Atherogenic Index of Plasma in Non-Alcoholic Fatty Liver Disease: Systematic Review and Meta-Analysis

Elevated atherogenic index of plasma is associated with increased cardiorenal syndrome prevalence: a cross-sectional study

PURPOSE

Cardiorenal syndrome (CRS) is a complex clinical condition characterized by the simultaneous dysfunction of the heart and kidneys. The atherogenic index of plasma (AIP), calculated as the logarithm of the ratio of triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C), has emerged as a potential biomarker for cardiovascular risk. This study investigates the association between AIP and CRS, aiming to explore the potential linkage between AIP and CRS.

METHODS

Data were sourced from the National Health and Nutrition Examination Survey spanning 2005-2018, involving 35,365 participants after applying exclusion criteria. The primary exposure variable was AIP, categorized into quartiles, while the primary outcome variable was CRS, defined by the coexistence of cardiovascular disease (CVD) and chronic kidney disease (CKD). Statistical analyses, considering sample weights, included ANOVA, Chi-square tests, logistic regression models, and restricted cubic spline (RCS) analysis to examine nonlinear relationships.

RESULTS

The weighted logistic regression analysis showed a positive correlation between AIP and CRS across all models. In the fully adjusted model, the highest AIP quartile had a significantly increased odds ratio (OR) for CRS (Q4: OR = 1.62; 95% CI: 1.21-2.15). RCS analysis confirmed a positive correlation between AIP and CRS, with TG positively and HDL-C negatively correlated with CRS. Subgroup analysis indicated a significant interaction with hypertension, showing a stronger association in non-hypertensive individuals.

CONCLUSION

Higher AIP levels are associated with an increased prevalence of CRS, with a notable hypertension-specific interaction indicating a higher effect in individuals without hypertension.

Exercise-induced changes in insulin sensitivity, atherogenic index of plasma, and CTRP1/CTRP3 levels: the role of combined and high-intensity interval training in overweight and obese women

BACKGROUND

Obesity, defined as excessive body fat accumulation, is closely linked to an increased risk of metabolic disorders, cardiovascular diseases, and insulin resistance. This study investigates the effects of combined training (CT) and high-intensity interval training (HIIT) on insulin sensitivity, atherogenic index of plasma (AIP), and serum levels of C1q/TNF-related proteins (CTRP1 and CTRP3) in overweight and obese women.

METHODS

Thirty-three overweight and obese women (aged 18-50 years) were randomly divided into three groups: control (CON, n = 10), HIIT(n = 9), and combined training (CT, n = 10). The HIIT protocol consisted of intervals performed at 100% of maximum aerobic velocity (MAV) and rest intervals at 50% of MAV, with a 30-s work-to-rest ratio. The CT sessions included RT followed by AT. RT comprised seven exercises performed in three sets of 10-16 repetitions at 60-75% of one-repetition maximum (1RM). AT involved running for 15-30 min at 60-75% of heart rate reserve. Subjects trained three times per week. Body composition, biochemical, and functional assessments were conducted 48 h before and after the interventions.

RESULTS

Body mass index 1.3% and 2% (p = 0.001); TG 1.7%, 1.2% (p = 0.001);LDL 0.93%,0.83% (p = 0.012); HOMA-IR 9.5%,11.7% (p = 0.018); AST 4.2%,11.7% (p = 0.001); ALT 9.3%,10.9% (p = 0.001); 1RM 2.5%, 14.2% (p = 0.001); and maximum oxygen consumption 8%,2.4% (p = 0.001) showed significant improvements in both the HIIT and CT groups,resectively. Additionally, serum levels of CTRP 10.47%,0.34% (p = 0.007); and CTRP3 1.51%,1.53% (p = 0.011) significantly decreased in the HIIT and CT groups,resectively.

CONCLUSIONS

The results suggest that HIIT and CT are effective strategies for improving body composition, lipid profile, glycemic control, liver enzyme levels, and functional capacity. Moreover, both exercise modalities were associated with reduced serum levels of the adipokines CTRP1 and CTRP3, highlighting a potential link between these biomarkers and improvements in body composition, lipid profile, glycemic control, and liver enzyme levels.

TRIAL REGISTRATION

Registered retrospectively in the Iranian Registry of Clinical Trials (IRCT20241207063967 N1) on 18/01/2025. Access at https:// https://irct.behdasht.gov.ir/trial/80615 .

