Threshold Effect Research Articles

Hemoglobin-to-red blood cell distribution width ratio is negatively associated with stroke: a cross-sectional study from NHANES.

Numerous studies have suggested that the hemoglobin-to-red blood cell distribution width ratio (HRR) is associated with the onset, progression, and prognosis of various diseases. However, to the best of our knowledge, no research has conducted statistical analyses to determine the association between HRR and stroke. This cross-sectional study was conducted among adults with complete data on hemoglobin-red cell distribution width ratio (HRR) and stroke from the 2005-2018 National Health and Nutrition Examination Survey (NHANES). HRR was calculated by dividing hemoglobin (HGB) in grams per deciliter (g/dL) by the red blood cell distribution width (RDW). Weighted multivariable logistic regression and generalized additive models were employed to investigate the independent and nonlinear relationships between HRR and stroke. Threshold effects were assessed using two-piece linear regression models. Additionally, subgroup analyses and interaction tests were performed. A total of 36,215 participants were included, with 2.92% classified as stroke patients. The prevalence of stroke decreased across increasing tertiles of HRR (Q1: 5.07%; Q2: 2.63%; Q3: 1.69%; P < 0.0001). A negative association between HRR and stroke was observed in both unadjusted and adjusted models. In Model III, each one-unit increase in HRR was associated with a 58% reduction in the likelihood of stroke (Model III: OR = 0.42, 95% CI: 0.29-0.63). Subgroup analyses and interaction tests revealed that the association between HRR and stroke was BMI-dependent (P < 0.05), with the negative association only observed in participants with BMI < = 25 and BMI 25-30, but not in those with BMI > 30. Using a two-piece linear regression model, a threshold effect was identified at a BMI of 30 (K = 1.16). To the left of this breakpoint, there was a negative association between HRR and stroke (OR = 0.55, 95% CI: 0.27-0.97), whereas no such association was detected to the right of the breakpoint (OR = 6.49, 95% CI: 0.75-56.11). HRR is negatively associated with the likelihood of stroke, with a lower risk of stroke in individuals with higher HRR levels.

Association between blood lead and periodontitis among American adults: a cross-sectional study of the national health and nutrition examination survey

BackgroundLead is persistent in the environment as a toxic substance and accumulates in the human body. Lead exposure has far-reaching harmful effects on all human systems and is widely recognized as a health and public health concern. Lead exposure poses a significant risk to oral health, as it destroys salivary glands and alveolar bone. It also induces oxidative stress which results in an immune response. Lead exposure appears to adversely affect periodontal tissues. Currently, the available evidence on the relationship between blood lead and periodontitis is insufficient and further research is necessary.ObjectiveIn this study, the objectives were to clarify the association between blood lead and periodontitis, as well as to explore potential dose-response relationships between blood lead exposure and periodontitis, as well as to determine appropriate thresholds for the effects of blood lead on periodontitis.MethodsWe conducted a cross-sectional study involving 8,550 participants with American adults aged 30 or older. blood Lead, periodontitis, age, sex, race, heart rate, education level, poverty index, marital status, body mass index, smoking status, alcohol drinking status, hypertension, diabetes and stroke. were collected from participants. Logistic regression, smooth curve fittingwere utilized to substantiate the research objectives.ResultsThere were a total of 8,550 participants of which 52.2% (4,467/8,550) had moderate/severe periodontitis. Compared with Q1 (0.15–0.93 ug/L), where blood lead levels were lower, the OR values for adjusted blood lead and periodontitis in Q2 (0.93–1.60 ug/L) and Q3 (1.60–61.29 ug/L) were 1.18 (95% CI: 1.12–1.25, P &amp;lt; 0.001) and 1.43 (95% CI: 1.34–1.52, P &amp;lt; 0.001). The association between blood lead levels and periodontitis exhibited a curve (non-linear, P &amp;lt; 0.001), with an inflection point of roughly 2.700 ug/L. The OR values for moderate/severe periodontitis in participants with blood lead levels &amp;lt;2.700ug/L was 1.318 (95% CI: 1.193–1.457, P &amp;lt; 0.001).ConclusionBlood lead levels are positively associated with periodontitis. Blood lead levels increased by five units and were associated with an increase in moderate and severe periodontitis risk by 36%. There is a curvilinear relationship between blood lead and periodontitis with a threshold effect and an inflection point of approximately 2.7 ug/L.

