Non-specific phospholipase C4 hydrolyzes phosphosphingolipids and phosphoglycerolipids and promotes rapeseed growth and yield.

Phosphorus is a major nutrient vital for plant growth and development, with a substantial amount of cellular phosphorus being used for the biosynthesis of membrane phospholipids. Here, we report that NON-SPECIFIC PHOSPHOLIPASE C4 (NPC4) in rapeseed (Brassica napus) releases phosphate from phospholipids to promote growth and seed yield, as plants with altered NPC4 levels showed significant changes in seed production under different phosphate conditions. Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease 9 (Cas9)-mediated knockout of BnaNPC4 led to elevated accumulation of phospholipids and decreased growth, whereas overexpression (OE) of BnaNPC4 resulted in lower phospholipid contents and increased plant growth and seed production. We demonstrate that BnaNPC4 hydrolyzes phosphosphingolipids and phosphoglycerolipids in vitro, and plants with altered BnaNPC4 function displayed changes in their sphingolipid and glycerolipid contents in roots, with a greater change in glycerolipids than sphingolipids in leaves, particularly under phosphate deficiency conditions. In addition, BnaNPC4-OE plants led to the upregulation of genes involved in lipid metabolism, phosphate release, and phosphate transport and an increase in free inorganic phosphate in leaves. These results indicate that BnaNPC4 hydrolyzes phosphosphingolipids and phosphoglycerolipids in rapeseed to enhance phosphate release from membrane phospholipids and promote growth and seed production.

Plasma Periostin Levels Are Increased in Chinese Subjects with Obesity and Type 2 Diabetes and Are Positively Correlated with Glucose and Lipid Parameters.

The purpose of this study is to examine the relations among plasma periostin, glucose and lipid metabolism, insulin resistance and inflammation in Chinese patients with obesity (OB), and type 2 diabetes mellitus (T2DM). Plasma periostin levels in the T2DM group were significantly higher than the NGT group (P < 0.01). Patients with both OB and T2DM had the highest periostin levels. Correlation analysis showed that plasma periostin levels were positively correlated with weight, waist circumference (WC), body mass index (BMI), waist-hip ratio (WHR), fasting plasma glucose (FPG), 2 h postchallenge plasma glucose (2 h PG), glycated hemoglobin (HbA1c), triglyceride (TG), total cholesterol (TC), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), TNF-α, and IL-6 (P < 0.05 or 0.001) and negatively correlated with high-density lipoprotein cholesterol (HDL-C) (P < 0.001). Multiple linear regression analysis showed that TG, TNF-α, and HOMA-IR were independent related factors in influencing the levels of plasma periostin (P < 0.001). These results suggested that Chinese patients with obesity and T2DM had significantly higher plasma periostin levels. Plasma periostin levels were strongly associated with plasma TG, chronic inflammation, and insulin resistance.

Dynamical behaviors of a Lotka-Volterra competition system with the Ornstein-Uhlenbeck process.

The competitive relationship is one of the important studies in population ecology. In this paper, we investigate the dynamical behaviors of a two-species Lotka-Volterra competition system in which intrinsic rates of increase are governed by the Ornstein-Uhlenbeck process. First, we prove the existence and uniqueness of the global solution of the model. Second, the extinction of populations is discussed. Moreover, a sufficient condition for the existence of the stationary distribution in the system is obtained, and, further, the formulas for the mean and the covariance of the probability density function of the corresponding linearized system near the equilibrium point are obtained. Finally, numerical simulations are applied to verify the theoretical results.

QiDiTangShen granules modulated the gut microbiome composition and improved bile acid profiles in a mouse model of diabetic nephropathy.

QiDiTangShen granules (QDTS), a traditional Chinese herbal medicine, have been used in clinical practice for treating diabetic kidney disease for several years. In our previous study, we have demonstrated that QDTS displayed good efficacy on reducing proteinuria in mice with diabetic nephropathy (DN). However, the exact mechanism by which QDTS exerts its reno-protection remains largely unknown. To ascertain whether QDTS could target the gut microbiota-bile acid axis, the db/db mice were adopted as a mouse model of DN. After a 12-week of treatment, we found that QDTS significantly reduced urinary albumin excretion (UAE), and attenuated the pathological injuries of kidney in the db/db mice, while the body weight and blood glucose levels of those mice were not affected. In addition, we found that QDTS significantly altered the gut microbiota composition, and decreased serum levels of total bile acid (TBA) and BA profiles such as ß-muricholic acid (ß-MCA), taurocholic acid (TCA), tauro ß-muricholic acid (Tß-MCA) and deoxycholic acid (DCA). These BAs are associated with the activation of farnesoid X receptor (FXR), which is highly expressed in kidney. However, there was no significant difference between QDTS-treated and -untreated db/db mice regarding the renal expression of FXR, indicating that other mechanisms may be involved. Conclusively, our study revealed that QDTS significantly alleviated renal injuries in mice with DN. The gut microbiota-bile acid axis may be an important target for the reno-protection of QDTS in DN, but the specific mechanism merits further study.

