Kidney function and tobacco smoke exposure in US adolescents

Assessment of oxidative balance score with hypertension and arterial stiffness in children and adolescents: NHANES 2001-2018

OBJECTIVE

To investigate the complex relationship between oxidative balance score (OBS), hypertension (HTN) and arterial stiffness in children and adolescents utilizing data gathered from the National Health and Nutrition Examination Survey (NHANES).

STUDY DESIGN

Through utilizing NHANES data (2001-2018), OBS, comprising dietary and lifestyle components, was calculated and categorized into tertiles. The correlation between OBS and HTN was explored employing weighted multivariate logistic regression. Stratified analyses were further performed to evaluate the associations across different subgroups.

RESULTS

A total of 11,754 children and adolescents were ultimately enrolled in analyses. High OBS tertiles demonstrated a consistent negative association with HTN across models. Compared with the lowest OBS tertile, the risk of HTN in the highest OBS tertile was decreased by 37% (95% CI 0.44-0.90, p = 0.011). After dividing OBS into dietary OBS and lifestyle OBS, Lifestyle OBS exhibited a significant inverse association with HTN, while dietary OBS showed no significant correlation. Stratified analyses notably revealed the protective impacts of OBS on the risk of HTN in males. Restricted cubic spline analysis confirmed a nonlinear association between OBS and HTN. Moreover, the elevated OBS was significantly associated with decreased ePWV, indicating a potential link between arterial stiffness and OBS.

CONCLUSION

In summary, the risk of HTN was inversely correlated with high OBS. Adopting a wholesome lifestyle enriched with antioxidants to boost OBS may help shield children from HTN risk.

Acid Sphingomyelinase and Ceramide Signaling Pathway Mediates Nicotine-Induced NLRP3 Inflammasome Activation and Podocyte Injury

Background: Recent studies have shown that Nlrp3 inflammasome activation is importantly involved in podocyte dysfunction induced by nicotine. The present study was designed to test whether acid sphingomyelinase (Asm) and ceramide signaling play a role in mediating nicotine-induced Nlrp3 inflammasome activation and subsequent podocyte damage. Methods and Results: Nicotine treatment significantly increased the Asm expression and ceramide production compared to control cells. However, prior treatment with amitriptyline, an Asm inhibitor significantly attenuated the nicotine-induced Asm expression and ceramide production. Confocal microscopic and biochemical analyses showed that nicotine treatment increased the colocalization of NLRP3 with Asc, Nlrp3 vs. caspase-1, IL-1β production, caspase-1 activity, and desmin expression in podocytes compared to control cells. Pretreatment with amitriptyline abolished the nicotine-induced colocalization of NLRP3 with Asc, Nlrp3 with caspase-1, IL-1β production, caspase-1 activity and desmin expression. Immunofluorescence analyses showed that nicotine treatment significantly decreased the podocin expression compared to control cells. However, prior treatment with amitriptyline attenuated the nicotine-induced podocin reduction. In addition, nicotine treatment significantly increased the cell permeability, O2 production, and apoptosis compared to control cells. However, prior treatment with amitriptyline significantly attenuated the nicotine-induced cell permeability, O2 production and apoptosis in podocytes. Conclusions: Asm is one of the important mediators of nicotine-induced inflammasome activation and podocyte injury. Asm may be a therapeutic target for the treatment or prevention of glomerulosclerosis associated with smoking.

Serum hydroxycotinine was associated with chronic kidney disease (CKD): a cross-sectional study based on NHANES

OBJECTIVE

Smoking has been suggested as a modifiable and cardiovascular risk factor for chronic kidney disease (CKD). Although long-term smoking has been associated with CKD, the potential relationship between its metabolite hydroxycotinine and CKD has not been clarified.

