Association between mixed exposure of phthalates and cognitive function among the U.S. elderly from NHANES 2011-2014: Three statistical models

Association between mixed exposure of phenols, parabens, phthalates and cognitive function in US elders

BACKGROUND

In an aging society, understanding the factors influencing cognitive function in older adults is of great significance. Phenols, parabens, and phthalates (PAEs) can disrupt normal neural signaling. This research aims to investigate the association between mixed exposure of phenols, parabens, PAEs and cognitive function in US elders. Given that older adults are a vulnerable group in terms of health, and cognitive decline can severely impact their quality of life and independence. Studying the effects of these commonly - encountered environmental chemicals on their cognitive function is crucial as it can provide scientific basis for formulating public health policies.

METHODS

A total of 856 participants were selected from National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014. The generalized linear (GLM), weighted quantile sum (WQS), and Bayesian kernel machine regression (BKMR) models were used to evaluate the associations between mixed PAEs and the standardized z-scores for the four cognitive tests.

RESULTS

The mixed effect of the nine exposures examined is positively associated with lower IRT scores (OR: 1.77, 95 % CI: 1.04-3.02) for males in the WQS regression model. MEHP exhibits the largest contribution of all combinations. In the BKMR regression model, mixed exposure and cognitive impairment show positive correlation in the IRT, the DSST, and the global test for males.

CONCLUSION

Exposure to phenols, parabens, and PAEs may negatively affect cognition in older adults, particularly the male population. The effect of mixed exposure is positively associated with lower IRT scores and MECP has a dominant role.

The association between sleep duration and cognitive function in the U.S. elderly from NHANES 2011-2014: A mediation analysis for inflammatory biomarkers

BACKGROUND

Studies have shown a close association between sleep duration and cognitive function in older adults. However, no studies have explored the underlying mechanisms of this relationship. This study was designed to assess the role of inflammatory markers in the relationship between sleep duration and cognitive function in older Americans.

METHODS

A total of 2502 participants from the National Health and Nutrition Examination Survey (NHANES) were included in the analysis. Cognitive function was assessed using three tests from NHANES. Sleep duration was evaluated through a self-reported sleep time questionnaire. Inflammatory biomarkers examined included leukocytes (WBC) count, neutrophil count (NE), the neutrophil-to-lymphocyte ratio (NLR), and the systemic immune-inflammation index (SII). Mediation models were constructed to clarify the mediating role of inflammatory biomarkers.

RESULTS

Long sleep duration (≥9 h) was associated with lower performance on CERAD (OR: -1.623; 95 % CI: -2.979 to -0.267) and DSST (OR: -3.084; 95 % CI: -5.861 to -0.308) compared to the normal sleep duration group (7-9 h). NE partially and indirectly mediated this association. Meanwhile, WBC moderated the association between long sleep duration (≥9 h) and DSST performance.

LIMITATIONS

The cross-sectional design prevents making causal inferences.

CONCLUSIONS

Long sleep duration is a risk factor for cognitive function. Inflammatory biomarkers based on blood cells present a readily accessible and cost-effective strategy for identifying sleep disorders and also significantly mediate the association between long sleep duration and cognitive function.

Association between organophosphate esters exposure and the prevalence of hyperuricemia in US adults from NHANES 2011-2016

Organophosphate esters (OPEs) exposure has potentially harmful effects on human health. However, the evidence between OPEs and hyperuricemia is insufficient. We aimed to assess the association between OPEs metabolites and the prevalence of hyperuricemia. Multivariable logistic regression, weighted quantile regression (WQS) model, and Bayesian kernel machine regression (BKMR) models were used to investigate the association of OPEs metabolites with the risk of hyperuricemia. Mediation analysis was conducted to assess whether inflammation mediated the effects of OPEs on the prevalence of hyperuricemia. The multivariable logistics regression indicated that bis (1,3-dichloro-2-propyl) phosphate (BDCPP) and bis-2-chloroethyl phosphate (BCEP) were positively correlated with the risk of hyperuricemia. In WQS and BKMR analyses, OPEs mixtures presented a positive association with the risk of hyperuricemia, with BDCPP being the primary contributor. C-reactive protein (CRP) and monocytes were found to mediate the association between BDCPP and the risk of hyperuricemia prevalence, with 8.46% and 3.97% of the mediated proportion, respectively. Our study revealed that OPEs mixtures were positively correlated with the prevalence of hyperuricemia, with BDCPP identified as the most significant contributor. Inflammation was a potential mechanism mediating the effect of BDCPP exposure on the risk of hyperuricemia.

The effect and potential mechanisms of per- and polyfluoroalkyl substances (PFAS) exposure on kidney stone risk

Exposure to per- and polyfluoroalkyl substances (PFAS) may be associated with an increased prevalence of some kidney diseases. Kidney stones are common and have a high prevalence of kidney diseases. However, there is no evidence for the effect and potential mechanisms of PFAS on kidney stone risk. In this study, we designed a cross-sectional study using the National Health and Nutrition Examination Surveys (NHANES) data from 2017 to 2020. Our results revealed that PFAS were positively associated with kidney stone risk, and PFDA was the main contributing compound among PFAS. The triglyceride-glucose (TyG) index and the systemic immune-inflammatory (SII) index had significant mediation effects. In addition, target proteins, such as IL-6, TNF, ALB, IL-1B, and AKT1, and signaling pathways, including TNF and IL-17 pathways, might be potential mechanisms of PFAS in promoting kidney stone risk. In conclusion, PFAS, especially PFDA, increases the risk of kidney stones by the mediation effects of the TyG index and SII index. TNF and IL-17 signaling pathways may be potential mechanisms. Our findings provide new evidence for the effects and potential mechanisms of PFAS exposure in increasing kidney stone risk. However, in the future, it is still imperative to further explore and validate the underlying mechanisms of PFAS-induced kidney stone formation through experimental studies.

Association between exposure to organophosphate esters and cognitive function in older adults in the United States: NHANES 2011-2014

BACKGROUND

Organophosphate esters (OPEs) are widely used as an alternative to the brominated flame retardant polybrominated diphenyl ethers. The effects of OPEs on the cognitive abilities of older adults remain unclear.

METHODS

A cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey 2011-2014. Cognitive function was assessed using the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) word learning test, the CERAD word recall test, the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). OPE metabolites with detection rates above 50% were included in the study. Weighted multiple linear regression, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) models were used to examine the effects of individual and mixed exposures to OPE metabolites on cognitive function.

RESULTS

A total of 762 older adults were included. The weighted linear regression model revealed a positive association between Ln DPHP, Ln BDCPP, and Ln BCPP and the DSST score, while a negative association was observed between Ln DBUP and the DSST score. In the positive WQS model, the index was correlated with DSST score (β = 2.65, 95% CI: 0.40 ~ 4.90, P = 0.02), with DPHP having the highest weight. The results of BKMR analysis indicated a borderline statistical significance in the increase of DSST score when the mixture of OPEs is set to a specific 90th percentile compared to all mixture concentrations set to the median.

CONCLUSIONS

Overall exposure to OPE metabolites are associated with improved cognitive function in older adults in the United States. Further prospective studies with large sample sizes are needed to confirm these results.

Prenatal exposure to essential metals and blood pressure at preschool age: A birth cohort study

AIMS

To investigate the association between prenatal exposure to essential metals and the offspring blood pressure (BP) at preschool age.

MATERIALS AND METHODS

Data from a birth cohort study including 1113 mother-child pairs were analyzed. The associations between individual prenatal essential elements and offspring BP were analyzed using generalized linear regression models. Bayesian Kernel Machine Regression (BKMR) and weighted quantile sum regression (WQS), were employed to examine the combined effects of prenatal metal exposures on offspring BP. The associations between essential metals and high blood pressure (HBP) of offspring were appraised using logistic regression model.

RESULTS

In the single-metal models, we found that maternal magnesium (Mg) concentrations were negatively associated with the offspring BP. The results of BKMR and WQS also identified a negative association between maternal essential metals mixtures and offspring BP. Logistic regression showed that compared to the highest quartiles of maternal Mg, the odds ratio (OR) for HBP in the lowest quartiles was 4.27 (95 % CI: 1.84-9.93). No significant associations were observed for other essential metals (all P value > 0.05). Additionally, no significant association was found between umbilical cord blood metal concentrations and offspring BP.

CONCLUSIONS

Maternal essential metals mixtures, rather than those in umbilical cord blood, were negatively associated with offspring BP. Besides, lower maternal Mg levels were linked to a higher prevalence of HBP in offspring. Our findings provide significant evidence for exploring the effects of maternal essential metal elements on offspring BP.

Polycyclic aromatic hydrocarbons exposure in early pregnancy on child neurodevelopment

The epidemiological evidence from studies on the impact of exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy on child neurodevelopment is inconclusive. This study aimed to assess the associations of PAHs exposure in early pregnancy and neurodevelopmental outcomes in children aged 6-12 months in a prospective cohort. In this study, we included 172 mother-child pairs with complete data in Tianjin City, China. Ten PAH metabolites were determined in early-pregnancy urine using gas chromatography and tandem mass spectrometry (GC-MS/MS). Child neurodevelopment was measured using the Griffiths Development Scales-Chinese (GDS-C) when children were between 6 and 12 months old. We employed multivariable linear regression, Weighted Quantile Sum (WQS) regression, and Bayesian Kernel Machine Regression (BKMR) to assess the relationships of individual PAH metabolites and mixtures of these metabolites with child neurodevelopment. Multiplicative interactions were analyzed to examine effect modification by child sex. In the multivariable linear regression analysis, six PAH metabolites were found to be negatively associated with personal social scores, while three PAH metabolites showed a negative association with language scores. The WQS model revealed that the PAHs mixture was linked to decreased personal social scores (β = - 4.18, 95% CI = -7.56, - 0.80) and language scores (β = - 4.17, 95% CI = -7.98, -0.37). Furthermore, the BKMR models also indicated the negative associations between the PAHs mixture and personal social scores and language scores. Notably, three PAH metabolites (1-hydroxynaphthalene(1-OHNap), 3-hydroxyfluorene(3-OHFlu), 3+9-hydroxyphenanthrene(3+9-OHPhe)) were identified as important contributors to these associations. All analyses of interactions were null. Exposure to PAHs during early pregnancy, whether individually or as a mixture, demonstrated a negative association with child neurodevelopment outcomes.