Protective potential of klotho protein on diabetic retinopathy: Evidence from clinical and in vitro studies.

AIMS/INTRODUCTION: The purpose of the present study was to observe the relationship between serum α-klotho (KL) protein level and diabetic retinopathy (DR), and to further examine the effects of KL protein on apoptosis induced by palmitic acid (PA) in human retinal endothelial cells. MATERIALS AND METHODS: A total of 17 healthy people and 60 type 2 diabetes patients were included. According to the results from fundus fluorescein angiography, the diabetes patients were divided into three subgroups: without DR, non-proliferative DR and proliferative DR. Serum KL level was measured by enzyme-linked immunosorbent assay. In vitro, human retinal endothelial cells were exposed to PA with or without KL protein. Apoptosis rates were analyzed by flow cytometry analysis. Apoptotic-related protein expressions were detected by western blotting analysis. RESULTS: Serum KL level was lower in diabetes patients than that in healthy participants (P = 0.007), and was gradually decreased among the without DR, non-proliferative DR and proliferative DR subgroups (P = 0.045). A logistic regression analysis showed that after adjusting for the other confounding factors, serum KL level was independently and negatively related with DR (P = 0.049). Furthermore, the increased apoptosis rates induced by PA were inhibited with the addition of KL protein. Consistently, KL protein reversed the expression levels of the increased pro-apoptotic protein Bax and the decreased anti-apoptotic protein Bcl-2 induced by PA. However, the anti-apoptotic effect of KL protein was attenuated by LY294002 through the phosphatidylinositol 3 kinase-serine∕threonine kinase pathway. CONCLUSIONS: The data suggested that KL protein was probably a potential protective factor against retinopathy in type 2 diabetes patients.

Effectiveness comparisons of traditional Chinese medicine on treating diabetic nephropathy proteinuria: A systematic review and meta-analysis.

BACKGROUND: Diabetic nephropathy (DN) is one of the microvascular complications of diabetes mellitus. Proteinuria is the most important clinical feature of DN and an independent risk factor for the progression of DN. Therefore, reducing urinary protein is the primary goal of DN treatment. Traditional Chinese medicine (TCM) has long been widely used in the treatment of DN. Therefore, this paper conducted a meta-analysis of the clinical efficacy of TCM in the treatment of DN proteinuria, to comprehensively analyze the role of TCM in the treatment of DN. METHODS: We will search for PubMed, Cochrane Library, AMED, EMbase, WorldSciNet, Nature, Science online and China Journal Full-text Database, China Biomedical Literature CD-ROM Database, and related randomized controlled trials included in the China Resources Database. The time is limited from the construction of the library to September 2019. We will use the criteria provided by Cochrane 5.1.0 for quality assessment and risk assessment of the included studies, and use the Revman 5.3 and Stata13.0 software for meta-analysis of the effectiveness, recurrence rate, and symptom scores of DN proteinuria. TRIAL REGISTRATION NUMBER: PROSPERO CRD42019139707.

Relationship between serum adipsin and the first phase of glucose-stimulated insulin secretion in individuals with different glucose tolerance.

