Impaired lung function is associated with non-alcoholic fatty liver disease independently of metabolic syndrome features in middle-aged and elderly Chinese

Is type 2 diabetes a link between lung function and metabolic dysfunction-associated steatotic liver disease? Insights from population studies and Mendelian randomization

AIM

This study aimed to investigate the relationship between lung function and metabolic dysfunction-associated steatotic liver disease (MASLD), and the potential mediating role of type 2 diabetes.

METHODS

Data from the 2007 to 2012 National Health and Nutrition Examination Survey were used. Logistic regression analysis was employed to assess the association between lung function parameters [forced vital capacity (FVC), forced expiratory volume in 1 s (FEV 1 ), FEV 1 /FVC] and MASLD prevalence while exploring type 2 diabetes mediation. Further analyses included linkage disequilibrium score regression, Mendelian randomization, and meta-analysis to examine the causal relationship between lung function and MASLD, considering type 2 diabetes mediation.

RESULTS

The results showed that higher FVC and FEV 1 levels were associated with decreased MASLD risk, with type 2 diabetes partially mediating this relationship. Genetic analyses supported a causal link between lung function and MASLD, with type 2 diabetes acting as an intermediary. However, no significant association was found between FEV 1 /FVC and MASLD.

CONCLUSION

The study identified a causal relationship between lung function and MASLD, with type 2 diabetes playing a partial mediating role.

Inverse association between lung function and nonalcoholic fatty liver disease: An observational and mendelian randomization study

BACKGROUND AND AIM

The association between lung function with non-alcoholic fatty liver disease (NAFLD) in the general population remains unknown. We aimed to examine the association between lung function and NAFLD among the general population in an observational and Mendelian randomization (MR) study.

METHODS AND RESULTS

340, 253 participants without prior liver diseases were included from the UK Biobank. Of these, 30,397 participants had liver proton density fat fraction (PDFF) measurements by magnetic resonance image (MRI). Lung function parameters included forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). The primary outcome was the presence of NAFLD, defined as a PDFF greater than 5.5%. The secondary outcome included incident severe NAFLD and severe liver diseases (including liver cirrhosis, liver failure, hepatocellular carcinoma and liver-related death), defined by the International Classification of Disease codes with different data sources. During a media follow-up duration of 9.3 years, 7335 (24.1%) the presence of NAFLD cases were documented. There was an inverse association of FEV1 (% predicted) (Per SD increment, adjusted OR = 0.91, 95%CI: 0.88-0.94) and FVC (% predicted) (Per SD increment, adjusted OR = 0.90, 95%CI: 0.87-0.92) with the presence of NAFLD. Similar results were found for incident severe NAFLD, severe liver disease, liver cirrhosis, liver failure and liver-related death. MR analyses showed that the genetically predicted FEV1 (adjusted OR = 0.63, 95%CI: 0.46-0.87) and FVC (adjusted OR = 0.69, 95%CI: 0.51-0.95) were both inversely associated with the presence of NAFLD.

CONCLUSIONS

There was an inverse causal relationship between lung function and NAFLD in the general population.

Pulmonary function, genetic predisposition, and the risk of cirrhosis: A prospective cohort study

OBJECTIVE

Pulmonary function is associated with the development of chronic liver disease. However, evidence of the association between pulmonary function and cirrhosis risk is still lacking. This study aimed to investigate the longitudinal associations of pulmonary function with the development of cirrhosis, and to explore whether genetic predisposition to cirrhosis could modify these associations.

METHODS

Of 294,835 participants free of cirrhosis and had undergone spirometry at baseline from the UK Biobank were included. Cirrhosis diagnoses were ascertained through linked hospital records and death registries. Cox proportional hazard models were employed to investigate the longitudinal associations between pulmonary function, genetic predisposition, and cirrhosis risk.

RESULTS

During a median follow-up of 12.0 years, 2598 incident cirrhosis cases were documented. Compared to individuals with normal spirometry findings, those with preserved ratio impaired spirometry (PRISm) findings (hazard ratio [HR] and 95% confidence interval [CI]: 1.32 [1.18, 1.48]) and airflow obstruction (HR [95%CI]: 1.19 [1.07, 1.31]) had a higher risk of developing cirrhosis after adjustments. These associations were consistent across all categories of genetic predisposition, with no observed modifying effect of genetic predisposition. In joint exposure analyses, the highest risk was observed in individuals with both a high genetic predisposition for cirrhosis and PRISm findings (HR [95% CI]: 1.74 [1.45, 2.08]).

CONCLUSIONS

Our findings indicate that worse pulmonary function is a significant risk factor of cirrhosis, irrespective of genetic predisposition. Early identification and appropriate intervention for pulmonary function may lead to more effective healthcare resource utilization and reduce the burden associated with cirrhosis.

