Spline Regression Models Research Articles

Optimal Implant Sizing Using Machine Learning Is Associated With Increased Range of Motion After Cervical Disk Arthroplasty.

Cervical disk arthroplasty (CDA) offers the advantage of motion preservation in the treatment of focal cervical pathology. At present, implant sizing is performed using subjective tactile feedback and imaging of trial cages. This study aims to construct interpretable machine learning (IML) models to accurately predict postoperative range of motion (ROM) and identify the optimal implant sizes that maximize ROM in patients undergoing CDA. Adult patients who underwent CDA for single-level disease from 2012 to 2020 were identified. Patient demographics, comorbidities, and outcomes were collected, including symptoms, examination findings, subsidence, and reoperation. Affected disk height, healthy rostral disk height, and implant height were collected at sequential time points. Linear regression and IML models, including bagged regression tree, bagged multivariate adaptive regression spline, and k-nearest neighbors, were used to predict ROM change. Model performance was assessed by calculating the root mean square error (RMSE) between predicted and actual changes in ROM in the validation cohort. Variable importance was assessed using RMSE loss. Area under the curve analyses were performed to identify the ideal implant size cutoffs in predicting improved ROM. Forty-seven patients were included. The average RMSE between predicted and actual ROM was 7.6° (range: 5.8-10.1) in the k-nearest neighbors model, 7.8° (range: 6.5-10.0) in the bagged regression tree model, 7.8° (range: 6.2-10.0) in the bagged multivariate adaptive regression spline model, and 15.8° (range: 14.3-17.5°) in a linear regression model. In the highest-performing IML model, graft size was the most important predictor with RMSE loss of 6.2, followed by age (RMSE loss = 5.9) and preoperative caudal disk height (RMSE loss = 5.8). Implant size at 110% of the normal adjacent disk height was the optimal cutoff associated with improved ROM. IML models can reliably predict change in ROM after CDA within an average of 7.6 degrees of error. Implants sized comparably with the healthy adjacent disk may maximize ROM.

Area-Based Hedonic Pricing of Urban Green Amenities in Beijing: A Spatial Piecewise Approach

AbstractThis study explores a spatial piecewise approach for the hedonic valuation of the area of urban green space at different distances from a property, using a rich census dataset collected from Beijing. We explore three novel empirical strategies that improve the identification of the spatial boundary or threshold distance within which green space is capitalised into housing prices. We first delineated a series of concentric circles surrounding each property and measured the area of green space within each doughnut-shaped ring. We next estimated the hedonic price using three methods. The first is a regression spline model combined with a machine learning type of model selection procedure which objectively selects the exact location of the threshold distance that optimises the model’s predictive performance. The second is a novel matching algorithm that minimises covariate imbalance for a continuous treatment variable (i.e., the area of green space) to provide stronger causal evidence on the hedonic prices of green space at different distances. The third is a spatial difference-in-differences approach that further accounts for endogeneity bias associated with unobserved factors. For our dataset, we found that housing prices are more likely to be affected by green space within a 1 km radius.

Serum Iron Levels, Dietary Iron Intake, and Supplement Use in Relation to Metabolic Syndrome in Adolescents: A Cross-Sectional Study.