Atherogenic index of plasma identifies subjects with severe liver steatosis

The Atherogenic Index of Plasma (AIP), calculated by log (Triglycerides/HDL-C), has been proposed as a marker of atherogenic and cardiovascular risk. Atherosclerosis and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) share some pathogenic features and may be considered clinical manifestations of Metabolic Syndrome. In this study, we aimed to investigate the role of increased AIP as a putative metabolic biomarker for MASLD. 1,496 individuals (49% males and 51% females) underwent clinical examination for Metabolic Syndrome at Internal Medicine Division "C. Frugoni" of University Hospital of Bari, Italy in the period between January 2016 and April 2024. Clinical history was recorded, and physical examination, anthropometric measures, biochemical assessment, and abdomen ultrasound were performed. In the overall population, AIP significantly correlated with fasting glycemia (FPG, r = 0.26, p < 0.0001), HbA1c (r = 0.20, p < 0.0001), LDL (r = 0.11, p < 0.0001) and total cholesterol (r = 0.09; p < 0.0001), and anthropometric measures of obesity BMI (r = 0.37, p < 0.0001) and Waist Circumference (r = 0.44; p < 0.001). We then investigated AIP values in patients with and without dysmetabolic conditions, finding that AIP significantly increased as steatosis worsened (p < 0.001). ROC curves identified an optimal cut-off of 0.31 for accurately diagnosing severe steatosis and AIP values above this cut-off discriminated patients with significantly increased (p < 0.0001) fasting glycemia, LDL, and waist circumference, and were strongly associated (p < 0.0001) with MASLD (LLR 85.3), type 2 diabetes (LLR 85.5), abdominal obesity (LLR 72.9), overweight (LLR 151.8), and systemic obesity (LLR 178.4). The risk for being diagnosed with such conditions was found to be even higher in the subpopulation of patients with severe liver steatosis. To validate our findings, we considered another cohort of patients with and without biopsy-proven liver steatosis (public dataset GSE89632), confirming that a significant increase (p < 0.001) in AIP values could be found in patients with liver steatosis compared to healthy controls. AIP can be considered a specific biomarker of fatty liver disease with high sensitivity for the diagnosis of the severe form of liver steatosis. Considering AIP in the evaluation of patients with liver steatosis may augment the accuracy for diagnosing metabolic impairment and MASLD.

L-shaped relationship between atherogenic index of plasma with uric acid levels and hyperuricemia risk

Background

Hyperuricemia is a major risk factor for cardiovascular disease. This study aimed to investigate the relationship between the atherogenic index of plasma (AIP) and serum uric acid (SUA) levels, as well as the risk of hyperuricemia.

Methods

Utilizing data from the National Health and Nutrition Examination Survey (NHANES), we conducted a cross-sectional study involving 9,439 participants aged 18 years and above with complete triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) data. AIP was calculated as the logarithm of the ratio of TG to HDL-C. Weighted linear regression, weighted logistic regression, subgroup analysis, generalized additive model, restricted cubic spline and two-part linear and logistic regression were utilized to examine the relationships between AIP and SUA levels and hyperuricemia risk.

Results

We identified a non-linear and L-shaped relationship between AIP and both SUA levels and hyperuricemia prevalence, with significant increasing observed up to a saturation point (0.588 for uric acid levels and 0.573 for hyperuricemia prevalence). Below these thresholds, the odds ratios (OR) for increased SUA and hyperuricemia were 0.854 (95% confidence interval [CI]: 0.762, 0.946) and 4.4 (95% CI: 3.528, 5.488), respectively (P<0.001). Beyond these points, the associations were not statistically significant.

Conclusion

Our findings suggest that AIP is significantly and non-linear associated with SUA levels and hyperuricemia risk, with a saturation effect observed beyond specific thresholds. These insights could inform clinical strategies for managing cardiovascular and metabolic risks associated with elevated AIP. Further longitudinal studies are warranted to confirm these associations and elucidate the underlying mechanisms.

Nonlinear association between atherogenic index of plasma and chronic kidney disease: a nationwide cross-sectional study

BACKGROUND

The interplay between metabolic disorders and chronic kidney disease (CKD) has been well-documented. However, the connection between CKD and atherogenic index of plasma (AIP) remains understudied. This research delves into the correlation between these two factors, aiming to shed new light on their potential association.

METHODS

The relationship between AIP and CKD was evaluated using a weighted multivariate logistic regression model, and the curvilinear relationship between AIP and CKD was explored through smooth curve fitting. We engaged a recursive partitioning algorithm in conjunction with a two-stage linear regression model to precisely determine the inflection point. By conducting stratified analyses, the heterogeneity within subpopulations was explored.