Association between metabolic dysfunction-associated steatotic liver disease and pulmonary function: a population-based and two-sample mendelian randomization study

BACKGROUND

Hepatic steatosis and its related complications are risk factors for multiple respiratory diseases; however, the causal relationship between metabolic dysfunction-associated steatotic liver disease (MASLD) and pulmonary function remains controversial. We aimed to identify it using a national cohort and Mendelian randomization (MR).

METHODS

We enrolled 30,442 participants from the 2007 to 2012 National Health and Nutrition Examination Survey. Demographics, pulmonary function indices (forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC]), and variables used to calculate the liver fat score (LFS) were collected. A two-sample MR analysis employing the summary data of genome-wide association studies on MASLD and FEV1/FVC, chronic obstructive pulmonary disease (COPD), and asthma from the Finngen Biobank and Medical Research Council Integrative Epidemiology Unit was performed.

RESULTS

A total of 3,462 participants, 1,335 of whom had MASLD (LFS > -0.640), were finally included in the study. The FEV1 (3,204.7 vs. 3,262.5 ml, P = 0.061), FVC (4,089.1 vs. 4,143.8 ml, P = 0.146), FEV1/FVC ratio (78.5% vs. 78.8%, P = 0.233), and FEV1/predicted FEV1 ratio (146.5% vs. 141.7%, P = 0.366) were not significantly different between people with MASLD and those without. Additionally, the MR analysis suggested no causal correlation between MASLD and FEV1/FVC (P = 0.817), MASLD and COPD (P = 0.407), and MASLD and asthma (P = 0.808). Reverse MR studies showed no causal relationships yet (all P > 0.05).

CONCLUSION

Our study provides convincing evidence that there is no causal association between MASLD and pulmonary function.

Combined Exercise and Diet Induce Airway Hyperreactivity While Reducing Liver Steatosis in Mice with Diet-Induced Obesity

BACKGROUND

Obesity is a multi-organ system disease, which is associated with, e.g., a higher prevalence of non-alcoholic fatty liver disease (NAFLD) and asthma. Little is known regarding the effect of obesity-related parameters (including liver integrity) and the respiratory phenotype after a combination of physical activity and diet.

METHODS

Thirty-two C57BL/6 mice were, after 27 weeks of a high fat diet (HFD), randomly assigned to two dietary interventions for three weeks: a HFD or a normal chow diet (NCD). In both dietary groups, half of the animals were subjected to a sub-maximal exercise protocol. Lung function, lung inflammation, liver histology, and metabolic profile were determined.

RESULTS

Mice with obesity did not show airway hyperreactivity after methacholine provocation. Sub-maximal exercise with diet (NCD/E) induced a significant reduction in forced expiratory volume in 0.1 s after methacholine provocation. NCD/E had significantly more neutrophils and inflammation (IFN-γ, TNF-α, IL-4, and IL-17F) in bronchoalveolar lavage compared to non-exercising mice on a HFD (HFD/NE). However, more epithelial injury (serum surfactant protein D and IL-33) was seen in HFD/NE. Additionally, hepatic steatosis and fibrosis were reduced by combined diet and sub-maximal exercise.

CONCLUSIONS

Combining sub-maximal exercise with diet induced airway hyperreactivity and pulmonary inflammation, while body weight, hepatic steatosis, and fibrosis improved.

Elevated neutrophil-to-lymphocyte ratio combined with decreased lymphocyte-to-monocyte ratio is associated with increased peripheral airway resistance in patients with hepatic steatosis

Although the link between hepatic steatosis and lung function has been confirmed, the focus has largely been on central airways. The association between hepatic steatosis and increased peripheral airway resistance has not yet been explored. Hepatic steatosis and increased peripheral resistance are connected with immunity dysregulation. High neutrophil-to-lymphocyte ratio (NLR) and low lymphocyte-to-monocyte ratio (LMR) have been recognized as indicators of immunity dysregulation. In this study, the association between hepatic steatosis and increased peripheral airway resistance was evaluated, and the effect of immunity dysregulation (high NLR/low LMR) on the increased peripheral airway resistance among patients with hepatic steatosis was explored. In this retrospective study, chest or abdomen CT scans and spirometry/impulse oscillometry (IOS) from 2018 to 2019 were used to identify hepatic steatosis and increased central/peripheral airway resistance in patients. Among 1391 enrolled patients, 169 (12.1%) had hepatic steatosis. After 1:1 age and abnormal ALT matching was conducted, clinical data were compared between patients with and without hepatic steatosis. A higher proportion of patients with hepatic steatosis had increased peripheral airway resistance than those without hepatic steatosis (52.7% vs 40.2%, P = .025). Old age, high body mass index, history of diabetes, and high NLR/low LMR were significantly correlated with increased peripheral airway resistance. The presence of hepatic steatosis is associated with increased peripheral airway. High NLR/low LMR is an independent associated factor of increased peripheral airway resistance in patients with hepatic steatosis. It is advisable for patients with hepatic steatosis to regularly monitor their complete blood count/differential count and undergo pulmonary function tests including IOS.