METHODS

A total of 8,544 participants aged 20 years and above from the National Health and Nutrition Examination Survey (NHANES) 2017 - March 2020 were enrolled in our study. CKD was defined by estimated glomerular filtration rate (eGFR) < 60 mL/(min*1.73 m2). Serum hydroxycotinine was measured by an isotope-dilution high-performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometric (ID HPLC-APCI MS/MS) method with a lower limit of detections (LLOD) at 0.015 ng/mL. The non-linear relationship was explored with restricted cubic splines (RCS). Pearson's correlation coefficient and a multivariate logistic regression model were used for correlation analysis.

RESULTS

Serum hydroxycotinine and eGFR were negatively correlated in both non-CKD group (r= -0.05, p < 0.001) and CKD group (r= -0.04, p < 0.001). After serum hydoxycotinine dichotominzed with LLOD, serum hydroxycotinine ≥ 0.015 ng/mL was negatively correlated with eGFR not only in non-CKD group (r = -0.05, p < 0.001) but also in CKD group (r = -0.09, p < 0.001). After adjusting for comprehensive confounders, results from the multivariate logistic regression analysis showed that participants with serum hydroxycotinine ≥ 0.015 ng/mL had increased odds of CKD (OR = 1.505, p < 0.001).

CONCLUSIONS

Serum hydroxycotinine might be positively associated with CKD. Further study is warranted to find the right concentration of hydroxycotinine to measure the CKD.

Joint effect of docosahexaenoic acid intake and tobacco smoke exposure on learning disability in children and adolescents: a cross-sectional study from the NHANES database

BACKGROUND

Docosahexaenoic acid (DHA) has been reported to be associated with the children's neurodevelopment, who may be exposed to tobacco smoke simultaneously. The evidence about joint effect of DHA intake and tobacco smoke exposure on children and adolescents' learning disabilities (LD) was limited. The objective of this study was to assess the joint effect of DHA intake and tobacco smoke exposure on children and adolescents' LD.

METHODS

A cross-sectional analysis of the NHANES 1999-2004 was performed. Children and adolescents aged 6-15 years old were included. The outcome was diagnosed by parental report of ever health professionals or school representative-identified LD. Dietary DHA intake data were obtained by food frequency questionnaire and tobacco smoke exposure levels were evaluated by serum cotinine levels. Weighted univariable and multivariate logistic regression analyses were conducted to determine the joint effect of DHA intake and tobacco smoke exposure on LD in children and adolescents, with odds ratios (ORs) and 95% confidence intervals (CIs). This joint association was further assessed after stratification by age, gender, body mass index, the history of attention deficit disorder and seen mental health professional.

RESULTS

We identified 5,247 children and adolescents in present study, of whom 593 (11.30%) had LD. After adjusting covariates, we observed children and adolescents with DHA intake (OR = 0.76, 95%CI: 0.61-0.96) was related to lower incidence of LD; children who exposure to tobacco smoke was related to higher incidence of LD (OR = 1.54, 95%CI: 1.07-2.23); children and adolescents who exposure to tobacco smoke and without DHA intake were related to highest odds of LD (OR = 2.08, 95%CI: 1.37-3.17, P for trend = 0.042), that was, DHA and tobacco smoke exposure may have a joint effect on the odds of LD in children and adolescents. Subgroup analyses suggested this joint effect was robust especially among children and adolescents with normal & underweight BMI and without the history of attention deficit disorder and seen mental health professional.

CONCLUSION

Increasing the DHA intake and reducing tobacco smoke exposure may have a potential role in the prevention of LD in children and adolescents. This joint effect warrants further investigation by large-scale prospective study.

Association between secondhand smoke exposure and rheumatoid arthritis in US never-smoking adults: a cross-sectional study from NHANES

