Risk factor compositions of nonalcoholic fatty liver disease change with body mass index in males and females

Depression and NAFLD risk: A meta-analysis and Mendelian randomization study

BACKGROUND

Both depression and nonalcoholic fatty liver disease (NAFLD) have a high global prevalence. Growing evidence suggests an association between depression and NAFLD, while the association remains unclear. Thus, in this study, we aimed to explore the effect of depression on the risk of developing NAFLD.

METHODS

The meta-analysis examined the association between depression and the risk of NAFLD by including observational studies. Relevant studies were searched in PubMed, Embase, the Cochrane Library, and Web of Science. Then a two-sample Mendelian randomization (MR) analysis was performed to explore causal association using genetic instruments identified from a genome-wide association study.

RESULTS

Six eligible studies were included in the meta-analysis, involving 289,22 depression cases among 167,554 participants. Meta-analysis showed a significant association between depression and a higher risk of developing NAFLD (OR = 1.14, 95 % CI: [1.05, 1.24], P = 0.002). However, we found no convincing evidence supporting a causal role of genetically predicted depression with NAFLD risk (OR = 0.861, 95 % CI: [0.598, 1.238], P = 0.420).

LIMITATIONS

The insufficient number of included studies, the use of summary-level data, and restrictions on population sources are the major limiting factors.

CONCLUSIONS

Meta-analysis and MR analysis demonstrated inconsistent results on the relationship between depression and a high risk of developing NAFLD. Specifically, meta-analysis confirmed that depression increases the risk of developing NAFLD, while MR analysis did not support a causal association between genetically determined depression and the risk of NAFLD.

Epidemiology of lean/non-obese nonalcoholic fatty liver disease in China: A systematic review and meta-analysis

OBJECTIVES

To assess the prevalence and metabolic characteristics of lean/non-obese (L/NO) nonalcoholic fatty liver disease (NAFLD) in China.

METHODS

The databses, inlcuding PubMed, Web of Science, EMBASE, as well as Cochrane databases, were retrieved for eligible studies. The prevalence together with clinical features of L/NO-NAFLD in China were analyzed using a random/fixed effects model. Lean or nonobese participants were characterized by the cut-offs of body mass index used in original studies. Heterogeneity was identified using meta-regression and subgroup analyses.

RESULTS

We included 25 studies for the final analysis comprising 229091 L/NO Chinese adults and 22641 diagnosed with NAFLD, with the NAFLD prevalence of 8.98% (95% confidence interval [CI]: [5.55-13.13] for L-NAFLD Chinese participants and 13.77% (95% CI: [11.13-16.63]) for NO-NAFLD Chinese participants. This prevalence gradually increased during the past few years. The community and health checkup populations presented similar prevalence (14.19% vs. 13.55%). Meanwhile, L/NO patients with NAFLD showed lower blood pressure (128.86/80.48 vs. 136.09/84.98 mmHg), waist circumference (80.63 vs. 92.73 cm), fasting blood glucose (5.53 vs. 5.69 mmol/L), uric acid (339.14 vs. 365.46 μmol/L), triglyceride levels (1.63 vs. 1.94 mmol/L), alanine transaminase (30.28 vs. 33.12 IU/L), and γ-glutamyl transferase (29.9 vs. 43.68 IU/L), but higher levels of high-density lipoprotein cholesterol (1.33 vs. 1.26 mmol/L) compared to overweight/obese (OW/O) patients with NAFLD.

CONCLUSION

Prevalence of NAFLD was slightly lower among the L/NO-NAFLD Chinese population than the global level but has obviously increased recently. In addition, the metabolic profile of L/NO-NAFLD patients was generally better compared to OW/O-NAFLD patients.PROSPERO Reg. No.: CRD42022327240.