Lung function and nonalcoholic fatty liver disease: a Mendelian randomization study

Introduction

Associations of pulmonary function as evaluated by forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) with non-alcoholic fatty liver disease (NAFLD) have been reported in observational studies. Nevertheless, observational studies are susceptible to bias and reverse causality, making it difficult to infer the existence and direction of causality. We aimed to evaluate the causal effect of pulmonary function on NAFLD using the Mendelian randomization (MR) method.

Material and methods

We performed univariate MR, multivariate MR, and bidirectional two-sample MR analyses to jointly assess the causal relationship between pulmonary function and NAFLD. In addition to the inverse variance weighting method as the primary MR analysis, three complementary methods were also performed. A series of sensitivity analyses were carried out to rule out pleiotropy.

Results

We found that each genetically predicted (standard deviation) SD increase in FEV1 and FVC was associated with decreased NAFLD risk. However, after adjusting for height in the multivariate MR, only the effect of FEV1 on NAFLD risk remained significant. Furthermore, we found no causal effect of NAFLD on lung function in the reverse MR analysis.

Conclusions

Our findings indicated that reduced lung function, especially FEV1, is causally associated with the risk of NAFLD. Although the mechanism remains unclear, FEV1 could be considered when assessing NAFLD risk and as a potential target for NAFLD prevention.

2019 Global NAFLD Prevalence: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

The increasing rates of obesity and type 2 diabetes mellitus may lead to increased prevalence of nonalcoholic fatty liver disease (NAFLD). We aimed to determine the current and recent trends on the global and regional prevalence of NAFLD.

METHODS

Systematic search from inception to March 26, 2020 was performed without language restrictions. Two authors independently performed screening and data extraction. We performed meta-regression to determine trends in NAFLD prevalence.

RESULTS

We identified 17,244 articles from literature search and included 245 eligible studies involving 5,399,254 individuals. The pooled global prevalence of NAFLD was 29.8% (95% confidence interval [CI], 28.6%-31.1%); of these, 82.5% of included articles used ultrasound to diagnose NAFLD, with prevalence of 30.6% (95% CI, 29.2%-32.0%). South America (3 studies, 5716 individuals) and North America (4 studies, 18,236 individuals) had the highest NAFLD prevalence at 35.7% (95% CI, 34.0%-37.5%) and 35.3% (95% CI, 25.4%-45.9%), respectively. From 1991 to 2019, trend analysis showed NAFLD increased from 21.9% to 37.3% (yearly increase of 0.7%, P < .0001), with South America showing the most rapid change of 2.7% per year, followed by Europe at 1.1%.

CONCLUSIONS

Despite regional variation, the global prevalence of NAFLD is increasing overall. Policy makers must work toward reversing the current trends by increasing awareness of NAFLD and promoting healthy lifestyle environments.

Metabolic Dysfunction-associated Fatty Liver Disease is Associated with Greater Impairment of Lung Function than Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIMS

We compared lung function parameters in nonalcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD), and examined the association between lung function parameters and fibrosis severity in MAFLD.

METHODS

In this cross-sectional study, we randomly recruited 2,543 middle-aged individuals from 25 communities across four cities in China during 2016 and 2020. All participants received a health check-up including measurement of anthropometric parameters, biochemical variables, liver ultrasonography, and spirometry. The severity of liver disease was assessed by the fibrosis (FIB)-4 score.

RESULTS

The prevalence of MAFLD was 20.4% (n=519) and that of NAFLD was 18.4% (n=469). After adjusting for age, sex, adiposity measures, smoking status, and significant alcohol intake, subjects with MAFLD had a significantly lower predicted forced vital capacity (FVC, 88.27±17.60% vs. 90.82±16.85%, p<0.05) and lower 1 s forced expiratory volume (FEV1, 79.89±17.34 vs. 83.02±16.66%, p<0.05) than those with NAFLD. MAFLD with an increased FIB-4 score was significantly associated with decreased lung function. For each 1-point increase in FIB-4, FVC was diminished by 0.507 (95% CI: -0.840, -0.173, p=0.003), and FEV1 was diminished by 0.439 (95% CI: -0.739, -0.140, p=0.004). The results remained unchanged when the statistical analyses was performed separately for men and women.