While smoking is widely acknowledged as a risk factor for rheumatoid arthritis (RA), the connection between secondhand smoke (SHS) exposure and RA in never-smoking adults remains limited and inconsistent. This study aims to explore and quantify this association using serum cotinine levels. We conducted a cross-sectional study with 14,940 adults who self-report as never smokers, using National Health and Nutrition Examination Survey data from 1999 to 2018. Based on previous literature, SHS exposure was categorized into four groups according to serum cotinine levels. Compared to individuals in the unexposed group (serum cotinine < 0.05 ng/mL), the adjusted odds ratio (OR) for RA was 1.37 (95% CI 1.14-1.64, p = 0.001) in the low exposure group (serum cotinine at 0.05 to 0.99 ng/mL) after adjusting for covariates. However, no significant association was found in the moderate exposure group (serum cotinine at 1 to 10 ng/mL) or the heavy exposure group (serum cotinine ≥ 10 ng/mL). Furthermore, we detected a non-linear, positively saturated correlation between the cotinine levels after log2 transformation and RA, with a turning point at approximately - 2.756 ng/mL (OR = 1.163, 95% CI 1.073-1.261, p = 0.0002). The stability of the results was confirmed by subgroup analysis.

Active smoking in urban households: An association between urinary cotinine metabolite level and serum eGFR concentration

INTRODUCTION

Smoking stands as a primary contributor to preventable deaths globally and is linked to an increased risk of developing kidney failure and other diseases. A few studies have focused on the negative correlation between serum cotinine and estimated glomerular filtration rate (eGFR), indicating decreased kidney function. This study investigated the associations between urinary cotinine metabolite concentration and serum eGFR among active smokers in urban households.

METHODS

This was a cross-sectional study of active smokers in urban households' community Bangkok, Thailand from January to April 2023. The study involved 85 participants aged ≥18 years who were active smokers. Both urinary cotinine and serum eGFR concentrations were used as biomarkers. Independent sample t-tests were used to compare the urinary cotinine metabolite based on differences in the characteristic variable. We used multiple linear regression to test the association between cotinine metabolite and characteristics variables. Spearman's analysis was used to test the correlation between cotinine metabolite and eGFR concentration.

RESULTS

The association between urinary cotinine metabolite and serum eGFR concentration decreased with increasing cotinine concentrations (r= -0.223, p=0.041), suggesting a decline in kidney function. However, this study found no significant difference between urinary cotinine metabolite and characteristic variables (p>0.05). Additionally, those who smoked for ≥10 years (117.40 ± 89.80 ng/mL), smoked ≥10 cigarettes per day (117.40 ± 89.80 ng/mL) and used conventional cigarettes (124.53 ± 115.10 ng/mL). The results of the multiple linear regression models analysis indicated that those who were smokers for ≥10 years (β=0.076; 95% CI: -31.575-59.715) and those who were smoked ≥10 cigarettes/day (β=0.126; 95% CI: -65.636-18.150) were not associated with urinary cotinine metabolite level.

CONCLUSIONS

This study shows that the urinary cotinine metabolite level is associated with serum eGFR concentration among active smokers in urban households. The current study suggests that clinical identification and a prospective cohort study are needed before robust conclusions about how tobacco affects kidney efficiency.

Association between secondhand smoke exposure and severe headaches or migraine in never-smoking adults

OBJECTIVE

The study aimed to examine the relationship between secondhand smoke (SHS) exposure and severe headaches or migraine in never-smoking adults verified by serum cotinine.

BACKGROUND

Current evidence about the association between self-reported SHS exposure and headaches or migraine is limited and contradictory. An important issue lies in the lack of actual SHS exposure assessment through biomarkers.

METHODS

We conducted a cross-sectional study on 4560 never-smoking adults from the National Health and Nutrition Examination Survey (NHANES), 1999-2004. The SHS exposure was evaluated by measuring serum cotinine concentrations. The information regarding severe headaches or migraine was based on self-reporting.

RESULTS

The overall prevalence rate of severe headaches or migraine was 20% (919/4560). After adjusting for relevant covariates, we found that heavy SHS exposure (serum cotinine at 1 to 10 ng/mL) was positively associated with severe headaches or migraine (OR: 2.02, 95% CI [1.19, 3.43]); however, no significant association was found between low SHS exposure (serum cotinine at 0.05 to 0.99 ng/mL) and severe headaches or migraine (OR: 1.15, 95% CI [0.91, 1.47]). Restricted cubic spline analysis showed that the natural logarithm of serum cotinine had a linear relationship with severe headaches or migraine (p = 0.335 for nonlinearity). Stratified analysis indicated that individuals with a BMI of <25 (p < 0.001 for interaction) and sedentary activity (p = 0.016 for interaction) modified the relationship between SHS exposure and severe headaches and migraine. Even after altering the definition of SHS exposure, excluding drugs that might affect the metabolism of serum cotinine, and multiple imputation, our sensitivity analysis results remained stable.