Threshold effects of vegetation cover on production-living-ecological functions coordination in Xiangyang City, China.

Clarifying the nonlinear impacts of vegetation cover on production-living-ecological function (PLEF) coordination is essential to ecological restoration regulation and sustainable land use. However, the threshold effect of vegetation cover on PLEF coordination, particularly in major function-oriented zones (MFZs), has yet to receive attention. This study selected Xiangyang City, China, as the case area to identify the impact threshold of vegetation cover on PLEF coordination from the perspectives of the region as a whole and MFZ, respectively. The results showed that the PLEF coordination was high in the center and east while low in the west. For production-ecological function, 51.46% of the area was primarily coordinated and above, while for production-living function, 61.35% of the city area was severely uncoordinated. Vegetation cover was high in the west and low in the east. A negative correlation existed between vegetation cover and PLEF coordination. Urban built-up areas with lower vegetation cover showed higher levels of PLEF coordination, whereas western mountainous regions with higher vegetation cover demonstrated lower levels of PLEF coordination. Furthermore, vegetation cover exhibited a pronounced threshold effect on PLEF coordination, featuring conspicuous regional variations. The identified thresholds of vegetation cover for PLEF coordination in key development, agricultural production, and key ecological function zones were 0.3896, 0.2272, and 0.8161, respectively. Our study provides scientific references for the impact assessment of ecological restoration and the synergistic enhancement of land functions.

Multi-method Coal Seam Floor Water Inrush Risk Evaluation Based on Variable Weight Theory

Frequent water inrush disasters in deep coal seam mining pose a significant threat to the safety of coal extraction operations. Due to the complexity and non-linearity of water inrush factors, evaluating the risk of water inrush in coal seam floor is challenging and the results can vary significantly. To achieve more accurate evaluations, the weighted rank-sum method and Grey-TOPSIS method were employed, alongside a master control indicator variable-weight model, for assessing the risk of water inrush in coal seam floor. Validation of the evaluation zoning map against actual conditions revealed that both methods produced accurate assessment results, thus affirming the reliability of the new evaluation approach. Compared with the water inrush coefficient method, the diversification of index factors weakened the absolute control effect of the water inrush threshold. The evaluation outcomes were more systematic and comprehensive, providing a new methodology and perspective for deep coal seam mining.

U-shaped relationship between triglyceride glucose-body mass index and suicide attempts in Chinese patients with untreated first-episode major depressive disorder.

An alternative metric for evaluating insulin resistance (IR) is the triglyceride glucose-body mass index (TyG-BMI). However, it is yet unclear how TyG-BMI and suicide attempts (SA) are related. The objective of this research was to explore the correlation between the TyG-BMI index and SA in individuals with untreated first-episode (UFE) major depressive disorder (MDD) in Shanxi Province. This cross-sectional study was conducted from September 2016 to December 2018 in the psychiatric outpatient clinic of Taiyuan General Hospital and included 1718 patients with UFE MDD, with a mean age of 34.9 ± 12.4years. The relationship between TyG-BMI and SA was assessed using logistic regression modeling. We investigated threshold effects using a two-piecewise linear regression model. Taking into consideration the potential influence of confounding variables, a comprehensive multivariate logistic regression analysis was conducted, which demonstrated the absence of a statistically significant association between the TyG-BMI index and the occurrence of SA, as evidenced by P-values that were all greater than 0.05. On the other hand, the visual analysis of the smoothed plots revealed a U-shaped relationship between the TyG-BMI index and the incidence of SA, with a notable inflection occurring at a TyG-BMI value of around 210. It was observed that the effect sizes flanking the inflection point, accompanied by their 95% confidence intervals, were 0.985 (95% CI: 0.972 to 0.999, P = 0.031) and 1.012 (95% CI: 1.003 to 1.047, P = 0.005), respectively. In UFE MDD patients, a U-shaped link was observed between TyG-BMI and SA, with the minimal SA incidence noted at a TyG-BMI level of 210, signifying that an augmented risk for SA might be connected to both diminished and augmented TyG-BMI levels.