Epidemiology and prevalence of lean nonalcoholic fatty liver disease and associated cirrhosis, hepatocellular carcinoma, and cardiovascular outcomes in the United States: a population-based study and review of literature

BACKGROUNDS

Nonalcoholic fatty liver disease (NAFLD) is linked to obesity and metabolic syndrome conditions. However, a subset of NAFLD patients express a normal or low body mass index (lean NAFLD [L-NAFLD]). Our aim is to compare the prevalence of L-NAFLD to the obesity-associated NAFLD in the United States by assessing prevalence, potential risk factors, liver-related complications, and coronary artery disease outcomes.

METHODOLOGY

A multicenter database (Explorys Inc.) of >70 million patients across the United States was screened. A cohort of patients with "nonalcoholic fatty liver" between 1999 and 2021 was identified. Two sub-cohorts of NAFLD patients were identified: those with a body mass index (BMI) < 25 kg/m² (L-NAFLD) and those with a BMI > 30 kg/m² (obesity-associated NAFLD). We excluded patients with age <18 and those who have viral hepatitis, hemochromatosis, Wilson's disease, biliary cirrhosis, alcoholic liver disease, cystic fibrosis, alpha-1-antitrypsin deficiency, and autoimmune hepatitis. Multivariate analysis was performed to adjust for confounders.

RESULTS

68 892 260 individuals were screened. NAFLD prevalence was four per 100 000, and L-NAFLD prevalence was 0.6 per 100 000. Compared with those without, patients with L-NAFLD tended to be older (OR 2.16), females (OR 1.28), and smokers (OR 4.67) and of Asian race (OR 2.12). L-NAFLD patients were more likely to have acute coronary syndromes (OR 30.00) and metabolic syndrome (OR 2.31) despite the normal/low BMI. Esophageal varices and hepatocellular carcinoma risks were high in both cirrhosis patients.

CONCLUSION

This is the largest study to assess L-NAFLD prevalence in the United States. L-NAFLD are at a significantly higher risk for acute coronary syndromes, esophageal varices, and hepatocellular carcinoma.

Risk Prevention and Health Promotion for Non-Alcoholic Fatty Liver Diseases (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a serious clinicopathological condition that is recognized as the most frequent chronic liver disease, affecting 14–30% of the world’s population. The prevalence of NAFLD has rapidly grown and is correlated with the growth in obesity and type 2 diabetes, among other factors. NAFLD often results in long-term complications including cardiovascular disease, liver cirrhosis, and liver fibrosis. This paper provides an updated overview of NAFLD with a focus on epidemiology, etiology, pathophysiology, screening, complications, and pharmacological therapies to identify effective risk prevention and health promotion.

Clinical and Laboratory Characteristics of Normal Weight and Obese Individuals with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has had, over the past few decades, a progressively growing prevalence among the general population all over the world, in parallel with metabolic conditions such as type 2 diabetes mellitus (T2DM), dyslipidemia, and obesity. However, NAFLD is also detected in 10−13% of subjects with a body mass index (BMI) ≤ 25 kg/m² (lean-NAFLD), whose major risk factors remain unknown. In this study, we aimed to characterize the clinical features and associated risk factors of lean-NAFLD in comparison with obese-NAFLD patients. Consecutive patients diagnosed with NAFLD by vibration-controlled transient elastography and controlled attenuation parameter were prospectively enrolled. Biological and clinical data obtained from the participants were stratified according to their BMI in two groups: lean-NAFLD and obese-NAFLD. In total, 331 patients (56.8% males) were included in the final analysis. Most of the subjects were obese-NAFLD (n = 258, 77.9%) and had a higher prevalence of T2DM, dyslipidemia, and components of the metabolic syndrome, together with abnormal biological parameters. Regarding liver stiffness measurements, the proportion of subjects with at least significant fibrosis (≥F2) was approximately twofold higher among obese-NAFLD (43.81%) in comparison with lean-NAFLD patients (23.29%). Moreover, obese individuals had a higher risk for liver fibrosis (OR = 2.6, 95%, CI 1.5−4.42, p < 0.001) than lean individuals. Although associated metabolic conditions and at least significant liver fibrosis were present in approximately one-quarter of the patients, these were more frequent among obese-NAFLD patients. Therefore, individualized screening strategies for NAFLD should be established according to BMI.