AIMS/INTRODUCTION: To detect serum adipsin levels in individuals with different glucose tolerance, and investigate the relationship between adipsisn and the first phase of insulin secretion. MATERIALS AND METHODS: A total of 56 patients with newly diagnosed type 2 diabetes mellitus, 36 patients with impaired glucose tolerance (IGT) and 45 individuals with normal glucose tolerance were enrolled. Intravenous glucose tolerance tests were carried out to evaluate pancreatic ß-cell function. The serum levels of adipsin, interleukin-1ß and high-sensitivity C-reactive protein were assayed. RESULTS: Serum adipsin levels were significantly lower in the type 2 diabetes mellitus and the IGT patients than those in the normal glucose tolerance group (P < 0.05). The acute insulin response and area under the curve showed a progressive decrease in the normal glucose tolerance and IGT groups, and decreased to the lowest levels in the type 2 diabetes mellitus group (P < 0.05). Adipsin was found to be negatively correlated with waist-to-hip ratio, free fatty acid, fasting plasma glucose, 2-h postprandial plasma glucose, glycated hemoglobin, homeostasis model assessment of insulin resistance, interleukin-1ß and high-sensitivity C-reactive protein (P < 0.05 or P < 0.001), and positively correlated with homeostasis model assessment of ß-cell function, high-density lipoprotein cholesterol, the area under the curve of the first phase insulin secretion and acute insulin response (P < 0.05 or P < 0.001). Stepwise multiple regression analysis showed that homeostasis model assessment for ß-cell function and acute insulin response were independently related to adipsin (P < 0.05). CONCLUSIONS: Serum adipsin levels were lower in type 2 diabetes mellitus and IGT patients, and correlated with the first phase of insulin secretion. Adipsin might be involved in the pathology of type 2 diabetes mellitus.

Association Between the Visceral Adiposity Index and Homeostatic Model Assessment of Insulin Resistance in Participants With Normal Waist Circumference.

We assessed the correlation between the visceral adiposity index (VAI; a useful indicator of adipose distribution and function) and homeostatic model assessment of insulin resistance (HOMA-IR) in participants with normal waist circumference. A cross-sectional study was conducted, which included 1834 Chinese adults. The blood pressure, anthropometric measurements, fasting and postprandial blood glucose, fasting insulin, and lipid profiles were measured. The VAI and HOMA-IR were calculated. Participants were divided into 4 groups according to the HOMA-IR level, and the correlation between the VAI and HOMA-IR was analyzed. The VAI gradually increased across the HOMA-IR quartiles ( P < .05), and a Pearson correlation analysis showed that VAI was positively related to the HOMA-IR ( P < .001) in males and females. After adjusting for the other covariates, VAI was independently correlated with the HOMA-IR. A logistic regression analysis indicated that VAI elevation was the main risk factor for the increased HOMA-IR in both genders. Overall, the VAI was closely correlated with the HOMA-IR in a population without central obesity.

Serum brain-derived neurotrophic factor levels and sleep disorders in Chinese healthy and newly diagnosed type 2 diabetic subjects.

BACKGROUND: The aims of the present study were to detect serum brain-derived neurotrophic factor (BDNF) protein concentrations in healthy and diabetic subjects with sleep disorders and to explore correlations among serum BDNF concentrations, metabolic parameters and inflammation. METHODS: In all, 377 eligible subjects were recruited to the study and underwent a 75-g oral glucose tolerance test. Various clinical parameters of metabolic disorders and cytokines were measured. Sleep disorders were assessed using the Pittsburgh Sleep Quality Index (PSQI). Subjects were grouped into those with normal glucose tolerance (NGT), those with NGT and sleep disorders (NGT-SDi), those with newly diagnosed type 2 diabetes mellitus (T2DM), and those with newly diagnosed T2DM and sleep disorders (T2DM-SDi). RESULTS: Serum BDNF levels were higher in the NGT-SDi and T2DM-SDi subgroups than in the NGT and T2DM groups, respectively. Multiple linear regression analysis revealed that serum BDNF concentrations were independently correlated with PSQI scores, homeostasis model assessment of insulin resistance, and HbA1c, interleukin 6 and tumor necrosis factor-α concentrations (P < 0.05 for all). Binary logistic regression analysis revealed that significant associations remained between serum BDNF concentrations and sleep disorders after adjustment for glucose- and metabolic-related factors in both the NGT-SDi and T2DM-SDi subgroups. CONCLUSIONS: Serum BDNF concentrations were higher in patients with sleep disorders and were associated with various metabolic parameters and inflammatory cytokines.

1,25(OH)2 D3 improves cardiac dysfunction, hypertrophy, and fibrosis through PARP1/SIRT1/mTOR-related mechanisms in type 1 diabetes.

