Elevated serum leptin levels are associated with lower renal function among middle-aged and elderly adults in Taiwan, a community-based, cross-sectional study

Ultra-processed foods and risk of declined renal function: a dose-response meta-analysis of 786,216 participants

OBJECTIVES

Earlier investigations have documented an association between elevated consumption of Ultra-Processed Foods (UPFs) and adverse renal outcomes. To explore this relationship further, we executed a comprehensive dose-response meta-analysis to examine the link between UPFs intake and the risk of declined renal function.

SETTING

A systematic search was completed utilizing the ISI Web of Science, Scopus, Embase as well as PubMed/MEDLINE databases (without any restrictions), up until September 5, 2024. Effect sizes of declined renal function were recalculated by applying a random effects model. The GRADE tool was adopted to assess the certainty of the evidence, while study quality and potential publication bias were examined via validated methods such as the Newcastle-Ottawa Scale, Egger's regression asymmetry and Begg's rank correlation test.

RESULTS

Thirty-three studies (comprising 786,216 participants) were incorporated in the quantitative analysis. The results demonstrated that a greater UPFs intake was significantly associated with an enhanced risk of declined renal function (RR = 1.16; 95% CI: 1.09, 1.23; I2 = 68.8%; p < 0.001; n = 37). Additionally, we observed that each 1-serving-per-day increase in UPFs consumption was associated to a 5% greater risk of reduced renal function (RR = 1.05; 95% CI: 1.02, 1.09; I2 = 80.9%; p = 0.013; n = 9). A positive, linear association between UPF intake and the risk of declined renal function (Pnonlinearity = 0.107, Pdose-response < 0.001) was further displayed in the non-linear dose-response analysis.

CONCLUSION

Greater exposure to UPFs is positively associated with the risk of declined renal function. The information emphasizes the importance of considering UPFs in the prevention and management of adverse renal outcomes.

Preoperative leptin levels were associated with postoperative acute kidney injury in patients with acute type A aortic dissection

OBJECTIVE

Acute kidney injury (AKI) is a common surgical complication of acute type A aortic dissection (AAAD) and strongly associated with an unfavorable prognosis. Although elevated leptin levels have been identified as a potential risk factor for chronic kidney disease in middle-aged and elderly individuals, their association with AKI following AAAD surgery remains unknown. This study investigated the association between preoperative leptin levels and postoperative AKI in patients with AAAD.

METHODS

This study included 159 patients with AAAD at Fujian Heart Medical Center. The Kidney Disease: Improving Global Outcomes standards were used to define and classify AKI. The receiver operating characteristic (ROC) curves were used to assess the ability of leptin levels to predict AKI. Binary logistic regression analysis was used to study the association between leptin level and AKI.

RESULTS

The incidence of AKI was 33.96%. Leptin levels in the AKI group and stage 1, 2, and 3 AKI groups were higher than those in the non-AKI group (p < 0.05). Multivariate analysis revealed that elevated leptin levels were an independent risk factor for AKI (p < 0.001). ROC analysis of leptin detection for AKI showed an area under the curve of 0.71. The risk of AKI in the high-level group (leptin levels ≥3.62 ng/mL) was 3.87 times to the low-level group (leptin levels < 3.62 ng/mL).

CONCLUSION

Elevated leptin levels are associated with AKI, and plasma leptin may serve as a potential early blood biomarker for AKI in patients with AAAD.

Leptin Is Associated with Testosterone, Nutritional Markers, and Vascular Muscular Dysfunction in Chronic Kidney Disease