NAFLD in normal weight individuals

Nonalcoholic fatty liver disease (NAFLD) can develop in lean individuals. Despite a better metabolic profile, the risk of disease progression to hepatic inflammation, fibrosis, and decompensated cirrhosis in the lean is similar to that in obesity-related NAFLD and lean individuals may experience more severe hepatic consequences and higher mortality relative to those with a higher body mass index (BMI). In the absence of early symptoms and abnormal laboratory findings, lean individuals are not likely to be screened for NAFLD or related comorbidities; however, given the progressive nature of the disease and the increased risk of morbidity and mortality, a clearer understanding of the natural history of NAFLD in lean individuals, as well as efforts to raise awareness of the potential health risks of NAFLD in lean individuals, are warranted. In this review, we summarize available data on NAFLD prevalence, clinical characteristics, outcomes, and mortality in lean individuals and discuss factors that may contribute to the development of NAFLD in this population, including links between dietary and genetic factors, menopausal status, and ethnicity. We also highlight the need for greater representation of lean individuals in NAFLD-related clinical trials, as well as more studies to better characterize lean NAFLD, develop improved screening algorithms, and determine specific treatment strategies based on underlying etiology.

Comparison and development of advanced machine learning tools to predict nonalcoholic fatty liver disease: An extended study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a public health challenge and significant cause of morbidity and mortality worldwide. Early identification is crucial for disease intervention. We recently proposed a nomogram-based NAFLD prediction model from a large population cohort. We aimed to explore machine learning tools in predicting NAFLD.

METHODS

A retrospective cross-sectional study was performed on 15 315 Chinese subjects (10 373 training and 4942 testing sets). Selected clinical and biochemical factors were evaluated by different types of machine learning algorithms to develop and validate seven predictive models. Nine evaluation indicators including area under the receiver operating characteristic curve (AUROC), area under the precision-recall curve (AUPRC), accuracy, positive predictive value, sensitivity, F1 score, Matthews correlation coefficient (MCC), specificity and negative prognostic value were applied to compare the performance among the models. The selected clinical and biochemical factors were ranked according to the importance in prediction ability.

RESULTS

Totally 4018/10 373 (38.74%) and 1860/4942 (37.64%) subjects had ultrasound-proven NAFLD in the training and testing sets, respectively. Seven machine learning based models were developed and demonstrated good performance in predicting NAFLD. Among these models, the XGBoost model revealed the highest AUROC (0.873), AUPRC (0.810), accuracy (0.795), positive predictive value (0.806), F1 score (0.695), MCC (0.557), specificity (0.909), demonstrating the best prediction ability among the built models. Body mass index was the most valuable indicator to predict NAFLD according to the feature ranking scores.

CONCLUSIONS

The XGBoost model has the best overall prediction ability for diagnosing NAFLD. The novel machine learning tools provide considerable beneficial potential in NAFLD screening.

Association between consumption of edible seaweeds and newly diagnosed non-alcohol fatty liver disease: The TCLSIH Cohort Study

BACKGROUND & AIMS

Seaweeds are rich sources of anti-oxidants and anti-inflammatory properties, which are beneficial to non-alcoholic fatty liver disease (NAFLD). However, whether seaweed consumption is associated with NAFLD is unknown. We investigated the association of seaweed consumption with newly diagnosed NAFLD in a large-scale adult population.

METHODS

This cross-sectional study involved 24 572 participants aged over 18 years. NAFLD was diagnosed by results of liver ultrasonography and alcohol intake. Dietary information was assessed using a validated and standardized 100-item food frequency questionnaire. Multivariate logistic analysis was used to evaluate the association between seaweed consumption and NAFLD.