RESULTS

In the regression model that accounted for all covariates, ORs (95% CI) for the association between CKD and AIP were 1.12 (0.91, 1.36), indicating no significant association between AIP and CKD. However, sensitivity analyses suggested that the relationship between them may be non-linear. Smooth curve analysis confirmed the non-linear relationship between AIP and CKD, identifying an inflection point at -0.55. Below this threshold, AIP exhibited a significant inverse correlation with CKD. Conversely, above this threshold, a pronounced positive correlation was detected. Stratified analyses elucidated that a non-linear association between AIP and CKD was observed among female participants and those aged 50 and above.

CONCLUSION

We found a curvilinear relationship between chronic kidney disease and atherogenic index of plasma.

Effects of 12-weeks resistance training and vitamin E supplementation on aminotransferases, CTRP-2, and CTRP-9 levels in males with nonalcoholic fatty liver disease: a double-blind, randomized trial

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) involves excessive liver fat accumulation and is closely linked to oxidative stress, which contributes to liver inflammation and damage. This study aimed to evaluate how interventions such as resistance training (RT) and vitamin E supplementation (VES) can modulate markers of NAFLD and key proteins regulating glucose and lipid metabolism, such as C1Q/TNF-related proteins (CTRPs).

METHODS

Forty participants with NAFLD (mean age: 32.4 ± 8.2 years) were randomly assigned to one of four groups for 12 weeks: placebo (PLB), VES, PLB + RT, and VES + RT. VES was administered at 800 IU/day in a double-blind manner. The RT regimen included eight exercises at 60-80% of one-repetition maximum (1RM), with three sets of 8-12 repetitions, performed three times per week. Pre- and post-intervention assessments included body composition, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lipid profile, glycemic control, CTRP-2, CTRP-9, and 1RM evaluations.

RESULTS

Following the interventions, there was a significant improvement in body composition, lipid profile, glycemic control, and 1RM indices in the exercise groups compared to non-exercise groups (p < 0.05). AST and ALT levels decreased in all groups (p < 0.05) compared to the PLB group. There was also a significant difference between the VES + RT group and both the VES and PLB + RT groups (p < 0.05). CTRP-2 and CTRP-9 levels decreased in the exercise groups compared to non-exercise groups (p < 0.05), and their changes showed a marked correlation with body composition, lipid profile, and glycemic control indices (p < 0.05).

CONCLUSIONS

This study highlights the benefits of RT on various health parameters among NAFLD patients. While adding VES to RT resulted in greater decreases in aminotransferases, it did not provide further improvements in other variables. Additionally, enhancements in body composition, lipid profile, and glycemic control indices were possibly associated with decreased levels of CTRPs.

TRIAL REGISTRATION

Registered retrospectively in the Iranian Registry of Clinical Trials (IRCT20220601055056N1) on December 21, 2023. Access at https://irct.behdasht.gov.ir/trial/69231 .

Association between the atherogenic index of plasma and kidney stones: a nationally representative study

PURPOSE

The atherogenic index of plasma (AIP) is a novel comprehensive lipid index. We aimed to investigate a possible relationship between AIP index and kidney stones in US adults.

METHODS

This cross-sectional study was conducted among adults with complete AIP index and questionnaire records on kidney stones from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2018. The AIP index served as the exposure variable, defined as the logarithm of the ratio between triglycerides (TG, mmol/L) and high-density lipoprotein cholesterol (HDL-c, mmol/L). Self-reported history of kidney stones was utilized as the outcome variable. The independent relationship between AIP index and the risk of kidney stones was fully assessed.

RESULTS

A total of 14,833 participants were included in this study, with an average AIP index of -0.07 ± 0.01. The proportion of kidney stones progressively increased with higher AIP index tertile intervals (7.33% vs. 9.97% vs. 12.57%, P < 0.001). Furthermore, AIP index was found to be independently associated with the risk of kidney stones after adjusting for confounding factors (OR = 1.32, 95% CI 1.08-1.61, P = 0.006). Restricted cubic spline (RCS) analysis confirmed the robustness of our results. There was no significant interaction observed based on subgroup analysis stratified by age, gender, race, body mass index (BMI, kg/m2), smokers, diabetes, hypertension, and cardiovascular disease (P for interaction > 0.05).

CONCLUSIONS

The AIP index may be a potential epidemiological tool to quantify the role of dyslipidemia in the risk of kidney stones in US adults.

Comprehensive analysis of shared risk genes and immunity-metabolisms between non-alcoholic fatty liver disease and atherosclerosis via bulk and single-cell transcriptome analyses

Objective

and design: Considering the clinical link between non-alcoholic fatty liver disease (NAFLD) and atherosclerosis (AS), we performed bioinformatics analysis to uncover their pathogenic interrelationship.

