Gallstones are a common digestive disorder, yet the association between the fibrosis-4 index (FIB-4) and gallstone formation remains poorly understood. This study explores the link between FIB-4 levels and gallstone prevalence among US adults. This study was based on data from the 2017–2020 National Health and Nutrition Examination Survey (NHANES), which included 7,771 participants. The association between FIB-4 and gallstone risk was analyzed using multivariate logistic regression with restricted cubic spline (RCS) analysis to assess nonlinear correlations, and threshold effects analysis to identify inflection points. Robustness checks included subgroup analysis. The weighted prevalence of gallstones in this study was 11%. Multiple logistic regression analysis showed that FIB-4 levels were significantly and positively associated with the risk of gallstones. In the fully adjusted model, each unit increase in FIB-4 as a continuous variable increased the risk of gallstones by 19% (OR = 1.19, 95% CI: 1.10, 1.29). When FIB-4 was grouped by quartiles, the risk of gallstones was increased by 60% (OR = 1.60, 95% CI: 1.25, 2.03) in the Q4 group compared to the Q1 group. RCS analysis further revealed a nonlinear positive correlation between FIB-4 and gallstones (P for nonlinear = 0.015) with an inflection point at 2.43, (P for log likelihood ratio test = 0.001). Bonferroni-corrected subgroup analyses showed that the association of FIB-4 with gallstones was statistically significant among non-Hispanic whites, those without heart failure, those without coronary heart disease, alcohol drinkers, and smokers (P < 0.00217). In this study, we found that elevated levels of FIB-4 were significantly and positively association with the risk of gallstones, and showed a non-linear trend. FIB-4 may have a potential application in the risk assessment of gallstones.

Obesity and the development of osteoporosis are closely related to abnormal visceral fat metabolism. The METS-VF is a novel body fat measurement method that integrates gender, waist circumference, and insulin resistance index. The purpose of this study was to look into the connection between METS-VF and lumbar spine bone mineral density (LS BMD). We performed a cross-sectional study to look into the connection between METS-VF and LS BMD using data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018. The association between METS-VF and LS BMD was analyzed using multiple linear regression with restricted cubic spline (RCS) curve analysis to assess nonlinear correlations, and threshold effects analysis to identify inflection points. Robustness checks included subgroup analysis. We also performed a sensitivity analysis. A total of 5005 participants with a weighted mean age of 39.57 ± 11.71 years were included in this study. After controlling for potential confounders, there was a significant negative correlation between METS-VF levels and LS BMD. According to further Restricted Cubic Splines (RCS) curve, METS-VF and LS BMD showed a substantial nonlinear association. According to threshold effect analysis, METS-VF’s inflection point was 5.47. To the right of the inflection point, LS BMD decreased by 0.09 g/cm² per unit increase in METS-VF. Subgroup analyses showed that the correlation between METS-VF and LS BMD varied by diabetes status (P < 0.05 for interaction). Significantly reduced LS BMD was linked to elevated METS-VF levels. This study supports the hypothesis that there is an association between visceral fat metabolism levels and LS BMD in the US population, and specifically, individuals with higher METS-VF levels should be of particular concern for their increased risk of osteoporosis.

Research suggests that lipid levels may be associated with suicide risk. However, the specific relationship between Apolipoprotein B and suicidal ideation remains unclear. The aim of this study was to investigate the association between ApoB levels and suicidal ideation and to further explore the causal relationship using Mendelian randomization. A cross-sectional study of 6520 U.S. adults was conducted using the 2011-2016 National Health and Nutrition Examination Survey (NHANES) dataset. Multiple logistic regression, smoothed curve fitting, stratified analyses, and interaction tests were used to reveal the relationship between ApoB levels and suicidal ideation. MR analyses were conducted using inverse variance weighting (IVW), GSMR, Maximum likelihood method, and cML-MA-BIC MR method. Sensitivity analyses included MR-Egger intercept test, MR-PRESSO global test, and leave-one-out (LOO) analysis. Multivariate logistic regression analysis showed that serum ApoB levels were positively associated with suicidal ideation, and the association remained significant even after multiple covariates (P = 0.0463). Subgroup analyses showed that the risk of suicidal ideation was significantly increased in the highest tertile (T3) of the population compared to the lowest tertile (T1) of ApoB levels (OR = 1.48, 95% CI: 1.04-2.12, P = 0.0312). In addition, the association between ApoB and suicidal ideation was more significant in the smoking subgroup (P interaction = 0.034). However, MR analysis failed to confirm a significant causal effect of ApoB levels on suicidal ideation (P > 0.05), and these results were robust to sensitivity analyses. The present study found a significant positive association between serum ApoB levels and suicidal ideation, especially among smokers. MR analysis failed to provide causal evidence of ApoB on suicidal ideation. More research is needed to clarify the potential role of ApoB in the development of suicidal ideation.