Relation of volatile organic compounds to renal function in American adolescents: three statistical models

This study was conducted to evaluate the relationship between 17 urinary metabolites of volatile organic compounds (mVOCs) in adolescents and renal function parameters (estimated glomerular filtration rate (eGFR), albumin-to-creatinine ratio (ACR), urinary albumin, serum uric acid (SUA), and blood urea nitrogen (BUN)). In adjusted generalised linear models (GLM), mVOCs were positively correlated with eGFR, urinary albumin, and BUN, and mVOCs were negatively correlated with ACR and SUA. Weighted Quartile Sum (WQS) index correlated with eGFR [β(95%CI): 0.040 (0.028, 0.052)], urine albumin [β(95%CI): 0.275 (0.203, 0.622)], SUA [β(95%CI): 0.040 (0.025, 0.055)] and BUN [β(95%CI): 0.102 (0.082, 0.122)]. In Bayesian Kernel Machine Regression (BKMR) model, total compound effect was positively correlated with eGFR, positive associations were observed in high concentration of the mixture with urine albumin and ACR. Findings suggest that single and mixed exposures to mVOCs may affect renal parameters in adolescents.

Association between ethylene oxide exposure and cognitive function in older adults from NHANES data

Ethylene Oxide (EO), a volatile organic compound, has garnered considerable attention for its potential impact on human health. Yet, the ramifications of EO exposure on the cognitive functionality of the elderly remain unclear. The aim of this study is to determine whether EO exposure in the elderly correlates with cognitive function. In this cross-sectional study, an analysis was conducted on 471 participants from the 2013 to 2014 United States National Health and Nutrition Examination Survey (NHANES). T1, T2, and T3 was used to represent the low, moderate, and high tertiles of log10-transformed HbEO levels, respectively. Weighted linear regression analysis, weighted logistic regression analysis, and restricted cubic spline models were employed to assess the association between HbEO and standardized z-scores of four cognitive tests. Firstly, analysis of variable characteristics across the different log10-transformed HbEO groups revealed that HbEO was higher in males, non-Hispanic whites, and smokers and that Z scores for Delayed Recall Test (DRT), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST) decreased as HbEO increased (p < 0.05). After adjusting for confounding factors, the log10-transformed HbEO levels were found to be negatively correlated with DRT-Z scores (T3 vs. T1 in Model 3: β (95% CI) = - 0.35 (- 0.54, - 0.15), p = 0.002, p for trend = 0.002). In addition, Stratified analyses showed that the four cognitive scores were negatively correlated with HbEO levels in those under 80 years of age. And men had worse AFT scores compared to women. Overall, the four Z-scores roughly trended downward as log10-transformed HbEO rose. Based on the findings of this research, EO exposure may be associated with adverse performance in the DRT among elderly individuals in the United States.

Associations between brominated flame retardants exposure and non-alcoholic fatty liver disease: Mediation analysis in the NHANES

BACKGROUND

Exposure to brominated flame retardants (BFRs) may negatively impact human health. The association of BFRs with nonalcoholic fatty liver disease (NAFLD) in the general population is unclear. Meanwhile, limited studies have investigated the potential role of oxidative stress and inflammation in this link.

METHODS

We included 4110 adults from the 2009-2014 National Health and Nutrition Examination Survey (NHANES). NAFLD was diagnosed by serum alanine aminotransferase (ALT), hepatic steatosis index (HSI), and United States fatty liver index (USFLI). The link between a single BFR exposure and NAFLD was estimated using weighted logistic regression and restricted cubic splines (RCS). The quantile-based g-computation (QGC), weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR) were applied to evaluate the overall correlation of BFRs mixtures with NAFLD and identify significant compounds. Furthermore, we investigated the potential mediation function of oxidative stress and inflammation.

RESULTS

Our study demonstrated that specific concentrations of BFRs are related to an increased risk of NAFLD, both individually and when combined. PBB153, PBDE28, PBDE209, and PBDE153 exhibited the highest importance for NAFLD and were potential risk factors worthy of concern. Additionally, mediation analysis showed that absolute neutrophil cell count (ANC) and lymphocyte count (LC) (inflammation markers) have significantly mediated influences on the correlations of PBB153, PBDE85, and PBDE28 with N AFLD risk. Albumin (ALB) (oxidative stress marker) has notably mediated influences on the correlations of PBDE99, PBDE154, and PBDE85 with NAFLD risk. Men had higher serum BFRs concentrations than women, and the association between BFRs and NAFLD was also more prominent in men, which may be related to physiological differences between the sexes.

CONCLUSIONS

Our findings offer evidence for single and mixed associations of BFRs and NAFLD in ordinary US adults. Furthermore, oxidative stress and chronic inflammation may mediate the effects of BFR exposure on NAFLD development.

Associations between Metals, Serum Folate, and Cognitive Function in the Elderly: Mixture and Mediation Analyses

Exposure to metals may potentially impact cognitive health in the elderly; however, the evidence remains ambiguous. The specific role of serum folate in this relationship is also unclear. We aimed to evaluate the individual and joint impact of metals on cognition in the elderly from the United States and explore the potential mediating effect of serum folate. Data from the NHANES 2011-2014 were used, with inductively coupled plasma mass spectrometry (ICP-MS) employed to measure blood metal concentrations. Cognitive function was assessed using tests for immediate, delayed, and working memory: Immediate Recall test (IRT), the Delayed Recall test (DRT), the Animal Fluency test (AFT), and the Digit Symbol Substitution test (DSST). Generalized linear regression models (GLMs), Bayesian kernel machine regression model (BKMR), and quantile g-computation (QG-C) models were used to assess associations between metals (lead, cadmium, mercury, selenium, manganese) and cognition, with mediation analyses examining serum folate's involvement in metal effects. This study included 2002 participants aged ≥60. GLMs revealed the negative association between cadmium and the z-scores of IRT (β: -0.17,95% CI: -0.30, -0.04) and DSST (β: -0.15,95% CI: -0.27, -0.04), with negative effects also observed in the BKMR and QG-C models. Selenium displayed significantly positive association with cognition across various statistical models, including GLMs, QG-C, and BKMR. Serum folate played a mediating role in the effects of cadmium and selenium exposure on DSST z-scores, with a proportion of mediation of 17% and 10%, respectively. Our study assessed the impact of metal mixtures on cognition in the elderly population, finding that high selenium level was strongly associated with better cognitive performance, while cadmium was associated with lower cognitive function scores. Serum folate might partially mediate the association between cadmium, selenium, and DSST z-scores.

Associations between dietary carotenoid and biological age acceleration: insights from NHANES 2009-2018

Carotenoids are naturally occurring pigments found in plants and certain microorganisms. Some carotenoids act as precursors to vitamin A, which is essential for various health aspects, including vision, immune function, and skin health. Carotenoids, including α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin, are known to reduce the risk of age-related diseases and promote healthy aging. This study examines the relationship between dietary carotenoid levels and biological age. This study utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2018, and 19,280 participants were included. The Phenotypic Age (PhenoAge) was used to measure biological age, and the Klemera-Doubal Method (KDM) was employed in sensitivity analyses. Biological age acceleration was determined by calculating the residuals of PhenoAge or KDM after regressing them against chronological age. Weighted multivariate linear and logistic regressions were conducted to examine the relationship between carotenoids and biological age acceleration. Additionally, restricted cubic spline regression, subgroup analysis, interaction analysis, and sensitivity analyses were employed for further examination. Both linear regression and logistic regression analyses indicated that participants with higher carotenoid intake exhibited lower rates of phenotypic age acceleration, with α-carotene, β-carotene, β-cryptoxanthin, lutein and zeaxanthin, and lycopene all demonstrating protective effects. Restricted cubic spline regression indicates non-linear associations between carotenoid levels and phenotypic age acceleration. Subgroup analyses revealed that younger participants, females, and individuals with hypertension or diabetes benefited more from higher carotenoid intake. Sensitivity analyses further confirmed the robustness of inverse relationship. The WQS analysis identifies β-carotene and β-cryptoxanthin as the most influential compounds. Higher dietary intake of carotenoids is associated with reduced biological age acceleration, underscoring their protective role against aging. Further longitudinal studies are needed to establish causal relationships and explore the underlying mechanisms of carotenoid benefits on aging.

Waist-to-weight index and cognitive impairment: Understanding the link through depression mediation in the NHANES

BACKGROUND

In recent years, several studies have suggested that obesity may play an important role in cognitive impairment. Individuals with cognitive impairment often also exhibit depressive symptoms. This study aimed to explore the association between obesity and cognitive impairment and to elucidate the mediating role of depressive symptoms in this association.

METHODS

Older participants in the U.S. were examined in this cross-sectional study (n = 2391). The WWI was computed as follows: WWI = waist circumference/square root of body weight. The Consortium for Alzheimer's Disease Word Learning (CERAD-WL), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST) were used to evaluate cognitive function. Depression symptoms were evaluated with the Patient Health Questionnaire 9 (PHQ-9). Subgroup analysis and multiple logistic regression analysis were utilized to investigate the relationships between the WWI and depressive symptoms and cognitive decline. Threshold effects were computed using a two-segment linear regression model. To ascertain whether depression mediates the relationship between the WWI and cognitive impairment, mediation analysis was also employed.