CONCLUSIONS

The study demonstrated that heavy SHS exposure (serum cotinine at 1 to 10 ng/mL) had a significant positive association with severe headaches or migraine in never-smoking adults. Prospective studies are necessary to verify this relationship in the future.

Relationship of cardiorenal risk factors with albuminuria based on age, smoking, glycaemic status and BMI: a retrospective cohort study of the UK Biobank data

Introduction

Smoking is harmful, and its cessation is recommended to prevent chronic kidney disease, which often begins with abnormal leakage of albumin in the urine, called albuminuria. Smoking cessation's effect on albuminuria depends on the pack-years smoked, length of abstinence, body mass index (BMI) and glycosylated haemoglobin (HbA1c). Using the UK Biobank data, we examined the relationship between these cardiorenal variables and albuminuria.

Methods

For this study, we selected a UK Biobank cohort with urinary albumin concentration (UAC) in the first and second visits. Participants were divided into progressor and regressor groups, where progressors were defined as those with increased UAC value, and regressors were those with decreased UAC value. Three different logistic regression models were fitted. In model 1, with a cohort design, we explored the impact of a change in age, HbA1c and BMI between the first and second visits and the UAC. In model 2 and 3, in a cross-sectional design, we explored which cardiorenal risk factors were associated with a rise or fall of UAC at the time point of the second visit. Results are expressed in OR and 95% CI.

Results

The prevalence of albuminuria was highest in ex-smokers who started smoking between the ages of 13 and 18. With a mean duration of 51 months, there was no statistically significant relationship between smoking status and BMI with albuminuria. Each year of ageing and each unit of increase in HbA1c (mmol/mol) increased the odds of progression of albuminuria by 20% and 3%, respectively. In ex-smokers, at the time point of the second visit, each year of smoking increased, and each year of abstinence decreased the odds by 4% and 6%, respectively.

Conclusion

Smokers should be supported to stop smoking and remain abstinent despite short-term weight gain. Childhood smoking should be actively discouraged.

Anemia and Hypoxia Impact on Chronic Kidney Disease Onset and Progression: Review and Updates

Chronic kidney disease (CKD) is caused by hypoxia in the renal tissue, leading to inflammation and increased migration of pathogenic cells. Studies showed that leukocytes directly sense hypoxia and respond by initiating gene transcription, encoding the 2-integrin adhesion molecules. Moreover, other mechanisms participate in hypoxia, including anemia. CKD-associated anemia is common, which induces and worsens hypoxia, contributing to CKD progression. Anemia correction can slow CKD progression, but it should be cautiously approached. In this comprehensive review, the underlying pathophysiology mechanisms and the impact of renal tissue hypoxia and anemia in CKD onset and progression will be reviewed and discussed in detail. Searching for the latest updates in PubMed Central, Medline, PubMed database, Google Scholar, and Google search engines were conducted for original studies, including cross-sectional studies, cohort studies, clinical trials, and review articles using different keywords, phrases, and texts such as "CKD progression, anemia in CKD, CKD, anemia effect on CKD progression, anemia effect on CKD progression, and hypoxia and CKD progression". Kidney tissue hypoxia and anemia have an impact on CKD onset and progression. Hypoxia causes nephron cell death, enhancing fibrosis by increasing interstitium protein deposition, inflammatory cell activation, and apoptosis. Severe anemia correction improves life quality and may delay CKD progression. Detection and avoidance of the risk factors of hypoxia prevent recurrent acute kidney injury (AKI) and reduce the CKD rate. A better understanding of kidney hypoxia would prevent AKI and CKD and lead to new therapeutic strategies.

