National Nutrition Research Articles

Relationship between timing of coffee and tea consumption with mortality (total, cardiovascular disease and diabetes) in people with diabetes: the U.S. National Health and Nutrition Examination Survey, 2003–2014

BackgroundPrevious observational studies have suggested diabetic patients should synchronize their foods and nutrient intake with their biological rhythm; however, the optimal intake time of coffee and tea for reducing all-cause and disease-specific mortality in diabetes is still unknown. This study aims to examine by investigating the association of timing for coffee and tea consumption with long-term survival in people with diabetes.MethodsA total of 5378 people with diabetes who enrolled in the National Health and Nutrition Examination Survey from 2003 to 2014 were recruited for this study. Coffee and tea intakes were measured by a 24-h dietary recall, which were divided by different time intervals across the day, including dawn to forenoon, forenoon to noon, noon to evening, and evening to dawn. Weighted cox proportional hazards regression models were developed to evaluate the survival-relationship of coffee and tea consumption with mortality of all-cause, cardiovascular disease (CVD), stroke, and diabetes.ResultsDuring 47,361 person-year follow up, total 1639 death cases were documented, including 731 CVD deaths, 467 heart disease deaths, 99 stroke deaths, and 462 diabetes deaths. After adjustment for potential confounders, compared with participants without drinking coffee during dawn to forenoon, drinking coffee at this period was associated with increased mortality risk of all-cause (HR 1.25, 95% CI 1.05–1.50), CVD (HR 1.41, 95% CI 1.07–1.86), heart-disease (HR 1.47, 95% CI 1.05–2.07), and diabetes (HR 1.50, 95% CI 1.10–2.04). In contrast, drinking coffee during forenoon to noon had lower mortality risk of all-cause (HR 0.80, 95% CI 0.69–0.92), CVD (HR 0.79, 95% CI 0.63–0.99), and heart disease (HR 0.70, 95% CI 0.52–0.94). Similarly, drinking tea during forenoon to noon had lower risk of CVD mortality (HR = 0.62, 95% CI 0.44–0.87).ConclusionsThis study suggests that drinking coffee in dawn to forenoon is linked to a higher risk of death, but having coffee and tea from forenoon to noon is linked to a lower risk of overall mortality, CVD, and heart disease in individuals with diabetes.Graphical

Association between the weight-adjusted-waist index and Familial hypercholesterolemia: a cross-sectional study

ObjectiveThe weight-adjusted-waist index (WWI) is a novel obesity measurement indicator, and this study aims to determine the relationship between WWI and Familial hypercholesterolemia (FH).MethodsUsing data from the National Health and Nutrition Examination Survey (NHANES) from 2017 to March 2020, cross-sectional data from 3698 participants were analyzed. The study examined the correlation between WWI and FH using multivariate logistic regression and smooth curve fitting, and conducted subgroup analysis and interaction tests.ResultsThe study sample consisted of 3698 subjects for whom the overall probable prevalence of FH was 5.43% and increased with WWI tertile (quantile 1: 4.00%; quantile 2: 4.94%; quantile 3: 7.34%); individuals with the highest WWI tertile were significantly more likely to have FH than those with the lowest tertile (OR = 4.60,95% CI: 2.00-10.60). Subgroup analysis and interaction tests showed significant significance between WWI and personal history of early Atherosclerotic cardiovascular disease (ASCVD), family history of early ASCVD and probable prevalence of FH (p < 0.05).ConclusionThis study demonstrates a nonlinear positive correlation between WWI and FH. This may provide new ideas for the prevention and treatment of FH in the future.

Association between oxidative balance score and cardiovascular diseases: mediating analysis of methylmalonic acid based on the NHANES database