Association between sick child facility readiness and quality of care at the individual and facility level in five low- and middle-income countries.

Raising the quality of health services is key to continued progress in improving child health, however, data on service quality are limited and difficult to interpret. The relationship between facility readiness and the quality of care is complex. Using publicly available data sets from five low- and middle-income countries (LMICs), we assessed the relationship between structural factors and the clinical quality of care for managing sick children. We developed indices for readiness and quality accounting for available indicators, expert opinion, and alignment with integrated management of childhood illness (IMCI) guidelines. In each country, we assessed the association between readiness and quality, with and without adjusting for other factors. We considered associations overall, by domain, and by provider type, explored non-linear associations, and compared associations at the individual and facility-level. The analysis included data from 3,149 health facilities and 11,159 sick child observations. In four of the five countries included in the analysis, we observed for every 10%-point increase in readiness, quality increased by about 1% point after adjusting for facility type and managing authority. There was little evidence of a non-linear relationship or a threshold effect altering the relationship between readiness and quality of care. Beyond readiness, younger child age, higher cost of care, and having a respiratory, digestive, or febrile diagnosis were most often associated with a higher quality of care. Higher "human resources" readiness domain scores were most consistently associated with better quality of care, while the quality of care domain of "treatment" was the least influenced by readiness. Facility-level associations did not vary greatly from individual-level associations. The weak correlation observed suggests readiness plays an important role in quality but as currently measured cannot be used to characterize clinical quality of care. Data for assessing quality of health services are limited, presenting challenges for understanding impediments, assessing interventions, and gauging changes in the quality of care over time. We need better data to assess the quality of care being delivered in LMICs to understand what factors drive quality, with the goal of improving the management of sick children.

The nonlineard association between triglyceride to HDL cholesterol ratio and long-term heart disease risk: findings from China Health and Retirement Longitudinal Study (CHARLS).

The aim of this study was to investigate the relationship between triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) and the risk of cardiovascular disease (CVD) in middle-aged and elderly Chinese population. CVD has high morbidity and mortality in China, with 5.09million CVD deaths in 2019 and a mortality rate of 364.5 cases per 100,000 people. Existing studies have focused on specific populations and lack studies on the general population. This study used data from the China Health and Aged Care Tracking Survey (CHARLS) to analyse the middle-aged and elderly population between 2011 and 2020. The exposure variable was TG/HDL-C ratio, the outcome variable was the occurrence of heart disease (including myocardial infarction, coronary heart disease, etc.), and the covariates included age, gender, education level, and body mass index. The final sample size was 4,551 participants. Weighted Cox regression models were used to assess the association between TG/HDL-C and CVD risk, and nonlinear associations and stratified analyses were performed. The results demonstrated a significant association between TG/HDL-C ratios and cardiac morbidity, with a risk ratio of 0.71 (95% CI: 0.71-0.71) in the adjusted model II. Nonlinear analysis revealed a threshold effect. Within the TG/HDL-C 0.15-1.5 interval (inflection point LnTG/HDL-C 0.41), each 1-unit increase in Ln (TG/HDL-C) was associated with a 17% reduction in the risk. The inflection point was associated with a 0.83-fold reduction in the risk of CVD (95% CI: 0.75, 0.92; p = 0.0003), but beyond this point, the association was no longer significant (1.00-fold reduction in risk; 95% CI: 0.95, 1.05; p = 0.9701). In contrast, stratified analyses demonstrated that the results were more applicable to women and those younger than 65 years. In summary, the study found a significant inverse relationship between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and the risk of cardiovascular disease in the middle-aged and elderly Chinese population, with a nonlinear threshold effect observed at a TG/HDL-C ratio of around 1.5.