RESULTS

The prevalence of newly diagnosed NAFLD was 20.1%. After adjustment for sociodemographic characteristics, lifestyle factors, and other dietary intakes, the multivariable adjusted odds ratios (95% confidence intervals) of newly diagnosed NAFLD across seaweed consumption were 1.00 (reference) for almost never, 1.03 (0.93, 1.15) for <1 time/wk, 1.01 (0.90, 1.13) for 1 time/wk, and 0.84 (0.73, 0.96) for >1 times/wk (P for trend < .001). Stratified analyses suggested a potential effect modification by obesity status; the odds ratios (95% confidence intervals) across extreme quartiles was 0.77 (0.66, 0.91) in non-obese participants and 1.02 (0.79, 1.33) in obese participants (P for interaction < .001).

CONCLUSION

Seaweed consumption is negatively associated with NAFLD, especially in non-obese participants.

Ultrasonographic Features Associated with Diffuse Hepatosteatosis among Diabetic Obese and Normal Body Mass Index Patients

BACKGROUND

The purpose of the study is to evaluate and compare the changes associated with hepatosteatosis in diabetic obese versus diabetic normal-weight patients through ultrasonography. It is estimated that with the prevalence of about 30%-75% of obese individuals accordingto the body mass index (BMI) criteria are at increase risk of developing simple fatty live. Besides obesity, diabetes mellitus is also considered to be one of the important causes of hepatosteatosis.

METHODS

This prospective study was conducted in February 2015-December 2015 on a group of 181 diabetic patients, including 65 males and 116 females with an age range of 40-80 years. The patients were divided into two diabetic groups: those having a BMI ≥30 kg/m2 were included in the obese group (n = 116) and those with a BMI of 18.5-25 kg/m2 were included in the normal BMI group (n = 65). Ultrasound machine Esaote MyLab 50 equipped with a 3.5-5 MHz curvilinear multifrequency transducer was used to scan the liver. Independent samples t-test was performed to compare the liver span in the two groups. Chi-square tests were applied to compare the frequencies of fatty changes, border, and surface characteristics.

RESULTS

The presence of fatty changes among obese groups was statistically significant in the diabetic obese group compared to the normal-weight individuals with P < 0.0001. Similarly, hepatic spans were found to be significantly greater in the diabetic obese group than the diabetic normal BMI group on independent samples t-test with P < 0.0001. Females were seen to develop hepatosteatosis more frequently compared to males in all diabetic individuals with P = 0.02.

CONCLUSION

It is concluded that diabetic obese patients are more prone to develop hepatosteatosis as compared to normal BMI diabetic individuals.

Rescue of Hepatic Phospholipid Remodeling Defectin iPLA2β-Null Mice Attenuates Obese but Not Non-Obese Fatty Liver

Polymorphisms of group VIA calcium-independent phospholipase A2 (iPLA₂β or PLA2G6) are positively associated with adiposity, blood lipids, and Type-2 diabetes. The ubiquitously expressed iPLA₂β catalyzes the hydrolysis of phospholipids (PLs) to generate a fatty acid and a lysoPL. We studied the role of iPLA₂β on PL metabolism in non-alcoholic fatty liver disease (NAFLD). By using global deletion iPLA₂β-null mice, we investigated three NAFLD mouse models; genetic Ob/Ob and long-term high-fat-diet (HFD) feeding (representing obese NAFLD) as well as feeding with methionine- and choline-deficient (MCD) diet (representing non-obese NAFLD). A decrease of hepatic PLs containing monounsaturated- and polyunsaturated fatty acids and a decrease of the ratio between PLs and cholesterol esters were observed in all three NAFLD models. iPLA₂β deficiency rescued these decreases in obese, but not in non-obese, NAFLD models. iPLA₂β deficiency elicited protection against fatty liver and obesity in the order of Ob/Ob › HFD » MCD. Liver inflammation was not protected in HFD NAFLD, and that liver fibrosis was even exaggerated in non-obese MCD model. Thus, the rescue of hepatic PL remodeling defect observed in iPLA₂β-null mice was critical for the protection against NAFLD and obesity. However, iPLA₂β deletion in specific cell types such as macrophages may render liver inflammation and fibrosis, independent of steatosis protection.