Methods and results

Data from the U.S. National Health and Nutritional Examination Survey (NHANES) 1999-2018 were included. Among 4851 participants in NHANES, NAFLD was significantly associated with atherosclerotic cardiovascular disease risk (ASCVD risk) (OR = 2.32, 95%CI: 2.04-2.65, P < 0.0001). We conducted WGCNA analysis for NAFLD (GSE130970) and AS (GSE28829) and identified three modules positively related to NAFLD severity and two modules accelerating atherosclerosis plaque progression. 198 key-modules genes were obtained via overlapping these modules. Next, we mined the disease-controlled differentially expressed genes (DEGs) from NAFLD (GSE89632) and AS (GSE100927), respectively. The final common risk genes (ACP5, TP53I3, RPS6KA1, TYMS, TREM2, CA12, and IFI27) were defined by intersecting the upregulated DEGs with 198 genes and validated in new datasets (GSE48452 and GSE43292). Importantly, they showed good diagnostic ability for NAFLD and AS. Immune infiltration analysis showed both illnesses have dysregulated immunity. Analysis of single-cell sequencing datasets NAFLD (GSE179886) and AS (GSE159677) uncovered different abnormal expressions of seven common genes in different immune cells while highlighting metabolic disturbances including upregulation of fatty acid biosynthesis, downregulation of fatty acid degradation and elongation.

Conclusion

We found 7 shared hub genes with good diagnostic ability and depicted the landscapes of immune and metabolism involved in NAFLD and AS. Our results provided a comprehensive association between them and may contribute to developing potential intervention strategies for targeting both disorders based on these risk factors.

Exploring the L-shaped relationship between Atherogenic Index of Plasma and depression: Results from NHANES 2005-2018

BACKGROUND

The Atherogenic Index of Plasma (AIP) is a novel metric linked to several diseases. However, there is inadequate evidence to investigate the relationship between AIP and depression. Therefore, we aim to elucidate the non-linear association between AIP and depression.

METHODS

12,453 participants from the National Health and Nutrition Examination Survey (NHANES) 2005-2018 were included. The AIP was calculated as log10 (triglycerides/high-density lipoprotein cholesterol). The Patient Health Questionnaire (PHQ-9) was used to identify depression (PHQ-9 ≥ 10). Weighted multivariate logistic regression, restricted cubic splines (RCS) models, subgroup analysis, and interaction tests were employed to reveal the relationship between AIP and depression.

RESULTS

AIP was found to be significantly correlated with depression. In the fully adjusted model, elevated AIP levels were associated with higher odds of depression (odds ratio [OR] = 1.50; 95 % CI: 1.06-2.12). The RCS analysis indicated an L-shaped pattern in the relationship between depression and AIP, with inflection points at -0.289. Beyond this inflection point, individuals with elevated AIP levels were associated with higher odds of depression (OR = 2.25; 95 % CI: 1.49-3.39). Notably, the association was particularly pronounced among individuals with diabetes.

LIMITATION

This cross-sectional study is unable to establish causal relationships.

CONCLUSION

There was an L-shaped association between AIP and depression among US adults. AIP has the potential value as a biological marker for depression, and maintaining AIP values below a certain threshold may help in managing depression.

Using new indices to predict metabolism dysfunction-associated fatty liver disease (MAFLD): analysis of the national health and nutrition examination survey database

BACKGROUND

Metabolism dysfunction-associated fatty liver disease (MAFLD), is the most common chronic liver disease. Few MAFLD predictions are simple and accurate. We examined the predictive performance of the albumin-to-glutamyl transpeptidase ratio (AGTR), plasma atherogenicity index (AIP), and serum uric acid to high-density lipoprotein cholesterol ratio (UHR) for MAFLD to design practical, inexpensive, and reliable models.

METHODS

The National Health and Nutrition Examination Survey (NHANES) 2007-2016 cycle dataset, which contained 12,654 participants, was filtered and randomly separated into internal validation and training sets. This study examined the relationships of the AGTR and AIP with MAFLD using binary multifactor logistic regression. We then created a MAFLD predictive model using the training dataset and validated the predictive model performance with the 2017-2018 NHANES and internal datasets.