Changes in Kidney Function Among Malaysian Adolescents and Its Determinants

Introduction

The health and wellbeing of adolescents are often neglected, including the knowledge of chronic kidney disease (CKD), especially in its early stages.

Methods

A total of 607 adolescents were recruited from the Malaysian Health and Adolescents Longitudinal Research Team (MyHeART) study, a prospective cohort study conducted from March 2012 to May 2016 that explored the noncommunicable diseases (NCDs) risk factors among 13 to 17 years old students in 3 states of Peninsular Malaysia. Students who participated in all 3 data collection periods in 2012, 2014, and 2016 with kidney function assessment across all 3-time points were included in the current study. The students' estimated glomerular filtration rate (eGFR) was calculated from isotope-dilution mass spectrometry-traceable Schwartz's equation and categorized based on Kidney Disease: Improving Global Outcomes (KDIGO) classification. Changes in kidney function were examined, and the longitudinal relationship between eGFR and multiple NCD risk factors was analyzed using the generalized estimating equation (GEE).

Results

The prevalence of decreased eGFR (60-89 ml/min per 1.73 m2) among the students increased from 6.1% (2012) to 30.0% (2014) and 40.2% (2016). Based on the GEE, the student's eGFR decreased over time, with a steeper decline during early to midadolescence. Males and rural students had lower eGFR compared to their counterparts. Students who are morbidly obese had lower eGFR than those with normal body mass index (BMI). Protein consumption also has a potential moderating effect on eGFR in adolescents.

Conclusion

Kidney function changes can be detected as early as adolescence and are likely attributable to multiple NCD risk factors. Therefore, more comprehensive prevention efforts from various stakeholders are needed to identify health issues like CKD.

Association between remnant cholesterol and chronic kidney disease in Chinese hypertensive patients

Background

Remnant cholesterol (RC) and chronic kidney disease (CKD) have not been definitively linked in individuals with different characteristics. This study aims to investigate the relationship between serum RC level and CKD and examine possible effect modifiers in Chinese patients with hypertension.

Methods

Our study is based on the Chinese H-type Hypertension Project, which is an observational registry study conducted in real-world settings. The outcome was CKD, defined as an estimated glomerular filtration rate of less than 60 ml/min·1.73 m2. Multivariate logistic regression and smooth curve fitting were used to analyze the association between RC and CKD. Subgroup analyses were subsequently conducted to examine the effects of other variables.

Results

The mean age of the 13,024 patients with hypertension at baseline was 63.8 ± 9.4 years, and 46.8% were male. A conspicuous linear positive association was observed between RC level and CKD (per SD increment; odds ratio [OR], 1.15; 95% confidence interval [CI], 1.08-1.23). Compared with the lowest quartile group of RC, the risk of CKD was 53% higher (OR, 1.53; 95% CI, 1.26-1.86) in the highest quartile group. Furthermore, a stronger positive association between RC level and CKD was found among participants with a higher body mass index (BMI <24 vs. ≥24 kg/m2; P-interaction = 0.034) or current non-smokers (smoker vs. non-smoker; P-interaction = 0.024).

Conclusions

Among Chinese adults with hypertension, RC level was positively associated with CKD, particularly in those with a BMI of ≥24 kg/m2 and current non-smokers. These findings may help improve lipid management regimens in patients with hypertension.

Tobacco exposure in adults and children with proteinuric glomerulopathies: a NEPTUNE cohort study

BACKGROUND

Tobacco exposure has been recognized as a risk factor for cardiovascular disease (CVD) and progression of kidney disease. Patients with proteinuric glomerulopathies are at increased risk for cardiovascular morbidity and mortality. Multiple studies have linked tobacco exposure to CVD and chronic kidney disease, but the relationships between smoking and proteinuric glomerulopathies in adults and children have not been previously explored.