AimTo explore the association between oxidative balance score (OBS) and cardiovascular diseases (CVD) in patients with hypertension, and further clarify the mediating role of methylmalonic acid (MMA) in the relationship between OBS and CVD risk.MethodsWe included 4,137 participants with hypertension from the 2011–2014 National Health and Nutrition Examination Survey cohort. The study endpoint was the incidence of CVD in patients with hypertension. OBS was calculated based on 16 dietary and 4 lifestyle components. Weighted multivariable logistic regression models were adopted to assess the associations between OBS and CVD risk, OBS and MMA levels, and MMA levels and CVD risk. Odds ratios (OR) and 95% confidence interval (CI) were estimated. We used distribution-of-product method to test for mediation effect, with a presence of mediation indicated by 95% CI that does not include 0 for the distribution-of-product method and 95% CI that does not include 1 for the indirect effect.ResultsTotally 812 developed CVD. In weighted multivariable logistic regression models, lower OBS category (OBS &amp;lt; 15.72) was associated with increased odds of CVD (OR = 1.53, 95%CI: 1.17–2.01) and MMA levels (OR = 1.32, 95%CI: 1.06–1.65), respectively, compared with higher OBS category as reference. A positive relationship between higher MMA levels (≥154.90 nmol/L) and CVD risk was observed (OR = 1.34, 95%CI: 1.07–1.68). Importantly, according to the distribution-of-product test, a potential mediating effect of MMA on the relationship between OBS and CVD was found (OR = 1.08, 95%CI: 1.01–1.19), with a 95% CI for distribution-of-product of 0.08 (95% CI: 0.01–0.17). The mediated proportion was 17.8%. Subgroup analysis revealed a mediating effect of MMA in individuals with dyslipidemia, with a mediated proportion of 14.9%.ConclusionMMA plays a critical mediating role in the pathway between OBS and CVD risk.

Explainable machine learning model for predicting the risk of significant liver fibrosis in patients with diabetic retinopathy.

Diabetic retinopathy (DR), a prevalent complication in patients with type 2 diabetes, has attracted increasing attention. Recent studies have explored a plausible association between retinopathy and significant liver fibrosis. The aim of this investigation was to develop a sophisticated machine learning (ML) model, leveraging comprehensive clinical datasets, to forecast the likelihood of significant liver fibrosis in patients with retinopathy and to interpret the ML model by applying the SHapley Additive exPlanations (SHAP) method. This inquiry was based on data from the National Health and Nutrition Examination Survey 2005-2008 cohort. Utilizing the Fibrosis-4 index (FIB-4), liver fibrosis was stratified across a spectrum of grades (F0-F4). The severity of retinopathy was determined using retinal imaging and segmented into four discrete gradations. A ten-fold cross-validation approach was used to gauge the propensity towards liver fibrosis. Eight ML methodologies were used: Extreme Gradient Boosting, Random Forest, multilayer perceptron, Support Vector Machines, Logistic Regression (LR), Plain Bayes, Decision Tree, and k-nearest neighbors. The efficacy of these models was gauged using metrics, such as the area under the curve (AUC). The SHAP method was deployed to unravel the intricacies of feature importance and explicate the inner workings of the ML model. The analysis included 5,364 participants, of whom 2,116 (39.45%) exhibited notable liver fibrosis. Following random allocation, 3,754 individuals were assigned to the training set and 1,610 were allocated to the validation cohort. Nine variables were curated for integration into the ML model. Among the eight ML models scrutinized, the LR model attained zenith in both AUC (0.867, 95% CI: 0.855-0.878) and F1 score (0.749, 95% CI: 0.732-0.767). In internal validation, this model sustained its superiority, with an AUC of 0.850 and an F1 score of 0.736, surpassing all other ML models. The SHAP methodology unveils the foremost factors through importance ranking. Sophisticated ML models were crafted using clinical data to discern the propensity for significant liver fibrosis in patients with retinopathy and to intervene early. Improved early detection of liver fibrosis risk in retinopathy patients enhances clinical intervention outcomes.

Impact of sociodemographic disparities on sarcopenia, telomere length, and mortality in patients with liver disease in the US population.

Sarcopenia is common in patients with liver disease and both sarcopenia and short telomeres are associated with mortality, however their relationship in patients with liver disease remains unknown. A cohort of 16,072 adults from the National Health and Nutrition Examination Survey from 1999 to 2006 was analyzed. Liver disease was defined by aminotransferases and classified into etiology-based categories. Sarcopenia was defined by dual-energy x-ray absorptiometry. All analyses were conducted separately on each multiple imputation data set and combined via Rubin's rules. P-values for group comparisons were calculated by testing logistic regression parameter estimates. Cox proportional hazards regression was used for mortality analysis with mortality data available until 2015. Sarcopenia was present in 9.5% of patients with liver disease. Age, race, income, education, physical inactivity, and certain medical comorbidities were associated with sarcopenia. Patients with liver disease and sarcopenia had significantly shorter telomeres than patients with liver disease without sarcopenia when unadjusted for age. The interaction between telomere length and sarcopenia was significantly associated with all-cause mortality. The implications of telomere length on all-cause mortality in patients with liver disease varied by age and sarcopenia status. Shorter telomeres appear to be more highly associated with increased mortality in older patients without sarcopenia.