Chronic kidney disease (CKD) causes specific hormonal disturbances, such as variations in leptin and testosterone levels and function. These disturbances can promote errors in signaling interaction and cellular information processing and can be implicated in the pathogenesis of atherosclerosis. This study investigates the factors that affect leptin in CKD patients and examines how leptin is related to markers of vascular disease. We conducted a cross-sectional study of 162 patients with CKD in pre-dialysis and dialysis stages. We recorded clinical and laboratory data, including leptin, testosterone, and subclinical atherosclerosis markers like brachial-ankle pulse wave velocity (ba PWV) in pre-dialysis CKD patients and flow-mediated vasodilation (FMD) and nitroglycerin-mediated vasodilation (NMD) in hemodialysis (HD) patients. Leptin was significantly correlated with testosterone in CKD pre-dialysis stages (p < 0.001) and also in HD (p = 0.026), with adipose tissue mass in pre-dialysis stages (p < 0.001), and also in HD (p < 0.001). In women HD patients, leptin correlated with NMD (p = 0.039; r = -0.379); in all HD patients, leptin correlated with C reactive protein (p = 0.007; r = 0.28) and parathormone (p = 0.039; r = -0.220). Our research emphasizes the connection between leptin, adipose tissue, and testosterone in all stages of CKD. Leptin was associated with NMD in HD women and correlated with inflammatory syndrome and parathyroid hormone in all HD patients.

Obesity-related glomerulopathy: recent advances in inflammatory mechanisms and related treatments

Obesity-related glomerulopathy, which is an obesity-triggered kidney damage, has become a significant threat to human health. Several studies have recently highlighted the critical role of inflammation in obesity-related glomerulopathy development. Additionally, excess adipose tissue and adipocytes in patients with obesity produce various inflammatory factors that cause systemic low-grade inflammation with consequent damage to vascular endothelial cells, exacerbating glomerular injury. Therefore, we conducted a comprehensive review of obesity-related glomerulopathy and addressed the critical role of obesity-induced chronic inflammation in obesity-related glomerulopathy pathogenesis and progression, which leads to tubular damage and proteinuria, ultimately impairing renal function. The relationship between obesity and obesity-related glomerulopathy is facilitated by a network of various inflammation-associated cells (including macrophages, lymphocytes, and mast cells) and a series of inflammatory mediators (such as tumor necrosis factor α, interleukin 6, leptin, adiponectin, resistin, chemokines, adhesion molecules, and plasminogen activator inhibitor 1) and their inflammatory pathways. Furthermore, we discuss a recently discovered relationship between micronutrients and obesity-related glomerulopathy inflammation and the important role of micronutrients in the body's anti-inflammatory response. Therefore, assessing these inflammatory molecules and pathways will provide a strong theoretical basis for developing therapeutic strategies based on anti-inflammatory effects to prevent or delay the onset of kidney injury.

The Relationship between Self-Reported Sitting Time and Vitamin D Levels in Middle-Aged and Elderly Taiwanese Population: A Community-Based Cross-Sectional Study

(1) Background: Many studies have revealed a relationship between serum 25-hydroxy vitamin D and physical activity. This study aimed to investigate the relationship between self-reported sitting time and serum 25-hydroxy vitamin D levels in middle-aged and elderly adults in Taiwan. (2) Methods: A total of 396 people were enrolled in our study during a community health examination in Taiwan in 2019. We grouped participants from low to high according to their tertile of serum 25-hydroxy vitamin D levels, using the following categories: deficiency, insufficiency, and sufficiency. Parameters including self-reported sitting time were analyzed between each group. Pearson correlation coefficients were calculated to explore the relationships of serum 25-hydroxy vitamin D levels with age-adjusted risk factors. A scatter plot demonstrated the relationship between serum 25-hydroxy vitamin D levels and self-reported sitting time. The association between serum 25-hydroxy vitamin D levels and self-reported sitting time was assessed by multivariate linear regression with adjustment for age, sex, waist circumference, low-density lipoprotein, triglycerides, and smoking and drinking status. (3) Results: We analyzed the data from 396 participants. A total of 41.4% of participants were male, and the average age of all participants was 64.91 (±8.80) years. The participants in the high serum 25-hydroxy vitamin D group were more likely to have shorter self-reported sitting time. Serum 25-hydroxy vitamin D was negatively correlated (Pearson's r) with self-reported sitting time, even after adjustment for age. According to the results of multivariate linear regression, vitamin D levels showed a negative association with self-reported sitting time (β = -0.131, p = 0.006) after adjustment for age, sex, waist circumference, low-density lipoprotein, triglycerides, and smoking and drinking status. (4) Conclusions: According to our research, self-reported sitting time was inversely correlated with serum 25-hydroxy vitamin D in middle-aged and elderly people in Taiwan. Meanwhile, longer self-reported sitting time can be an independent risk factor for lower serum 25-hydroxy vitamin D levels.