RESULTS

A total of 2391 participants were included, 33.29 % of whom had cognitive impairment. There was a significant correlation between the WWI and depressive symptoms and cognitive function (P < 0.05). With increasing WWI quartiles, the prevalence of cognitive impairment increased (Q1: 27.09 %, Q2: 33.00 %, Q3: 31.44 %, Q4: 41.64 %). It was highly likely that the WWI and cognitive impairment were positively correlated (OR = 1.34, 95 % CI = 1.13, 1.59), and this link was steady across all subgroups (P for trend >0.05). A nonlinear curve with an inflection point of 10.71 connected the WWI and cognitive deterioration. A significant correlation was found between the WWI and cognitive impairment on the left side of the inflection point (OR = 3.58, 95 % CI = 1.57, 8.15). With a 5.4 % mediation rate, mediation analysis revealed that depressive symptoms mediated the relationship between cognitive impairment and the WWI.

CONCLUSIONS

There was a positive association between the WWI and the incidence of cognitive impairment in older Americans. Among other factors, depressive symptoms slightly mediated the association between the WWI and cognitive impairment. However, large-scale prospective studies are still needed to analyse the interactions between the three factors in depth.

Exposure to volatile organic compounds and growth indicators in adolescents: Unveiling the association and potential intervention strategies

Environmental pollutant is considered to be one of the important factors affecting adolescent growth. However, the effects of volatile organic compounds (VOCs) exposure on adolescent growth have not been assessed. Data from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 was used to examine the associations between VOCs exposure and adolescent growth indicators through three statistical models. The mediating effect of bone mineral density (BMD) on these associations was examined. The potential pathways and key targets were identified by the network pharmacology analysis methods. This study included 746 adolescents. Three statistical methods consistently showed a negative correlation between VOCs exposure and adolescent growth indicators. Furthermore, BMD mediated the relationship between VOCs exposure and adolescent growth indicators, with mediated proportion ranging from 4.3 % to 53.4 %. Network pharmacology analysis found a significant enrichment in IL-17 signaling pathway. Moreover, the adverse effects of VOCs exposure on adolescent growth were observed to significantly attenuate in adolescents with high serum vitamin D levels. Our results suggested that VOCs exposure was an adverse factor affecting adolescent growth, with BMD playing a significant regulatory role, and IL-17 signaling pathway was the underlying mechanism. Vitamin D supplementation may be a viable strategy to prevent VOCs exposure from affecting adolescent growth.

Relationship between residual cholesterol and cognitive performance: a study based on NHANES

Background and aims

Age-related cognitive impairment impacts a significant portion of the elderly population. Remnant cholesterol (RC) has attracted increased attention in relation to cardiovascular disease, diabetes, hypertension, and fatty liver disease. Nevertheless, its role in cognitive function is still enigmatic, prompting our exploration into the potential associations between them.

Methods

A total of 1,331 participants from the NHANES (2011-2014) database, all aged over 60, were included in this investigation. Cognitive function was assessed using four widely applied tests, including the Consortium to Establish a Registry for Alzheimer's Disease Word Learning (CERAD-WL), CERAD Delayed Recall (CERAD-DR), Animal Fluency Test (AFT), as well as Digit Symbol Substitution test (DSST). Z-score is calculated by scores from the above four tests. The association between RC, total cholesterol (TC) to RC and cognitive performance was assessed by logistic regression analyses. In addition, restricted cubic spline (RCS) regression was performed to assess non-linearity between RC and cognitive function. Subgroup analysis was performed to evaluate the robustness of the results in populations with relevant covariate variables.

Results

Those with Z-scores below the 25% quartile are defined as having cognitive impairment, totaling 498 individuals. Observationally, higher RC levels and a lower TC/RC were associated with an increased risk of cognitive impairment. After adjusting for confounding factors, the impact of RC levels on cognitive performance quartiles was consistent across various subgroups, except in individuals with trouble sleeping, no/unknown alcohol use, and no hypertension. Americans with high RC levels and trouble sleeping are more likely to develop cognitive impairment, with an odds ratio of 2.33 (95% CI: 1.18-4.59).

Conclusion

This study suggests that higher RC levels and lower levels of TC/RC are associated with an increased likelihood of cognitive impairment, suggesting that RC can serve as a novel and convenient indicator for predicting the risk of cognitive impairment in the US population.

Inflammatory biomarkers mediate the association between polycyclic aromatic hydrocarbon exposure and dyslipidemia: A national population-based study

Exploring the association between exposure to polycyclic aromatic hydrocarbons (PAHs) and the risk of dyslipidemia and possible mediating effects is essential for conducting epidemiological health studies on related lipid disorders. Therefore, our study aimed to elucidate the potential association between PAH exposure and dyslipidemia risk and further identify the mediating effects based on blood cell-based inflammatory biomarkers. This cross-sectional study was conducted on 8380 individuals with complete survey data from the National Health and Nutrition Examination Survey (2001-2016). Multiple models (generalized linear regression model, restricted cubic spline model, Bayesian kernel machine regression, weighted quantiles sum regression) were used to assess the relationship between PAH co-exposure and the dyslipidemia risk and further identify potential mediating effects. Among the 8380 subjects, 2886 (34.44 %) had dyslipidemia. After adjusting for the confounding factors, the adjusted OR and 95% CI for dyslipidemia in the highest quartile of subjects were 1.30 (1.11, 1.51), 1. 22 (1.04, 1.43), 1.21 (1.03, 1.42), 1.29 (1.10, 1.52), 1.18 (1.01, 1.37), and 1.04 (0.89, 1.23) for 1-hydroxynaphthalene, 2-hydroxynaphthalene, 3-hydroxyfluorene, 2-hydroxyfluorene (2-FLU), 1-hydroxyphenanthrene, and 1-hydroxypyrene. The Bayesian kernel machine regression model also showed a positive correlation between PAH mixtures and dyslipidemia, and 2-FLU has the highest contribution. Mediation effect analyses showed that white blood cells and neutrophils were statistically significant in the association between PAHs and dyslipidemia. The present study suggests that individual and mixed PAH exposures may increase the risk of dyslipidemia in adults. Inflammatory biomarkers significantly mediated the relationship between PAH exposure and dyslipidemia. Environmental pollutants and their mechanisms should be more intensively monitored and studied.

Associations of heavy metal exposure with diabetic retinopathy in the U.S. diabetic population: a cross-sectional study

Background

Mounting evidence suggests a correlation between heavy metals exposure and diabetes. Diabetic retinopathy (DR) is a prevalent and irreversible complication of diabetes that can result in blindness. However, studies focusing on the effects of exposure to heavy metals on DR remain scarce. Thus, this study aimed to investigate the potential correlation between heavy metals exposure and DR.

Methods

A total of 1,146 diabetics from the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2018 were included in this study. Heavy metal levels were measured via urine testing. Weighted logistic regression, Bayesian kernel machine regression (BKMR), weighted quantile sum (WQS) regression, and restricted cubic spline (RCS) were utilized to investigate the potential relationships between exposure to 10 heavy metals and DR. Finally, subgroup analysis was conducted based on the glycemic control status.

Results

Among the 1,146 participants, 239 (20.86%) were diagnosed with DR. Those with DR had worse glycemic control and a higher prevalence of chronic kidney disease compared to those without DR. Moreover, both the WQS regression and BKMR models demonstrated a positive relationship between exposure to mixed heavy metals and the risk of DR. The results of weighted logistic regression revealed a positive correlation between cobalt (Co) and antimony (Sb) exposure and the risk of DR (OR = 1.489, 95%CI: 1.064-2.082, p = 0.021; OR = 1.475, 95% CI: 1.084-2.008, p = 0.014), while mercury (Hg) exposure was found to promote DR exclusively in the group with good glycemic control (OR = 1.509, 95% CI: 1.157-1.967, p = 0.003). These findings were corroborated by the results of the RCS analysis.

Conclusion

Heavy metal exposure is associated with an increased risk of DR, especially Sb, Co, and Hg exposure. Nevertheless, well-designed prospective studies are warranted to validate these findings.

Reduction of haemoglobin is related to metal mixtures exposure in Chinese preschoolers: Joint effect models

Heavy metal exposure is a known risk factor for hematologic disorders in children, yet the impact of co-exposure to multiple metals remains underexplored. This cross-sectional study investigates the relationship between urinary levels of 23 metals and haemoglobin (Hb) in 1460 Chinese preschoolers. The concentrations of the 23 urinary metals were quantified using an inductively coupled plasma mass spectrometer, while Hb levels were assessed through finger prick blood samples. To evaluate the co-exposure effects, we employed three approaches: Generalized linear regression model, joint effect models including Quantile g-Computation and Bayesian Kernel Machine Regression (BKMR). From the generalized linear regression and Quantile g-computation, urinary uranium, thallium, aluminium, iron and tungsten were correlated negatively with Hb, while urinary barium was correlated positively (all P < 0.05). Moreover, significant negative associations between metal mixtures exposure with Hb were identified in both Quantile g-computation [β (95% CI): -0.083 (-0.132, -0.033), P = 0.0012] and BKMR [90th percentile vs. 50th percentile β (95% CI): -0.238 (-0.368, -0.107), P < 0.001] with aluminium emerging as the primary contributor to this joint effect (weight in Quantile g-computation = 0.399, PIPs in BKMR = 0.896). These findings provide a potential explanation for environmental exposure to metals and Hb-related disease in preschoolers.