Global prevalence, incidence, and outcomes of non-obese or lean non-alcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND

Although non-alcoholic fatty liver disease (NAFLD) is commonly associated with obesity, it is increasingly being identified in non-obese individuals. We aimed to characterise the prevalence, incidence, and long-term outcomes of non-obese or lean NAFLD at a global level.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Embase, Scopus, and the Cochrane Library from inception to May 1, 2019, for relevant original research articles without any language restrictions. The literature search and data extraction were done independently by two investigators. Primary outcomes were the prevalence of non-obese or lean people within the NAFLD group and the prevalence of non-obese or lean NAFLD in the general, non-obese, and lean populations; the incidence of NAFLD among non-obese and lean populations; and long-term outcomes of non-obese people with NAFLD. We also aimed to characterise the demographic, clinical, and histological characteristics of individuals with non-obese NAFLD.

FINDINGS

We identified 93 studies (n=10 576 383) from 24 countries or areas: 84 studies (n=10 530 308) were used for the prevalence analysis, five (n=9121) were used for the incidence analysis, and eight (n=36 954) were used for the outcomes analysis. Within the NAFLD population, 19·2% (95% CI 15·9-23·0) of people were lean and 40·8% (36·6-45·1) were non-obese. The prevalence of non-obese NAFLD in the general population varied from 25% or lower in some countries (eg, Malaysia and Pakistan) to higher than 50% in others (eg, Austria, Mexico, and Sweden). In the general population (comprising individuals with and without NAFLD), 12·1% (95% CI 9·3-15·6) of people had non-obese NAFLD and 5·1% (3·7-7·0) had lean NAFLD. The incidence of NAFLD in the non-obese population (without NAFLD at baseline) was 24·6 (95% CI 13·4-39·2) per 1000 person-years. Among people with non-obese or lean NALFD, 39·0% (95% CI 24·1-56·3) had non-alcoholic steatohepatitis, 29·2% (21·9-37·9) had significant fibrosis (stage ≥2), and 3·2% (1·5-5·7) had cirrhosis. Among the non-obese or lean NAFLD population, the incidence of all-cause mortality was 12·1 (95% CI 0·5-38·8) per 1000 person-years, that for liver-related mortality was 4·1 (1·9-7·1) per 1000 person-years, cardiovascular-related mortality was 4·0 (0·1-14·9) per 1000 person-years, new-onset diabetes was 12·6 (8·0-18·3) per 1000 person-years, new-onset cardiovascular disease was 18·7 (9·2-31·2) per 1000 person-years, and new-onset hypertension was 56·1 (38·5-77·0) per 1000 person-years. Most analyses were characterised by high heterogeneity.

INTERPRETATION

Overall, around 40% of the global NAFLD population was classified as non-obese and almost a fifth was lean. Both non-obese and lean groups had substantial long-term liver and non-liver comorbidities. These findings suggest that obesity should not be the sole criterion for NAFLD screening. Moreover, clinical trials of treatments for NAFLD should include participants across all body-mass index ranges.

FUNDING

None.

The Prevalence of Lean/Nonobese Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIM

The prevalence of lean/nonobese nonalcoholic fatty liver disease (NAFLD) ranges widely in studies. Thus, here, we aimed to perform a meta-analysis on NAFLD prevalence in the lean or nonobese population to give clarity.

MATERIALS AND METHODS

PubMed, Embase, and the Cochrane Library databases were systematically searched to identify studies reporting NAFLD prevalence in the lean/nonobese population. Lean or nonobese was defined by body mass index cutoffs reported by authors in original studies. NAFLD prevalence based on community, population, or health checkups was combined with random-effect model after logit transformation. Subgroup analysis and meta-regression were further performed to investigate the heterogenicity.