CONCLUSIONS

MAFLD was significantly associated with a greater impairment of lung function parameters than NAFLD.

Increased Oxygen Desaturation Time During Sleep Is a Risk Factor for NASH in Patients With Obstructive Sleep Apnea: A Prospective Cohort Study

Introduction

Given that obstructive sleep apnea (OSA) is commonly associated with metabolic disorders, in this prospective study, we sought to determine the prevalence and risk factors for hepatosteatosis, non-alcoholic steatohepatitis (NASH), and advanced liver fibrosis in patients with clinical and polygraphic criteria of OSA (n = 153) and in subjects with normal lung function parameters (NLP, n = 43).

Methods

Hepatosteatosis, NASH, and advanced liver fibrosis were determined by blood-based non-invasive tools, such as the fatty liver index and the hepatic steatosis index, a serum lipidomic (OWLiver™) test, and three distinct fibrosis algorithms, respectively. Logistic regression models adjusted by potential confounders were performed to evaluate risk factors.

Results

Insulin resistance and dyslipidemia were more frequent in patients with OSA than in subjects with NLP. The prevalence of hepatosteatosis was significantly higher in patients with OSA than in subjects with NLP. NASH was also found more frequently in patients with OSA than in subjects with NLP. In contrast, advanced liver fibrosis was rarely detected in the entire study population, and no significant differences were observed between patients with OSA and subjects with NLP. Besides male gender, increased body mass index (BMI), and presence of type 2 diabetes, percentage of sleep time with oxygen saturation <90% (Tc90%) was the only polygraphic variable significantly associated with NASH in patients with OSA.

Conclusions

This study shows that hepatosteatosis and NASH are highly prevalent in patients with OSA and indicates that those with a Tc90% higher than 10% are at increased risk for NASH.

Pulmonary function test abnormalities in children and adolescents with non-alcoholic fatty liver disease

Association between pulmonary function tests (PFTs) and non-alcoholic fatty liver disease (NAFLD) has been reported in adult studies; however, there is lack of pediatric studies. Our study aimed to evaluate PFTs in children with NAFLD. A total of 137 children with NAFLD and 100 healthy children of matched age and sex were included in the study. Different PFTs including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, residual volume (RV), and total lung capacity (TLC) were performed for all included children. Lipid profile, insulin resistance, fasting and postprandial glucose level, and high sensitive C reactive protein (hs-CRP) were measured. FEV1 %, FVC %, FEV1/FVC ratio, RV, and TLC were significantly lower in the patient group compared with the control group (P < 0.05), while RV and hs-CRP were significantly higher in children with NAFLD. Restrictive lung dysfunction was the commonest pulmonary dysfunction detected in children with NAFLD (21.9%). PFT indices were significantly correlated with grade and duration of NAFLD, insulin resistance, waist circumference, and hs-CRP. Regression analysis revealed that insulin resistance and hs-CRP were independently associated with decreased PFT indices.Conclusion: PFT indices were impaired in children with NAFLD and this impairment was independently associated with insulin resistance and hs-CRP. What is Known: • Pulmonary function tests (PFTs) abnormalities are common in adults with nonalcoholic fatty liver disease (NAFLD). • Studies involving PFTs abnormalities in pediatric NAFLD are lacking. What is New: • It is the first study that assessed PFT in pediatric patients with NAFLD. • PFTs abnormalities are present in children with NAFLD. • Insulin resistance and high sensitive C reactive protein are independently associated with the decline of PFTs in children with NAFLD.

The association of impaired lung function and nonalcoholic fatty liver disease: a systematic review

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) and impaired lung function share similar risk factors and phenotypes, such as obesity and type 2 diabetes. The study is an updated meta-analysis to evaluate the association between NAFLD and impaired lung function.

METHODS

A total of 696 articles were identified with mention of NAFLD and lung function (or pulmonary function testing) in MEDLINE, EMBASE, and Scopus. After de-duplication, 455 articles were screened, 18 underwent full-text review. Five studies met our review and inclusion criteria with an interrater reliability kappa score of 1.

RESULTS

Five studies with a total of 118 118 subjects (28.4% with NAFLD) were included. The cross-sectional studies supported a statistically significant relationship between decreased pulmonary function tests and NAFLD. There was no association observed with obstructive lung pattern. One of the longitudinal studies revealed an association with increased rate of decline in forced vital capacity in patients with NAFLD and FIB4 score ≥1.30 (-21.7 vs. -27.4 mL/year, P = 0.001 in males, -22.4 vs. -27.9 mL/year, P = 0.016 in females). The second longitudinal study revealed that patients with impaired pulmonary function had an increased hazard ratio of developing NAFLD dependent on the severity of pulmonary impairment.