Associations of phthalates with accelerated aging and the mitigating role of physical activity

Phthalates are positioned as potential risk factors for health-related diseases. However, the effects of exposure to phthalates on accelerated aging and the potential modifications of physical activity remain unclear. A total of 2317 participants containing complete study-related information from the National Health and Nutrition Examination Survey 2007-2010 were included in the current study. We used two indicators, the Klemera-Doubal method biological age acceleration (BioAgeAccel) and phenotypic age acceleration (PhenoAgeAccel), to assess the accelerated aging status of the subjects. Multiple linear regression (single pollutant models), weighted quantile sum (WQS) regression, Quantile g-computation, and Bayesian kernel machine regression (BKMR) models were utilized to explore the associations between urinary phthalate metabolites and accelerated aging. Three groups of physical activity with different intensities were used to evaluate the modifying effects on the above associations. Results indicated that most phthalate metabolites were significantly associated with BioAgeAccel and PhenoAgeAccel, with effect values (β) ranging from 0.16 to 0.21 and 0.16-0.37, respectively. The WQS indices were positively associated with BioAgeAccel (0.33, 95% CI: 0.11, 0.54) and PhenoAgeAccel (0.50, 95% CI: 0.19, 0.82). Quantile g-computation indicated that phthalate mixtures were associated with accelerated aging, with effect values of 0.15 (95% CI: 0.02, 0.28) for BioAgeAccel and 0.39 (95% CI: 0.12, 0.67) for PhenoAgeAccel respectively. The BKMR models indicated a significant positive association between the concentrations of urinary phthalate mixtures with the two indicators. In addition, we found that most phthalate metabolites showed the strongest effects on accelerated aging in the no physical activity group and that the effects decreased gradually with increasing levels of physical activity (P < 0.05 for trend). Similar results were also observed in the mixed exposure models (WQS and Quantile g-computation). This study indicates that phthalates exposure is associated with accelerated aging, while physical activity may be a crucial barrier against phthalates exposure-related aging.

Assessing the contribution of the chemical exposome to neurodegenerative disease

Over the past few decades, numerous environmental chemicals from solvents to pesticides have been suggested to be involved in the development and progression of neurodegenerative diseases. Most of the evidence has accumulated from occupational or cohort studies in humans or laboratory research in animal models, with a range of chemicals being implicated. What has been missing is a systematic approach analogous to genome-wide association studies, which have identified dozens of genes involved in Alzheimer's disease, Parkinson's disease and other neurodegenerative diseases. Fortunately, it is now possible to study hundreds to thousands of chemical features under the exposome framework. This Perspective explores how advances in mass spectrometry make it possible to generate exposomic data to complement genomic data and thereby better understand neurodegenerative diseases.

Environmental risk score of multiple pollutants for kidney damage among residents in vulnerable areas by occupational chemical exposure in Korea

This study aimed to develop an environmental risk score (ERS) of multiple pollutants (MP) causing kidney damage (KD) in Korean residents near abandoned metal mines or smelters and evaluate the association between ERS and KD by a history of occupational chemical exposure (OCE). Exposure to MP, consisting of nine metals, four polycyclic aromatic hydrocarbons, and four volatile organic compounds, was measured as urinary metabolites. The study participants were recruited from the Forensic Research via Omics Markers (FROM) study (n = 256). Beta-2-microglobulin (β2-MG), N-acetyl-β-D-glucosaminidase (NAG), and estimated glomerular filtration rate (eGFR) were used as biomarkers of KD. Bayesian kernel machine regression (BKMR) was selected as the optimal ERS model with the best performance and stability of the predicted effect size among the elastic net, adaptive elastic net, weighted quantile sum regression, BKMR, Bayesian additive regression tree, and super learner model. Variable importance was estimated to evaluate the effects of metabolites on KD. When stratified with the history of OCE after adjusting for several confounding factors, the risks for KD were higher in the OCE group than those in the non-OCE group; the odds ratio (OR; 95% CI) for ERS in non-OCE and OCE groups were 2.97 (2.19, 4.02) and 6.43 (2.85, 14.5) for β2-MG, 1.37 (1.01, 1.86) and 4.16 (1.85, 9.39) for NAG, and 4.57 (3.37, 6.19) and 6.44 (2.85, 14.5) for eGFR, respectively. We found that the ERS stratified history of OCE was the most suitable for evaluating the association between MP and KD, and the risks were higher in the OCE group than those in the non-OCE group.

Association of vitamin B1 intake with geriatric cognitive function: An analysis of the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2014

BACKGROUND

The association between dietary vitamin B1 intake and cognitive performance in the noninstitutionalized older adult population of the United States remains unclear.

PURPOSE

This study aimed to investigate the association between vitamin B1 intake and cognitive performance in older adults in the United States.

METHODS

Vitamin B1 intake was assessed through two 24-h dietary recalls. Weighted logistic regression was used to evaluate the association between vitamin B1 intake and three cognitive scores (immediate recall test [IRT], animal fluency test [AFT], and digit symbol substitution test [DSST]). Cognitive performance was measured by these three tests, and individuals scoring below the lowest quartile were categorized as cognitive impairment. Sensitivity analysis, including dose-response curves, subgroup analyses, interaction effects, per 1 SD, and quartiles, were performed to ensure the accuracy of the conclusion.

RESULTS

A total of 2896 participants over the age of 60 were included in this study. In the adjusted final model, the association between vitamin B1 intake and low cognitive performance in old age was statistically significant, with the following odds ratios (ORs) and 95% confidence intervals (CIs): IRT, 0.75 (0.57, 0.97), P = 0.018; AFT, 0.68 (0.50, 0.92), P = 0.007; DSST, 0.71 (0.54, 0.92), P = 0.005. Subgroup analyses showed that this association was statistically significant among males, white, low-education, and no memory impairment. The results of the sensitivity analyses confirmed the association between VB1 and cognitive function in old age and the absence of interactions in the final calibrated model.

CONCLUSION

Dietary vitamin B1 intake is negatively associated with cognitive performance in older adults.

Association between Socioecological Status, Nutrient Intake, and Cancer Screening Behaviors in Adults Aged 40 and Over: Insights from the Eighth Korea National Health and Nutrition Examination Survey (KNHANES, 2019)

Cancer screening is pivotal for early detection and improved survival rates. While socio-ecological factors are known to influence screening uptake, the role of lifestyle, dietary habits, and general health in shaping these decisions remains underexplored. Utilizing the 2019 Korea National Health and Nutrition Examination Survey (KNHANES), this study examined the myriad of factors impacting cancer screening utilization. Data from 274,872 adults aged 40 years or older were scrutinized, highlighting demographics, income, lifestyle behaviors, health-related variables, nutrient intake, and dietary quality. A combination of descriptive statistics and logistic regression helped us ascertain influential determinants. Higher educational attainment and income quartiles were positively correlated with cancer screening rates. Regular walkers, those engaged in moderate physical activity, and individuals with a previous cancer diagnosis were more likely to get screened. High-risk drinkers and smokers were less inclined towards screening. Dietary habits also influenced screening decisions. Notably, participants with healthier eating behaviors, indicated by factors such as regular breakfasts and fewer meals out, were more likely to undergo screening. Additionally, nutrient intake analysis revealed that those who had undergone screening consumed greater quantities of most nutrients, bar a few exceptions. For individuals aged 50-64, nutritional assessment indicators highlighted a higher mean adequacy ratio (MAR) and index of nutritional quality (INQ) value among those who participated in screening, suggesting better nutritional quality. This study elucidates the complex socio-ecological and nutritional landscape influencing cancer screening decisions. The results underscore the importance of a holistic approach, emphasizing lifestyle, dietary habits, and socio-economic considerations. It provides a roadmap for policymakers to craft more inclusive screening programs, ensuring equal access and promoting early detection.

Association between Ambient Volatile Organic Compounds Exposome and Emergency Hospital Admissions for Cardiovascular Disease

The limited research on volatile organic compounds (VOCs) has not taken into account the interactions between constituents. We used the weighted quantile sum (WQS) model and generalized linear model (GLM) to quantify the joint effects of ambient VOCs exposome and identify the substances that play key roles. For a 0 day lag, a quartile increase of WQS index for n-alkanes, iso/anti-alkanes, aromatic, halogenated aromatic hydrocarbons, halogenated saturated chain hydrocarbons, and halogenated unsaturated chain hydrocarbons were associated with 1.09% (95% CI: 0.13, 2.06%), 0.98% (95% CI: 0.22, 1.74%), 0.92% (95% CI: 0.14, 1.69%), 1.03% (95% CI: 0.14, 1.93%), 1.69% (95% CI: 0.48, 2.91%), and 1.85% (95% CI: 0.93, 2.79%) increase in cardiovascular disease (CVD) emergency hospital admissions, respectively. Independent effects of key substances on CVD-related emergency hospital admissions were also reported. In particular, an interquartile range increase in 1,1,1-trichloroethane, methylene chloride, styrene, and methylcyclohexane is associated with a greater risk of CVD-associated emergency hospital admissions [3.30% (95% CI: 1.93, 4.69%), 3.84% (95% CI: 1.21, 6.53%), 5.62% (95% CI: 1.35, 10.06%), 8.68% (95% CI: 3.74, 13.86%), respectively]. We found that even if ambient VOCs are present at a considerably low concentration, they can cause cardiovascular damage. This should prompt governments to establish and improve concentration standards for VOCs and their sources. At the same time, policies should be introduced to limit VOCs emission to protect public health.

Associations between mixed exposure to phthalates and latent tuberculosis infection among the general U.S. population from NHANES 2011-2012

Background

People are constantly exposed to phthalates, but few reliable studies have focused on the connection between phthalate exposure and latent tuberculosis infection (LTBI).

