Objective: To screen for predictive obesity factors in overweight populations using an optimal and interpretable machine learning algorithm.Methods: This cross-sectional study was conducted between June 2011 and January 2012. The participants were randomly selected using a simple random sampling technique. Seven commonly used machine learning methods were employed to construct obesity risk prediction models. A total of 5,236 Chinese participants from Ningde City, Fujian Province, Southeast China, participated in this study. The best model was selected through appropriate verification and validation and suitably explained. Subsequently, a minimal set of significant predictors was identified. The Shapley additive explanation force plot was used to illustrate the model at the individual level.Results: Machine learning models for predicting obesity have demonstrated strong performance, with CatBoost emerging as the most effective in both model validity and net clinical benefit. Specifically, the CatBoost algorithm yielded the highest scores, registering 0.91 in the training set and an impressive 0.83 in the test set. This was further corroborated by the area under the curve (AUC) metrics, where CatBoost achieved 0.95 for the training set and 0.87 for the test set. In a rigorous five-fold cross-validation, the AUC for the CatBoost model ranged between 0.84 and 0.91, with an average AUC of ROC at 0.87 ± 0.022. Key predictors identified within these models included waist circumference, hip circumference, female gender, and systolic blood pressure.Conclusion: CatBoost may be the best machine learning method for prediction. Combining Shapley’s additive explanation and machine learning methods can be effective in identifying disease risk factors for prevention and control.

COVID‐19 vaccine is critical in preventing SARS‐CoV‐2 infection and transmission. However, obesity's effect on immune responses to COVID‐19 vaccines is still unknown. We performed a meta‐analysis of the literature and compared antibody responses with COVID‐19 vaccines among persons with and without obesity. We used Pubmed, Embase, Web of Science, and Cochrane Library to identify all related studies up to April 2022. The Stata.14 software was used to analyze the selected data. Eleven studies were included in the present meta‐analysis. Five of them provided absolute values of antibody titers in the obese group and non‐obese group. Overall, we found that the obese population was significantly associated with lower antibody titers (standardized mean difference [SMD] = −0.228, 95% CI [−0.437, −0.019], P < 0.001) after COVID‐19 vaccination. Significant heterogeneity was present in most pooled analyses but was reduced after subgroup analyses. No publication bias was observed in the present analysis. The Trim and Fill method did not change the results in the primary analysis. The present meta‐analysis suggested that obesity was significantly associated with decreased antibody responses to SARS‐CoV‐2 vaccines. Future studies should be performed to unravel the mechanism of response to the COVID‐19 vaccine in obese individuals.

Purpose: Sleeve gastrectomy (SG) is a surgical intervention for polycystic ovary syndrome (PCOS), especially for patients with obesity. Here, we explored the effects of SG on the gut microbiota of rats with PCOS and investigated the association between the intestinal flora and efficacy of SG in PCOS.Methods: Dehydroepiandrosterone (DHEA) injection was administered alone and in combination with a high-fat diet to induce PCOS in rats. SG was performed in rats with PCOS, and the effects of SG on the fecal and gut microbiota and the short-chain fatty acid (SCFA) content were observed. Furthermore, the association among gut microbiota, SCFA content and hyperandrogenism or other hallmarks of PCOS was evaluated.Results: The abundance of Firmicutes reduced and that of Bacteroidetes increased in response to SG in the DHEA-induced PCOS rat model. At the genus level, the abundances of Bacteroides and Blautia increased and those of Ruminococcus, Clostridium, and Alistipes reduced distinctly in the PCOS-SG groups. Moreover, the levels of fecal SCFAs, especially butyric acid, reduced after SG. SG significantly ameliorated PCOS-related symptoms such as hyperandrogenism, disrupted ovary function, and impaired glucose tolerance. Bacteroides and Blautia exhibited a negative correlation and Ruminococcus, Clostridium, and Alistipes exhibited a positive correlation with the levels of fecal SCFAs, luteinizing hormone, testosterone, and inflammatory factors.Conclusions: The amelioration of PCOS-related reproductive and metabolic disorders following SG was associated with the regulation of microbial taxa and SCFA content. Our findings provide a novel perspective on the microbial mechanisms in PCOS after SG.

Background: The anti-aging protein Klotho plays a protective role in kidney disease, but its potential as a biomarker for chronic kidney disease (CKD) is controversial. Additionally, the main pathways through which Klotho exerts its effects on CKD remain unclear. Therefore, we used bioinformatics and clinical data analysis to determine its role in CKD. Results: We analyzed the transcriptomic and clinical data from the Nephroseq v5 database and found that the Klotho gene was mainly expressed in the tubulointerstitium, and its expression was significantly positively correlated with estimated glomerular filtration rate (eGFR) and negatively correlated with blood urea nitrogen (BUN) in CKD. We further found that Klotho gene expression was mainly negatively associated with inflammatory response and positively associated with lipid metabolism in CKD tubulointerstitium by analyzing two large sample-size CKD tubulointerstitial transcriptome datasets. By analyzing 10-year clinical data from the National Health and Nutrition Examination Survey (NHANES) 2007–2016, we also found that Klotho negatively correlated with inflammatory biomarkers and triglyceride and positively correlated with eGFR in the CKD population. Mediation analysis showed that Klotho could improve renal function in the general population by modulating the inflammatory response and lipid metabolism, while in the CKD population, it primarily manifested by mediating the inflammatory response. Restricted cubic spline (RCS) analysis showed that the optimal concentration range for Klotho to exert its biological function was around 1000 pg/ml. Kaplan–Meier curves showed that lower cumulative hazards of all-cause mortality in participants with higher levels of Klotho. We also demonstrated that Klotho could reduce cellular inflammatory response and improve cellular lipid metabolism by establishing an in vitro model similar to CKD. Conclusions: Our results suggest that Klotho exerts protection in CKD, which may be mainly related to the regulation of inflammatory response and lipid metabolism, and it can serve as a potential biomarker for CKD.

Background: Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, affecting energy homeostasis and reproduction. The aim of this study was to investigate whether stress affected energy metabolism and reproduction through the glucocorticoid receptor on Kisspeptin neurons in the hypothalamus.Methods: Four groups included control group, chronic restraint stress group, Kisspeptin specific glucocorticoid receptor knock out group (KGRKO) and KGRKO+stress group. Body weight, food intake, estrous cycle of female mice, serum sex hormone levels, serum corticosterone and prolactin, Kisspeptin expression in the hypothalamus were measured.Results: The restraint stress group showed a significant weight loss compared with the control group. KGRKO+restraint stress group had a reduced weight loss, suggesting that restraint stress might partially affect the energy metabolism through GR on Kisspeptin neurons. In terms of reproductive function, the restraint stress group and the KGRKO+restraint stress group showed missing pre-estrus period or prolonged estrous cycles. Serum LH and FSH in KGRKO + restraint stress group decreased significantly compared with KGRKO group. However, no significant difference in the level of serum testosterone was observed. After restraint stress, the levels of serum cortisol and prolactin in male and female mice were significantly higher than the control group, and the hypothalamus Kiss1 gene mRNA expression and Kisspeptin protein expression were significantly decreased.Conclusion: Chronic restraint stress induced weight loss and negative changes in reproduction, which were partially mediated by glucocorticoid receptor on Kisspeptin neurons in the hypothalamus.