Historical Changes in Weight Classes and the Influence of NAFLD Prevalence: A Population Analysis of 34,486 Individuals

Can modulation of gut microbiota affect anthropometric indices in patients with non-alcoholic fatty liver disease? An umbrella meta-analysis of randomized controlled trials

Background and aim

Modulating the gut microbiota population by administration of probiotics, prebiotics, and synbiotics has shown to have a variety of health benefits in different populations, particularly those with metabolic disorders. Although the promising effects of these compounds have been observed in the management of patients with non-alcoholic fatty liver disease (NAFLD), the exact effects and the mechanisms of action are yet to be understood. In the present study, we aimed to evaluate how gut microbiota modulation affects anthropometric indices of NAFLD patients to achieve a comprehensive summary of current evidence-based knowledge.

Methods

Two researchers independently searched international databases, including PubMed, Scopus, and Web of Science, from inception to June 2023. Meta-analysis studies that evaluated the effects of probiotics, prebiotics, and synbiotics on patients with NAFLD were entered into our umbrella review. The data regarding anthropometric indices, including body mass index, weight, waist circumference (WC), and waist-to-hip ratio (WHR), were extracted by the investigators. The authors used random effect model for conducting the meta-analysis. Subgroup analysis and sensitivity analysis were also performed.

Results

A total number of 13 studies were finally included in our study. Based on the final results, BMI was significantly decreased in NAFLD patients by modulation of gut microbiota [effect size (ES): -0.18, 05% CI: -0.25, -0.11, P<0.001]; however, no significant alteration was observed in weight and WC (ES: -1.72, 05% CI: -3.48, 0.03, P=0.055, and ES: -0.24, 05% CI: -0.75, 0.26, P=0.353, respectively). The results of subgroup analysis showed probiotics had the most substantial effect on decreasing BMI (ES: -0.77, 95% CI: -1.16, -0.38, P<0.001) followed by prebiotics (ES: -0.51, 95% CI: -0.76, -0.27, P<0.001) and synbiotics (ES: -0.12, 95% CI: -0.20, -0.04, P=0.001).

Conclusion

In conclusion, the present umbrella meta-analysis showed that although modulation of gut microbiota by administration of probiotics, prebiotics, and synbiotics had promising effects on BMI, no significant change was observed in the WC and weight of the patients. No sufficient data were available for other anthropometric indices including waist-to-hip ratio and waist-to-height ratio and future meta-analyses should be done in this regard.

Association between weight change and risk of liver fibrosis in adults with type 2 diabetes

Background

Liver fibrosis plays a key role in the progression of non-alcoholic fatty liver disease to cirrhosis. Considering weight change is known to be closely associated with increased risk of liver fibrosis, we aimed to address a gap in evidence regarding the existence of this association in patients with type 2 diabetes (T2D).

Methods

We included data on 622 T2D patients and 1618 non-T2D participants from the 2017-2018 cycle of the National Health and Nutrition Examination Survey (NHANES). We assessed liver fibrosis by the median values of liver stiffness measurement (LSM). According to the participants' body mass index (BMI) at age 25 (early adulthood), 10 years prior (middle adulthood), and at the 2017-2018 cycle (late adulthood), we categorised weight change patterns into stable non-obese, weight loss, weight gain, and stable obese. We applied logistic regression to association analysis and used population attributable fraction (PAF) to analyses hypothetical prevention regimens.

Results

The prevalence of liver fibrosis was higher in T2D patients (23.04%) than in non-T2D participants (6.70%), while weight change was associated with a greater risk of fibrosis in the former compared to the latter group. Compared with T2D patients in the stable non-obese group, stable obese individuals from 10 years prior to the 2017-2018 cycle had the highest risk of developing liver fibrosis, corresponding to an adjusted odds ratio (aOR) of 3.13 (95% confidence interval = 1.84-5.48). Absolute weight change patterns showed that the risk of liver fibrosis was highest (aOR = 2.94) when T2D patients gained at least 20 kg of weight from 10 years prior to 2017-2018 cycle.

Conclusions

Obesity in middle and late adulthood is associated with an increased risk of T2D complicated with liver fibrosis.

