no consensus regarding the contribution of blood serum lipids in the pathogenesis of gallbladder stone disease (GSD). This study aimed to investigate the relationship between hypercholesterolemia and the risk of new-onset asymptomatic GSD, and to determine the prevalence of factors associated with new-onset asymptomatic GSD in patients with hypercholesterolemia.

Methods

In this study, 927 Chinese patients with new-onset asymptomatic gallstone disease and 845 healthy controls were enrolled starting from August 2012. Patients were matched for age, gender, race, occupation, systolic blood pressure, diastolic blood pressure, and fasting blood glucose levels (FBG). Body mass index (BMI), nonalcoholic fatty liver disease (NAFLD) and serum lipids indexes were compared and the relationships between BMI, blood lipid and gallbladder stone hazards were examined by logistic multivariate regression models.

Results

The result showed a significantly higher morbidity with GSD in hypercholesterolemia than non-hypercholesterolemia patients (Χ² = 17.211, P < 0.001). Of hypercholesterolemia patients, low density lipoprotein (OR = 1.493, P = 0.029) and NAFLD (OR = 2.723, P = 0.022) were significant risk factors for GSD, while being male (OR = 0.244, P = 0.033), weight (OR = 0.961, P = 0.022), high density lipoprotein (OR = 0.305, P < 0.001), and FBG (OR = 0.687, P = 0.034) were significantly negatively correlated with GSD in univariate analysis. Multivariate logistic regression indicated weakly positive correlations with NAFLD (OR = 3.284, P = 0.054), and significant negative correlations with weight (OR = 0.930, P = 0.018), HDL-c (OR = 0.144, P < 0.001), and GSD.

Conclusion

Hypercholesterolemia acts as an independent risk factor for new-onset asymptomatic GSD, while obesity and NAFLD are synergistic factors. Interestingly, it is first reported that elevated weight was inversely associated with GSD in patients with hypercholesterolemia. The results of this study suggest that effective control of hyperlipidemia is of greater significance than weight loss, which might make the situation worse, in the prevention of GSD in obese patients with hyperlipidemia.

Liver fat accumulation measured by high-speed T2-corrected multi-echo magnetic resonance spectroscopy can predict risk of cholelithiasis

BACKGROUND

Liver fat accumulation is associated with increased cholesterol synthesis and hypersecretion of biliary cholesterol, which may be related to the development of cholelithiasis.

AIM

To investigate whether liver fat accumulation measured by high-speed T2-corrected multi-echo magnetic resonance spectroscopy (MRS) is a risk factor for cholelithiasis.

METHODS

Forty patients with cholelithiasis and thirty-one healthy controls were retrospectively enrolled. The participants underwent high-speed T2-corrected multi-echo single-voxel MRS of the liver at a 3T MR scanner. The proton density fat fraction (PDFF) and R2 value were calculated. Serum parameters and waist circumference (WC) were recorded. Spearman’s correlation analysis was used to analyze the relationship between PDFF, R2, and WC values. Multivariate logistic regression analysis was carried out to determine the significant predictors of the risk of cholelithiasis. Receiver operating characteristic curve (ROC) analysis was used to evaluate the discriminative performance of significant predictors.

RESULTS

Patients with cholelithiasis had higher PDFF, R2, and WC values compared with healthy controls (5.8% ± 4.2% vs 3.3% ± 2.4%, P = 0.001; 50.4 ± 24.8/s vs 38.3 ± 8.8/s, P = 0.034; 85.3 ± 9.0 cm vs 81.0 ± 6.9 cm, P = 0.030; respectively). Liver iron concentration extrapolated from R2 values was significantly higher in the cholelithiasis group (2.21 ± 2.17 mg/g dry tissue vs 1.22 ± 0.49 mg/g dry tissue, P = 0.034) than in the healthy group. PDFF was positively correlated with WC (r = 0.502, P < 0.001) and R2 (r = 0.425, P < 0.001). Multivariate logistic regression analysis showed that only PDFF was an independent risk factor for cholelithiasis (odds ratio = 1.79, 95%CI: 1.22-2.62, P = 0.003). ROC analysis showed that the area under the curve of PDFF was 0.723 for discriminating cholelithiasis from healthy controls, with a sensitivity of 55.0% and specificity of 83.9% when the cut-off value of PDFF was 4.4%.