Methods

Data were obtained from the National Health and Nutrition Examination Survey (NHANES) database (2011-2012). The LTBI was assessed by QuantiFERON®-TB Gold-In-Tube (QFT) or tuberculin skin testing (TST). The odds ratios (ORs) and 95% confidence intervals (CIs) per log10 unit change in the concentration of phthalate metabolites were calculated using crude and adjusted logistic regression models. The relationships between mixed phthalate concentrations and LTBI were assessed using Bayesian kernel machine regression (BKMR) models.

Results

According to the results of the multivariable logistic regression, in a fully adjusted model, only monobenzyl phthalate (MBZP) was negatively associated with LTBI in Q3 (OR (95% CI): 0.485 (0.286,0.823), P = 0.007). According to the restricted cubic spline (RCS) model, there was a linear dose‒response association between all 11 phthalate metabolites and LTBI (p for nonlinearity >0.05). We found a significant positive correlation between mixed phthalate metabolites and LTBI by using fully adjusted BKMR model.

Conclusions

Our analysis demonstrated that LTBI in the general U.S. population is linearly linked with exposure to single or combined phthalates.

Association between Multiple Trace Elements, Executive Function, and Cognitive Impairment with No Dementia in Older Adults

Many studies suggest a significant association between individual essential trace elements (ETEs) and cognitive impairment in older adults, but evidence of the synchronized effect of multiple ETEs on cognitive function is lacking. We investigated the association between multiple ETEs, cognitive impairment with no dementia (CIND), and executive function in older Korean adults, using the Bayesian kernel machine regression (BKMR) model. Three hundred and thirty-six older adults were included as the study population and classified as the CIND and control groups. Blood manganese (Mn), copper (Cu), zinc (Zn), selenium (Se), and molybdenum (Mo) were measured as relevant ETEs. The frontal/executive tests included digit symbol coding (DSC), the Korean color word Stroop test (K-CWST), a controlled oral word association test (COWAT), and a trial-making test (TMT). Overall, the BKMR showed a negative association between multiple ETEs and the odds of CIND. Mn was designated as the most dominant element associated with the CIND (PIP = 0.6184), with a U-shaped relationship. Cu and Se levels were positively associated with the K-CWST percentiles (β = 31.78; 95% CI: 13.51, 50.06) and DSC percentiles (β = 25.10; 95% CI: 7.66, 42.53), respectively. Our results suggest that exposure to multiple ETEs may be linked to a protective mechanism against cognitive impairment in older adults.

Individual and combined effects of phthalate metabolites on eczema in the United States population

Phthalates might trigger immune dysregulation. The relationship between a phthalate mixture exposure and eczema remains unclear. To address this research gap, four statistical models were used to investigate the individual, combined, and interaction relationships between monoesters of phthalates (MPAEs) and eczema, including the logistic regression, weighted quantile sum regression (WQS), quantile g computation (qg-computation), and bayesian kernel machine regression (BKMR). Moreover, subgroup analyses were performed by sex and age. After adjusting for all covariates, the logistic regression model suggested a positive correlation between mono-(3-carboxypropyl) phthalate (MCPP) and eczema. Subgroup analysis suggested that the effect of the MPAEs on eczema was predominantly present in men and children. In the WQS model, the joint effect of 11 MPAEs on eczema was marginally significant [odds ratio = 1.36, 95% confidence interval: 0.97-1.90]. Moreover, a positive association was observed between the combined exposure to 11 MPAEs and eczema in the BKMR model. MCPP and mono-(carboxynonyl) phthalate were the most substantial risk factors based on the results of WQS and qg-computation models. The exposure to a mixture of MPAEs may lead to an elevated prevalence of eczema in the United States population, with men and children being particularly vulnerable to their effects.

Serum neurofilament light chain and cognition decline in US elderly: A cross-sectional study

OBJECTIVE

Early identification of cognitive impairment in neurodegenerative diseases like Alzheimer's disease (AD) is crucial. Neurofilament, a potential biomarker for neurological disorders, has gained attention. Our study aims to investigate the relationship between serum neurofilament light (sNfL) levels and cognitive function in elderly individuals in the United States.

METHODS

This cross-sectional study analyzed data from participants aged 60 and above in the National Health and Nutrition Examination Survey (2013-2014). We collected sNfL levels, cognitive function tests, sociodemographic characteristics, comorbidities, and other variables. Weighted multiple linear regression models examined the relationship between ln(sNfL) and cognitive scores. Restricted cubic spline (RCS) visualization explored nonlinear relationships. The stratified analysis examined subgroups' ln(sNfL) and cognitive function association.

RESULTS

The study included 446 participants (47.73% male). Participants with ln(sNfL) levels between 2.58 and 2.81 pg/mL (second quintile) performed relatively well in cognitive tests. After adjusting for multiple factors, ln(sNfL) levels were negatively correlated with cognitive function, with adjusted β (95% CI) as follows: immediate recall test (IRT): -0.763 (-1.301 to -0.224), delayed recall test (DRT): -0.308 (-0.576 to -0.04), animal fluency test (AFT): -1.616 (-2.639 to -0.594), and digit symbol substitution test (DSST): -2.790 (-4.369 to -1.21). RCS curves showed nonlinear relationships between ln(sNfL) and DRT, AFT, with inflection points around 2.7 pg/mL. The stratified analysis revealed a negative correlation between ln(sNfL) and cognition in specific subgroups with distinct features, with an interaction between diabetes and ln(sNfL).

INTERPRETATION

Higher sNfL levels are associated with poorer cognitive function in the elderly population of the United States. sNfL shows promise as a potential biomarker for early identification of cognitive decline.

Single- and combined-phthalate exposures are associated with biological ageing among adults

BACKGROUND

Previous research has emphasized the effects of lifestyle and genetics on ageing. However, the association between exposure to phthalates, which are extensively used in cosmetics and personal care products, and ageing is still unclear.

METHOD

Data for 4711 subjects from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2010 were incorporated in the present study. The acceleration of the Klemera-Doubal method-biological age (KDM-BA) and phenotypic Age (PhenoAge) were measured by the composite of 13 biomarkers. Multiple-linear and weighted-quantile sum (WQS) regression models were constructed to explore the relationships of single- and combined-phthalate exposures, as indicated by urinary phthalate metabolites, with KDM-BA and PhenoAge. A generalized additive model (GAM) was fitted to explore the potential nonlinear relationships among the above variables.

RESULTS

Except for mono-(carboxynonyl), all urinary phthalate metabolites were associated with biological ageing, with correlation coefficients ranging from 0.241 to 0.526; however, mono-ethyl presented a negative correlation. The WQS models revealed mixed effects of combined urinary phthalate metabolites on ageing, with a 0.22-year ((95 % CI) 0.09, 0.32) increase in KDM-BA acceleration and a 0.27-year ((95 % CI) 0.13, 0.37) increase in PhenoAge acceleration for each decile increase in urinary phthalate metabolites. Moreover, MCPP, MEOHP, and MBzP seemed to be the top three phthalates in terms of biological ageing, with weights of 33.3 % and 32.2 %, 29.2 % and 17.2 %, and 21.5 % and 30.1 % in KDM-BA and PhenoAge acceleration, respectively.

CONCLUSION

Single-phthalate exposure was mostly associated with the ageing process, and combined-phthalate exposure presented mixed effects on biological ageing, emphasizing phthalate exposure as a significant risk factor for ageing.

Association of phthalate exposure with pulmonary function in adults: NHANES 2007-2012

BACKGROUND

Epidemiological evidence for the adverse effect of phthalate exposure on respiratory health is on the rise, but cross-sectional studies regarding its effects on lung function are limited and contradictory, especially in adults.

OBJECTIVE

To assess the associations between individual and a mixture of urinary phthalate metabolites and adult pulmonary function in the United States, and to identify which ones were primarily responsible for impaired respiratory function.

METHODS

We obtained a cross-sectional data on 3788 adults aged 20 years and older from the National Health and Nutrition Examination Survey (2007-2012). Respiratory function was evaluated using spirometry, and phthalate exposure was assessed by measuring the levels of ten urinary phthalate metabolites. The effects of individual and mixed phthalate metabolites exposure on lung function were assessed using multivariate linear regression models and the repeated holdout weighted quantile sum (WQS) regression models, respectively, after adjusting for potential confounders including age, gender, family poverty income ratio, body mass index, and serum cotinine.

RESULTS

When modeled as continuous variables or quantiles, urinary phthalate metabolites, including mono-ethyl phthalate (MEP), mono-n-butyl phthalate, mono-iso-butyl phthalate, mono-benzyl phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-(3-carboxypropyl) phthalate, and mono-carboxyoctyl phthalate, were identified to be negatively associated with forced vital capacity in percent predicted values (ppFVC) and forced expiratory volume in the first second in percent predicted values (ppFEV1). In addition, per each decile increase in the WQS index, ppFVC (β = -2.87, 95% CI: -3.56, -2.08) and ppFEV1 (β = -2.53, 95% CI: -3.47, -1.54) declined significantly, primarily due to the contribution of MEP and MECPP. Furthermore, there were no significant interactions between co-exposure to urinary phthalate metabolites and each covariate.

CONCLUSION

Our findings reveal that urinary phthalate metabolites are significantly associated with adult respiratory decrements, with diethyl and di-(2-ethylhexyl) phthalate contributing the most to the impaired lung function.