Improving diets and multimorbidity prevention.

In 2023, the UK government announced a Major Conditions Strategy, publishing 'The case for change and our strategic framework', which set out the focus on cancers, diabetes, dementia, mental ill health, musculoskeletal disorders, CVD and chronic respiratory diseases. Together, these conditions account for 60% of total disability-adjusted life years lost to early death or ill health in England, and one in four adults has at least two (multimorbidity). This review considers some of the key dietary risks for these major conditions and population policies that may improve diets and reduce risks. UK Government dietary recommendations, based on independent risk assessment and advice from the Scientific Advisory Committee on Nutrition, are encapsulated in the national food model, the Eatwell Guide. Based on key sources of dietary data - chiefly consumption data from the National Diet and Nutrition Survey and consumer purchase data from Kantar - most people do not meet dietary recommendations. This review considers how science and evidence inform health improvement policy. This includes policies that encourage healthier food choices, such as labelling and public procurement standards to those that minimise the impact of the less healthy choice such as sugar and salt reduction and reformulation. The review also considers nutritional approaches to managing some non-communicable diseases. Given the role nutrition and excess weight play in the onset, prognosis and quality of life for those living with one or more of the major conditions, there are huge potential gains from even small dietary improvements across population groups.

Novel BMI cutoff points for obesity diagnosis in older Hispanic adults.

Current body mass index (BMI) cutoff points (≥ 30kg/m2) underestimate obesity prevalence in older adults. The aim of the present study wasto propose new BMI cutoff points for identifying obesity in older Hispanic adults. In this study, new internally derived (ID) BMI cutoff point for obesity in older Hispanic adults was developed by analyzing data from the National Health and Nutrition Survey of 2018-2019 from Mexico. To evaluate the performance/validation of this newly proposed cutoff point, data from the "Study of the 1000", conducted in Northern Mexico, was utilized. Sensitivity, and negative predictive value (NPV) were assessed using receiver operating characteristic analysis, with obesity defined by fat mass index (FMI; ≥ 9.0kg/m2 for men and ≥ 12.0kg/m2 for women) as the reference method. The newly proposed ID BMI cutoff point was ≥ 27.2kg/m2 which demonstrated high sensitivity (≥ 99.4%) and NPV (≥ 99.5%) in the total sample. Furthermore, the prevalence of obesity estimated by the new BMI cutoff point was comparable to that estimated by the FMI. The newly proposed BMI cutoff point provides a more accurate identification of obesity in older Hispanic adults. These findings have implications for improving obesity diagnosis and management in this population.

Association between triglyceride glucose-body mass index and depression among US adults: A cross-sectional study

ObjectivesThe triglyceride glucose-body mass index (TyG-BMI) is a well-established surrogate marker for insulin resistance. While an association between insulin resistance and depression has been identified, that between TyG-BMI and depression remains unclear. Therefore, we used data from the National Health and Nutrition Examination Survey (NHANES) database to investigate this. Study designThis cross-sectional study included 9673 adults (aged ≥20 years) from the NHANES in the United States from 2011 to 2020. MethodsDepressive symptoms were assessed using a nine-item version of the Patient Health Questionnaire. The covariates included age, sex, race/ethnicity, marital status, educational level, poverty-income ratio, smoking status, alcohol intake, diabetes status, cardiovascular disease, hypertension, physical activity, high-density lipoprotein, low-density lipoprotein, and total cholesterol. Multivariate logistic regression models, subgroup analyses, and threshold saturation effect analyses were conducted. ResultsAfter adjusting for age, sex, race/ethnicity, marital status, education level, poverty-income ratio, smoking status, drinking status, diabetes status, cardiovascular disease, hypertension, physical activity, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, the threshold saturation effect showed a TyG-BMI inflection point of 174.4. Below the inflection point, a 10-unit increase in TyG-BMI was associated with a 12 % lower prevalence of depression. Above the inflection point, each 10-unit increase in TyG-BMI was associated with a 4 % increase in prevalence of depression. ConclusionsTyG-BMI had a U-shaped relationship with prevalence of depression. There was a significant link between higher TyG-BMI levels and increased prevalence of depression. When the TyG-BMI value was below 174.4, any further increase in TyG-BMI was associated with a significantly lower prevalence of depression.