CONCLUSION

PDFF derived from high speed T2-corrected multi-echo MRS can predict the risk of cholelithiasis.

[Clinical features of the comorbid course of non-alcoholic fatty liver disease and gallstone disease]

AIM

To determine the diagnostic value of clinical features of the comorbid course of non-alcoholic fatty liver disease (NAFLD) and gallstone disease (GD) to improve the effectiveness of patient management.

MATERIALS AND METHODS

183 patients with NAFLD were included into the open comparative study. The main group was represented by patients with NAFLD and GD (n=88), of which 53 patients underwent cholecystectomy (CE). The comparison group was represented by patients with NAFLD without GD (n=95). A standard laboratory and instrumental examinations were performed, including elastometry to assess of the stage of liver fibrosis.

RESULTS

There were more women in the main group (2=8.48; p0.01). There were positive correlations between the age of patients and the duration of NAFLD with the presence of GD and CE (rs=0.135; p0.01 and rs=0.168; p0.01 respectively). Patients of the main group had the general weakness and fatigue (2=11.33, rs=0.234; p0.01 and 2=15.68, rs=0.281; p0.01 respectively), as well as a bitter taste in the mouth (2=11.66; p0.01; rs=0.147; p0.01). Coronary heart disease was diagnosed more often among people suffering from NAFLD and GD (25% vs 9.47% in patients of the comparison group, p0.01). Both of NAFLD and GD were associated with the development of type 2 diabetes (rs=0.164; p0.01). Individuals suffering from GD after CE had higher LDL and GGT values (rs=0.228; p0.01 and rs=0.298; p0.01 respectively). The number of people with advanced fibrosis were significantly higher (26.31%) in the GD group, especially among people after CE (30.18%). The stage of liver fibrosis had a positive significant relationship with CE (rs=0.366; p0.01).

CONCLUSION

Patients suffering from GD and NAFLD had a symptom of dyspepsia and general weakness. High prevalence of type 2 diabetes and сoronary heart disease, high level of LDL and GGT were found in patients with GD and after CE. CE in patients suffering from GD and NAFLD was associated with the formation of progressive stages of liver fibrosis.

Pathophysiological connections between gallstone disease, insulin resistance, and obesity

Obesity and cholesterol gallstone disease (GSD) are frequently coexisting diseases; therefore and considering the current worldwide obesity epidemics, a precise understanding of the pathophysiological relationships between GSD and insulin resistance (IR) is important. Classically, obesity has been understood as a risk factor for GSD and the gallbladder (GB) viewed as a simple bile reservoir, with no metabolic roles whatsoever. However, consistent evidence has showed that both GSD and cholecystectomy associates with fatty liver and IR, raising the possibility that the GB is indeed an organ with metabolic regulatory roles. Herein, we review the pathophysiological mechanisms by which GSD, IR, and obesity are interconnected, with emphasis in the actions of the GB as a regulator of bile acids kinetics and a hormone secreting organ, with metabolic actions at the systemic level. We also examine the relationships between increased hepatic lipogenic in IR states and GSD pathogenesis. We propose a model in which GSD and hepatic IR mutually interact to determine a state of dysregulated lipid and energy metabolism that potentiate the metabolic dysregulation of obesity.

The Effect of Cholecystectomy on the Risk of Colorectal Cancer in Patients with Gallbladder Stones

To evaluate the risk of colorectal cancer (CRC) after cholecystectomy for gallbladder stones (GBS).

METHODS

This nationwide population-based cohort study analyzed the inpatient data from the Taiwan National Health Insurance Research Database. The study cohort comprised of 83,963 patients aged 20 years undergoing cholecystectomy for GBS between 2000 and 2010. The control cohort comprised the GBS patients without cholecystectomy, who were propensity matched with the study cohort at a 1:1 ratio based on age, sex, comorbidities, and the index date for cholecystectomy.

RESULTS

The cumulative incidence of CRC within 6 months of follow-up was higher in the cholecystectomy cohort than that in the non-cholecystectomy cohort (aHR (adjusted hazard ratio) = 7.90, 95% confidence interval (CI) = 6.27-9.94; log-rank test, p < 0.001). The cumulative incidence of CRC after 6 months of follow-up was lower in the cholecystectomy cohort than that in the non-cholecystectomy cohort (aHR = 0.66, 95% CI = 0.60-0.73; log-rank test, p < 0.001), but the reduced risk of CRC for the cholecystectomy cohort was statistically significant only in rectal cancer after separately considering females (aHR = 0.64, 95% CI = 0.46-0.88) and males (aHR = 0.59, 95% CI = 0.44-0.79).