Association between advanced lung cancer inflammation index and unstable asthma: a population-based study from the NHANES 2007–2018

BackgroundAsthma exacerbation is associated with obesity and systemic inflammatory diseases, and advanced lung cancer inflammation index (ALI) is a novel biomarker of nutritional inflammation. The purpose of this study was to investigate the potential relationship between ALI and unstable asthma.MethodsThis cross-sectional study utilized data from the 2007–2018 National Health and Nutrition Examination Survey (NHANES). Asthma was assessed through self-reported questionnaires. Multifactorial logistic regression, subgroup analyses, interaction assessments, smoothed curve fitting, and threshold effect analysis models were conducted to investigate the association between ALI and unstable asthma.ResultsThe study included 1,822 subjects with current asthma, and we found a linear positive association between ALI and unstable asthma, with higher levels of ALI significantly associated with an increased risk of asthma exacerbations in fully corrected models. However, the associations were not entirely consistent across subgroups. In subgroup analyses by body mass index (BMI) and race, unstable asthma and ALI were independently significant in the BMI (25–29.9) range and the Non-Hispanic White group. Interaction analysis suggested that BMI moderated the relationship between ALI and unstable asthma. Furthermore, smoothed curve fitting showed an inverted U-shaped relationship between log ALI and unstable asthma in subjects with a BMI &amp;lt;25 and male individuals, with inflection points observed at 1.53 and 2.13, respectively.ConclusionWe found a linear positive association between ALI and unstable asthma, which remained constant in the fully adjusted model. These findings suggest that higher levels of ALI were significantly associated with an increased risk of asthma exacerbation, particularly in asthmatic populations with BMI in the 25–29.9 range. However, more prospective studies are required to confirm our findings.

Digital economy, technology, and urban carbon emissions nexus: an investigation using the threshold effects and mediation effects tests

IntroductionThis study aims to explore the mechanisms by which the digital economy influences urban carbon emissions in China, with a particular focus on potential threshold effects and the mediating role of technology. As the digital economy grows, it impacts various environmental metrics, including carbon emissions, necessitating a deeper understanding of its nonlinear dynamics and implications for sustainable urban development.MethodsUsing panel data from 286 prefecture-level cities in China spanning from 2012 to 2021, we apply threshold effect models and mediation effect tests. The threshold effect model is employed to investigate non-linear characteristics of the digital economy’s impact on carbon emissions, while the mediation effect model assesses the role of technology as an intermediary in this relationship.ResultsThe threshold effect model reveals a single threshold in the impact of the digital economy on urban carbon emissions, indicating a nonlinear relationship. Initially, the influence of the digital economy on emissions is weak, but as the digital economy develops, its effect becomes more pronounced. The mediation effect model demonstrates that technological advancement can offset the increase in emissions associated with digital economic growth, thus showcasing technology’s potential to mitigate environmental impacts.DiscussionThe findings suggest that while the digital economy generally promotes urban carbon emissions, its impact is non-linear and mitigatable through technological innovation. To curb emissions in urban areas, fostering technological innovation and supporting green technology research and development are critical. Moreover, enhancing management and supervision within the digital economy sector can contribute to balancing economic growth with environmental goals. These insights are valuable for policymakers striving to harmonize digital economic expansion with sustainable environmental practices.

Abstract 4125511: L-shaped association of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and arterial stiffness: a cross-sectional study

Background: Serum lipids and ratios are known to be associated with cardiovascular disease (CVD). However, studies on NHHR and the association with arterial stiffness in the US population have not been reported. We sought to investigate the relationship between NHHR and arterial stiffness by arterial stiffness in subjects from the US population assessed by ePWV. Methods: This study included 23, 456 adults from the National Health and Nutrition Examination Survey (NHANES) spanning from 2007 to 2016. Multivariate linear regression analysis, threshold effects, smooth curve fitting, and subgroup analysis. We aimed to elucidate the relationship between NHHR and risk of arterial stiffness. Results: The mean age of the population in this study was 49.56 ± 17.58 yrs. The mean NHHR was 2.97 ± 1.48, and in the fully adjusted model, a negative correlation was observed between NHHR and ePWV scores (β = -0.01, 95% CI: -0.02, -0.00), with the highest tertile of the NHHR having a mean ePWV score that was 0.06 units lower than the lowest quartile of the NHHR by 0.06 units (β = -0.06, 95% CI: -0.09, -0.02; P for trend = 0.0068). An L-shaped relationship between NHHR and ePWV scores was found by using smoothed curve fitting. The cutoff value was 2.13, and in the hypertensive population, the cutoff value was 1.93. Conclusions: There is an L-shaped association between NHHR levels and atherosclerosis in adults in the United States, and controlling NHHR is clinically important for reducing the risk of developing atherosclerosis.