The objective of this study was to investigate the potential associations between serum iron levels, dietary iron intake, and iron supplementation, and the prevalence of metabolic syndrome (MetS) in adolescents A cross-sectional analysis was conducted, utilizing data from adolescents participating in the 2003-2018 cycle of the National Health and Nutrition Examination Survey (NHANES). Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) pertaining to serum iron, dietary iron, and iron supplementation were derived through multivariate logistic regression models. Additionally, a restricted cubic spline (RCS) regression model was applied to explore the nonlinear relationship between dietary iron and serum iron concerning MetS. The study encompassed 4858 American adolescents aged 12 to 19, among whom 413 (8.5%) manifested MetS. The study cohort exhibited an average age of 15.52years, comprising 2551 males (52.51%) and 2307 females (47.49%). Relative to individuals in the lowest serum iron quartile, those in the highest quartile for serum iron (OR = 0.33, 95% CI 0.21-0.50), the highest quartile for dietary iron (OR = 0.53, 95% CI 0.32-0.89), and those utilizing iron supplements (OR = 0.61, 95% CI 0.37-0.99) evinced a diminished prevalence of MetS, even post adjustment for potential confounding variables. A non-linear relationship was discerned between serum iron and MetS, exhibiting a statistically significant negative correlation when serum iron concentrations exceeded the inflection point (serum iron = 8.66µmol/L, P for nonlinear < 0.001). This investigation reveals that higher levels of serum iron, increased dietary iron intake, and the use of iron supplements are linked to a lower prevalence of MetS in US adolescents. These findings suggest that dietary modifications could play a role in promoting the health of adolescents.

The relationship between sarcopenia and metabolic dysfunction-associated fatty liver disease among the young and middle-aged populations

BackgroundMetabolic dysfunction-associated fatty liver disease (MAFLD) has been proposed as a new term for diagnosing fatty liver disease, which is considered to be a multi-systemic disease with multiple extrahepatic manifestations, including sarcopenia. The link between sarcopenia and MAFLD remains uncertain, especially among young and middle-aged adults. Thus, we examined the relationship between MAFLD and sarcopenia in young and middle-aged individuals in this study.MethodsA total of 2214 individuals with laboratory tests, dual-energy X-ray absorptiometry and ultrasound transient elastography from NHANES 2017–2018 were selected for this study. MAFLD was diagnosed as fatty liver disease with any one of the situations: overweight/obesity, diabetes mellitus, presence of metabolic dysregulation. Sarcopenia was defined by appendicular lean mass adjusted for body mass index (BMI). Multivariable logistic regression and restricted cubic spline (RCS) model were applied to explore the relationship between MAFLD and sarcopenia, and the mediation analyses were also conducted. Moreover, subgroup analyses stratified by BMI and lifestyles were done.ResultsThe prevalence of MAFLD was 47.85%, and nearly 8.05% of participants had sarcopenia. The prevalence of sarcopenia was higher in participants with MAFLD (12.75%; 95% CI 10.18–15.31%) than in the non-MAFLD (3.73%; 95% CI 2.16–5.31%). MAFLD was significantly positively associated with sarcopenia after adjustments [OR = 2.87 (95% CI: 1.62–5.09)]. Moreover, significant positive associations were observed between liver fibrosis and sarcopenia prevalence in MAFLD patients (OR = 2.16; 95% CI 1.13–4.15). The RCS curve revealed that MAFLD was linearly associated with sarcopenia. The relationship between the MAFLD and sarcopenia were mediated by C-reactive protein (mediation proportion: 15.9%) and high-density lipoprotein cholesterol (mediation proportion: 18.9%). Subgroup analyses confirmed the association between MAFLD and sarcopenia differed in different lifestyle groups.ConclusionsBoth MAFLD prevalence and severity was significantly associated with sarcopenia. Thus, clinicians should advise comorbidity screening and lifestyle changes to young and middle-aged patients.

Dietary and Smoking Acrylamide and Prostate Cancer Risk: CAPLIFE Study.