CONCLUSIONS

This is the first systematic review that supports an association of NAFLD with decreased (restrictive) lung function. The estimated severity of liver fibrosis correlates with the rate of progression of restrictive lung function. There are also data showing that patients with impaired lung function have a higher risk of developing NAFLD.

Visceral adiposity index is associated with lung function impairment: a population-based study

Background

The effects of visceral adiposity on decreased lung function have drawn much attention. Recently, the visceral adiposity index (VAI) has been proposed as a visceral fat distribution and dysfunction marker. However, the relationship between the VAI and lung function has not been investigated. The objective of the study was to analyze the association between the VAI and lung function and evaluate the potential of VAI as a predictor of lung function.

Methods

We collected data from a population-based study of 1786 subjects aged 40 years or older. All subjects completed a questionnaire and underwent anthropometric measurements and laboratory tests. Linear and logistic regression models were developed to assess the association between the VAI and lung function.

Results

The VAI was inversely related to FVC%predicted in men and negatively associated with both FVC%predicted and FEV1%predicted in women. In the linear regression analysis, the decrease in FVC%predicted associated with each 10% increase in the VAI was 1.127% in men and 1.943% in women; the decrease in FEV1%predicted associated with each 10%increase in the VAI was 0.663% in men and 1.738% in women. Further regression analysis revealed that the VAI was positively correlated with FVC and FEV1 impairment in women.

Conclusions

We were the first to show a clear correlation between the VAI and lung function impairment in the Chinese population. The VAI could be a simple and reliable approach in daily practice, and individuals, especially women with a high VAI, should receive additional screening and preventive interventions for respiratory disease.

Sarcopenia Is an Independent Risk Factor for NAFLD in COPD: A Nationwide Survey (KNHANES 2008-2011)

Background

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in patients with chronic obstructive pulmonary disease (COPD) and is independently associated with cardiometabolic comorbidities and systemic inflammation. Although several factors are associated with NAFLD, the influence of sarcopenia on NAFLD has not been fully determined in patients with COPD. We explored whether sarcopenia is associated with NAFLD in a COPD population.

Methods

Data from the Korean National Health and Nutrition Examination Surveys 2008–2011 were analyzed. The subjects were defined as having NAFLD when they had a hepatic steatosis index (HSI) score >36, which is a previously validated NAFLD prediction score. Sarcopenia_BMI (=total appendicular skeletal muscle mass [kg]/body mass index [kg/m²]), sarcopenia_BW (=total appendicular skeletal muscle mass [kg]/body weight [kg] × 100), and sarcopenia_height (= total appendicular skeletal muscle mass (kg)/height² (m)) measured using dual-energy X-ray absorptiometry was used to diagnose sarcopenia.

Results

NAFLD was identified in 124 (14.6%) of 850 COPD subjects using the HSI. Multivariable logistic analyses adjusted for age, sex, hypertension, diabetes mellitus (DM), forced vital capacity (FVC), and metabolic syndrome demonstrated that sarcopenia (sarcopenia_BMI, odds ratio [OR] = 1.95; 95% confidence interval [CI], 1.11–3.46, p = 0.022; sarcopenia_BW, OR = 2.25; 95% CI, 1.30–3.92, p = 0.004) was associated with NAFLD in patients with COPD. The proportion of sarcopenia_BMI was higher in patients with a high fibrotic burden from NAFLD (Q3, Q4) than in subjects with a low fibrotic burden from NALFD (Q1, Q2) (54.8% vs 24.2%, p = 0.024). The proportion of sarcopenia_BW was also higher in patients with a high fibrotic burden from NAFLD than in patients with a low fibrotic burden from NAFLD (51.6% vs 30.6%, p = 0.029).

Conclusion

Sarcopenia was associated with an increased risk for NAFLD in patients with COPD, independent of age, sex, lung function, and metabolic factors. Sarcopenic COPD was also associated with a high fibrotic burden in NAFLD patients. Pulmonologists should be aware of possible liver comorbidities in the sarcopenic COPD phenotype.

Association between non-alcoholic fatty liver disease and decreased lung function in adults: A systematic review and meta-analysis

AIM

Recent observational studies assessed the association between non-alcoholic fatty liver disease (NAFLD) and lung function in adults, but the magnitude of this association remains uncertain. We estimated the magnitude of the association between NAFLD and lung function on spirometry (predicted forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]).

METHODS

We searched publication databases using predefined keywords to identify studies (published up to October 4, 2018), in which NAFLD was diagnosed by imaging or biochemistry (no studies with biopsy-proven NAFLD were available). Data from selected studies were extracted, and meta-analysis was performed using random-effects modelling.