RESULTS

A total of 45 studies were enrolled in the final analysis, with 55,936 lean/nonobese subjects included, among whom 7351 NAFLD patients were diagnosed. Overall, the pooled NAFLD prevalence of the lean or nonobese population was 10.2% (95% confidence interval: 7.6%-13.6%) and 15.7% (95% confidence interval: 12.5%-19.6%), respectively. Compared with western studies, the NAFLD prevalence in the lean or nonobese population was lower in eastern studies. In addition, the NAFLD prevalence in both the lean and nonobese population showed a general upward trend during recent years. The prevalence was similar in community-based and health checkup-based studies. Lean/nonobese NAFLD patients had significantly lower rates of hypertension, lower uric acid and fasting plasma glucose, and a higher level of high-density lipoprotein than nonlean/obese patients.

CONCLUSIONS

The prevalence of NAFLD in the lean/nonobese population is not rare in either the western or eastern regions of the world. This meta-analysis of prevalence assessment and clinical characteristics should enable higher confidence in more specific interventions and health care standards for these patients.

Predictors of non-alcoholic fatty liver disease (NAFLD) among children with obesity

Background The prevalence of childhood obesity and its related comorbidities in Malaysia are alarming. Malaysia ranked second in childhood obesity among South-east Asian countries with a prevalence of 12.7%. This study was conducted to investigate the prevalence of non-alcoholic fatty liver disease (NAFLD) among obese children and to ascertain the predictors associated with NAFLD. Methods NAFLD was diagnosed via ultrasonographic evidence of fatty liver in obese and overweight children who presented to the Paediatric Obesity Clinic of University Malaya Medical Centre (UMMC), Malaysia. Demographic, anthropometric, clinical and biochemical parameters were analysed and compared between the NAFLD and non-NAFLD groups. Statistical analyses were carried out. Results Twenty-one out of 33 obese and overweight children (63.6%) were found to have NAFLD. We found that 62% of our study population in the NAFLD group had metabolic syndrome based on the definition by the International Diabetes Federation (IDF). Mean body mass index (BMI), waist circumference (WC), triglyceride (TG) and alanine aminotransferase (ALT) were found to be significantly greater in the NAFLD group compared to the non-NAFLD group (35.2 [6.1] vs. 29.3 [4.7] kg/m2 [p-value 0.007]; 104.1 [11.4] vs. 94.1 [12] cm [p-value 0.034]; 1.5 [0.9] vs. 0.9 [0.3] mmol/L [p-value 0.002]; 60.7 [53.8] vs. 27.3 [13] U/L [p-value 0.007]). Multivariate regression analysis revealed TG as the independent predictor for NAFLD, with an odds ratio of 41.7 (95% confidence interval [CI] 0.001, 0.819) (p-value 0.04). Conclusions Prevalence of NAFLD among children who are obese and overweight is alarming with 62% having metabolic syndrome. TG was found to be a strong predictor for NAFLD.

Sex, Age, and BMI Modulate the Association of Physical Examinations and Blood Biochemistry Parameters and NAFLD: A Retrospective Study on 1994 Cases Observed at Shuguang Hospital, China

Objective

Previous studies have shown that some metabolic risk factors are related to nonalcoholic fatty liver disease (NAFLD). This retrospective study was performed to investigate the associations between physical examinations and blood biochemistry parameters and NAFLD status and to identify possible risk factors of NAFLD.

Methods

Study participants underwent general physical examinations, blood biochemistry, and abdominal ultrasound evaluations. In addition, data regarding sex, age, ethnicity, medical history, and alcohol consumption of participants were recorded. Among the study participants (N=1994), 57.8% were male, 41.2% over the age of 50, and 52.6% with BMI≥24. 986 patients had NAFLD and 1008 had no NAFLD. We used effect size analysis and logistic regression to determine which physical examinations and blood biochemistry parameters were significant for the association between these parameters and NAFLD status.