METHODS

Data from the Nephrotic Syndrome Study Network (NEPTUNE), a multi-center prospective observational study of participants with proteinuric glomerulopathies, was analyzed. 371 adults and 192 children enrolled in NEPTUNE were included in the analysis. Self-reported tobacco exposure was classified as non-smoker, active smoker, former smoker, or exclusive passive smoker. Baseline serum cotinine levels were measured in a sub-cohort of 178 participants.

RESULTS

The prevalence of active smokers, former smokers and exclusive passive smoking among adults at baseline was 14.6%, 29.1% and 4.9%, respectively. Passive smoke exposure was 16.7% among children. Active smoking (reference non-smoking) was significantly associated with greater total cholesterol among adults (β 17.91 95% CI 0.06, 35.76, p = 0.049) while passive smoking (reference non-smoking) was significantly associated with greater proteinuria over time among children (β 1.23 95% CI 0.13, 2.33, p = 0.03). Higher cotinine levels were associated with higher baseline eGFR (r = 0.17, p = 0.03).

CONCLUSION

Tobacco exposure is associated with greater risk for CVD and worse kidney disease outcomes in adults and children with proteinuric glomerulopathies. Preventive strategies to reduce tobacco exposure may help protect against future cardiovascular and kidney morbidity and mortality in patients with proteinuric glomerulopathies.

A cross-validation based approach for estimating specific gravity in elementary-school aged children using a nonlinear model

Environmental research often relies on urinary biomarkers which require dilution correction to accurately measure exposures. Specific gravity (SG) and creatinine (UCr) are commonly measured urinary dilution factors. Epidemiologic studies may assess only one of these measures, making it difficult to pool studies that may otherwise be able to be combined. Participants from the National Health and Nutrition Examination Survey 2007-2008 cycle were used to perform k-fold validation of a nonlinear model estimating SG from UCr. The final estimated model was applied to participants from the School Inner-City Asthma Intervention Study, who submitted urinary samples to the Children's Health Exposure Analysis Resource. Model performance was evaluated using calibration metrics to determine how closely the average estimated SG was to the measured SG. Additional models, with interaction terms for age, sex, body mass index, race/ethnicity, relative time of day when sample was collected, log transformed 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and asthma status were estimated and assessed for improvement. The association between monobenzyl phthalate (MBZP) and asthma symptom days, controlling for measured UCr, measured SG, and each estimated SG were compared to assess validity of the estimated SG. The model estimating SG from UCr alone, resulted in a beta estimate of 1.10 (95% CI: 1.01, 1.19), indicating agreement between model-predicted SG and measured SG. Inclusion of age and sex in the model improved estimation (β = 1.06, 95% CI: 0.98, 1.15). The full model accounting for all interaction terms with UCr resulted in the best agreement (β = 1.01, 95% CI: 0.93,1.09). Associations between MBZP and asthma symptoms days, controlling for each estimated SG, were within the range of effect estimates when controlling for measured SG and measured UCr (Rate ratios = 1.28-1.34). Our nonlinear modeling provides opportunities to estimate SG in studies that measure UCr or vice versa, enabling data pooling despite differences in urine dilution factors.

Secondhand smoke, genetic susceptibility, and incident chronic kidney disease in never smokers: A prospective study of a selected population from the UK Biobank

INTRODUCTION

A large number of people around the world are exposed to the risks of passive smoking. This prospective study aimed to examine the association between secondhand smoke exposure, exposure time, and the incidence of chronic kidney disease (CKD) and determine whether this association was influenced by genetic susceptibility.

METHODS

The study included 214244 participants of the UK Biobank who were initially free of CKD. Cox proportional hazards model was used to estimate the associations between secondhand smoke exposure time and the risks of CKD in people who have never smoked. The genetic risk score for CKD was calculated by a weighted method. The likelihood ratio test comparing models was used to examine the cross-product term between secondhand smoke exposure and genetic susceptibility to CKD outcomes.