Acrylamide is a probable carcinogen. Its main sources are the diet and tobacco. The association between acrylamide intake from the diet and tobacco and prostate cancer (PCa) has not been previously evaluated. We aimed to evaluate the relationship between dietary acrylamide intake and exposure to acrylamide through cigarettes and PCa risk. A population-based case-control (CAPLIFE) study was conducted, including 428 incident PCa cases and 393 controls. Smoking and dietary information, with a validated food frequency questionnaire, was collected. We calculated the amount of acrylamide from both sources, and tertiles (Ts) were created. Multivariable logistic regression and restricted cubic spline models were applied to assess the association between exposure to acrylamide and PCa risk. The median was similar for acrylamide in both dietary and smoking acrylamide among PCa cases and controls. No association was observed between dietary acrylamide intake and overall PCa risk (adjusted ORT3vsT1 = 0.90 (95% CI 0.59, 1.37)). A risk trend was observed for acrylamide exposure from cigarette smoking (p-trend = 0.032), with the highest odds in those subjects with the high exposure to acrylamide through cigarettes (adjusted ORT3vsT1 = 1.67 (95% CI 0.92, 3.04)). The restricted cubic splines suggested a linear relationship. In conclusion, acrylamide from smoking could be positively associated with PCa risk, but no association was observed for dietary acrylamide.

Association between triglyceride-glucose index and intracranial/extracranial atherosclerotic stenosis: findings from a retrospective study

ObjectiveThe association of the triglyceride-glucose (TyG) index with intracranial atherosclerotic stenosis (ICAS) and extracranial atherosclerotic stenosis (ECAS) is unclear. This study aimed to investigate the relationship of TyG index with the distribution and severity of ICAS and ECAS.MethodPatients who underwent digital subtraction angiography (DSA) for evaluating ICAS/ECAS in Zhongnan Hospital of Wuhan University from January 2017 to October 2021 were retrospectively enrolled in our study. Clinical characteristics, DSA data, blood routine, lipid profile and fasting glucose were recorded. The association of TyG index and ICAS/ECAS status were investigated in four aspects: location and distribution of stenosis, stenosis severity and whether stenosis is symptomatic. Logistic regression models were used to evaluate the association. Restricted cubic splines were constructed to model the non-linear relationship between the TyG index and different arterial stenosis status.ResultsAmong 1129 included patients, the median age was 62 (IQR 55–68) years, and 71.3% were male. The median TyG index was 8.81 (8.40, 9.21). Elevated TyG index was significantly associated with ICAS, combined ICAS/ECAS, anterior circulation stenosis, posterior circulation stenosis, combined anterior/posterior circulation stenosis, severe stenosis, both asymptomatic and symptomatic stenosis. This association was maintained after adjusting for age, sex, smoking, drinking, medical history of hypertension and stroke, platelet, total cholesterol, high-density lipoprotein, and low-density lipoprotein. Multivariable-adjusted spline regression models showed that a progressively increasing risk of arterial stenosis was related to an elevated TyG index.ConclusionElevated TyG index was associated with ICAS/ECAS. TyG index might be a useful indicator of ICAS and severe stenosis.

Exploring the strategic role of Marketer-Generated-Content analytics towards Airbnb hosts sales optimization

ABSTRACT Although user-generated content is reported to improve Airbnb host’s sales, the impact of Marketer-Generated Content (MGC) on the minimum sales generated from the reviewers who have reviewed the MGC is yet to be explored. This study examines MGC of title descriptions analysis from the City of Los Angeles listing data to understand their importance in predicting hosts’ net sales. The analysis employs two complementary econometric approaches: parametric multiple regression and the non-parametric multivariate adaptive regression spline model across three neighbourhood groups and two price groups. The findings indicate hosts can employ MGC to optimize sales and should highlight feature words in the title that best reflect the property characteristics and appeal to a target group that may be location-specific, price-sensitive, or both. The title should be informative and detailed within a limit of 10 words. The novelty of the work is to identify the influence of total sales for respective feature words from the title description of Airbnb property and to analyze their uses in marketing communications. The practical implications indicate that host-generated feature words are crucial in maximizing net sales for the property.

The ratio of systolic and diastolic pressure is associated with carotid and femoral atherosclerosis.