SCOPE: Diabetic cardiomyopathy is one of the most important cardiac complications associated with diabetes. However, the mechanisms underlying diabetic cardiomyopathy remain unclear. The PARP1, SIRT1, and mTOR pathways have been implicated in cardiac diseases, and they are also associated with diabetes. 1,25(OH)2 D3 was recently recognized as a potential PARP1inhibitor in a macrophage cell line. The aim of our study was to investigate whether 1,25(OH)2 D3 can improve diabetic cardiomyopathy through a vitamin D receptor (VDR)-dependent mechanism associated with the PARP1/SIRT1/mTOR pathway. METHODS AND RESULTS: 1,25(OH)2 D3 -treated diabetic rats displayed improved left ventricular wall thickness and end-diastolic/systolic diameter, end-diastolic/systolic volume, left ventricular ejection fraction, fractional shortening, atrial natriuretic peptide, and brain natriuretic peptide gene expression, and interstitial fibrosis compared with untreated diabetic rats, while silencing the VDR gene in DM rats blocked the above results. 1,25(OH)2 D3 treatment also decreased PARP1 and increased SIRT1 expression levels and repressed the phosphorylation of mTOR. Treating neonatal cardiomyocytes with 1,25(OH)2 D3 and a PARP1 inhibitor decreased PARP1 and increased SIRT1 protein expression. CONCLUSION: The present study demonstrates that 1,25(OH)2 D3 treatment has the potential to improve diabetic cardiomyopathy in rats and suggests that VD-VDR signaling induces this protective effect against diabetic cardiomyopathy might partly through the PARP1/SIRT1/mTOR pathway.

1,25-Dihydroxyvitamin-D3 prevents the development of diabetic cardiomyopathy in type 1 diabetic rats by enhancing autophagy via inhibiting the ß-catenin/TCF4/GSK-3ß/mTOR pathway.

Diabetic cardiomyopathy (DCM) can increase the risk of heart failure and death in diabetic patients. However, no effective approaches are available to prevent its progression and development. Studies have shown that vitamin D is greatly implicated in cardiac hypertrophy and fibrosis, and there is a high prevalence of vitamin D deficiency in diabetic patients. In this study, we investigated whether 1,25-Dihydroxyvitamin-D3 (1,25D3) can improve DCM through a vitamin D receptor (VDR)-dependent mechanism associated with autophagy and the ß-catenin/T-cell factor/lymphoid enhancer factor (TCF4)/glycogen synthase kinase-3ß (GSK-3ß)/mammalian target of rapamycin (mTOR) pathway. In this study, streptozotocin (STZ)-induced type 1 diabetic rats were established and were treated with 1,25D3 and/or chloroquine and/or VDR gene silencing for 8 weeks before being sacrificed. Compared with untreated diabetic rats, 1,25D3 partly attenuated the myocardial hypertrophy and interstitial fibrosis, improved cardiac function and restored the impaired cardiac autophagy in diabetic rats, all of which were reversed by silencing the VDR gene in diabetic rats. In high-glucose cultured H9C2 cells, 1,25D3 increased autophagy in a dose-dependent manner. Besides, the ß-catenin/TCF4/GSK-3ß and mTOR signaling were activated both in diabetic rats and in high-glucose cultured H9C2 cells. Treatment with 1,25D3 inhibited the ß-catenin/TCF4/GSK-3ß and mTOR signaling in H9C2 cells, whereas co-treatment with lithium chloride (LiCl) reversed this situation and abolished the beneficial effect of 1,25D3 on autophagy. These data suggest that 1,25D3 may improve DCM in type 1 diabetic rats by modulating autophagy through the ß-catenin/TCF4/GSK-3ß and mTOR pathway. Vitamin D may exist as a new therapeutic target for the treatment of DCM.

Associations between sitting time and non-alcoholic fatty liver diseases in Chinese male workers: a cross-sectional study.

OBJECTIVES: Various studies have revealed a close association between sedentary behaviour and metabolic diseases, yet the association between sedentary time and non-alcoholic fatty liver disease (NAFLD) remains unclear. In this study, we investigated the association between sitting time and NAFLD in a Chinese male population and explored its underlying mechanism. STUDY DESIGN: A cross-sectional study. SETTING: Chongqing, China. PARTICIPANTS: Our study included 2054 male participants; all of the participants were of Han nationality. PRIMARY OUTCOME MEASURES: Sitting time was assessed using a self-reported questionnaire concerning the time devoted to sitting behaviour. Various clinical and demographic biomarkers were measured. Logistic regression analyses were used to investigate the ORs and the 95% CIs between sitting time and NAFLD. RESULTS: We found a higher proportion of NAFLD across the tertiles of sitting time (p trend=0.003). Multivariate linear regression analyses showed sitting time independently correlated with homoeostasis model assessment for insulin resistance (HOMA-IR), alanine aminotransferase, γ-glutamyl transpeptidase, body mass index, triglyceride and the high-sensitive C reactive protein (hsCRP) (all p<0.05). Further logistic regression analyses showed that longer sitting time (>7.1 hours/day) was associated with a higher prevalence of NAFLD (OR 1.09; 95% CI (1.04 to 1.67)) after adjusting for confounders. However, this association was insignificant after further adjusting for hsCRP (OR 1.03; 95% CI (0.92 to 1.84)). CONCLUSIONS: Sitting time was positively associated with the prevalence of NAFLD, and this association might be affected by inflammation.