The Spectrum and Impact of Metabolic Dysfunction in MAFLD: A Longitudinal Cohort Analysis of 32,683 Overweight and Obese Individuals

BACKGROUND

Metabolic associated fatty liver disease (MAFLD) was recently proposed as an alternative name change for better encapsulation of disease. However, there exists a spectrum of MAFLD where both metabolically healthy (MH) and metabolically unhealthy (MU) individuals are included. In view of limited evidence, we sought to examine the prevalence, clinical characteristics, and differences in outcomes of MH-MAFLD at the population level.

METHODS

Data were used from the United States National Health and Nutrition Examination Survey 1999 to 2018. Multivariate logistic regression analysis was used to obtain odds ratios for the estimation of events. Survival analysis was conducted with Cox regression and the Fine-Gray subdistribution model.

RESULTS

There were 32,683 overweight and obese individuals included in the analysis. In MAFLD patients, the prevalence of MH-MAFLD was 6.92% (95% confidence interval [CI], 6.58%-7.27%), and 93.08% (95% CI, 92.73%-93.42%) were considered as MU-MAFLD. Multivariate analysis found a significantly higher risk of MACE (odds ratio, 1.38; 95% CI, 1.28-1.49; P < .01), all-cause (hazard ratio, 1.24; 95% CI, 1.17-1.32; P < .01), cardiovascular disease (SHR, 1.20; 95% CI, 1.02-1.42; P = .03), and cancer mortality (SHR, 1.24; 95% CI, 1.07-1.44; P < .01) in MU-MAFLD relative to non-MAFLD. However, MH-MAFLD individuals were not associated with a statistically significant increased risk of these adverse outcomes compared with non-MAFLD. MU-MAFLD diabetics were also at a higher risk of adverse events compared with non-diabetics.

CONCLUSIONS

This study reports on the heterogeneity and spectrum of metabolic dysfunction that exists in overweight and obese MAFLD. Although MAFLD may potentially be advantageous in improving awareness and patient outcomes, there remains substantial heterogeneity within patients included in MAFLD on the basis of the underlying metabolic burden.

Gender Differences in the Risk for Incident Non-Alcoholic Fatty Liver Disease According to the Transition of Abdominal Obesity Status: A 16-Year Cohort Study

Waist circumference (WC) is an important predictor of long-term adverse outcomes. We aimed at assessing the correlation between abdominal obesity (AO) patterns and non-alcoholic fatty liver disease (NAFLD). Data from 4467 adults aged 40-69 years and without NAFLD who participated in the Korean Genome and Epidemiology Study were analyzed. Participants were classified according to two-year WC pattern into four groups: persistent lean WC, improved AO, progressed to AO, and persistent AO. NAFLD was defined as NAFLD-liver fat score >-0.640. Multiple Cox proportional hazards regression analysis revealed that the fully adjusted hazard ratio (HR) (95% confidence intervals (CIs)) for NAFLD in persistent AO, progressed to AO, and improved AO groups compared to the persistent lean WC group was 1.33 (1.13-1.57), 1.73 (1.48-2.02), and 1.06 (0.84-1.33), respectively. Women in persistent AO or progressed to AO groups had significantly higher risk for NAFLD than those in persistent lean WC or improved AO groups. Men who had progressed to an AO event over two years had significantly higher risk for NAFLD than those without any AO event over two years. Maintaining lean WC and improving AO would be successful strategies for preventing NAFLD in women, while maintaining lean WC would be more effective in men.

Metabolic dysfunction and nonalcoholic fatty liver disease risk in individuals with a normal body mass index

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity, but is also common in individuals with a normal body mass index (BMI), who also experience the hepatic inflammation, fibrosis, and decompensated cirrhosis associated with NAFLD progression. The clinical evaluation and treatment of NAFLD in this patient population are challenging for the gastroenterologist. A better understanding of the epidemiology, natural history, and outcomes of NAFLD in individuals with normal BMI is emerging. This review examines the relationship between metabolic dysfunction and clinical characteristics associated with NAFLD in normal-weight individuals.

RECENT FINDINGS

Despite a more favorable metabolic profile, normal-weight NAFLD patients exhibit metabolic dysfunction. Visceral adiposity may be a critical risk factor for NAFLD in normal-weight individuals, and waist circumference may be better than BMI for assessing metabolic risk in these patients. Although screening for NAFLD is not presently recommended, recent guidelines may assist clinicians in the diagnosis, staging, and management of NAFLD in individuals with a normal BMI.