Although the impact of hypertension on carotid intima-media thickness (IMT) and plaques has been well established, its association with femoral IMT and plaques has not been extensively examined. In addition, the role of the ratio of systolic and diastolic pressure (SDR) in the subclinical atherosclerosis (AS) risk remains unknown. We assessed the relationship between SDR and carotid and femoral AS in a general population. A total of 7,263 participants aged 35-74 years enrolled from January 2019 to June 2021 in a southeast region of China were included in a cross-sectional study. Systolic and diastolic blood pressure (SBP and DBP) were used to define SDR. Ultrasonography was applied to assess the AS, including thickened IMT (TIMT) and plaque in the carotid and femoral arteries. Logistic regression and restricted cubic spline (RCS) models were the main approaches. The prevalence of TIMT, plaque, and AS were 17.3%, 12.4%, and 22.7% in the carotid artery; 15.2%, 10.7%, and 19.5% in the femoral artery; and 23.8%, 17.9% and 30.0% in either the carotid or femoral artery, respectively. Multivariable logistic regression analysis found a significant positive association between high-tertile SDR and the higher risk of overall TIMT (OR = 1.28, 95% CI = 1.10-1.49), plaques (OR = 1.36, 95%CI = 1.16-1.61), or AS (OR = 1.36, 95% CI = 1.17-1.57), especially in the carotid artery. RCS analysis further revealed the observed positive associations were linear. Further analyses showed that as compared to the low-tertile SDR and non-hypertension group, high-tertile SDR was associated with increased risks of overall and carotid TIMT, plaques, or AS in both groups with or without hypertension. SDR is related to a higher risk of subclinical AS, regardless of hypertension or not, suggesting that as a readily obtainable index, SDR can contribute to providing additional predictive value for AS.

Sleep patterns and long-term mortality among older Israeli adults: a population-based study

IntroductionThe joint association of night-time sleep duration and daytime napping (siesta) with mortality remains elusive. We explored sleep patterns and long-term mortality in older adults and tested whether the relationship...

Association of high-sensitivity CRP and FEV1%pred: a study on non-pulmonary disease in a population in Beijing, China

BackgroundNo studies have investigated whether high-sensitivity C reactive protein (hsCRP) can be used to predict the forced expiratory volume in 1 s (FEV1)/estimated value of FEV1 (FEV1%pred). This study aimed...

Serum heme oxygenase-1 level predicts clinical outcome after acute ischemic stroke.

The relationship between heme oxygenase-1 (HO-1) and human ischemic stroke outcome remains unclear, which was investigated in this study. Acute ischemic stroke patients admitted within 24 h were enrolled. Serum HO-1 levels at baseline were measured via ELISA. Poor 3-month functional outcome was defined as modified Rankin Scale (mRS) score 3-6. Multivariable-adjusted binary logistic regression and restricted cubic spline models were employed to examine association between serum HO-1 and functional outcome. HO-1's additive prognostic utility was assessed by net reclassification index (NRI) and integrated discrimination improvement (IDI). Of 194 eligible patients, 79 (40.7%) developed poor functional outcomes at 3-month follow-up. The highest quartile of serum HO-1 was independently associated with a lower risk of poor functional outcome (adjusted OR 0.13, 95% CI 0.04-0.45; p = 0.001) compared with the lowest HO-1 category. The relationship between higher HO-1 levels and reduced risk of poor functional outcome was linear and dose responsive (p = 0.002 for linearity). Incorporating HO-1 into the analysis with conventional factors significantly improved reclassification for poor functional outcomes (NRI = 41.2%, p = 0.004; IDI = 5.0%, p = 0.004). Elevated serum HO-1 levels at baseline were independently associated with improved 3-month functional outcomes post-ischemic stroke. Serum HO-1 measurement may enhance outcome prediction beyond conventional clinical factors.

Systemic immune-inflammatory biomarkers (SII, NLR, PLR and LMR) linked to non-alcoholic fatty liver disease risk.