Plasma C1q/TNF-Related Protein-3 (CTRP-3) and High-Mobility Group Box-1 (HMGB-1) Concentrations in Subjects with Prediabetes and Type 2 Diabetes.

Aims. To detect the association of C1q/TNF-related protein-3 (CTRP-3) and high-mobility group box-1 (HMGB-1) in subjects with prediabetes (pre-DM) and newly diagnosed type 2 diabetes (nT2DM). Methods. 224 eligible participants were included. The 75 g oral glucose tolerance test (OGTT) and several clinical parameters of metabolic disorders and cytokines were measured. All participants were divided into three groups: normal glucose tolerance (NGT, n = 62), pre-DM (n = 111), and nT2DM group (n = 56). Results. Plasma CTRP-3 concentrations were significantly lower in subjects with pre-DM and nT2DM than that of the NGT group, while plasma HMGB-1 levels were higher in pre-DM and nT2DM group compared with the NGT group (P < 0.05). A multiple linear regression analysis showed both plasma CTRP-3 and HMGB-1 concentrations were independently associated with homeostasis model assessment for insulin resistance (HOMA-IR) and interleukin-6 (IL-6) (P < 0.05 for all). Further multiple logistical regression analyses revealed that both plasma CTRP-3 and HMGB-1 levels were significantly associated with pre-DM and nT2DM after adjusting for several confounders (P < 0.001 for all). Conclusions. Circulating CTRP-3 and HMGB-1 concentrations might be promising biomarkers to predict prediabetes and type 2 diabetes.

The ZJU index: a useful indicator for recognizing insulin resistance in the Chinese general population.

AIMS: Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome and is closely associated with insulin resistance (IR). The ZJU index is based on body mass index (BMI), fasting plasma glucose (FPG), triglycerides (TG) and the serum alanine aminotransferase-to-aspartate transaminase ratio, and is proven to be a novel and effective parameter for screening NAFLD in the Chinese population. We aimed to analyze the relationship between the ZJU index and IR. METHODS: A cross-sectional study of 3329 Chinese adults was performed. Blood pressure (BP), anthropometric measurements and biochemical parameters were tested. The BMI, ZJU index and homeostasis model assessment of IR (HOMA-IR) were calculated. RESULTS: In both genders, BP, waist circumference, BMI, total cholesterol, TG, low-density lipoprotein cholesterol levels, FPG, postprandial glucose levels, fasting insulin and the HOMA-IR gradually increased, while the HDL-C decreased across the quartiles of the ZJU index (P < 0.001). The logistic regression analysis showed that the risk of IR was significantly elevated in the highest quartile of the ZJU index. Additionally, the area under the receiver operating characteristic curve of the ZJU index was 0.833 (95 % CI 0.809-0.858) in males and 0.788 (95 % CI 0.758-0.818) in females and was relatively higher than other common variables. CONCLUSIONS: The ZJU index is a useful indicator for recognizing IR in the Chinese general population.

In vitro and in vivo inhibition of mTOR by 1,25-dihydroxyvitamin D3 to improve early diabetic nephropathy via the DDIT4/TSC2/mTOR pathway.

We investigated whether 1,25-dihydroxy-vitamin D3 (1,25(OH)2D3) could improve early diabetic nephropathy through the DNA-damage-inducible transcript 4/tuberous sclerosis 2/mammalian target of rapamycin pathway. Rat mesangial cells were cultured in media containing normal glucose or high glucose and were treated with or without 1,25(OH)2D3. Mesangial cells proliferation was measured. Streptozotocin-induced diabetic rats were injected intravenously with a recombinant lentivirus against the rat vitamin D receptor gene. Urinary and serum albumin, fasting plasma glucose, serum triglyceride, total cholesterol, calcium, parathyroid hormone and serum 25-dihydroxy-vitamin D (25(OH)D) levels, mean glomerular volume, glomerular basement membrane thickness and total kidney volume were determined. The expressions of vitamin D receptor, DNA-damage-inducible transcript 4, and mammalian target of rapamycin were measured. 1,25(OH)2D3 inhibited the proliferation of mesangial cells induced by hyperglycemia. 1,25(OH)2D3 also significantly reduced albumin excretion, mean glomerular volume, glomerular basement membrane, and total kidney volume in rats with diabetic nephropathy. The expression of DNA-damage-inducible transcript 4 was elevated by 1,25(OH)2D3 treatment. The phosphorylation of mammalian target of rapamycin was reduced by 1,25(OH)2D3 treatment. Vitamin D receptor gene silencing blocked all of the above results. The current study demonstrates that 1,25(OH)2D3 can effectively inhibit mesangial cells proliferation induced by hyperglycemia, thus suppressing the development of diabetic nephropathy. This study also shows that the nephron-protective effect of 1,25(OH)2D3 occurs partly through the DDIT4/TSC2/mTOR pathway.