CONCLUSIONS

The positive association between cholecystectomy and the CRC risk within the first 6 months after cholecystectomy might be due to a detection bias or pre-existing CRC. However, cholecystectomy is associated with a decreased risk of rectal cancer, rather than proximal or distal colon cancer, after more than 6 months of follow-up.

Association Between Non-Alcoholic Fatty Liver Disease and Metabolic Syndrome with Gallstone Disease, South Iran: A Population-Based Study

AIM

Gallstone disease (GSD), non-alcoholic fatty liver disease (NAFLD), and metabolic syndrome (MetS) are common problems. The aim of this study was to investigate the association between NAFLD, MetS and its components with GSD.

MATERIALS AND METHODS

This cross-sectional study was conducted as a part of the Kavar Cohort Study (KCS) affiliated to Shiraz University of Medical Sciences, Shiraz, Iran between January 2012 and January 2018. A total of 2239 participants of the general population of the KCS were selected randomly. Ultrasonography for GSD and NAFLD diagnosis and clinical and laboratory assaying for MetS evaluation were performed for the participants. The National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATP-III) and Criteria for Clinical Diagnosis of MetS in Iranian Adults (CCDMIA) were used for diagnosis of MetS.

RESULTS

Overall, 59 patients with GSD and 177 age- and sex- matched participants without gallstones as a comparison group were enrolled. According to GSD groups, NAFLD was observed in 42.4% and 22.6% of patients with and without GSD, respectively, and the difference between the two groups was statistically significant (P = 0.003). MetS was present in 33.9% and 39.0% of GSD subjects, compared with 32.8% and 33.3% of the non-GSD group, based on NCEP/ATPIII and CCDMIA, respectively. Although the mean of all components of MetS except HDL-cholesterol were higher in the GSD group than in the non-GSD group,  the difference was only significant in waist circumference (P = 0.041).

CONCLUSION

The present study found an obvious association between NAFLD and GSD. This study also showed a significant association between increasing waist circumference and risk of GSD. We recommend that patients with GSD should be evaluated for the likelihood of NAFLD and its treatment in addition to lifestyle changes to gain proper weight. However, further researches are needed to clarify the relationship between the nature of GSD, NAFLD, and obesity.

Mechanisms Underlying the Prevention and Treatment of Cholelithiasis Using Traditional Chinese Medicine

Cholelithiasis is a major public health concern that necessitates highly effective, feasible, and recurrence-preventing therapies. Currently available surgical treatments and medications cannot effectively avoid the recurrence of cholelithiasis. Hence, several Chinese herbal compounds (CHCs) are considered for the treatment of cholelithiasis, considering that they can effectively discharge gallstones and prevent the recurrence of such condition. In the present narrative review, we aim to summarize the underlying mechanisms of currently used CHCs in the treatment of cholelithiasis and to describe the current situation of traditional Chinese medicine (TCM) use for cholelithiasis. Several commonly used CHCs were used to illustrate these issues. We found that the mechanisms underlying the CHC treatments rely on the amelioration of the biliary dynamics factors, maintenance and protection of the liver function, reduction of the cholesterol and bilirubin levels, and regulation of the inflammatory reactions. CHCs as treatments based on TCM can ameliorate the overall bodily function, thereby preventing the recurrence of cholelithiasis. Appropriate application of CHCs would be beneficial for patients and clinicians, although the safety and efficacy of CHCs need further verification.

Clinical and Pathogenetic Parallels of Nonalcoholic Fatty Liver Disease and Gallstone Disease

Aim:to analyze the data that has so far been accumulated on the pathogenetic association of gallstone disease (GD) and non-alcoholic fatty liver disease (NAFLD), as well as to assess the effect of cholecystectomy on the NAFLD course.

Key findings.The relationship between GD and NAFLD is very complex and seems to be mutually aggravating. There is no doubt that there is an increased risk of GB in NAFLD patients, which is primarily associated with common pathogenetic mechanisms. These include central and peripheral insulin resistance, changes in the expression of transcription factors (liver X-receptor and farnesoid X-receptor) and the bile acid membrane receptors (TGR5). Conversely, the effect of GD on the NAFLD course is assumed, although the pathogenetic factors of this association are still unknown. In recent years, convincing data has emerged concerning the role of cholecystectomy in the NAFLD progression, which may be connected with the development of small intestinal bacterial overgrowth, as well as with the disruption of the endocrine balance and the signal function of bile acids.