Systemic immune-inflammatory biomarkers including systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) have been demonstrated to be associated with the risk and severity of various liver diseases. However, studies on their role and clinical significance in metabolic diseases, especially in nonalcoholic fatty liver disease (NAFLD), are limited and results are inconsistent. 10821 adults aged 20 years or older were enrolled in this cross-sectional study, sourced from six cycles of the National Health and Nutrition Examination Survey (NHANES). Survey-weighted logistic regression was employed to investigate the correlation between systemic immune-inflammatory biomarkers (SII, NLR, PLR, and LMR) and NAFLD risk. Restricted cubic spline regression models and segmented regression models were used to describe nonlinear relationships and threshold effects. Subgroup and sensitivity analyses were also conducted. After adjusting for all confounding variables, there was a significant positive association observed between ln-transformed SII (OR= 1.46, 95% CI: 1.27-1.69, P <0.001), NLR (OR= 1.25, 95% CI: 1.05-1.49, P =0.015), LMR (OR= 1.39, 95% CI: 1.14-1.69, P = 0.002) with NAFLD. A nonlinear dose-response relationship with an inverted "U"-shaped threshold of 4.64 was observed between ln(PLR) and NAFLD risk. When ln(PLR) was below 4.64, each unit increase in ln(PLR) was associated with a 0.55-fold increase in the risk of NAFLD (OR= 1.55, 95% CI: 1.05-2.31, P <0.05). Conversely, when ln(PLR) exceeded 4.64, each unit increase in ln(PLR) was associated with a 0.40-fold decrease in the risk of NAFLD (OR= 0.60, 95% CI. 0.44-0.81, P <0.05). ln-transformed SII, NLR, and LMR were linearly associated with NAFLD risk. ln(PLR) showed an inverted "U"-shaped nonlinear dose-response relationship with the risk of NAFLD.

Association between the trajectory of ideal cardiovascular health metrics and incident chronic kidney disease among 27,635 older adults in northern China–a prospective cohort study

BackgroundThere is a lack of relevant studies evaluating the long-term impact of cardiovascular health factor (CVH) metrics on chronic kidney disease (CKD).ObjectiveThis study investigates the long-term change in CVH metrics in older people and explores the relationship between CVH metrics trajectory and CKD.MethodsIn total, 27,635 older people aged over 60 from the community-based Tianjin Chronic Kidney Disease Cohort study were enrolled. The participants completed five annual physical examinations between January 01, 2014, and December 31, 2018, and a subsequent follow-up between January 01, 2019, and December 31, 2021. CVH metrics trajectories were established by the group-based trajectory model to predict CKD risk. The relationships between baseline CVH, CVH change (ΔCVH), and CKD risk were also explored by logistic regression and restricted cubic spline regression model. In addition, likelihood ratio tests were used to compare the goodness of fit of the different models.ResultsSix distinct CVH metrics trajectories were identified among the participants: low-stable (11.19%), low-medium-stable (30.58%), medium-stable (30.54%), medium-high-decreased (5.46%), medium-high-stable (18.93%), and high-stable (3.25%). After adjustment for potential confounders, higher CVH metrics trajectory was associated with decreased risk of CKD (P for trend < 0.001). Comparing the high-stable with the low-stable group, the risk of CKD decreased by 46%. All sensitivity analyses, including adjusting for baseline CVH and removing each CVH component from the total CVH, produced consistent results. Furthermore, the likelihood ratio test revealed that the model established by the CVH trajectory fit better than the baseline CVH and Δ CVH.ConclusionThe higher CVH metrics trajectory and improvement of CVH metrics were associated with decreased risk of CKD. This study emphasized the importance of improving CVH to achieve primary prevention of CKD in older people.