Association between urinary phthalate metabolites and chronic obstructive pulmonary disease incidence in US adults: results from NHANES 2007-2018

Despite associations between urinary phthalates and respiratory symptoms and disorders have been investigated, knowledge about their impact on COPD incidence remains limited. Using data of 8242 adults (aged 20-80 years) from the 2007-2018 National Health and Nutrition Examination Survey (NHANES), the association of mixed urinary phthalate metabolites with COPD incidence was evaluated. Among them, 789 were COPD patients, and the rest were non-COPD participants. In the single-pollutant models, a variety of phthalate metabolites were identified as independent positive factors for COPD incidence, including mono-(carboxynonyl) phthalate (MCNP), mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP), mono-n-butyl phthalate (MnBP), mono-(3-carboxylpropyl) phthalate (MCPP), mono-ethyl phthalate (MEP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-benzyl phthalate (MBzP). Multi-pollutant models, including weighted quantile sum (WQS) regression, quantile-based g computation (qgcomp), and Bayesian kernel machine regression (BKMR) approaches consistently revealed the positive association between phthalates co-exposure and COPD incidence, and MCPP was recognized as the dominant positive driver. The positive association was more evident in the youth group and the male group. The interactions between certain phthalate metabolites in COPD were also observed. Given the limitations of the cross-sectional design of NHANES study, well-designed longitudinal studies are needed to verify or disprove these findings.

Association between exposure to multiple polyaromatic hydrocarbons and periodontitis: findings from a cross-sectional study

The impact of environmental pollutant exposure on periodontitis has raised significant concerns. But the association between exposure to multiple polyaromatic hydrocarbons (PAHs) and periodontitis still remained unclear. Our study investigated the association of exposure to multiple PAHs with periodontitis. A total of 1880 participants from the National Health and Nutrition Examination Survey (NHANES) were included in this study. Urinary samples of the participants exposed to six PAHs, namely, 1-hydroxynaphthalene (1-OHN), 2-hydroxynaphthalene (2-OHN), 3-hydroxyfluorene (3-OHF), 2-hydroxyfluorene (2-OHF), 1-hydroxyphenanthrene (1-OHPhe), and 1-hydroxypyrene (1-OHPyr), were investigated. Multiple logistic regression, restricted cubic spline, and Bayesian kernel machine regression (BKMR) models were employed to identify the association between PAH exposures and periodontitis. The dose-response analysis exhibited a gradual increase in the periodontitis risk with an increase in multiple PAHs. After adjustment for several potential confounders, the odds ratio of the highest quartile (Quartile 4) was 1.648 (95% confidence interval (CI) 1.108-2.456, P = 0.014, P-t = 0.017) for 2-OHN, 2.046 (95%CI 1.352-3.104, P < 0.001, P-t = 0.005) for 3-OHF, 1.996 (95% CI 1.310-3.046, P = 0.001, P-t = 0.003) for 2-OHF, 1.789 (95% CI 1.230-2.604, P = 0.002, P-t = 0.003) for 1-OHPhe, and 1.494 (95% CI 1.025-2.181, P = 0.037, P-t = 0.021) for 1-OHPyr compared with that of the lowest quartile (Quartile 1). BKMR illustrated that the overall effect of the PAH mixture was positively related to periodontitis. Mediation analysis identified blood neutrophils as a partial mediator of 3-OHF and 2-OHF. Exposure to multiple PAHs was positively associated with periodontitis in US adults, and blood neutrophils mediate the effects of 3-OHF and 2-OHF therein.

Associations between exposure to phthalates and rheumatoid arthritis risk among adults in NHANES, 2007-2016

BACKGROUND

The etiology of rheumatoid arthritis (RA) is multifactorial, encompassing genetics and environment. Despite the widespread use of phthalates as chemical additives, their potential impact on RA has received limited investigation. This study aimed to evaluate the potential associations between exposure to phthalates and rheumatoid arthritis risk among adults.

METHODS

Participants ≥20 years were analyzed from the National Health and Nutrition Examination Survey (NHANES) 2007-2016. Multivariable logistic regression was used to examine the association between exposure to phthalates and RA in two models. Additionally, subgroup analyses stratified by gender and age were also performed. The nonlinear relationship between RA and phthalates was characterized by smooth curve fittings and generalized additive models.

RESULTS

Ultimately, 9322 participants (RA: 601, without RA: 8632) were analyzed. The prevalence of RA increased with higher quantiles of MECPP (Q4, OR: 1.43, 95% CI: 1.07-1.91), MBP (Q2, OR: 1.30, 95% CI: 1.01-1.67), MEHHP (Q3, OR: 1.39, 95% CI: 1.07-1.81; Q4, OR: 1.35, 95% CI: 1.02-1.87) and MEOP (Q2, OR:1.35, 95% CI: 1.03-1.76) compared to the lowest quartile. A nonlinear relationship positive association was also observed between MECPP (P for non-linearity = 0.0074)) and MEHHP (P for non-linearity = 0.0046)) levels and RA. Subgroup analysis showed the association between phthalate levels and RA was mainly present in males or participants aged more than 60 years.

CONCLUSIONS

Our results demonstrated that exposure to phthalates is associated with an increased prevalence of RA among adults. Notably, such associations appear to be more pronounced in males and older people.

Association between dietary niacin intake and cognitive function in the elderly: Evidence from NHANES 2011-2014

Recent studies have shown an inconsistent association between dietary niacin and cognitive function. And this remains unclear in the American outpatient population. The aim of this study was to assess whether there is an association between dietary niacin and cognitive performance in an older American population aged ≥60 years. A total of 2523 participants from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 were enrolled. Cognitive function was assessed by the CERAD Word Learning (CERAD-WL) test, the CERAD Delayed Recall (CERAD-DR) test, the Animal Fluency test (AFT), and the Digit Symbol Substitution test (DSST). Cognitive impairment that meets one of the four scoring conditions listed above is defined as low cognitive function. Dietary niacin intake was obtained from 2 days of a 24-h recall questionnaire. Based on the quartiles of dietary niacin intake, they were divided into four groups: Q1 (<15.51 mg), Q2 (15.51-20.68 mg), Q3 (20.69-26.90 mg), and Q4 (>26.91 mg). The stability of the results was assessed using multifactorial logistic regression, restricted cubic spline (RCS) models, and sensitivity stratified analysis. More than half of the participants had cognitive impairment (52.52%). In the fully adjusted model, niacin was associated with a significantly reduced risk of cognitive impairment in Q3 and Q4 compared with the Q1 group (OR: 0.610, 95% CI: 0.403, 0.921, p = .022; OR: 0.592, 95% CI: 0.367, 0.954, p = .034). Meanwhile, niacin was negatively associated with poor cognition as assessed by the CERAD-WL test, CERAD test, AFT, and DSST. An L-shaped dose-response relationship between dietary niacin and cognitive function was observed in all participants (nonlinear p < .001). There were also interactions that existed in populations with different carbohydrate intakes and cholesterol intakes (p for interaction = .031, p for interaction = .005). These findings provide new evidence for the potential role of dietary niacin intake on cognitive function in the elderly.

Dose-response association of polycyclic aromatic hydrocarbon with self-reported trouble sleeping in adults: evidence from the National Health and Nutrition Examination Survey

Previous epidemiological evidence from large population-based studies on the association between polycyclic aromatic hydrocarbons (PAH) exposure and the risk of sleep disorders is inadequate. To comprehensively examine the relationship between independent and combined PAHs and trouble sleeping, we analyzed data from 8194 participants from the National Health and Nutrition Survey (NHANES) cycles. Multivariate adjusted logistic regression and restricted cubic spline models were applied to assess the relationship between PAH exposure and the risk of trouble sleeping. Bayesian kernel machine regression and weighted quantile sum regression models were used to estimate the combined association of urinary PAHs with trouble sleeping. In the single-exposure analyses, compared with the lowest level, the respective adjusted odds ratios (ORs) for trouble sleeping among subjects from the highest quartile were 1.34 (95% CI, 1.15, 1.56), 1.23 (95% CI, 1.05, 1.44), 1.31 (95% CI, 1.11, 1.54), 1.35 (95% CI, 1.15, 1.58), and 1.29 (95% CI, 1.08, 1.53) for 1-hydroxynaphthalene (1-NAP), 2-hydroxynaphthalene (2-NAP), 3-hydroxyfluorene (3-FLU), 2-hydroxyfluorene(2-FLU), and 1-hydroxypyrene(1-PYR). An overall positive correlation between the PAH mixture and trouble sleeping was observed when the mixture was at the 50th percentile or higher. The current study reveals that PAH metabolites (1-NAP, 2-NAP, 3-FLU, 2-FLU, and 1-PYR) may be detrimental to trouble sleeping. PAH mixture exposure was positively associated with trouble sleeping. The results suggested the potential impacts of PAHs and expressed concerns regarding the potential impact of PAHs on health. More intensive research and monitoring of environmental pollutants in the future will contribute to preventing environmental hazards.

Association of a mixture of phthalates and phenols with frailty among middle-aged and older adults: A population-based cross-sectional study

BACKGROUND

Frailty is a complex geriatric syndrome caused by degenerative changes in the body or various chronic diseases. The use of personal care and consumer products is associated with a wide range of health outcomes, but its relationship with frailty remains unknown. Therefore, our primary aim was to explore the potential links between exposure to phenols and phthalates, either separately or in combination, and frailty.

METHODS

The exposure levels of phthalates and phenols were evaluated through the measurement of metabolites in urine samples. Frailty state was assessed by a 36-item frailty index with values ≥ 0.25 indicating frailty. Weighted logistic regression was used to explore the relationship between individual chemical exposure and frailty. In addition, multi-pollutant strategies (WQS, Qgcomp, BKMR) were used to examine the joint effect of chemical mixture on frailty. A series of subgroup analyses and sensitivity analyses were conducted as well.