RESULTS

Six observational studies (5 cross-sectional and 1 longitudinal) with aggregate data on 133,707 individuals (27.8% with NAFLD) of predominantly Asian ethnicity (74.6%) were included in the final analysis. There were significant differences in predicted FEV1 (n = 5 studies; pooled weighted mean difference [WMD]: -2.43%, 95% CI: -3.28 to -1.58; I2 = 69.7%) and predicted FVC (pooled WMD: -2.96%, 95% CI: -4.75 to -1.17; I2 = 91.7%) between individuals with and without NAFLD. Decreased FEV1 and FVC at baseline were also independently associated with a ∼ 15% increased risk of incident NAFLD (n = 1 study in Korean individuals). Subgroup analyses did not materially modify these findings.

CONCLUSIONS

NAFLD is associated with significant reductions of both FEV1 and FVC in Asian and United States adults, and such small, but significant, reductions of lung volumes at baseline may be also associated with increased NAFLD incidence in Asian individuals. Further research is needed to better elucidate the link between NAFLD and impaired lung volumes.

Association between dietary iron intake and the prevalence of nonalcoholic fatty liver disease: A cross-sectional study

The aim was to test the association between dietary iron intake and the prevalence of nonalcoholic fatty liver disease (NAFLD) in a large sample of middle-aged and elderly Chinese population.The data included in this analysis were collected from a population-based cross-sectional study, that is, the Xiangya Hospital Health Management Center Study. Dietary iron intake was assessed using a validated semiquantitative food frequency questionnaire. The relationship between dietary iron intake and the prevalence of NAFLD was examined using logistic and spline regressions.A cross-sectional study including 5445 subjects was conducted. The prevalence of NAFLD was 36.9%. Compared with the lowest quintile, the energy-adjusted odds ratios (ORs) of NAFLD were 1.33 (95% confidence interval [CI]: 1.07-1.64), 1.80 (95% CI: 1.41-2.29) and 2.11 (95% CI: 1.60-2.80) in the 3rd, 4th, and 5th quintile of iron intake, respectively (P-value for trend <.001). In addition, dietary iron intake was positively associated with the OR of NAFLD in a dose-response relationship manner (test for trend P < .001). However, after stratifying the data by gender, such association only remained in the male, but not in the female population. With adjustment of additional potential confounders, the results did not change materially.Subjects with higher dietary iron intake were subject to a higher prevalence of NAFLD in a dose-response relationship manner. However, such association probably only exists in males, but not in females.

Extra-hepatic manifestations and complications of nonalcoholic fatty liver disease

This review article aims to synthesize the evidence regarding nonalcoholic fatty liver disease (NAFLD) as a systemic disorder. We critically discuss the metabolic syndrome and its components; the cardiovascular and the endocrine system; chronic respiratory disorders; the musculoskeletal system; the skin; and extra-hepatic tumors. We conclude that, while some of these extra-hepatic conditions clearly predispose to the development of secondary forms of NAFLD (typically hypothyroidism-induced NAFLD), others result from pre-existent NAFLD (e.g., certain extra-hepatic tumors) and others (such as Type 2 Diabetes) have, with NAFLD, mutual and bidirectional associations. Analyzed data imply that NAFLD is not merely a hepatic disease. It is also and possibly more importantly, a systemic disorder requiring a special awareness, a multidisciplinary approach and a multidimensional vision.

Non-specific impairment of Lung Function on Spirometery in Patients with Chronic Hepatitis-C

OBJECTIVES

To document frequency of non-specific impairment of lung functions (NILF) in patients of HCV and to compare according to gender, genotype, liver fibrosis score and smoking status.

METHODS

Patients of chronic hepatitis C were included after informed consent. Demographic data was recorded, and they underwent baseline investigations, fibroscan, abdominal ultrasound and PFT. Patients were segregated on basis of gender, fibroscan stages and smoking status. NILF was labelled if any two of three criteria are fulfilled (a) FVC < 80% of Predicted, (b) FEV1 < 80% Predicted, (c) FEV1/FVC ≥ 70.

RESULTS

Two hundred thirty four patients were of chronic HCV who fulfilled the selection criteria were inducted in study. These included 49.6% males and 50.4% females. There were 15.0% smokers, 16.2% were ex-smokers while 68.8% were never smokers. NILF was present in 130 (55.6%) out of which 61.5% were female and 38.5% were male (p <0.001), its presence in smokers was 56.2% and in never smokers was 55.3% (p=0.507). Presence of NILF increased with Fibroscan stages from F1 to F4 (p <0.001).

CONCLUSIONS

NILF pattern on spirometry with normal chest radiograph is common among HCV patients. It was found more common in females and frequency increased progressively with fibro scan stages.