Abstract 4124709: Accelerometer-Measured Sedentary Behavior and Future Cardiovascular Disease

Background: Current consensus guidelines emphasize the importance of achieving 150 minutes or more of moderate to vigorous physical activity (MVPA) per week to promote cardiovascular health but give little guidance about sedentary behavior. Research Question: Is sedentary behavior associated with cardiovascular (CV) disease in a manner distinct from insufficient physical activity? Aims: Examine associations between accelerometer-measured sedentary behavior with risk of specific CV outcomes, including potential interactions with MVPA. Methods: Using 89,530 individuals providing one week of accelerometer-based physical activity data from the UK Biobank, we fit Cox models adjusted for demographic and lifestyle factors to assess associations between sedentary time (as a spline term) and incident atrial fibrillation (AF), myocardial infarction (MI), heart failure (HF), and CV mortality. We assessed the potential effect of MVPA on these associations by including MVPA as an adjustment variable, as well as performing subgroup analyses stratified at the guideline-recommended MVPA threshold. Results: Among 89,530 individuals (age 62±8 years, 56.4% women) undergoing accelerometry, median sedentary time was 9.4 hours/day (quartile-1: 8.2, quartile-3: 10.6). In multivariable models, using the second quartile (8.2-9.4 hours/day) as a referent, sedentary time in the top quartile (&gt;10.6 hours/day) was associated with greater risk of HF (hazard ratio [HR] 1.45, 95% CI 1.28-1.65), and CV mortality (HR 1.62, 95% CI 1.34-1.96), with evidence of a threshold effect at 10.6 hours/day. Higher sedentary time was also associated with greater risk of incident AF (HR 1.11, 95% CI 1.01-1.21) and MI (HR 1.15, 95% CI 1.00-1.32), with an approximately linear relation. Associations with HF and CV mortality persisted after adjustment for MVPA, as well as among individuals both above and below the guideline-based activity threshold of ≥150 minutes MVPA/week. Conclusions and Relevance: Sedentary behavior is broadly associated with future adverse CV outcomes. For HF and CV mortality, associations appear distinct from insufficient MVPA, and sedentary time in excess of 10.6 hours/day conferred an increased risk.

Identification and Causes of Neighborhood Commercial Areas: Focusing on the Development of Daily Life Circles in Urban Built Environments

Urban planning in China is shifting from an administrative unit-based approach to community life circle planning, aiming to align planning units with residents’ actual activity ranges. As the most fundamental life circle, daily life circle (DLC) planning must adopt a bottom-up approach. However, the widely applicable methods for delineating DLCs remain lacking. This study presents a strategy for delineating DLCs centered on neighborhood commercial areas that aggregate essential daily life services. Correspondingly, a method is proposed for identifying neighborhood commercial areas based on residents’ actual usage of facilities. The method was applied in Qinhuai District, Nanjing, where neighborhood commercial areas were identified and the factors influencing their formation and types were quantitatively analyzed. The results indicate the following: (1) the proposed method accurately identifies neighborhood commercial areas that can serve as DLC central areas; (2) commercial diversity, public transportation stops, and parking spots are the three most influential factors in neighborhood commercial area formation, exhibiting non-linear and threshold effects; and (3) the type of neighborhood commercial areas varies by population density, housing prices, and street betweenness, with betweenness being the most significant factor. These findings provide methods and indicators for DLC delineation and planning, contributing to the realization of the DLC construction concept.

Triglyceride to high-density lipoprotein cholesterol ratio is associated with diabetes incidence in non-obese individuals with normoglycemia: a retrospective cohort study based on individuals from East Asia