Association between dietary intake of iron and heart failure among American adults: data from NHANES 2009-2018.

Patients with heart failure (HF) often experience iron deficiency. Intravenous iron supplementation has been widely used in clinical practice to facilitate the treatment of HF. However, the association between dietary iron intake and HF still needs to be elucidated. This study aimed to evaluate the impact of dietary iron intake on HF in American adults. The data were extracted from the National Health and Nutrition Examination Survey (NHANES) 2009-2018. Iron dietary intake data were obtained from two 24-h dietary recall interviews. We examined baseline data and HF prevalence in different quartile groups of dietary iron intake (Q1-Q4). Two logistic regression models were established to evaluate the impact of Q4 (highest iron consumption) on the risk of HF. The study included 20,853 American adults (age ≥ 20 years). The participants with the highest iron intake (Q4) had the lowest prevalence of HF (Q1: 3.25%, Q2: 2.18%, Q3: 1.92%, Q4: 1.72%; P < 0.001). After adjusting for possible confounding factors, the highest iron intake (Q4) was significantly associated with a reduced risk of HF compared with that of Q1 (odds ratio 0.58, 95% confidence interval 0.41-0.82; P = 0.003). This association remained stable in subgroups of women, current smokers, and Hispanics other than Mexican Americans. This study revealed that the dietary intake of iron was negatively associated with HF in adults without exceeding the tolerable maximum daily intake of 45mg/day.

Inverse association between uric acid levels and muscle quality index in adults: a cross-sectional analysis of NHANES 2011-2014.

The objective of this study was to delineate the association between serum uric acid (UA) levels and Muscle Quality Index (MQI), assessing muscle strength relative to mass, in adults aged 20 to 59 years. Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, this study examined the association between UA levels and MQI-a ratio of muscle strength to mass. Weighted linear models, adjusted for potential confounders, assessed the relationship, with a generalized additive model (GAM) probing for non-linear patterns. Subgroup analyses and interaction effects were conducted using weighted linear regression across diverse demographic and clinical groups to ensure the robustness and reliability of our findings. Among 5,277 participants, a significant inverse association was observed between UA levels and MQI, with a 0.08 decrease in MQI per 1mg/dL increase in UA (95% CI: -0.11 to -0.06, p < 0.001). The negative trend was dose-dependent across UA quartiles, which was most pronounced in the highest quartile (Q4: -0.28, 95% CI: -0.36 to -0.19, p < 0.001). Curve-fitting analysis revealed a consistent inverse relationship without evidence of non-linearity. Stratified analyses reinforced the core findings across all examined subgroups, highlighting the universal relevance of the observed association. Our findings demonstrate a significant inverse association between elevated serum UA levels and MQI, highlighting the potential importance of uric acid management in enhancing muscle quality among young and middle-aged adults. The consistency of this relationship across different subgroups underscores the need for targeted strategies and interventions to manage UA levels. Future research should explore longitudinal impacts and intervention outcomes to further elucidate the potential benefits of uric acid management on muscle health.