Decreased lung function is associated with risk of developing non-alcoholic fatty liver disease: A longitudinal cohort study

BACKGROUND

Decreased lung function is associated with non-alcoholic fatty liver disease (NAFLD), based on linking mechanisms such as insulin resistance and systemic inflammation However, its association with the risk of developing NAFLD is unclear. Our aim was to investigate whether baseline lung function is associated with incident NAFLD in middle-aged healthy Koreans.

METHODS

A cohort study of 96,104 subjects (mean age: 35.7 years) without NAFLD were followed up from 2002 to 2015. NAFLD was diagnosed by ultrasound after the exclusion of other possible causes of liver diseases. Baseline percent predicted forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) were categorized in quartiles. Adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) (using the highest quartile as reference) were calculated for incident NAFLD at follow-up, controlling for covariates and potential confounders.

RESULTS

During 579,714.5 person-years of follow-up, 24,450 participants developed NAFLD (incidence rate, 42.2 per 1,000 person-years). The mean follow-up period was 5.9±3.4 years. Regardless of smoking history, the risk for incident NAFLD increased with decreasing quartiles of FEV1 (%) and FVC (%) in a dose-response manner (p for trend<0.001). In never smokers, the aHRs (95% CIs) for incident NAFLD were 1.15 (1.08-1.21), 1.11 (1.05-1.18), and 1.08 (1.02-1.14) in quartiles 1-3 for FEV1 (%) and 1.12 (1.06-1.18), 1.11 (1.05-1.18), and 1.09 (1.03-1.15) in quartiles 1-3 for FVC (%), compared with the highest quartile reference. Similar inverse association was present in smoke-exposed subjects (aHR for incident NAFLD were 1.14, 1.21, 1.13 and 1.17, 1.11, 1.09 across FEV1(%) and FVC(%) quartile in increasing order, respectively).

CONCLUSIONS

Reduced lung function was a risk factor for incident NAFLD in a large middle-aged Korean cohort with over half a million person-years of follow-up.

Nonalcoholic fatty liver disease is associated with decreased lung function

BACKGROUND & AIMS

The association between nonalcoholic fatty liver disease and lung function has not been fully examined. The aim of this study was to clarify the association between nonalcoholic fatty liver disease and lung function in general population by performing cross-sectional and longitudinal analysis.

METHODS

Participants without hepatic and respiratory disease who underwent regular health exams including hepatic sonography and spirometry with at least 3 years' follow-up were included. In cross-sectional analysis, the association between nonalcoholic fatty liver disease and lung function at baseline was examined with multiple regression models. The longitudinal analysis was performed by mixed linear regression models with propensity score matching.

RESULTS

Of 11 892 eligible participants (mean age, 47.7 years; male, 47.2%), 3815(32.1%) had nonalcoholic fatty liver disease based on sonography. In cross-sectional analysis, the nonalcoholic fatty liver disease group had lower adjusted forced expiratory volume in 1-second (men, 3.52 vs 3.44 L, P < .001; women, 2.62 vs 2.45 L, P < .001) and forced vital capacity (men, 4.33 vs 4.24 L, P < .001; women, 3.11 vs 2.97 L, P < .001) than the control group. In longitudinal analysis, during the mean follow-up period of 6.6 years, there were no significant differences in forced expiratory volume in 1-second or forced vital capacity decline rates between two groups in the propensity score-matched cohorts (n = 4558). However, those with high nonalcoholic fatty liver disease fibrosis score and fibrosis-4 (men, -21.7 vs -27.4 mL/y, P = .001; women, -22.4 vs -27.9 mL/y, P = .016) showed significantly faster decline in forced vital capacity compared to those with low scores.

CONCLUSIONS

Nonalcoholic fatty liver disease was associated with decreased lung function at baseline but was not associated with accelerated lung function decline in the propensity score-matched cohort. However, hepatic fibrosis was significantly associated with rapid forced vital capacity decline.

Relationship between obstructive lung disease and non-alcoholic fatty liver disease in the Korean population: Korea National Health and Nutrition Examination Survey, 2007-2010

Purpose

Previous studies have shown that progressive forms of non-alcoholic fatty liver disease (NAFLD) occur frequently in patients with obstructive lung disease (OLD). However, few studies have written about this relationship. This study aimed to investigate the relationship between OLD and NAFLD.

Subjects and methods

The Korea National Health and Nutrition Examination Survey is a national population-based, cross-sectional surveillance program that was initiated to assess the health and nutritional status of the Korean population. From 2007 to 2010, 11,738 subjects were enrolled. The subjects were defined as having NAFLD when they had scores higher than -0.640 in a NAFLD liver fat score prediction model, which was a previously validated prediction score. Individuals with forced expiratory volume in one second/forced vital capacity <0.7 were considered to have OLD. The subjects were divided into non-OLD and OLD groups and non-NAFLD and NAFLD groups. All analyses were performed using sample weighting using the complex samples plan.