BackgroundAlthough several studies have explored the association between the triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-c) and diabetes risk, most of these studies are cross-sectional and typically involve small sample sizes, limiting the ability to draw causal inferences. Additionally, there is currently a few studies specifically focusing on non-obese individuals. Consequently, we conducted a retrospective cohort study to investigate the impact of TG/HDL-c on the risk of developing diabetes among non-obese, normoglycemic individuals across East Asian countries.MethodsThis secondary retrospective cohort study recruited 85,029 non-obese individuals with normal glycemic levels from East Asian countries (China and Japan). We employed Cox proportional hazards regression models, incorporating cubic splines function for smooth curve fitting and using two-piecewise Cox regression for threshold effect analysis, to evaluate the nonlinear associations between baseline TG/HDL-c ratios and diabetes risk in non-obese individuals with normoglycemia. In addition, A range of subgroup and sensitivity analyses were performed to confirm the robustness of our results.ResultsAmong the individuals included, the average age was 42.14 ± 11.88 years, and 37,944 participants (44.62%) were male. After adjusting for covariates, the study revealed a significant correlation between the TG/HDL-c ratio and the risk of diabetes among non-obese individuals (HR=1.37, 95%CI: 1.22-1.54). Furthermore, a non-linear correlation was observed between the TG/HDL-c ratios and the incidence of non-obese diabetes, with an inflection point of 1.36. Under this threshold, the TG/HDL-c ratio notably boosts diabetes risk in non-obese populations, with an HR of 2.38 (95% CI: 1.57-3.59). Conversely, beyond the critical juncture, the upsurge in diabetes risk seems to level off, displaying no significant variation, with an HR of 1.18 (95% CI: 0.98-1.41).ConclusionsThis study reveals a non-linear association between the TG/HDL-c ratios and the likelihood of diabetes in non-obese individuals from East Asia. Maintaining a ratio of TG/HDL-C below 1.36 significantly reduces diabetes risk. However, once the ratio of TG/HDL-C exceeds 1.36, reducing it does not substantially lower diabetes onset risk.

Corrosion inhibition threshold effect of 1,2,4-triazole in alkaline chemical mechanical polishing of copper: Investigations using synchrotron radiation microinfrared

Corrosion inhibition threshold effect of 1,2,4-triazole in alkaline chemical mechanical polishing of copper: Investigations using synchrotron radiation microinfrared

Association between the composite dietary antioxidant index and erectile dysfunction in US men: a cross-sectional study.

Erectile dysfunction (ED) is a common issue among adult males. The Composite Dietary Antioxidant Index (CDAI) reflects anti-inflammatory levels and has been linked to various diseases, but its relationship with ED is unclear. This cross-sectional study utilised comprehensive data on clinical factors from the 2001-2004 National Health and Nutrition Examination Survey (NHANES). To investigate the link between variables and ED, we used multivariate regression analysis, univariate analysis, and subgroup analysis. The linear relationship between CDAI and ED was investigated by dose-response curve analysis. For sensitivity analysis, propensity score matching (PSM) was utilised to exclude the influence of potential confounders. Finally, we investigated the association between CDAI and ED using threshold effects analysis. We included in our research a total of 2896 persons with data on CDAI from NHANES 2001-2004. Among these, 2,098 participants were thought to be free of ED, whereas 798 participants had ED. We found that compared to the ED group, men in the non-ED group had higher levels of CDAI (p < 0.0001 before PSM and p = 0.0145 after PSM). Additionally, after adjusting for covariates, it was found that an elevated CDAI was associated with a reduced incidence of ED [OR = 0.65(p = 0.001) before PSM and OR = 0.62(p = 0.002) after PSM]. Subgroup analysis indicated stronger associations in high-risk groups, and dose-response curves confirmed a linear negative correlation between CDAI and ED. This study revealed a negative linear relationship between CDAI and the incidence of ED. The CDAI can be used as an indicator for assessing ED risk and for ED prevention.

Data‐driven estimation for multithreshold accelerated failure time model

AbstractThis article develops a novel estimation framework for the multithreshold accelerated failure time model, which has distinct linear forms within different subdomains. One major challenge is to determine the number of threshold effects. We first show the selection consistency of a modified Bayesian information criterion under mild conditions. It is useful sometimes but heavily depends on the penalization magnitude, which usually varies from the model configuration and data distribution. To address this issue, we leverage a cross‐validation criterion alongside an order‐preserved sample‐splitting scheme to yield a consistent estimation. The new criterion is completely data driven without additional parameters and thus robust to model setting and data distributions. The asymptotic properties for the parameter estimates are also carefully established. Additionally, we propose an efficient score‐type test to examine the existence of threshold effects. The new statistic is free of estimating any potential threshold effects and is thus suitable for multithreshold scenarios. Numerical experiments validate the reliable finite‐sample performance of our methodologies, which corroborates the theoretical results.