The association between oxidative balance score and sleep duration: a mediation analysis of a cross-sectional study

Study objectivesThe Oxidative Balance Score (OBS), which reflects overall oxidation through diet and lifestyle, has been linked to sleep, but few studies have clarified this relationship. We investigated the association between OBS and sleep duration, and whether oxidative stress (OS) and inflammation mediate the underlying mechanisms.MethodsData were obtained from the National Health and Nutrition Examination Survey spanning the years 2007 to 2018. Multivariable logistic regression analyses were used to evaluate the association between OBS and the risk of sleep duration. Mediation analyses were conducted to investigate the role of OS and inflammatory markers.ResultsA significant negative association was found between OBS and sleep duration (p &amp;lt; 0.01). Meanwhile, compared to participants in OBS tertile 1, the ORs (95% CIs) of incident short sleep duration were 0.78 (0.72–0.86) and 0.72 (0.67–0.79) (both p &amp;lt; 0.01) for OBS tertile 2 and 3, respectively. And the ORs (95% CIs) of incident long sleep duration were 0.83 (0.73, 0.95) and 0.66 (0.57, 0.75) (both p &amp;lt; 0.01) for OBS tertiles 2 and 3 after adjustment for multivariate variables. A linear relationship between OBS and short/long sleep duration (p for non-linearity = 0.69/0.94, both p &amp;lt; 0.01) were revealed. Mediation analysis showed absolute neutrophil count, serum total bilirubin mediated the association between OBS and short/long sleep duration with 5.72, 13.41% proportion of mediation, respectively (both p &amp;lt; 0.001).ConclusionOBS is negatively associated with sleep duration. OS and inflammatory biomarkers mediate the relationship.

Long-term effect of eating duration on all-cause mortality under different energy intake and physical activity levels.

The long-term impact of eating duration on the risk of all-cause mortality remains unclear, with limited exploration of how different levels of energy intake and physical activity might influence this impact. To investigate, 24484 American adults from the National Health and Nutrition Examination Survey spanning 1999-2018 were included. Eating duration was assessed via 24-h dietary recall, and all-cause mortality data were sourced from the National Death Index. The relationship between eating duration and all-cause mortality was analysed using Cox proportional hazards regression models, restricted cubic splines and stratification analysis with complex weighted designs. The median (IQR) of eating duration for participants was 12·5 (11·0, 14·0) h. In this study, 2896 death events were observed, and the median follow-up time (IQR) was 125 (77, 177) months. After multivariable adjustment, compared with Q1, Q2, Q3 and Q4 had reduced risks of all-cause mortality by 17, 15 and 13 %, respectively. Furthermore, each additional hour of eating duration was correlated with a 2 % decrease in the risk of all-cause mortality. Additionally, a non-linear dose-response relationship was observed between eating duration and the risk of all-cause mortality, showing a U-shaped relationship from 8·9 h to 15·3 h (P for non-linearity < 0·05). Interestingly, the non-linear dose-response relationship was observed exclusively among individuals with high energy intake or a lightly active physical activity level. These findings suggest potential health benefits from adjusting eating duration, though further prospective studies are needed for validation.

The triglyceride-glucose index: a predictor of mortality risk among myocardial infarction survivors.

The relationship between the triglyceride-glucose (TyG) index and mortality among survivors of myocardial infarction (MI) remains understudied. This study aims to evaluate the association between the TyG index and mortality among adult MI patients in the US. Our study included 986 MI patients, sourced from the National Health and Nutrition Examination Survey conducted from 1999 to 2018. Employing a multivariate Cox proportional hazards model, we examined the association between the TyG index and mortality. To explore potential nonlinear relationships, we employed restricted cubic splines in our analysis. Additionally, we applied a two-piecewise Cox proportional hazards model for a more nuanced analysis of the data, using key turning points as boundaries. To validate the robustness of our research findings, we also performed subgroup analyses. During a 7,342 person-years follow-up period, 434 MI survivors succumbed to various causes, including 158 cardiovascular disease-related deaths. The study revealed a U-shaped pattern between the TyG index and mortality. At TyG index levels below the thresholds (8.85 for all-cause mortality and 9.02 for cardiovascular mortality), mortality exhibited a negative correlation with the TyG index (HR = 0.56, 95%CI 0.39-0.82; HR = 0.67, 95%CI 0.39-1.14). Conversely, mortality rates increased when the TyG index surpassed these thresholds (HR = 1.38, 95%CI 1.08-1.76; HR = 1.56, 95%CI 1.02-2.38). Furthermore, among diabetic patients, subgroup analyses demonstrated that the U-shaped pattern between the TyG index and cardiovascular mortality was particularly pronounced. Our research indicates that among MI survivors, a U-shaped pattern exists between the TyG index and mortality rates, which is particularly pronounced in the diabetic patient subgroup. The corresponding threshold values for all-cause and cardiovascular mortality are 8.85 and 9.02, respectively.