RESULTS

In the multivariate logistic regression model, each unit increase in natural log-transformed BPA (OR: 1.21; 95%CI: 1.04, 1.40), MBP (OR: 1.25; 95%CI: 1.07, 1.46), MBzP (OR: 1.18; 95%CI: 1.03, 1.36), and MiBP (OR: 1.19; 95%CI: 1.03, 1.37) were significantly associated with higher odds of frailty. The results of the WQS and Qgcomp indicated that increasing quartiles of chemical mixture was associated with odds of frailty with ORs of 1.29 (95%CI: 1.01, 1.66) and 1.37 (95%CI: 1.06, 1.76). The weight of MBzP is dominant in both the WQS index and the positive weight of Qgcomp. In the BKMR model, the cumulative effect of chemical mixture was positively correlated with the prevalence of frailty.

CONCLUSIONS

In summary, higher levels of BPA, MBP, MBzP, and MiBP are significantly associated with higher odds of frailty. Our study provides preliminary evidence that phenol and phthalate biomarker mixture is positively associated with frailty, with MBzP contributing most to the positive association.

Cognitive and hippocampal effects of adult male mice exposure to environmentally relevant doses of phthalates

We recently showed that chronic exposure of adult male mice to environmental doses of DEHP alone or in a phthalate mixture altered blood brain barrier integrity and induced an inflammatory profile in the hippocampus. Here, we investigate whether such exposure alters hippocampus-dependent behavior and underlying cellular mechanisms. Adult C57BL/6 J male mice were continuously exposed orally to the vehicle or DEHP alone (5 or 50 μg/kg/d) or to DEHP (5 μg/kg/d) in a phthalate mixture. In the Morris water maze, males showed reduced latencies across days to find the platform in the cue and spatial reference memory tasks, regardless of their treatment group. In the probe test, DEHP-50 exposed males displayed a higher latency to find the platform quadrant. In the temporal order memory test, males exposed to DEHP alone or in a phthalate mixture were unable to discriminate between the most recently and previously seen objects. They also displayed reduced ability to show a preference for the new object in the novel object recognition test. These behavioral alterations were associated with a lowered dendritic spine density and protein levels of glutamate receptors and postsynaptic markers, and increased protein levels of the presynaptic synaptophysin in the hippocampus. Metabolomic analysis of the hippocampus indicated changes in amino acid levels including reduced tryptophan and L-kynurenine and elevated NAD + levels, respectively, a precursor, intermediate and endproduct of the kynurenine pathway of tryptophan metabolism. Interestingly, the protein amounts of the xenobiotic aryl hydrocarbon receptor, a target of this metabolic pathway, were elevated in the CA1 area. These data indicate that chronic exposure of adult male mice to environmental doses of DEHP alone or in a phthalate mixture impacted hippocampal function and structure, associated with modifications in amino acid metabolites with a potential involvement of the kynurenine pathway of tryptophan metabolism.

Butyl benzyl phthalate as a key component of phthalate ester in relation to cognitive impairment in NHANES elderly individuals and experimental mice

Phthalates are a group of neurotoxicants with cognitive-disrupting potentials. Given the structural diversity of phthalates, the corresponding neurotoxicity is dramatically altered. To identify the potential contributions of different phthalates on the process of cognitive impairment, data of 836 elders from the NHANES 2011-2014 cycles were used. Survey-weighted logistic regression and principal component analysis-weighted quantile sum regression (PCA-WQSR) models were applied to estimate the independent and combined associations of 11 urinary phthalate metabolites with cognitive deficit (assessed by 4 tests: Immediate Recall (IR), Delayed Recall (DR), Animal Fluency (AF), and Digit Symbol Substitution Test (DSST)) and to identify the potential phthalate with high weight. Laboratory mice were further used to examine the effect of phthalates on cognitive function and to explore the potential mechanisms. In logistic regression models, MBzP was the only metabolite positively correlated with four tests, with ORs of 2.53 (quartile 3 (Q3)), 2.26 (Q3), 2.89 (Q4) and 2.45 (Q2), 2.82 (Q4) for IR, DR, AF, and DSST respectively. In PCA-WQSR co-exposure models, low-molecular-weight (LMW) phthalates were the only PC positively linked to DSST deficit (OR: 1.93), which was further validated in WQSR analysis (WQS OR7-phthalates: 1.56 and WQS OR8-phthalates: 1.55); consistent with the results of logistic regression, MBzP was the dominant phthalate. In mice, butyl benzyl phthalate (BBP), the parent phthalate of MBzP, dose-dependently reduced cognitive function and disrupted hippocampal neurons. Additionally, the hippocampal transcriptome analysis identified 431 differential expression genes, among which most were involved in inhibiting the neuroactive ligand-receptor interaction pathway and activating the cytokine-cytokine receptor interaction pathway. Our study indicates the critical role of BBP in the association of phthalates and cognitive deficits among elderly individuals, which might be speculated that BBP could disrupt hippocampal neurons, activate neuroinflammation, and inhibit neuroactive receptors. Our findings provide new insight into the cognitive-disrupting potential of BBP.

The combined effect of heavy metals and polycyclic aromatic hydrocarbons on arthritis, especially osteoarthritis, in the U.S. adult population

The evaluation of heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) impact on arthritis is usually limited to the analysis of the arthritis subtype (rheumatoid arthritis, RA), whereas studies on osteoarthritis (OA) are relatively sparse. Furthermore, the combined effect of HMs and PAHs co-exposure on arthritis also has rarely been analyzed. Herein, we aimed to comprehensively estimate the association between HMs and PAHs (three blood HMs and six urinary PAHs metabolites) co-exposure and arthritis. Using data from the National Health and Nutrition Examination Survey (NHANES), 2003-2016, we included 9735 adults, of whom 2464 had total arthritis, 1371 had OA, and 468 had RA. The logistic regression model was conducted to estimate the single effect of HMs and PAHs on arthritis. Moreover, weighted quantile sum (WQS) regression, quantile-based g computation (qgcomp), and Bayesian kernel machine regression (BKMR) were separately performed to assess the combined effect of HMs and PAHs co-exposure on arthritis. In the single-exposure analyses, cadmium (Cd) and lead (Pb) statistically grew the risk of total arthritis, OA, and RA. Among PAHs, 1-hydroxynaphthalene (1-NAP) and 3-hydroxyfluorene (3-FLU) showed a positive association with total arthritis, OA, and RA. Meanwhile, 2-NAP also was significantly associated with total arthritis. 2-NAP, 2-FLU, and 1-hydroxyphenanthrene (1-PHE) also were significantly associated with RA. Furthermore, the three complementary models consistently demonstrated that co-exposure to high levels of HMs and PAHs was positively associated with total arthritis, OA, and RA risk. The above associations were more obvious in young and medium-aged people. Interestingly, BKMR analyses indicated that 1-NAP might interact with Cd and 3-FLU in total arthritis, while Pb might interact with Cd in OA. Therefore, this study provided novel evidence that co-exposure to HMs and PAHs positively correlated with arthritis, especially OA, and these results were worthy of further prospective studies.

Relationship between phthalates exposures and hyperuricemia in U.S. general population, a multi-cycle study of NHANES 2007-2016

BACKGROUND

Phthalates exposure might cause kidney damage and a potential risk for hyperuricemia. However, direct evidence on phthalates and hyperuricemia is somewhat limited.

OBJECTIVE

To examine associations between 10 phthalates metabolites and hyperuricemia in a large-scale representative of the U.S.

METHODS

A cross-sectional study of 6865 participants aged over 20 from NHANES 2007-2016 was performed. All participants had complete data on ten phthalate metabolites (MECPP, MnBP, MEHHP, MEOHP, MiBP, cx-MiNP, MCOP, MCPP, MEP, MBzP), hyperuricemia, and covariates. We used multivariable logistics regression, restricted cubic splines (RCS) model, and Bayesian kernel machine regression (BKMR) models to assess single, nonlinear, and mixed relationships between phthalate metabolites and hyperuricemia. As a complement, we also assessed the relationship between phthalate metabolites and serum uric acid (SUA) levels.

RESULTS

The multivariable logistics regression showed that MECPP, MEOHP, MEHHP, MBzP, and MiBP were generally positively associated with hyperuricemia (P_FDR < 0.05), especially in MiBP (Q3 (OR (95 %): 1.31 (1.02, 1.68)) and Q4 (OR (95 %): 1.68 (1.27, 2.24)), compared to Q1). All ten phthalate metabolites had a linear dose-response relationship with hyperuricemia in the RCS model (P for non-linear >0.05). BKMR showed that mixed phthalate metabolites were associated with a higher risk of hyperuricemia, with MBzP contributing the most (groupPIP = 0.999, condPIP = 1.000). We observed the consistent results between phthalate metabolites and SUA levels in three statistical models. The relationship between phthalate metabolites and hyperuricemia remained in the sensitivity analysis.

CONCLUSIONS

The present study suggests that exposure to phthalates, individually or jointly, might increase the risk of hyperuricemia. Since hyperuricemia influences on the quality of life, more explorations are needed to confirm these findings.

Association between exposure to phenols and parabens and cognitive function in older adults in the United States: A cross-sectional study

BACKGROUND

People are commonly exposed to mixtures of parabens and phenols. Most studies investigating such exposure and cognitive performance tend to assess only single chemicals, and the tools used to assess cognitive function are not uniform.

OBJECTIVE

This study aimed to examine the association between multiple parabens and phenols and cognitive function in older Americans.

METHODS

The study included data of older Americans from two cycles of the NHANES survey. Participants were divided into normal cognitive performance and low cognitive performance groups based on the scores of four cognitive tests: the Immediate Recall test (IRT), the Delayed Recall test (DRT), the Animal Fluency test (AFT) and the Digit Symbol Substitution test (DSST). Generalized linear regression models (GLMs), restricted cubic spline (RCS), weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) were used to assess relationships between chemical exposure and cognitive performance.

