Non-alcoholic fatty liver disease and the risk of dementia: A meta-analysis of cohort studies

Fatty liver index as an independent predictor of all-cause and disease-specific mortality

PURPOSE

This study aims to assess the prognostic value of the fatty liver index (FLI), a noninvasive tool for hepatic steatosis assessment, in predicting all-cause and disease-specific mortality.

METHODS

We linked data from the National Health and Nutrition Examination Survey III (1988-1994) with Public-Use Mortality Files, forming a cohort of 11 297 participants with a median follow-up period of 26.25 years. Cox proportional hazards models were used to evaluate the association between FLI and all-cause mortality, while Fine and Gray's models assessed the relationship between FLI and disease-specific mortality.

RESULTS

The FLI ≥ 60 was independently associated with an increased risk of all-cause mortality (hazard ratio = 1.24, P  < 0.001), as well as mortality from malignant neoplasms (hazard ratio = 1.18, P  = 0.048), diabetes (hazard ratio = 2.62, P  = 0.001), and cardiovascular diseases (CVDs) (hazard ratio = 1.18, P  = 0.018), compared to FLI < 30. No significant associations were found with Alzheimer's disease, influenza and pneumonia, chronic lower respiratory diseases, or renal disorders. Subgroup analyses indicated that individuals who were females aged 40-60 (hazard ratio = 1.67, P  = 0.003), non-overweight (hazard ratio = 1.75, P  = 0.007), or without abdominal obesity (hazard ratio = 1.75, P  = 0.007) exhibited a stronger association between FLI ≥ 60 and all-cause mortality.

CONCLUSION

These findings support the prognostic value of the FLI for predicting mortality from all causes, malignant neoplasms, diabetes, and CVDs. Targeted attention is needed in postmenopausal women, non-overweight, and non-abdominally obese populations.

Digestive System Diseases, Genetic Risk, and Incident Dementia: A Prospective Cohort Study

INTRODUCTION

Although digestive system disease affects gut microbiota and their metabolites associated with dementia risk, the association between digestive system diseases and incident dementia has not yet been established.

METHODS

This cohort analysis included 458,181 participants free of baseline dementia in the UK Biobank (2006-2021). The associations of 14 digestive system diseases with dementia incidence were examined in 2022 using Cox proportional hazards regression models. Analyses were performed to differentiate the associations for early-onset (age <65 years) and late-onset (age ≥65 years) dementia. Interaction and stratification analyses were performed for polygenic risk score and APOE.

RESULTS

During a median follow-up of 12.4 years, 6,415 incident dementia cases were diagnosed. Eleven digestive system diseases showed significant associations with an increased risk of dementia after controlling for covariates and multiple testing. Compared with hazard ratios for individuals without digestive system diseases, the hazard ratios of dementia increased from 1.15 (95% confidence interval=1.09, 1.23) for patients with intestinal diverticular disease to 2.31 (95% confidence interval=1.98, 2.70) for patients with cirrhosis. The associations were different between certain digestive system diseases and dementia by onset age. The associations appeared to be stronger for cirrhosis (Q=0.001), irritable bowel syndrome (Q<0.001), gastritis and duodenitis (Q=0.002), gastroesophageal reflux disease (Q<0.001), ulcerative colitis (Q=0.047), gallbladder disease (Q=0.012), and peptic ulcer (Q=0.030) with early-onset dementia. There were no interactions for polygenic risk score or APOE (p>0.05).

CONCLUSIONS

These findings suggest an increased need for dementia prevention among patients with digestive system diseases.

Risk Stratification for Sarcopenic Obesity in Subjects With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

The impact of the severity of sarcopenic obesity (SO) in nonalcoholic fatty liver disease (NAFLD) on the risk of significant liver fibrosis or cardiovascular disease (CVD) remains unclear. We aimed to identify high-risk subjects with SO for significant liver fibrosis or CVD among subjects with SO and NAFLD.

METHODS

This multicenter, retrospective study involved 23,889 subjects with NAFLD who underwent a health screening program (2014-2020). Sarcopenia was defined based on gender-specific sarcopenia index cutoff using multi-frequency bioelectric impedance analysis. High-risk subjects with SO were defined as those with significant liver fibrosis by fibrosis-4 index >2.67 or atherosclerotic CVD risk score >20%. Multivariable logistic regression analysis for identifying high-risk subjects with SO was performed in a cross-sectional cohort with SO, and further validation was performed in a longitudinal cohort.