SUMMARY

Individuals with a normal BMI likely develop NAFLD as a result of different etiologies. Subclinical metabolic dysfunction may be a key component of NAFLD in these patients, and efforts to better understand this relationship in this patient population are needed.

Mortality, Cardiovascular, and Medication Outcomes in Patients With Myocardial Infarction and Underweight in a Meta-Analysis of 6.3 Million Patients

Although most of the current evidence on myocardial infarction focuses on obesity, there is growing evidence that patients who are underweight have unfavorable prognosis. This study aimed to explore the prevalence, clinical characteristics, and prognosis of this population at risk. Embase and Medline were searched for studies reporting outcomes in populations who were underweight with myocardial infarction. Underweight and normal weight were defined according to the World Health Organization criteria. A single-arm meta-analysis of proportions was used to estimate the prevalence of underweight in patients with myocardial infarction, whereas a meta-analysis of proportions was used to estimate the odds ratio of all-cause mortality, medications prescribed, and cardiovascular outcomes. Twenty-one studies involving 6,368,225 patients were included, of whom 47,866 were underweight. The prevalence of underweight in patients with myocardial infarction was 2.96% (95% confidence interval 1.96% to 4.47%). Despite having fewer classical cardiovascular risk factors, patients who were underweight had 66% greater hazard for mortality (hazard ratio 1.66, 95% confidence interval 1.44 to 1.92, p <0.0001). The mortality of patients who were underweight increased from 14.1% at 30 days to 52.6% at 5 years. Nevertheless, they were less likely to receive guideline-directed medical therapy. Relative to subjects with normal weight, Asian populations who were underweight had greater mortality risks than those of their Caucasian counterparts (p = 0.0062). In conclusion, in patients with myocardial infarction, those who were underweight tend to have poorer prognostic outcomes. A lower body mass index is an independent predictor of mortality, which calls for global efforts in addressing this modifiable risk factor in clinical practice guidelines.

The global syndemic of metabolic diseases in the young adult population: A consortium of trends and projections from the Global Burden of Disease 2000-2019

BACKGROUND

A significant proportion of premature deaths globally are related to metabolic diseases in young adults. We examined the global trends and mortality of metabolic diseases in individuals aged below 40 years using data from the Global Burden of Diseases, Injuries and Risk Factors Study (GBD) 2019.

METHODS

From 2000 to 2019, global estimates of deaths and disability-adjusted life years (DALYs) were described for metabolic diseases (type 2 diabetes mellitus [T2DM], hyperlipidemia, hypertension, obesity, non-alcoholic fatty liver disease [NAFLD]). Subgroup analyses were performed based on sex, geographical regions and Socio-Demographic Index (SDI). Age-standardised death and DALYs were presented per 100,000 population with 95 % uncertainty intervals (UI). Projections of mortality and DALYs were estimated using regression models based on the GBD 2019 data and combining them with Institute for Health Metrics and Evaluation projection counts for years up to 2050.

RESULTS

In 2019, the highest age-standardised death rates were observed in hypertension (133·88 [121·25-155·73]), followed by obesity (62·59 [39·92-89·13]), hyperlipidemia (56·51 [41·83-73·62]), T2DM (18·49 [17·18-19·66]) and NAFLD (2·09 [1·61-2·60]). Similarly, obesity (1932·54 [1276·61-2639·74]) had the highest age-standardised DALYs, followed by hypertension (2885·57 [2580·75-3201·05]), hyperlipidemia (1207·15 [975·07-1461·11]), T2DM (801·55 [670·58-954·43]) and NAFLD (53·33 [40·73-68·29]). Mortality rates decreased over time in hyperlipidemia (-0·6 %), hypertension (-0·47 %), NAFLD (-0·31 %) and T2DM (-0·20 %), but not in obesity (1·07 % increase). The highest metabolic-related mortality was observed in Eastern Mediterranean and low SDI countries. By 2050, obesity is projected to contribute to the largest number of deaths (102·8 % increase from 2019), followed by hypertension (61·4 % increase), hyperlipidemia (60·8 % increase), T2DM (158·6 % increase) and NAFLD (158·4 % increase), with males continuing to bear the greatest burden across all metabolic diseases.