RESULTS

In this cross-sectional study, a total of 961 participants, 470 males and 491 females, were included. GLMs revealed positive association between high levels of bisphenol A (BPA) and low cognitive performance on DRT, especially in male (OR (95%CI): 2.25 (1.10-4.61)), and this association was consistent with WQS and BKMR. In female participants, the third quartile of BPA exposure showed a positive association with low cognition on IRT and global cognition. GLMs also showed that high levels of propylparaben were positively associated with cognitive performance on the IRT in male participants (OR (95%CI): 0.37 (0.18-0.76)). In BKMR, an overall positive correlation between the mixture and low cognition as measured with DRT was observed in male subjects when the mixture was at the 65th percentile or higher.

CONCLUSION

Exposure to a mixture of parabens and phenols was positively associated with low cognitive performance on DRT in older male subjects, while BPA was the main driver of this outcome.

Residential greenness and air pollution concerning excessive gestational weight gain during pregnancy: A cross-sectional study in Wuhan, China

BACKGROUND

Previous studies have indicated that exposure to residential greenness may benefit the health status of pregnant women, and air pollution may exert a mediating effect. Gestational weight gain (GWG) is an important indicator of pregnant women and fetuses' health and nutrition status. However, evidence concerning the impact of residential greenness on excessive gestational weight gain (EGWG) is scarce, and to what extent air pollution in urban settings mediates this relationship remains unclear.

OBJECTIVE

This study aims to explore the association of residential greenness with EGWG, consider the mediating effect of air pollution, and estimate the combined impact of residential greenness and air pollution exposures on EGWG.

METHOD

This population-based cross-sectional study involved 51,507 pregnant women with individual-level data on residential addresses in the Wuhan Maternal and Child Health Management Information System. Two spectral indexes, the normalized difference vegetation index (NDVI) and soil-adjusted vegetation index (SAVI), were used to proxy residential greenness. The air pollution data included six indicators (PM_2.5, PM₁₀, SO₂, CO, NO₂, O₃) and used the Ordinary Kriging interpolation method to estimate overall pregnancy exposure to air pollutants. Generalized linear mixed regression models were utilized to explore the relationship between residential greenness and EGWG. Restricted cubic spline (RCS) models were developed to examine the dose-response relationships. Mediation analyses explored the potential mediating role of air pollution in the residential greenness-EGWG associations. Finally, the weighted-quantile-sum (WQS) regression model was used to investigate the association between residential greenness-air pollutants co-exposure and EGWG.

RESULT

Among all participants, 26,442 had EGWG. In the adjusted model, the negative association was found significant for NDVI_100-m, NDVI_200-m, and NDVI_500-m with EGWG. For example, each IQR increase in NDVI_100-m was associated with 2.8% (95% CI: 0.6-5.0) lower odds for EGWG. The result of WQS regression showed that, when considering the six air pollutants and NDVI_-100m together, both positive and negative WQS indices were significantly associated with EGWG, PM₁₀, PM_2.5, with SO₂ having significant weights in the positive effect direction and CO, O₃, NO₂, and NDVI_100-m having a negative effect. Our results also suggested that SO₂, NO₂, PM₁₀, PM_2.5, and CO significantly mediated the association between NDVI_-100m and EGWG, and our estimates were generally robust in the sensitivity analysis.

CONCLUSION

Exposure to a higher level of residential greenness is associated with a reduced risk of EGWG, in which air pollution may exert a mediating effect. Pregnant women might benefit more in gaining healthy gestational weight when greenness levels increase from low to medium than from medium to high. Given the current cross-sectional study design, large-sale prospective cohort studies are needed to confirm our findings further.

Dietary Total Antioxidant Capacity and Cognitive Function in Older Adults in the United States: The NHANES 2011-2014

OBJECTIVES

Oxidative stress level takes part in the development of cognitive decline. However, the association between total antioxidant capacity (TAC) from diet and cognitive function is controversial. The aim of this study was to investigate the relationship between TAC and the cognitive function of older adults in the U.S.

DESIGN

A cross-sectional study.

SETTING

National Health and Nutrition Examination Surveys database.

PARTICIPANTS

2712 older adults aged over 60 years.

MEASUREMENTS

TAC was calculated from 8 antioxidative vitamins based on the reference values for vitamin C equivalent antioxidant capacity obtained from individuals' 24 h dietary recall. Four memory-related assessments were employed [Immediate Recall test (IRT), Delayed Recall test (DRT), Animal Fluency test (AFT), and Digit Symbol Substitution test (DSST)].

RESULTS

Among the 2712 participants, the median age was 68 years, and 50.4% were women. Participants in the group with higher TAC levels had relatively higher IRT, AFT and DSST scores (P=0.025, P=0.008, P<0.001, respectively). In adjusted weighted linear regression, log-transformed TAC was positively associated with AFT (β=1.10, 95%CI: 0.51, 1.70) and DSST (β=2.81, 95%CI: 1.16, 4.45). Compared with the first quartile, the participants in the second (Q2 vs. Q1, OR=0.66, 95%CI: 0.43,1.02) and fourth quartile (Q4 vs. Q1, OR=0.47, 95%CI:0.28, 0.78) of log-transformed TAC showed a decreased risk of impaired cognitive function (ICF) after adjusting for confounders. The dose-response analysis indicated a gradual descent in the risk of ICF as TAC increases. Diabetes mellitus (DM) mediated part of the effect of TAC on ICF. The relationship between TAC and ICF was more pronounced in subjects with DM (Q4 vs Q1, OR=0.36, 95%CI:0.17, 0.74).

CONCLUSION

Our findings support that higher dietary antioxidant potential was related to a decreased risk of cognitive dysfunction, particularly in the subjects with DM who may have oxidative injury. DM was one of the factors mediating the effect of TAC on ICF.

Mixed exposure to phenol, parabens, pesticides, and phthalates and insulin resistance in NHANES: A mixture approach

PURPOSE

The effects of environmental chemicals on insulin resistance have attracted extensive attention. Previous studies typically focused on the single chemical effects. This study adopted three different models to analyze the mixed effects of nine common chemicals (one phenol, two parabens, two chlorophenols and four phthalates) on insulin resistance.

METHODS

Urinary concentrations of chemicals were extracted from National Health and Nutrition Examination Survey (NHANES) 2009-2016. Insulin resistance was assessed using homeostatic model assessment (HOMA) and defined as HOMA-IR >2.6. The generalized linear regression (GLM), weighted quantile sum regression (WQS) and Bayesian kernel machine regression models (BKMR) were applied to assess the relationship between chemical mixture and HOMA-IR or insulin resistance.

RESULTS

Of the 2067 participants included, 872 (42.19 %) were identified as insulin resistant. In single-chemical GLM model, di-2-ethylhexyl phthalate (DEHP) had the highest parameter (β/OR, 95 % CIs) of 0.21 (quartile 4, 0.12- 0.29) and 1.95 (quartile 4, 1.39- 2.74). Similar results were observed in the multi-chemical models, with DEHP (quartile 4) showing the positive relationship with HOMA-IR (0.18, 0.08- 0.28) and insulin resistance (1.76, 1.17- 2.64). According to WQS models, the WQS indices were significantly positively correlated with both HOMA-IR (β: 0.07, 95 % CI: 0.03- 0.12) and insulin resistance (OR: 1.25, 95 % CI: 1.03- 1.53). DEHP was the top-weighted chemical positively correlated with both HOMA-IR and insulin resistance. In the BKMR model, the joint effect was also positively correlated with both outcomes. DEHP remained the main contributor to the joint effect, consistent with WQS analysis.

CONCLUSION

Our findings suggested that these chemical mixtures had the positive joint effects on both HOMA-IR and insulin resistance, with DEHP being the potentially predominant driver. The inter-validation of the three models may indicate that reducing the DEHP concentration could improve glucose homeostasis and reduce the risk of insulin resistance. However, further studies are recommended to deepen our findings and elucidate the mechanisms of insulin resistance and chemical mixture.

Associations of single and multiple perfluoroalkyl substances exposure with folate among adolescents in NHANES 2007-2010

BACKGROUND

The accumulation of perfluoroalkyl substances (PFAS) in human body has raised concerns about the potential health impacts on children and adolescents. However, no study has evaluated the associations of PFAS exposure with folate concentrations among adolescents.

METHODS

In the present study, we mainly used three statistical approaches, namely multiple linear regression, Bayesian Kernel Machine Regression (BKMR), and quantile-based g-computation (Q-gcomp) models, to evaluate associations of individual PFAS and their mixtures with serum and red blood cell (RBC) folate concentrations in a sample of 721 adolescents from the NHANES 2007-2010.

RESULTS

In multiple linear regression models, for per unit increase in ln-transformed perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) concentrations, RBC folate concentrations decreased by 72.4 (95% confidence interval (CI): -112.7, -32.2), 58.3 (95% CI: -115.0, -1.6), 60.7 (95% CI: -107.5, -13.8), and 76.5 (95% CI: -119.0, -33.9) nmol/L, respectively. A similar significant inverse association was also observed between ln-transformed PFDA and serum folate. BKMR models further confirmed inverse associations of serum PFOS and PFDA with RBC folate, and serum PFDA with serum folate. However, the inverse associations of PFOA and PFNA with RBC folate shown in multiple linear regression model were not observed or less evident in BKMR analyses. We observed interactions of PFOA with PFOS, PFNA, and PFDA on RBC folate in BKMR models, with the negative slopes for PFOS, PFNA, and PFDA increased when PFOA concentration increased from the 10th percentile to the 90th percentile. Both BKMR and Q-gcomp models suggested that the mixtures of five PFAS showed inverse overall associations with RBC folate concentration.

CONCLUSIONS

The present study revealed that adolescent exposure to PFAS might affect serum and RBC folate concentrations.