Background: Obesity is a major global health issue, driving high morbidity and mortality rates. The body roundness index (BRI), which includes waist circumference, offers a more accurate measure of visceral and total body fat. However, despite evidence of BRI's effectiveness in predicting obesity-related diseases, national-level data, especially from non-Western populations like China, remain limited.Methods: This study utilized data from the China Health and Retirement Longitudinal Study (CHARLS), a large, nationally representative cohort of Chinese adults, to examine the temporal trends of BRI, identify associated risk factors, and investigate the longitudinal associations between BRI and cardiovascular disease (CVD) outcomes. BRI was calculated using height and waist circumference measurements. Temporal trends and risk factors were analyzed cross-sectionally, while longitudinal associations were examined using Cox proportional hazards models adjusted for confounders. Mediation analyses were conducted to assess the role of intermediate factors such as hypertension and diabetes in the relationship between BRI and CVD.Results: A total of 12,902 participants were included for risk factor analysis, 10,525 for longitudinal analysis, and 7,310 for cumulative analysis. BRI continued to rise slowly across survey cycles but was higher in women, older adults, and urban residents. Multivariable analysis identified age, alcohol consumption, elevated blood pressure, and diabetes as positive predictors of BRI, while male sex, rural residence, and smoking were negatively associated. Higher baseline BRI was significantly associated with increased CVD risk (HR: 1.44, 95% CI: 1.22–1.69), stroke (HR: 1.49, 95% CI: 1.12–1.98), and heart disease (HR: 1.47, 95% CI: 1.22–1.77). Cumulative BRI similarly predicted increased risks of CVD, stroke, and heart disease. Mediation analysis showed that hypertension accounted for 20.69% of the association between BRI and CVD risk.Conclusions: BRI is a robust predictor of CVD risk. Targeting hypertension and other metabolic conditions could mitigate the elevated CVD risk associated with high BRI in Chinese adults. These findings underscore the importance of incorporating BRI into public health strategies to better manage obesity-related health risks in China.

Systemic immune inflammation index (SII) and systemic inflammation response index (SIRI) have recently emerged as more comprehensive indicators of systemic inflammation. However, few studies have been conducted to evaluate the effect of serum cotinine levels and weight-adjusted waist index (WWI) with SII and SIRI. This study aims to evaluate the independent and combined impact of serum cotinine levels and WWI with SII and SIRI. This study enrolled 9,099 adults based on the National Health and Nutrition Examination Survey 2013-2016. Generalized linear models were employed to assess the associations between cotinine exposure and WWI with SII and SIRI. Moreover, smoothing curve fitting was conducted to investigate the potential nonlinear relationships between the WWI with SII and SIRI levels. Additionally, subgroup analyses and interaction tests were conducted. The combined associations of the WWI and cotinine with systemic inflammatory indices were further assessed. High serum cotinine exposure was associated with increased SII and SIRI. The WWI was positively correlated with SII and SIRI. Smoothing curve fitting demonstrated a nonlinearly increasing dose-response connection between WWI and SII and SIRI. Stratified analyses also showed a positive association of cotinine levels and WWI with the systemic inflammatory indices across subgroups. Furthermore, a positive joint association was observed between serum cotinine level and WWI with SII and SIRI. These findings suggest that serum cotinine levels and WWI may be positively related to SII and SIRI. Serum cotinine levels and WWI may have a positive combined effect.

Neonicotinoid insecticides (NEOs) are widely used globally, leading to human exposure including pregnant women, and may pose risks of neurocognitive toxicity. In this study, we analyzed 114 mother–child pairs from the Guangxi Zhuang birth cohort. Umbilical cord plasma concentrations of 10 NEOs were measured using ultra-high-performance liquid chromatography–mass spectrometry (UPLC–MS), and child neurocognitive development was assessed using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) and the Ages and Stages Questionnaire, Third Edition (ASQ-3). NEOs were frequently detected, with detection rates ranging from 15.8% to 96.5%, and dinotefuran (DIN) showed the highest prevalence. Prenatal exposure to several NEOs was associated with lower neurocognitive scores. Specifically, DIN and clothianidin (CLO) exposure were associated with lower Full-Scale Intelligence Quotient (FSIQ), while thiacloprid (THIA) exposure was linked to poorer communication performance. In addition, imidacloprid (IMI) and THIA exposure were associated with reduced gross motor function, and thiamethoxam (TMX) was further associated with reduced fine motor development. Mixed exposure analysis suggested a negative but non-significant association between overall NEO exposure and FSIQ or fine motor outcomes. These findings suggest a potential association between prenatal exposure to NEOs and neurocognitive development in preschool children, highlighting the need for further research to inform public health strategies.