Low-carbohydrate-diet score, dietary macronutrient intake, and depression among adults in the United States

BackgroundThe aim was to ascertain whether low-carbohydrate-diet (LCD) score and dietary macronutrient intake are associated with depression. MethodsThis cross-sectional study included 23,204 United States adults from the National Health and Nutrition Examination Survey (NHANES) 2005–2018. Dietary macronutrient intake was evaluated by the average of two 24-h dietary recall interviews. LCD score was calculated by summing the 11 quantiles values of the percentages of energy derived from carbohydrate, protein, and fat. Major depression was defined as a nine-item Patient Health Questionnaire score of 10 or more. Logistic regression and restricted cubic spline models were used to explore the relationship between LCD score, dietary macronutrient intake, and depression. ResultsLCD score was significantly associated with the risk of depression after adjustment for covariates (odds ratio, 0.98; 95 % confidence interval, 0.97–0.99; p < 0.001). Restricted cubic splines showed that the pattern of this inverse association was nonlinear. Among macronutrients, carbohydrate and protein intake was nonlinearly associated with the risk of depression, whereas fat intake was not related to the risk of depression. A decreased risk of depression was observed when the carbohydrate intake was moderate (45.3 %–59.1 %). The pattern of the association between protein intake and the risk of depression was L-shaped. ConclusionsLCD score was inversely associated with the risk of depression in a nonlinear manner in a nationally representative sample of adults from the United States. Furthermore, moderate carbohydrate intake and high protein intake were correlated with a lower risk of depression.

Association and dose-response relationship of plasma magnesium with metabolic syndrome in Chinese adults older than 45 years.

Magnesium (Mg) is an essential nutrient for the maintenance of vital physiological functions. Magnesium deficiency is associated with diseases such as obesity, type 2 diabetes mellitus (T2DM), and metabolic syndrome (MetS); however, conclusions have been inconsistent, and there is a particular lack of evidence regarding this association in Chinese population older than 45 years. This study aimed to assess the association between plasma magnesium and the risk of MetS and its components, the dose-response relationship, and the threshold effect relationship in a Chinese population involving older than 45 years. A total of 2,101 individuals were randomly selected from the China Nutrition and Health Surveillance (CNHS) (2015-2017) by considering monitoring points. We used the joint statement of the International Diabetes Federation (IDF) in 2009 to define participants with MetS. The plasma magnesium was tested by inductively coupled plasma mass spectrometry (ICP-MS). The logistic regression and restricted cubic spline (RCS) models were used to analyze the association and dose-response relationship between plasma Mg and MetS and its components. Compared with the lowest quintile (Q1) for plasma Mg, the odds ratios (ORs) and 95% confidence intervals (95% CI) for MetS, impaired fasting glucose (IFG), hypertension, and triglyceride (TG) elevation at the highest quintile (Q5) were 0.419 (0.301, 0.583), 0.303 (0.221, 0.415), 0.446 (0.322, 0.618), and 0.526 (0.384, 0.720), respectively, with all p < 0.05. However, in the components of decreased high-density lipoprotein cholesterol (HDL-C) and central obesity, no trend toward lowering with higher plasma magnesium was observed (p = 0.717, p = 0.865). These associations were not altered by further adjustment for potential confounding variables, including age, gender, education, nationality, area, residence, body mass index (BMI), and heart rate. The RCS analysis showed that, when plasma magnesium was lower than 0.85 mmol/L, the curve was leveled off, and then, the curve showed a decreasing trend with the increase in plasma magnesium. Therefore, plasma Mg was negatively associated with MetS and its components (including IFG, hypertension, and elevated TG) in people older than 45 years. In addition, plasma Mg greater than or equal to 0.85 mmol/L, which is higher than the commonly used threshold of 0.75 mmol/L, may be protective against MetS and its components (including elevated FPG, elevated blood pressure, and elevated TG). More prospective studies, such as randomized controlled trials, are necessary to confirm the effective impact of Mg on MetS and its components. Plasma Mg levels in the MetS population older than 45 years require attention.