Plasma CTRP-3 concentrations in Chinese patients with obesity and type II diabetes negatively correlate with insulin resistance.

BACKGROUND: To analyze the association between the plasma C1q/TNF-related protein-3 (CTRP-3) concentrations, obesity, and type II diabetes in the Chinese population. METHODS: The plasma CTRP-3 concentrations were analyzed in 174 Chinese subjects with obesity (n = 43), type II diabetes (n = 41), obesity combined with type II diabetes (n = 45), and healthy subjects (n = 45), as were various clinical parameters of obesity-related metabolic disorders and adipokines. RESULTS: The plasma CTRP-3 concentrations were significantly lower in patients with obesity and type II diabetes than in healthy subjects (P < .01). Obese type II diabetic patients had the lowest CTRP-3 concentrations. Correlation analysis revealed that the plasma CTRP-3 concentrations were significantly negatively correlated with body mass index, waist circumferences, fasting plasma glucose, 2 h plasma glucose, hemoglobin A1c, triglyceride, fasting insulin, homeostasis model assessment for insulin resistance, and interleukin 6 levels and were positively correlated with high-density lipoprotein cholesterol level (all P < .01). Multiple linear regression analysis showed that hemoglobin A1c (ß = -0.232, P = .023), triglyceride (ß = -0.147, P = .040), and homeostasis model assessment for insulin resistance (ß = -0.172, P = .031) were independently correlated with circulating CTRP-3. Multivariate logistic regression analysis revealed that plasma CTRP-3 concentrations were significantly correlated with obesity, even after adjusting for glucose metabolic factors. CONCLUSIONS: Chinese patients with obesity and type II diabetes have significantly lower plasma CTRP-3 concentrations than healthy subjects do, and plasma CTRP-3 is strongly associated with glucose and lipid metabolism, chronic inflammation, and insulin resistance.

Associations between longer habitual day napping and non-alcoholic fatty liver disease in an elderly Chinese population.

CONTEXT: Both longer habitual day napping and Non-Alcoholic Fatty Liver Disease (NAFLD) are associated with diabetes and inflammation, but the association between day napping and NAFLD remains unexplored. OBJECTIVE: To investigate the association between the duration of habitual day napping and NAFLD in an elderly Chinese population and to gain insight into the role of inflammatory cytokines in this association. DESIGN AND SETTING: We conducted a series of cross-sectional studies of the community population in Chongqing, China, from 2011 to 2012. PARTICIPANTS: Among 6998 participants aged 40 to 75 years, 6438 eligible participants were included in the first study and analyzed to observe the association between day napping duration and NAFLD. In a separate study, 80 non-nappers and 90 nappers were selected to identify the role of inflammatory cytokines in this association. Logistic regression models were used to examine the odds ratios (ORs) of day nap duration with NAFLD. RESULTS: Day nappers had a significantly higher prevalence of NAFLD (P<0.001). Longer day napping duration was associated in a dose-dependent manner with NAFLD (P trend <0.001). After adjustment for potential confounders, the ORs were 1.67 (95% CI 1.13-2.46) for those reporting 0.5-1 h and 1.49 (95% CI 1.01-2.19) for those reporting >1 h of day napping compared with individuals who did not take day naps (all P<0.05). Longer-duration day nappers had higher levels of IL-6 and progranulin (PGRN) but lower levels of Secreted frizzled-related protein-5 (SFRP5, all P trend <0.001). After adjusting for IL-6, PGRN, and SFRP5, the association between day napping duration and NAFLD disappeared (all P>0.05). CONCLUSION: Longer day napping duration is associated with a higher prevalence of NAFLD, and inflammatory cytokines may be an essential link between day napping and NAFLD.