CONCLUSION

The growing burden of metabolic diseases, increasing obesity-related mortality trends, and the sex-regional-socioeconomic disparities evident in young adulthood, underlie the concerning growing global burden of metabolic diseases now and in future.

General Public's knowledge, awareness, and perception of Cardiometabolic diseases: data from a Singapore study population

Background

Health literacy and illness perception play crucial roles in tackling the cardiometabolic disease epidemic. We aim to compare the attitudes, knowledge, self-perceived risks and actions taken, between individuals with and without metabolic risk factors (MFs).

Methods

From 5 June to 5 October 2022, participants of the general public were invited to complete a self-administered questionnaire. MF status was defined as the presence of hypertension, hyperlipidemia, diabetes mellitus and/or current/previous smoking. Participants were assessed based on four categories (knowledge-based, attitude-based, perceived risk, and action-based) of questions pertaining to four cardiometabolic diseases - diabetes mellitus, hypertension, hyperlipidemia, and non-alcoholic fatty liver disease.

Results

A total of 345 participants were enrolled, of whom 34.5% had at least one MF. Compared to those without MFs, participants with MFs had lower knowledge scores, but higher perceived risk scores across all cardiometabolic diseases. The largest knowledge gap pertained to hypertension-related questions. After adjustment, linear regression demonstrated that the presence of MFs (β:2.752, 95%CI: 0.772-4.733, p = 0.007) and higher knowledge scores (β:0.418, 95%CI: 0.236-0.600, p < 0.001) were associated with higher perceived risk. Despite increased perceived risk in those with MFs, this translated to only few increased self-reported preventive actions, when compared to those without MFs, namely the reduction in red meat/processed food consumption (p = 0.045) and increase in fruits/vegetables consumption (p = 0.009).

Conclusion

This study identified a vulnerable subpopulation living with MFs, with high perceived risks, and discordant levels of knowledge and preventive actions taken. Nationwide efforts should be channeled into addressing the knowledge-to-action gap.

Diagnostic comparison of vibration-controlled transient elastography and MRI techniques in overweight and obese patients with NAFLD

Non-invasive imaging techniques have greatly advanced the assessment of liver fibrosis and steatosis but are not fully evaluated in overweight patients. We evaluated the diagnostic performance of vibration-controlled transient elastography (VCTE) and magnetic resonance elastography (MRE) to assess fibrosis and controlled attenuation parameter (CAP) and MR imaging (MRI)-proton density fat fraction (MRI-PDFF) to assess steatosis in overweight and obese patients with non-alcoholic fatty liver disease (NAFLD). We included 163 biopsy-proven patients with NAFLD who underwent VCTE, MRE/MRI-PDFF, and liver biopsy (years 2014-2020) who were classified according to their body mass index (BMI) as normal (BMI < 25 kg/m2, n = 38), overweight (25 ≤ BMI < 30 kg/m2, n = 68), and obese (BMI ≥ 30 kg/m2, n = 57). VCTE and MRE detected fibrosis of stages ≥ 2, ≥ 3, and 4 with an area under the receiver operating curve (AUROC) of 0.83-0.94 (VCTE) and 0.85-0.95 (MRE) in all groups, without considerable differences. MRI-PDFF detected steatosis of grades ≥ 2 and 3 with high AUROC in all groups (0.81-1.00). CAP's diagnostic ability (0.63-0.95) was lower than that of MRI-PDFF and decreased with increasing BMI compared to MRI-PDFF. VCTE and MRE similarly accurately assess fibrosis, although MRI-PDFF is more accurate than CAP in detecting steatosis in overweight and obese patients with NAFLD.

DEXA Scan Body Fat Mass Distribution in Obese and Non-Obese Individuals and Risk of NAFLD-Analysis of 10,865 Individuals