The association between remnant cholesterol and rheumatoid arthritis: insights from a large population study

ObjectivesWhile lipid metabolism disorder is widely acknowledged as a contributing factor to inflammation, the association between remnant cholesterol (RC), which indicates lipid metabolism, and rheumatoid arthritis (RA) has not been investigated. Accordingly, this study evaluated whether RC is associated with RA disease events.MethodsData were collected and specifically extracted from the National Health and Nutrition Examination Survey (NHANES) 1999–2008 database. The RC value was derived by subtracting the combined amount of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) from the total cholesterol (TC). The association between RC and RA was evaluated using multivariate regression analysis and subgroup analysis.ResultsThe study analyzed 7777 patients, of which 581 patients (7.47%) were diagnosed with RA. After accounting for different covariates, the multivariate logistic regression analysis revealed a notable correlation between increased RC levels and an increased likelihood of RA (odds ratio OR = 1.54; 95% confidence interval CI: 1.11–2.13; P = 0.0092). The interaction test did not yield statistically significant effects on this association. The linear correlation between RC and RA was observed within restricted cubic spline regression model limitations.ConclusionThe results suggest that higher RC levels are associated with increased odds of RA, indicating that RC can serve as a novel and convenient index for forecasting the likelihood of RA in the United States. Additionally, these findings offer insights into early intervention strategies for susceptible populations at risk of developing RA.

Association of dietary niacin intake with the prevalence and incidence of chronic obstructive pulmonary disease

Evidence regarding the association between dietary niacin intake and chronic obstructive pulmonary disease (COPD) is limited. Our study investigates the relationship between dietary niacin intake and the prevalance and incidence of COPD in the adult population of the United States, using data from the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2018. Data on niacin intake were extracted through dietary intake interviews. COPD diagnoses were based on lung function, medical history, and medication usage. We analyzed the association between niacin consumption and COPD using multiple logistic regression and restricted cubic spline models. The study included 7055 adult participants, divided into COPD (n = 243; 3.44%) and non-COPD (n = 6812; 96.56%) groups. Those with COPD had lower average niacin intake (21.39 ± 0.62 mg/day) compared to the non-COPD group (25.29 ± 0.23 mg/day, p < 0.001). In the adjusted multivariable model, the odds ratios (OR) and 95% confidence intervals (CI) for COPD in the highest versus lowest quartile of dietary niacin intake were 0.55 (0.33 to 0.89, P for trend = 0.009). Subgroup analysis, after adjustment for various variables, revealed no significant interaction effects. Dietary niacin intake was inversely associated with COPD prevalence in US adults. Participants with the highest dietary niacin intake demonstrated the lowest odds of COPD. The potential of dietary niacin supplementation as a strategy to mitigate COPD warrants further investigation.

Association between the cumulative triglyceride-glucose index and the recurrence of atrial fibrillation after radiofrequency catheter ablation.

Triglyceride-glucose (TyG) index values are a new surrogate marker for insulin resistance. This study aimed to explore the relationship between cumulative TyG index values and atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA). A total of 576 patients with AF who underwent RFCA at the Second Affiliated Hospital of Xi'an Jiaotong University were included in this study. The participants were grouped based on cumulative TyG index values tertiles within 3 months after ablation. Cox regression and restricted cubic spline analyses were used to determine the relationship between cumulative TyG index values and AF recurrence. The predictive value of all risk factors was assessed by receiver operating curve analysis. There were 375 patients completed the study (age: 63.23 ± 10.73 years, 64.27% male). The risk of AF recurrence increased with increasing cumulative TyG index values tertiles. After adjusting for potential confounders, patients in the medium cumulative TyG index group [hazard ratio (HR) = 4.949, 95% CI: 1.778-13.778, P = 0.002] and the high cumulative TyG index group (HR = 8.716, 95% CI: 3.371-22.536, P < 0.001) had a higher risk of AF recurrence than those in the low cumulative TyG index group. The restricted cubic spline regression model also showed an increased risk of AF recurrence with increasing cumulative TyG index values. When considering cumulative TyG index values, left atrial diameter, and lactate dehydrogenase levels as a comprehensive factor, the model could effectively predict AF recurrence after RFCA [area under the curve (AUC) = 0.847, 95% CI: 0.797-0.897, P < 0.001]. Cumulative TyG index values were a risk factor for AF recurrence after RFCA. Monitoring longitudinal TyG index values may assist with optimized for risk stratification and outcome prediction for AF recurrence.