Results

The prevalences of NAFLD and OLD were 30.2% and 8.9%, respectively. Although not statistically significant, subjects in the NAFLD group involved a higher tendency of having OLD than did those in the non-NAFLD group (8.5% vs 10.0%, respectively, P=0.060). Subjects with OLD showed a higher tendency to have NAFLD than non-OLD subjects (30.0% vs 33.7%, respectively, P=0.060). NAFLD subjects were at higher odds of OLD (odds ratio=1.334; 95% confidence interval=1.108-1.607, P=0.002) than non-NAFLD subjects, after adjusting for age, sex, and smoking history. OLD subjects were at higher odds of NAFLD (odds ratio=1.556; 95% confidence interval=1.288-1.879, P<0.001) than non-OLD subjects, after adjusting for age, sex, and smoking history.

Conclusion

This study showed that NAFLD is related to OLD. Clinicians should be aware of possible liver comorbidities in OLD patients and that extrahepatic disease in NAFLD patients may vary more than previously thought.

The association between the metabolic syndrome and metabolic syndrome score and pulmonary function in non-smoking adults

OBJECTIVE

This study assessed the association of metabolic syndrome and metabolic syndrome score with the predicted forced vital capacity and predicted forced expiratory volume in 1 s (predicted forced expiratory volume in 1 s) values in Korean non-smoking adults.

METHODS

We analysed data obtained from 6684 adults during the 2013-2015 Korean National Health and Nutrition Examination Survey.

RESULTS

After adjustment for related variables, metabolic syndrome ( p < 0.001) and metabolic syndrome score ( p < 0.001) were found to be inversely associated with the predicted forced vital capacity and forced expiratory volume in 1 s values. The odds ratios of restrictive pulmonary disease (the predicted forced vital capacity < 80.0% with forced expiratory volume in 1 s/FVC ⩾ 70.0%) by metabolic syndrome score with metabolic syndrome score 0 as a reference group showed no significance for metabolic syndrome score 1 [1.061 (95% confidence interval, 0.755-1.490)] and metabolic syndrome score 2 [1.247 (95% confidence interval, 0.890-1.747)], but showed significant for metabolic syndrome score 3 [1.433 (95% confidence interval, 1.010-2.033)] and metabolic syndrome score ⩾ 4 [1.760 (95% confidence interval, 1.216-2.550)]. In addition, the odds ratio of restrictive pulmonary disease of the metabolic syndrome [1.360 (95% confidence interval, 1.118-1.655)] was significantly higher than those of non-metabolic syndrome.

CONCLUSION

Metabolic syndrome and metabolic syndrome score were inversely associated with the predicted forced vital capacity and forced expiratory volume in 1 s values in Korean non-smoking adults. In addition, metabolic syndrome and metabolic syndrome score were positively associated with the restrictive pulmonary disease.

Risk factors and community intervention for nonalcoholic fatty liver disease in community residents of Urumqi, China

This study is to investigate the prevalence and risk factors of nonalcoholic fatty liver disease (NAFLD) and to analyze the effect of comprehensive community intervention on NAFLD in community residents in Urumqi, China.Cluster sampling method with street community as a unit was adopted in this study. Questionnaire survey, body measurement, blood biochemistry (including liver function, fasting blood glucose [FPG], and uric acid [UA]) examination as well as liver B ultrasound were performed. Then, comprehensive intervention was conducted in NAFLD patients.A total of 1000 people were enrolled, including 344 men and 656 women, with an average age of 51.79 ± 4.28 years. Of them, 660 were Han Chinese, 327 were Uygur, and 13 were Hui. The overall prevalence rate of NAFLD was 54.3%. The prevalence rate of NAFLD is higher in middle-aged population and is higher in ethnic minority than that in Han. NAFLD was associated with the past medical history of metabolic diseases. The factors of body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), waist circumference, hip circumference, neck circumference, subcutaneous fat thickness, FPG, alanine aminotransferase, and aspartate aminotransferase were identified as risk factors for NFALD. Neck circumference predicts the occurrence of NAFLD in female better, whereas subcutaneous fat predicts the occurrence of NAFLD in male better. After 8 months of community intervention in NAFLD patients, the changes of BMI, SBP, DBP, waist circumference, neck circumference, subcutaneous fat thickness, and UA were statistically significant (P < .05).The prevalence rate of NAFLD is high in Urumqi, China. Community intervention is effective in reducing the degree of NAFLD and promoting the overall health of NAFLD patients.