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide yet predicting non-obese NAFLD is challenging. Thus, this study investigates the potential of regional fat percentages obtained by dual-energy X-ray absorptiometry (DXA) in accurately assessing NAFLD risk. Using the United States National Health and Nutrition Examination Survey (NHANES) 2011−2018, multivariate logistic regression and marginal analysis were conducted according to quartiles of regional fat percentages, stratified by gender. A total of 23,752 individuals were analysed. Males generally showed a larger increase in marginal probabilities of NAFLD development than females, except in head fat, which had the highest predictive probabilities of non-obese NAFLD in females (13.81%, 95%CI: 10.82−16.79) but the lowest in males (21.89%, 95%CI: 20.12−23.60). Increased percent of trunk fat was the strongest predictor of both non-obese (OR: 46.61, 95%CI: 33.55−64.76, p < 0.001) and obese NAFLD (OR: 2.93, 95%CI: 2.07−4.15, p < 0.001), whereas raised percent gynoid and leg fat were the weakest predictors. Ectopic fat deposits are increased in patients with non-obese NAFLD, with greater increases in truncal fat over gynoid fat. As increased fat deposits in all body regions can increase odds of NAFLD, therapeutic intervention to decrease ectopic fat, particularly truncal fat, may decrease NAFLD risk.

Depression in non-alcoholic fatty liver disease is associated with an increased risk of complications and mortality

Background and aims

The global prevalence of non-alcoholic fatty liver disease (NAFLD) is expected to rise continuously. Furthermore, emerging evidence has also shown the potential for concomitant depression in NAFLD. This study aims to examine the prevalence, risk factors, and adverse events of depression in NAFLD and evaluate whether treated depression can reverse the increased risks of adverse outcomes.

Materials and methods

This study analyses the 2000–2018 cycles of NHANES that examined liver steatosis with fatty liver index (FLI). The relationship between NAFLD and depression was assessed with a generalized linear mix model and a sensitivity analysis was conducted in the no depression, treated depression, and untreated depression groups. Survival analysis was conducted with cox regression and fine gray sub-distribution model.

Results

A total of 21,414 patients were included and 6,726 were diagnosed with NAFLD. The risk of depression in NAFLD was 12% higher compared to non-NAFLD individuals (RR: 1.12, CI: 1.00–1.26, p = 0.04). NAFLD individuals with depression were more likely to be older, females, Hispanics or Caucasians, diabetic, and have higher BMI. Individuals with depression have high risk for cardiovascular diseases (CVD) (RR: 1.40, CI: 1.25–1.58, p < 0.01), stroke (RR: 1.71, CI: 1.27–2.23, p < 0.01), all-cause mortality (HR: 1.50, CI: 1.25–1.81, p < 0.01), and cancer-related mortality (SHR: 1.43, CI: 1.14–1.80, p = 0.002) compared to NAFLD individuals without depression. The risk of CVD, stroke, all-cause mortality, and cancer-related mortality in NAFLD individuals with treated depression and depression with untreated treatment was higher compared to individuals without depression.

Conclusion

This study shows that concomitant depression in NAFLD patients can increase the risk of adverse outcomes. Early screening of depression in high-risk individuals should be encouraged to improve the wellbeing of NAFLD patients.

A poor perspective of self weight significantly increases adverse outcomes in non-alcoholic fatty liver disease (NAFLD)

Background

Non-alcoholic fatty liver disease (NAFLD) is prevalent amongst overweight and obese individuals, and weight loss remains the main mode of treatment for NAFLD patients. Weight perception plays a key role in the efficacy of such treatment. The current study aims to investigate the prevalence, associating factors and implications of poor weight perception amongst such individuals.

Methods

An analysis was done on data collected from NHANES between 1999 and 2018. Comparison was made between NAFLD individuals with and without poor weight perception in terms of prevalence, associated characteristics, and clinical outcomes. Multivariate analysis was used to compare effect size of adverse events associated with NAFLD individuals with poor weight perception.

Results

Of the 12,170 NAFLD patients, 19.2% (CI: 18.5 to 19.9%) had poor weight perception. Poor weight perception was significantly associated with lower education levels, reduced levels of exercise and unhealthier lipid profiles. There was an increased risk in all-cause mortality (HR: 1.18, CI: 1.00 to 1.38, p = 0.047), cardiovascular disease mortality (SHR: 1.33, CI: 1.03 to 1.71, p = 0.026), major adverse cardiovascular events (OR: 1.21 CI: 1.10 to 1.32, p < 0.001), and advanced fibrosis (OR: 1.30, CI: 1.03 to 1.64, p = 0.025) for individuals with poor weight perception.

Conclusion

This study highlights the positive association between appropriate weight perception and better outcomes in individuals with NAFLD. Poor weight perception increased the risk of adverse events and decreased inclination toward seeking weight loss treatment. Greater emphasis should be placed on dealing with weight perception in individuals with NAFLD for better treatment outcomes.