Conclusion.The connection between NAFLD, GD and cholecystectomy is complex and multifaceted. The study of this connection will allow new methods of treatment to be developed.

Comparative analysis of bile acid spectrum in non-alcoholic fatty liver disease and cholelithiasis

AIM

Сomparative studying of changes in the spectrum of bile acids in bile in patients with nonalcoholic fatty liver disease and cholelithiasis.

MATERIALS AND METHODS

140 patients were included in the survey: 50 - with nonalcoholic fatty liver disease and 90 - with cholelithiasis. The diagnosis of nonalcoholic fatty liver disease was established on the basis of ultrasound examination of the liver, the elasticity and fibrosis of liver by using the sonoelastography and liver biopsy. The prestone stage of cholelithiasis was established on the basis of ultrasound examination of the gallbladder and biochemical examination of bile. The level of total cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, total bilirubin, alkaline phosphatase and gamma glutamyl transpeptidase were studied using the analyzer &quot;Labsystems&quot; (Finland). The spectrum of bile acids in bile is studied by mass spectrometry on AmazonX apparatus (Bruker Daltonik GmbH, Bremen, Germany).

RESULTS

Biochemical blood test revealed increase of cholesterol, triglycerides, cytolysis markers, and cholestasis, the most pronounced in patients with nonalcoholic fatty liver disease. Biochemical study of bile showed increase of cholesterol, decrease the total amount of bile acids and cholatecholesterol coefficient in the vesicle and hepatic bile in patients with nonalcoholic fatty liver disease and cholelithiasis. Mass spectrometry showed decrease the total amount of free bile acids (choloidal, chenodeoxycholic, deoxycholic) and increase the content of conjugated bile acids (glycocholic, glycodesoxycholic, taurocholic, taurodeoxycholic, ursodeoxycholic), the most pronounced in patients with nonalcoholic fatty liver disease.

CONCLUSION

Unidirectional changes in the spectrum of bile acids in nonalcoholic fatty liver disease and cholelithiasis give reason to believe that the trigger mechanism in the disturbance of bile acids metabolism is the liver. Reduction of primary bile acids, imbalance of phospholipids and cholesterol disrupt the stabilization of bile, resulting in unfavorable conditions in the bile ducts to form stones.

Cholesterol cholelithiasis: part of a systemic metabolic disease, prone to primary prevention

Cholesterol gallstone disease have relationships with various conditions linked with insulin resistance, but also with heart disease, atherosclerosis, and cancer. These associations derive from mechanisms active at a local (i.e. gallbladder, bile) and a systemic level and are involved in inflammation, hormones, nuclear receptors, signaling molecules, epigenetic modulation of gene expression, and gut microbiota. Despite advanced knowledge of these pathways, the available therapeutic options for symptomatic gallstone patients remain limited. Therapy includes oral litholysis by the bile acid ursodeoxycholic acid (UDCA) in a small subgroup of patients at high risk of postdissolution recurrence, or laparoscopic cholecystectomy, which is the therapeutic radical gold standard treatment. Cholecystectomy, however, may not be a neutral event, and potentially generates health problems, including the metabolic syndrome. Areas covered: Several studies on risk factors and pathogenesis of cholesterol gallstone disease, acting at a systemic level have been reviewed through a PubMed search. Authors have focused on primary prevention and novel potential therapeutic strategies. Expert commentary: The ultimate goal appears to target the manageable systemic mechanisms responsible for gallstone occurrence, pointing to primary prevention measures. Changes must target lifestyles, as well as experimenting innovative pharmacological tools in subgroups of patients at high risk of developing gallstones.