Results

Both the effect size and logistic regression indicated that BMI, diastolic blood pressure (DBP), triglycerides (TG), and serum uric acid (SUA) show a significant association with NAFLD. Females are overall at a higher risk of NAFLD, but factors such as high BMI, DBP, TG, and SUA increase the associated risk for both sexes. Compared with males, females have a higher risk of NAFLD given that they are over 50, overweight and obese (BMI at or over 24), or have high SUA. In terms of age, people older than 50 with high SUA, and people younger than 50 with high DBP and low-density lipoprotein cholesterol (LDL-C) all increase the risk of NAFLD. For BMI, high DBP and low high-density lipoprotein cholesterol (HDL-C) are risk factors for NAFLD in overweight and obese people (BMI at or over 24), whereas in normal weight and underweight people (BMI under 24), elevated LDL-C increases the risk of NAFLD.

Conclusions

Our results revealed sex, age, and BMI modulate the association of physical examinations and blood biochemistry parameters and NAFLD, which may facilitate the development of personalized early warning and prevention strategies of NAFLD for at-risk populations.

Association between body mass index and fatty liver risk: A dose-response analysis

Body mass index (BMI) is associated with fatty liver risk, however, the dose-response relationship between continuous BMI changes and fatty liver risk has not been clearly defined. In this study, a cross-sectional study was conducted and a total of 3202 individuals were included. Unconditional logistic regression and restricted cubic spline model were used to analyze the dose-response association of BMI with fatty liver risk. After adjusting for confounding factors (age, gender, hypertension, total cholesterol, triglycerides, glucose, high-density lipoprotein, low-density lipoprotein, uric acid, homocysteine, creatinine, aspartate aminotransferase and alanine transaminase), overweight (OR = 3.55, 95% CI: 2.49–5.06, P = 2.79 × 10⁻¹²), obesity (OR = 7.59, 95% CI: 4.91–11.71, P = 6.56 × 10⁻²⁰) were significantly related to fatty liver risk. Stratified by gender (male/female), age (<50 years/≥50 years), prevalence of hypertension (yes/no), the above association was still significant (P = 0.004 or lower). In dose-response analysis, BMI was statistically significantly associated with fatty liver risk in a nonlinear fashion (approximately J-shaped fashion, P_nonlinearity = 1.71 × 10⁻⁴ or lower) in the total population and all subgroups mentioned above. Findings from this dose-response analysis suggest that higher BMI (overweight/obesity) is an independent, dose-dependent risk factor for fatty liver, and prevention of fatty liver focusing on continuous changes in BMI should be noted.

The role of anthropometric indices in the prediction of non-alcoholic fatty liver disease in the PERSIAN Guilan Cohort study (PGCS)

Introduction: Non-alcoholic fatty liver disease (NAFLD) is an obesity-associated health problem that causes other liver diseases for the patient. Four anthropometric indices: body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were analyzed as NAFLD predictors in the present study. Methods: From the total number of individuals who referred to the PERSIAN Guilan Cohort study (PGCS) located in the north of Iran during the period of study, a total of 960 people were enrolled in the present study. NAFLD was diagnosed using through an abdominal ultrasound exam. Height, weight, WC, BMI, WHR and WHtR were later calculated. Chi-square, ANOVA and logistic regression analyses were used to analyze the risk factors. Results: Out of the 960 individuals who were enrolled in the study, 597 (62.2%) were male and 363 (37.8%) were female (with an average age of 47.21 ± 7.29 years). There was a significant relationship between weight and NAFLD (P<0.001). There was also a significant relationship between BMI (OR= 8.41; 95% CI = 5.59-12.75), WC (OR= 2.67; 95% CI = 2.05-3.48), WHR (OR= 3.84; 95% CI = 2.26-6.52), WHtR (OR= 28.53; 95% CI = 6.94-117.31) and NAFLD (P<0.001). The results of the logistic regression analysis showed that WHtR, BMI and WC were effective predictors for the risk of NAFLD while WHtR played a more important role in the prediction of NAFLD. Conclusion: Anthropometric indices, especially WHtR, as a simple screening tool, seem to be an important criterion for the detection of NAFLD.