Poor serum uric acid control increases risk for developing hypertension: a retrospective cohort study in China.

Serum uric acid (SUA) has been suggested as a contributor of hypertension. However, reports on the relationship between changes in SUA and hypertension are limited. Hence, we aimed to investigate the potential impact of SUA, especially its change over time, on hypertension incidence. This dynamic cohort included 6052 participants without hypertension at baseline. Participants were categorized into six grades based on whether baseline SUA was high and whether changes in SUA progressed to hyperuricemia or decreased to normal levels. Grades 1 to 6 represented the participants' SUA control from best to worst. Logistic regression and restricted cubic spline (RCS) models were used to explore the association of the grades of SUA control and hypertension incidence. During a median follow-up of 6 years, 2550 (42.1%) participants developed hypertension. After adjusting confounding factors, compared to grade 1 with the best control of SUA, the odds ratios for grades 2 to 6 with worse control were 1.347 (1.109-1.636), 1.138 (0.764-1.693), 1.552 (1.245-1.934), 1.765 (1.170-2.663), and 2.165 (1.566-2.993), respectively. RCS indicated a linear correlation between the risk of hypertension and changes in SUA, and an elevated risk in participants with baseline hyperuricemia. Subgroup analyses showed that grades of SUA control had an interaction with systolic (P = 0.003) and diastolic blood pressure (P < 0.001). Sensitivity analyses further determined the robustness of the result that participants with poor SUA control have a higher risk of developing hypertension. Poor SUA control, an increase in SUA over time, rises the risk of developing hypertension regardless of whether the initial SUA is normal or not. Initial hyperuricemia will exacerbate this risk. Effective SUA control should be an important measure for primary prevention of hypertension.

Associations between serum per- and polyfluoroalkyl substances and thyroid hormones in Chinese adults: A nationally representative cross-sectional study

Disruption of thyroid homeostasis has been indicated in human studies on the effects of per- and polyfluoroalkyl substances (PFASs). However, limited research exists on this topic within the general Chinese population. Based on a substantial and representative sample of the Chinese adult population, our study provides insight into how PFASs specifically affect thyroid homeostasis. The study included 10 853 participants, aged 18 years and above, sampled from nationally representative data provided by the China National Human Biomonitoring (CNHBM). Weighted multiple linear regression and restricted cubic spline (RCS) models were used to explore the associations between eight individual PFAS concentrations and total thyroxine (T4), total triiodothyronine (T3), and the T4/T3 ratio. Bayesian kernel machine regression (BKMR) and quantile-based g-computation (qgcomp) were employed to explore the joint and independent effects of PFASs on thyroid homeostasis. Both individual PFASs and PFAS mixtures exhibited a significant inverse association with serum T3 and T4 levels, and displayed a positive association with the T4/T3 ratio. Perfluoroundecanoic acid (PFUnDA) [–0.07 (95 % confidence interval (CI): –0.08, –0.05)] exhibited the largest change in T3 level. PFUnDA also exhibited a higher weight compared to other PFAS compounds in qgcomp models. Additionally, a critical exposure threshold for each PFAS was identified based on nonlinear dose–response associations; beyond these thresholds, the decreases in T3 and T4 levels plateaued. Specifically, for perfluoroheptane sulfonic acid (PFHpS) and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), an initial decline in hormone levels was observed, followed by a slight increase when concentrations surpassed 0.7 ng/mL and 2.5 ng/mL, respectively. Sex-specific effects were more pronounced in females, and significant associations were observed predominantly in younger age groups. These insights contribute to our understanding of how PFAS compounds impact thyroid health and emphasize the need for further research and environmental management measures to address these complexities.