Bidirectional Association between Nonalcoholic Fatty Liver Disease and Gallstone Disease: A Cohort Study

Nonalcoholic fatty liver disease (NAFLD) and gallstone disease (GD) are often found to coexist but the sequential relationship of NAFLD and GD to each other remains controversial. We prospectively evaluated the bidirectional relationship of NAFLD with GD. A cohort study was performed on Korean adults who underwent a health checkup and were followed annually or biennially for a mean of 6.0 years. Fatty liver and gallstones were diagnosed by ultrasound. NAFLD was defined as hepatic steatosis on ultrasonography in the absence of excessive alcohol use or other identifiable causes. The NAFLD severity was determined by non-invasive fibrosis markers. Among 283,446 participants without either gallstones or cholecystectomy at baseline, 6440 participants developed gallstones. Among 219,641 participants without NAFLD at baseline, 49,301 participants developed NAFLD. The multivariable-adjusted hazard ratio (95% confidence interval) for incident gallstone comparing the NAFLD group vs. the non-NAFLD group was 1.26 (1.17–1.35). Increased non-invasive fibrosis markers of NAFLD were positively associated with an increased incidence of gallstones in a graded and dose-responsive manner (p-trend < 0.01). The multivariable-adjusted hazard ratios (95% confidence intervals) for incident NAFLD comparing gallstone and cholecystectomy to no GD were 1.14 (1.07–1.22) and 1.17 (1.03–1.33), respectively. This large-scale cohort study of young and middle-aged individuals demonstrated a bidirectional association between NAFLD and GD. NAFLD and its severity were independently associated with an increased incidence of gallstones, while GD and cholecystectomy were also associated with incident NAFLD. Our findings indicate that the conditions may affect each other, requiring further studies to elucidate the potential mechanisms underlying this association.

Cholelithiasis and choledocholithiasis in children; risk factors for development

PURPOSE

To compare anthropometric data (body mass index [BMI]) in patients without lithiasis to patients with symptomatic simple cholelithiasis or choledocholithiasis.

METHODS

We retrospectively reviewed data from 147 patients undergoing laparoscopic cholecystectomy between 2001-2015. Complete growth data from 98 patients was compared with anthropometric data from the population of the Czech Republic and a control group (BMI of 100 consecutive patients without biliary stones in abdominal ultrasound who were admitted to a surgical department for suspected appendicitis).

RESULTS

The BMI of 75 children with simple cholelithiasis and 23 with choledocholithiasis was compared to the standard Czech pediatric population and to the control group. The median age (simple cholelithiasis and choledocholithiasis) was 16 years, and 35 patients (24%) had a family history of gallstones. Types of lithiasis included multiple (n = 120), solitary (n = 11), and sludge (n = 10). Five cases had polyps and one had gallbladder dysplasia. Patients with simple cholelithiasis had significantly higher BMI compared to the control group without cholelithiasis (p<0.0001) and the standard Czech population (p = 0.03). Patients with choledocholithiasis had a mean BMI significantly higher than that of the general population (p = 0.001) and the control group (p = 0.0001). Patients with choledocholithiasis had significantly higher BMI than those with simple cholelithiasis (p = 0.03).

CONCLUSION

Patients with cholelithiasis had significantly higher BMI than the general population, and patients with choledocholithiasis had significantly higher BMI than patients with simple lithiasis. Elevated BMI is a risk factor for developing choledocholithiasis. ERCP and early laparoscopic cholecystectomy in patients with choledocholithiasis offer equivalent outcomes in patients with simple cholelithiasis.

Mouse models of gallstone disease

PURPOSE OF REVIEW

The establishment of mouse models of gallstones, and the contribution of mouse models to genetic studies of gallstone disease, as well as the latest advances in the pathophysiology of gallstones from mouse experiments are summarized.

RECENT FINDINGS

The combined uses of genomic strategies and phenotypic studies in mice have successfully led to the identification of many Lith genes, which pave the way for the discovery of human LITH genes. The physical-chemical, genetic, and molecular biological studies of gallstone disease in mice with knockout or transgene of specific target genes have provided many novel insights into the complex pathophysiological mechanisms of this very common hepatobiliary disease worldwide, showing that interactions of five primary defects play a critical role in the pathogenesis of cholesterol gallstones. Based on mouse studies, a new concept has been proposed that hepatic hypersecretion of biliary cholesterol is induced by multiple Lith genes, with insulin resistance as part of the metabolic syndrome interacting with cholelithogenic environmental factors to cause the phenotype.

SUMMARY

The mouse model of gallstones is crucial for elucidating the physical-chemical and genetic mechanisms of cholesterol crystallization and gallstone formation, which greatly increase our understanding of the pathogenesis of this disease in humans.