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.

Prevalence of cardiometabolic diseases in underweight: a nationwide cross-sectional study.

This study aimed to estimate the nationwide prevalence of cardiometabolic diseases (CMDs) among adults with underweight in the US general population. Using data from the National Health and Nutrition Examination Survey (1999-2020), we estimated the age-standardized prevalence of dyslipidemia, hypertension, diabetes, chronic kidney disease, cardiovascular disease, and the presence of 0 or at least 2 CMDs. Multivariable Poisson regressions were used to compare CMD prevalence between subgroups, adjusting for age, sex, and race/ethnicity. Among the 855 adults with underweight included, the weighted mean age was 40.8 years, with 68.1% being women and 70.4% non-Hispanic White. The estimated prevalence rates were 23.4% for dyslipidemia (95% CI, 19.4%-27.5%), 15.6% for hypertension (95% CI, 13.3%-17.8%), 2.5% for diabetes (95% CI, 1.5%-3.5%), 7.9% for chronic kidney disease (95% CI, 6.9%-8.8%), and 6.1% for cardiovascular disease (95% CI, 4.3%-7.9%). The prevalence of having 0 and at least 2 CMDs was 50.6% (95% CI, 44.1%-57.0%) and 12.3% (95% CI, 8.1%-16.4%), respectively. Non-Hispanic Black adults had significantly higher prevalence of diabetes (adjusted prevalence ratio, 3.35; 95% CI, 1.35-8.30) compared to non-Hispanic White adults. In conclusion, approximately half of the underweight adults had at least one CMD, and 12.3% had at least two CMDs. Prevention and management of CMDs in underweight adults are critical yet neglected public health challenges.

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.

Impact of sleep problems on the cardiometabolic risks: an integrated epidemiological and metabolomics study

BackgroundWe investigated the association between sleep problems and cardiometabolic risks and the potential linking effect of metabolites and metabolic pathways based on multi-layered research, including observational, mendelian randomization (MR), and metabolomics analysis.MethodsA cross-sectional analysis of the 2015–2018 National Health and Nutrition Examination Survey (NHANES) dataset was conducted to identify the association between sleep problems and cardiometabolic risks. A subsequent MR study based on genetic data was performed to explore the causal correlation of significant associations in the NHANES study. The underlying alteration of metabolism was explored by constructing zebrafish models and wide-targeted metabolomics analysis.ResultsThe cross-sectional analysis of the NHANES database revealed a significant association of snoring with obesity [OR = 2.65, 95% confidence intervals (CI): 1.87, 3.74]; sleep apnea with hypertension (OR = 1.68, 95% CI: 1.14, 2.48) and obesity (OR = 1.44, 95% CI: 1.05, 1.96); trouble sleeping with hypertension (OR = 1.84, 95% CI: 1.18, 2.86), obesity (OR = 1.56, 95% CI: 1.07, 2.26), and type 2 diabetes (T2DM) (OR = 1.52, 95% CI: 1.02, 2.25). MR analysis verified the causal relationship between genetically proxied sleep apnea or snoring and obesity. The decreased activity levels and altered expression levels of six circadian genes (bmal1b, cry1aa, cry1ab, clock1a, per1b, per2) were identified in the zebrafish of the sleep disorder group. Multiple metabolites related to disturbed glucose metabolism (e.g., 20-HETE), lipid metabolism (e.g., inosine), and vascular-related metabolites (e.g., riboflavin) were finally identified, indicating the latent effect of metabolism.ConclusionsThis study identified the chain of sleep-circadian rhythm-metabolism-cardiometabolic risks. These findings can promote improved prevention implementation and therapeutic strategies.

The functional average treatment effect

Abstract This article establishes the functional average as an important estimand for causal inference. The significance of the estimand lies in its robustness against traditional issues of confounding. We prove that this robustness holds even when the probability distribution of the outcome, conditional on treatment or some other vector of adjusting variables, differs almost arbitrarily from its counterfactual analogue. This article also examines possible estimators of the functional average, including the sample mid-range, and proposes a new type of bootstrap for robust statistical inference: the Hoeffding bootstrap. After this, the article explores a new class of variables, the U {\mathcal{U}} class, that simplifies the estimation of functional averages. This class of variables is also used to establish mean exchangeability in some cases and to provide the results of elementary statistical procedures, such as linear regression and the analysis of variance, with causal interpretations. Simulation evidence is provided. The methods of this article are also applied to a National Health and Nutrition Survey data set to investigate the causal effect of exercise on the blood pressure of adult smokers.