Association between blood lead levels and serum creatinine: a cross-sectional study.

The aim of this cross-sectional study was to investigate the association between blood lead levels and serum creatinine. In the present study, sample data were derived from the National Health and Nutrition Examination Survey (NHANES) 2015-2018 of participants with complete data of blood lead levels and serum creatinine. Multivariate linear regression models were used to examine the association between blood lead levels and serum creatinine. The nonlinear connection was described using fitted smoothing curves and threshold effect analysis. Furthermore, subgroup analyses and interaction tests were performed. A total of 9026 participants were enrolled in this study, and the mean serum creatinine for all subjects was 0.86 ± 0.34mg/dL. When blood lead levels were divided into quartiles, it was found that participants' serum creatinine levels gradually increased with increasing blood lead levels (Q1: 0.77 ± 0.19mg/dL, Q2: 0.84 ± 0.23mg/ dL, Q3: 0.89 ± 0.34mg/dL, Q4: 0.94 ± 0.50mg/dL). Compared to the lowest serum quartile, the highest quartile of blood lead levels had a positive correlation with serum creatinine in the fully adjusted model (β = 0.05 95% CI 0.01-0.08). Smooth curve fittings and threshold effect analysis showed an inverted J-shaped nonlinear relationship between blood lead levels and serum creatinine, with an inflection point of 3.10 (μg/dL). Subgroup analyses and interaction tests revealed that diabetes mellitus impacted the relationship between serum creatinine and blood lead levels. This study suggests a positive correlation between blood lead levels and serum creatinine.

Threshold effects of credit risk on renewable energy consumption and green financial policies nexus: evidence from OECD countries

Threshold effects of credit risk on renewable energy consumption and green financial policies nexus: evidence from OECD countries

Research on the impact and mechanism of digital economy on China’s food production capacity

Enhancing and strengthening food production capacity has always been a top priority in agricultural research, serving as a cornerstone for ensuring national food security and stable economic development. This study, based on panel data spanning from 2011 to 2021 across 30 provinces in China, delves into the mechanism through which the digital economy impacts food production capacity. Employing a double fixed effect model, a mediation effect model, and a panel threshold model, we uncover several key findings: The digital economy significantly boosts food production capacity, with robustness tests affirming the reliability of our results. Mechanism analysis reveals that the digital economy enhances food production capacity by elevating total factor productivity and bolstering agricultural resilience. The threshold effect underscores that urbanization levels exhibit a single-threshold impact, wherein the influence of the digital economy on food production capacity intensifies upon crossing this threshold. Heterogeneity analysis reveals that the digital economy significantly boosts food production capacity in central and primary grain-producing regions, while its impact is comparatively weaker in the eastern and western regions, as well as in non-primary grain-producing areas. In summary, this research sheds light on the pivotal role of the digital economy in augmenting food production capacity, offering valuable insights into regional variations and thresholds in its impact across China.

Nonlinear association between platelet to albumin ratio and disease activity in patients with early rheumatoid arthritis

The relationship between the platelet to albumin ratio (PAR) and the disease activity of early rheumatoid arthritis (ERA) remains to be elucidated. This cross-sectional study included 372 patients with ERA who were hospitalized at Xingtai People’s Hospital between January 2022 and January 2024. Multiple linear regression analysis was employed to assess the correlation of PAR with Disease Activity Score 28 (DAS28) using erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and then generalized additive models were used to explore their relationship. After accounting for confounding variables, a positive correlation was observed between the PAR and DAS28-ESR and DAS28-CRP in ERA patients (β (95% CI): 0.20 (0.08, 0.32) and 0.20 (0.08, 0.33), respectively), and the general trends were consistent from the lowest tertile group (T1) to the highest tertile group (T3). Furthermore, a nonlinear relationship was identified between PAR and both DAS28-ESR and DAS28-CRP. Threshold effect analysis indicated that a value of 13.73 was a significant inflection point. In brief, PAR has a threshold effect on the disease activity of ERA. Increased PAR levels were independently positive associated with DAS28-ESR and DAS28-CRP among ERA patients with PAR < 13.73.