Nonalcoholic fatty liver disease, cholesterol gallstones, and cholecystectomy: new insights on a complex relationship

PURPOSE OF REVIEW

Gallstone disease (GSD) and nonalcoholic fatty liver disease (NAFLD often coexist in a given patient and both conditions are associated to obesity and insulin resistance. The relationship between GSD and NAFLD is complex and bidirectional. In the present review, we summarize the existing information on the complex link between GSD and NAFLD and the potential implications for patient care.

RECENT FINDINGS

Several clinical studies and systematic reviews have addressed the association between NAFLD and GSD underscoring that NAFLD is an independent risk factor for GSD. Conversely, GSD has been found also to be an independent risk factor for NAFLD with GSD potentially being linked to greater disease severity. In addition to the data showing association of NAFLD and GSD, recent evidence has also showed that cholecystectomy may itself be a risk factor for NAFLD development. The complex and bidirectional relationship between these diseases is partially explained by a number of common pathogenic links but the precise underlying mechanisms of the association of GSD and NAFLD need to be better delineated. Also, although the mechanisms of the promotional effect of cholecystectomy on NAFLD development are unknown, recent findings unveiling new aspects of gallbladder physiology and endocrine actions of bile acids provide a framework to advance research in this field.

SUMMARY

In this review, we address the different aspects of the complex association between NAFLD and GSD. The potential underlying mechanisms and recent information on endocrine actions of bile acids and the gallbladder are reviewed.

Nonalcoholic fatty liver disease: Evolving paradigms

In the last years new evidence has accumulated on nonalcoholic fatty liver disease (NAFLD) challenging the paradigms that had been holding the scene over the previous 30 years. NAFLD has such an epidemic prevalence as to make it impossible to screen general population looking for NAFLD cases. Conversely, focusing on those cohorts of individuals exposed to the highest risk of NAFLD could be a more rational approach. NAFLD, which can be diagnosed with either non-invasive strategies or through liver biopsy, is a pathogenically complex and clinically heterogeneous disease. The existence of metabolic as opposed to genetic-associated disease, notably including ”lean NAFLD” has recently been recognized. Moreover, NAFLD is a systemic condition, featuring metabolic, cardiovascular and (hepatic/extra-hepatic) cancer risk. Among the clinico-laboratory features of NAFLD we discuss hyperuricemia, insulin resistance, atherosclerosis, gallstones, psoriasis and selected endocrine derangements. NAFLD is a precursor of type 2 diabetes (T2D) and metabolic syndrome and progressive liver disease develops in T2D patients in whom the course of disease is worsened by NAFLD. Finally, lifestyle changes and drug treatment options to be implemented in the individual patient are also critically discussed. In conclusion, this review emphasizes the new concepts on clinical and pathogenic heterogeneity of NAFLD, a systemic disorder with a multifactorial pathogenesis and protean clinical manifestations. It is highly prevalent in certain cohorts of individuals who are thus potentially amenable to selective screening strategies, intensive follow-up schedules for early identification of liver-related and extrahepatic complications and in whom earlier and more aggressive treatment schedules should be carried out whenever possible.

Increased arterial stiffness in nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND

Arterial function is a marker of early atherosclerotic changes and cardiovascular disease. Several studies have suggested the possible association between nonalcoholic fatty liver disease (NAFLD) and increased arterial stiffness. Thus, we conducted a systematic review and meta-analysis to better characterize this association.

PATIENTS AND METHODS

A comprehensive search of the databases of the MEDLINE and EMBASE was carried out from inception through September 2016. All observational studies that compared arterial stiffness between NAFLD patients and healthy controls were included. Arterial stiffness was measured by pulse wave velocity (PWV) and augmentation index. We calculated pooled mean difference (MD) with 95% confidence intervals (CIs) using the random-effects model.

RESULTS

Data were extracted from 12 studies involving 9351 NAFLD patients and 17 684 controls. NAFLD is significantly associated with increased arterial stiffness as determined by carotid-femoral PWV (MD=0.75 m/s, 95% CI: 0.43-1.07, I=88%), brachial-ankle PWV (MD=0.82 m/s, 95% CI: 0.57-1.07, I=92%), and augmentation index (pooled MD=2.54%, 95% CI: 0.07-5.01, I=73%) compared with healthy controls.

CONCLUSION

In conclusion, our study demonstrated a higher degree of arterial stiffness in NAFLD patients compared with controls. However, this association might be related to the higher prevalence of cardiometabolic risk factors in NAFLD patients. Further studies are needed to determine an independent association between NAFLD and arterial stiffness adjusting to cardiometabolic risks.