Serum vitamin C levels and risk of osteoporosis: results from a cross-sectional study and Mendelian randomization analysis

BackgroundThe role of vitamin C as an antioxidant in guarding against osteoporosis in adults is still debated. This research employs both a cross-sectional study and a two-sample bidirectional Mendelian randomization (MR) analysis to explore how serum vitamin C levels correlate with the incidence of osteoporosis among adults.MethodsIn this study, we utilized data from the National Health and Nutrition Examination Survey (NHANES) database for the years 2003–2006, and 2017–2018 to conduct both a cross-sectional analysis and MR to investigate the relationship between serum vitamin C levels and the risk of osteoporosis in adults. We adjusted our analyses for essential demographic and lifestyle variables, and applied logistic regression techniques. Genetic determinants of vitamin C levels were analyzed through MR, using methods like inverse-variance weighted (IVW) and MR-Egger to assess causality. Statistical computations were carried out in R, incorporating visual tools such as restricted cubic spline curves (RCS) and forest plots to clarify the dose–response dynamics and variations across different subgroups. This study was approved by the NCHS Ethics Review Board, and informed consent was obtained from all participants.ResultsIn our investigation, we analyzed data from 3,940 participants, among whom 291 were diagnosed with osteoporosis. The logistic regression analysis of serum vitamin C quartiles did not indicate a significant trend. The most adjusted model showed a slight, albeit inconsistent, protective effect in the highest quartile (OR = 0.68, 95% CI: 0.47–0.99, P = 0.22). Mendelian randomization, employing methods such as IVW, reinforced the absence of a significant causal relationship between serum vitamin C levels and osteoporosis risk (IVW OR = 1.000, 95% CI: 0.999–1.001, P = 0.601).Subgroup analyses, visualized through forest plots and restricted cubic spline (RCS) curves, supported the primary findings, showing no significant effects or interactions between vitamin C levels and osteoporosis risk across different demographic and lifestyle subgroups. The RCS analysis particularly highlighted a lack of significant non-linear relationships between serum vitamin C concentration and the odds of osteoporosis (P for nonlinear = 0.840).ConclusionsThe cross-sectional study revealed that higher serum vitamin C levels do not consistently correlate with a reduced risk of osteoporosis. Meanwhile, the Mendelian randomization analysis confirmed that there is no genetic evidence to suggest a causal relationship between vitamin C levels and osteoporosis risk. Recent research highlights the polygenic nature of osteoporosis, with genetic predispositions playing a significant role in disease risk. The relationship between serum vitamin C and osteoporosis requires further research. This suggests the need for further investigation into the connection between vitamin C and bone health.

Exploring the correlation between dietary zinc intake and stroke risk in adults based on NHANES database

ABSTRACT Objective To explore the relationship between dietary zinc intake and stroke. Methods Subjects from the National Health and Nutrition Examination Survey (NHANES) database (2015 to 2020) were included. Zinc intake was determined using two 24-h dietary recall interviews, and stroke was determined using the Medical Condition Questionnaire (MCQ). Logistic analysis was used to analyze the association between zinc intake and stroke risk. 1:1 nearest neighbor propensity score matching (PSM) was used to reduce selection bias. Results 4705 subjects were included in the study. Multivariate logistic regression analysis before and after matching showed that increased zinc intake was associated with a reduced risk of stroke. And as zinc intake increases, the risk of stroke shows a gradually decreasing trend. Compared with the Q1 group, the risk of stroke in the Q2, Q3, and Q4 groups was reduced by approximately 0.27 times, 0.29 times, and 0.31 times respectively. And there is no interaction between dietary zinc intake and gender in stroke patients. Conclusion Dietary zinc intake may be a protective factor against stroke, and increasing its intake may prevent or reduce the symptoms of stroke and related diseases.