RESULTS

SO prevalence was 5.4% (n = 1297 of 23,889). Older age (unstandardized beta [β] = 3.23; P < .001), male (β = 1.66; P = .027), sarcopenia index (β = -6.25; P = .019), and metabolic syndrome (β = 1.75; P < .001) were significant risk factors for high-risk SO. Based on a high-risk SO screening model, high-risk subjects with SO had significantly higher odds of significant liver fibrosis (training: adjusted odds ratio [aOR], 3.72; validation: aOR, 2.38) or CVD (training: aOR, 5.20; validation: aOR, 3.71) than subjects without SO (all P < .001). In subgroup analyses, the cumulative incidence of significant liver fibrosis or CVD development was significantly higher in high-risk subjects with SO than in low-risk subjects with SO in a longitudinal cohort considering all-cause mortality and liver transplantation as competing risks (sub-distribution hazard ratio, 5.37; P < .001).

CONCLUSION

The high-risk screening model may enable the identification of high-risk subjects with SO with NAFLD.

The association between regional adiposity, cognitive function, and dementia-related brain changes: a systematic review

Background

Adiposity has been previously associated with cognitive impairment and Alzheimer's disease and related disorders (ADRD). Body mass index (BMI) is the most common measure of global adiposity, but inconsistent results were found since it is a global measurement. BMI does not represent regional fat distribution which differs between sexes, race, and age. Regional fat distribution may contribute differently to cognitive decline and Alzheimer's disease (AD)-related brain changes. Fat-specific targeted therapies could lead to personalized improvement of cognition. The goal of this systematic review is to explore whether regional fat depots, rather than central obesity, should be used to understand the mechanism underlying the association between adiposity and brain.

Methods

This systematic review included 33 studies in the English language, conducted in humans aged 18 years and over with assessment of regional adiposity, cognitive function, dementia, and brain measures. We included only studies that have assessed regional adiposity using imaging technics and excluded studies that were review articles, abstract only or letters to editor. Studies on children and adolescents, animal studies, and studies of patients with gastrointestinal diseases were excluded. PubMed, PsychInfo and web of science were used as electronic databases for literature search until November 2022.

Results

Based on the currently available literature, the findings suggest that different regional fat depots are likely associated with increased risk of cognitive impairment, brain changes and dementia, especially AD. However, different regional fat depots can have different cognitive outcomes and affect the brain differently. Visceral adipose tissue (VAT) was the most studied regional fat, along with liver fat through non-alcoholic fatty liver disease (NAFLD). Pancreatic fat was the least studied regional fat.

Conclusion

Regional adiposity, which is modifiable, may explain discrepancies in associations of global adiposity, brain, and cognition. Specific regional fat depots lead to abnormal secretion of adipose factors which in turn may penetrate the blood brain barrier leading to brain damage and to cognitive decline.

NAFLD does not increase the risk of incident dementia: A prospective study and meta-analysis

The association between nonalcoholic fatty liver disease (NAFLD) and incident dementia remains unclear. This study aimed to explore whether NAFLD was associated with the risk of incident dementia. We conducted a prospective analysis of 179,222 UK Biobank participants. NAFLD was diagnosed based on the fatty liver index. Cox proportional hazards models were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI) of NAFLD for incident dementia. The results from this and six previous prospective studies were combined in meta-analyses. During a median follow-up of 12.4 years (2,149,839 person-years), 4950 incident dementia cases, including 2318 Alzheimer's disease (AD) cases and 1135 vascular dementia (VD) cases, were identified. There was no significant association between NAFLD and the risks of all-cause dementia (HR: 0.97, 95% CI: 0.90-1.06; P = 0.528). NAFLD was also not significantly associated with AD or VD (HR: 0.95, 95% CI: 0.84-1.07, P = 0.401; HR: 1.03, 95% CI: 0.88-1.22, P = 0.689, respectively). Our meta-analyses of prospective studies included 879,749 subjects. The pooled HR of NAFLD for all-cause dementia was 1.01 (95% CI: 0.94-1.08), and that for VD was 0.99 (95% CI: 0.86-1.13). All included cohort studies were of high quality as assessed by the Newcastle‒Ottawa scale. We found no evidence of an association between NAFLD and incident dementia.

The Relationship between Cancer and Dementia: An Updated Review

The risk of cancer and dementia increases with age, raising complex questions about whether it is appropriate to continue cancer treatment in older patients. There is emerging research suggesting the association between cancer and dementia. However, the mechanistic underpinnings are still under investigation. Progress has already been made toward understanding the cognitive effects associated with cancer therapy. Such associations raise awareness about the need to establish better prevention methods and early screening in clinical practice. Additionally, recent studies have suggested possible therapeutic strategies for better preserving cognitive function and reducing the risk for dementia before patients start cancer treatment. We review the current literature and summarize the incidence and mechanisms of cognitive impairment in patients with lung cancer, breast cancer, head and neck cancer, gastric cancer, prostate cancer, colorectal cancer, and brain tumor/brain metastasis following different kinds of therapies. Possible risk factors are suggested to identify the early onset of cognitive changes in cancer patients and provide more insight into the pathophysiological process of dementia.