Nonalcoholic Fatty Liver Disease Is Not Associated with Thyroid Hormone Levels and Hypothyroidism: A Systematic Review and Meta-Analysis

BACKGROUND

Whether hypothyroidism is related to nonalcoholic fatty liver disease (NAFLD) is unclear. Thyroid dysfunction is closely related with components of metabolic syndrome. Given the hepatic manifestation of metabolic syndrome, several studies have investigated the association between NAFLD and thyroid dysfunction and have demonstrated inconsistent results. Thus, we conducted a systematic review and meta-analysis to better characterize the association between NAFLD and thyroid dysfunction.

METHODS

MEDLINE and Embase were searched through July 2016. The primary outcome was the association between NAFLD and subclinical, overt, and overall hypothyroidism. The secondary outcome was the difference in thyroid hormone levels (free triiodothyronine [FT₃], free thyroxine [FT₄], or thyroid-stimulating hormone [TSH]) between NAFLD patients and non-NAFLD controls. Pooled odds ratios (OR) and 95% CI were calculated using a random-effects model. All continuous data are summarized as the mean difference along with 95% CI.

RESULTS

Data were extracted from 14 studies involving 7,191 NAFLD patients and 30,003 controls. NAFLD was not associated with subclinical, overt, or overall hypothyroidism compared with non-NAFLD controls. Patients who had NAFLD did not show a significant difference in FT₃, FT₄, or TSH compared with non-NAFLD controls.

CONCLUSIONS

Our meta-analysis demonstrates no significant association between NAFLD and subclinical, overt, or overall hypothyroidism, and we also found no significant difference in thyroid hormone levels between participants with and without NAFLD.

Alcohol consumption and risk of gallstone disease: a meta-analysis

Epidemiology studies have been carried out to investigate the association between alcohol consumption and the risk of gallstone disease, but the results remain controversial. We carried out a meta-analysis to quantitatively summarize the evidences from observational studies on alcohol consumption and the risk of gallstone disease. Eligible studies published in English were identified by searching PubMed, Web of Science, and Embase databases. The random-effect model was used to calculate the pooled relative risks (RRs) with 95% confidence intervals (CIs). Restricted cubic splines were used to assess the dose-response relationship. Eight cohort studies and 10 case-control studies were included in our meta-analysis. The pooled RR of gallstone disease for the highest versus the lowest alcohol consumption was 0.62 (95% CI: 0.49-0.78). Statistically significant associations were also found in stratified analysis by study design (cohort studies: RR=0.66, 95% CI: 0.48-0.91 and case-control studies: RR=0.58, 95% CI: 0.45-0.73). With respect to sex, both men (RR=0.57, 95% CI: 0.4-0.8) and women (RR=0.64, 95% CI: 0.53-0.77) showed statistically significant associations between alcohol consumption and the risk of gallstone disease. A linear dose-response relationship was found between alcohol consumption and gallstone disease risk and the risk of gallstone disease decreased by 12% (RR=0.88, 95% CI: 0.84-0.92; Pnonlinearity=0.079) for each 10 g/day increment in alcohol consumption. This meta-analysis suggests that alcohol consumption is associated with significantly decreased risk of gallstone disease.

Gallstone Disease and the Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Observational Studies

OBJECTIVES

Gallstone disease shares certain risk factors with cardiovascular disease, particularly metabolic risk factors. Patients with gallstone disease may be at increased risk of cardiovascular disease. Several recent studies exploring the effect of gallstone disease on cardiovascular disease outcomes demonstrated inconsistent results.

DESIGN

We conducted a systematic review and meta-analysis of cohort, case-control, and cross-sectional studies that compared the risk of developing cardiovascular disease events in patients with gallstone disease versus non-gallstone disease controls. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate the pooled hazard ratio, odd ratio, and 95% confidence interval.

RESULTS

Data were extracted from six studies involving 176,734 cases and 803,714 controls. The pooled hazard ratio of cardiovascular events in patients with gallstone disease was 1.28 (95% confidence interval: 1.23-1.33, I² = 42%). The pooled odd ratio of cardiovascular events in patients with gallstone disease was 1.82 (95% confidence interval: 1.47-2.24, I² = 68%).

CONCLUSIONS

Our study demonstrated a statistically significant increase in the risk of cardiovascular disease among patients with gallstone disease.