RESULTS

In the total population, the predictive ability (AUC) of the AIP, AGTR, UHR, and the combination of all three for MAFLD showed in the following order: 0.749, 0.773, 0.728 and 0.824. Further subgroup analysis showed that the AGTR (AUC1 = 0.796; AUC2 = 0.690) and the combination of the three measures (AUC1 = 0.863; AUC2 = 0.766) better predicted MAFLD in nondiabetic patients. Joint prediction outperformed the individual measures in predicting MAFLD in the subgroups. Additionally, the model better predicted female MAFLD. Adding waist circumference and or BMI to this model improves predictive performance.

CONCLUSION

Our study showed that the AGTR, AIP, and UHR had strong MAFLD predictive value, and their combination can increase MAFLD predictive performance. They also performed better in females.

Two sides of the same coin: Non-alcoholic fatty liver disease and atherosclerosis

The prevalence of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis remain high, which is primarily due to widespread adoption of a western diet and sedentary lifestyle. NAFLD, together with advanced forms of this disease such as non-alcoholic steatohepatitis (NASH) and cirrhosis, are closely associated with atherosclerotic-cardiovascular disease (ASCVD). In this review, we discussed the association between NAFLD and atherosclerosis and expounded on the common molecular biomarkers underpinning the pathogenesis of both NAFLD and atherosclerosis. Furthermore, we have summarized the mode of function and potential clinical utility of existing drugs in the context of these diseases.

Association with the plasma atherogenic index with hepatic steatosis and fibrosis in the US population

Plasma atherogenic index (AIP) reflects a novel intricate biochemical indicator of lipids' metabolism. The involvement of lipid metabolism for pathogenesis concerning nonalcoholic fatty liver disease (NAFLD) has been established. However, the precise association across AIP and hepatic steatosis and fibrosis remains unclear. This present investigation explored the potential correlation across AIP, hepatic steatosis and fibrosis. Data were acquired through National Health and Nutrition Examination Survey (NHANES) from 2017 to 2020. Hepatic steatosis was detected through the controlled attenuation parameter (CAP), while hepatic fibrosis was examined via liver stiffness measurement (LSM). The study employed multiple linear, Fitted smoothed curves and subgroup analyses were used for investigating relationships between the AIP, CAP, and LSM. The study recruited 6239 participants. In multivariate linear regression analysis, findings indicated a remarkable correlation between AIP and exacerbated NAFLD risk [odds ratio (95% confidence interval), 1.17 (1.12, 1.21)]. Analysis further revealed a positive link across AIP and hepatic steatosis, as indicated through the CAP [β (95% CI), 4.07 (3.32, 4.82)]. Tests for non-linearity, revealed a non-linear correlation between AIP and CAP (inflection point = 0.22). Subgroup analyses assessed the consistency of the link across AIP and CAP, indicating that the association remained comparable across all subgroups. Following the adjustment for all relevant variables, the linear regression analysis revealed a lack of statistical significance across the AIP and hepatic fibrosis. [LSM, β (95% CI), -0.39 (-1.06, 0.28), P = .2501]. Smooth-fitting curves examined the link across AIP and LSM and showed a U-shaped pattern, indicating their positive correlation with AIP less than 0.48. However, no significant correlation was observed with AIP more than 0.48. This study highlighted a substantial positive relationship across AIP and hepatic steatosis, as measured through CAP, and suggests that it may be used as an efficient and rapid measure for clinical prediction of hepatic steatosis.

A Study of Biomarkers Associated with Metabolic Dysfunction-Associated Fatty Liver Disease in Patients with Type 2 Diabetes

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a new term that no longer excludes patients that consume alcohol or present other liver diseases, unlike nonalcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate the role of different biomarkers as predictors of MAFLD in patients with type 2 diabetes mellitus (T2DM). In this regard, a cross-sectional, non-interventional study was conducted over a period of 8 months in patients with T2DM. Liver steatosis displayed by abdominal ultrasound certified the MAFLD diagnosis. A percentage of 49.5% of the studied patients presented MAFLD. Through logistic regression adjusted for gender, age, T2DM duration, lipid-lowering therapy, smoking status, nutritional status, we demonstrated that elevated triglycerides (TG) levels, high non-high-density-lipoprotein (HDL)-cholesterol-to-HDL-cholesterol (non-HDL/HDL) ratio, high atherogenic index of plasma (AIP), and increased Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) had predictive value for MAFLD in patients with T2DM. Furthermore, we calculated the optimal cut-off values for these biomarkers (184 mg/dL for TG, 0.615 for AIP, 3.9 for the non-HDL/HDL ratio, and 2.01 for HOMA-IR) which can predict the presence of MAFLD in patients with T2DM. To our knowledge, this is the first study to assess the predictive value of the non-HDL/HDL ratio for MAFLD in patients with T2DM.