RESULTS

During a median of 11.9 years of follow-up, 6583 incidents of CKD were documented. Secondhand smoke exposure increased the risk of CKD (HR=1.09; 95% CI: 1.03-1.16, p<0.01), and a dose-response relationship between CKD prevalence and secondhand smoke exposure time was found (p for trend<0.01). Secondhand smoke exposure increases the risk of CKD even in people who never smoke and have a low genetic risk (HR=1.13; 95% CI: 1.02-1.26, p=0.02). There was no statistically significant interaction between secondhand smoke exposure and genetic susceptibility to CKD (p for interaction=0.80).

CONCLUSIONS

Secondhand smoke exposure is associated with higher risk of CKD, even in people with low genetic risk, and the relationship is dose dependent. These findings change the belief that people with low genetic susceptibility and without direct participation in smoking activities are not prone to CKD, emphasizing the need to avoid the harm of secondhand smoke in public places.

The association of perfluoroalkyl substances (PFAS) exposure and kidney function in Korean adolescents using data from Korean National Environmental Health Survey (KoNEHS) cycle 4 (2018–2020): a cross-sectional study

Background

Perfluoroalkyl substances (PFAS) are chemicals widely used in various products in everyday life. Due to its unique strong binding force, the half-life of PFAS is very long, so bioaccumulation and toxicity to the human body are long-standing concerns. In particular, effects on kidney function have recently emerged and there are no studies on the effect of PFAS on kidney function through epidemiological investigations in Korea. From 2018 to 2020, the Korean National Environmental Health Survey (KoNEHS) cycle 4, conducted an epidemiological investigation on the blood concentration of PFAS for the first time in Korea. Based on this data, the relationship between PFAS blood concentration and kidney function was analyzed for adolescents.

Methods

We investigated 5 types of PFAS and their total blood concentration in 811 middle and high school students, living in Korea and included in KoNEHS cycle 4, and tried to find changes in kidney function in relation to PFAS concentration. After dividing the concentration of each of the 5 PFAS and the total concentration into quartiles, multivariable linear regression was performed to assess the correlation with kidney function. The bedside Schwartz equation was used as an indicator of kidney function.

Results

As a result of multivariable linear regression, when observing a change in kidney function according to the increase in the concentration of each of the 5 PFAS and their total, a significant decrease in kidney function was confirmed in some or all quartiles.

Conclusions

In this cross-sectional study of Korean adolescents based on KoNEHS data, a negative correlation between serum PFAS concentration and kidney function was found. A well-designed longitudinal study and continuous follow-up are necessary.

The Influence of Smoking on Renal Functions Among Apparently Healthy Smokers

Background

Cigarette smoking is an important modifiable risk factor in kidney disease progression. Although long-term smoking has been associated with chronic kidney disease (CKD), its effect on kidney function in early stages has not been clarified.

Objective

To detect the early effects of smoking either active or passive on kidney functions.

Methodology

The current study was comparative cross sectional study conducted on 280 participants, 140 were non‑smokers and 140 were smokers (70 passive smokers and 70 active smokers). The two groups were comparable in terms of all parameters. We investigated the possible effects of smoking on kidney functions using both serum kidney function tests especially; serum urea, serum creatinine, serum cotinine levels and detection of albumin in urine. Smoking history, full Laboratory investigations, Ventilatory function test including (FEV1/FVC, FEV1, FEF 25-75%, VC and FVC) were done.

Results

Serum urea, serum creatinine, serum cotinine levels and urinary albumin were statistically significant higher in smokers group in comparison to nonsmokers, also the serum cotinine levels and urinary albumin were statistically significant in active smokers in comparison to passive smokers. There were positive correlations between the level of urinary albumin and pack/year (r = 0.9, p<0.05), smoking index (r = 0.9, p<0.05), smoking duration (r = 0.4, p<0.05), and serum cotinine (r = 0.6, p<0.050) with good statistical significance. The most significant predictive risk factors of microalbuminuria among smokers group in descending orders were active smoking, passive smoking, age and serum cotinine level.

Conclusion

Both active and passive smoking, especially among heavy smokers, is a significant risk factor for microalbuminuria. This finding increase the importance of early cessation of smoking in order to minimize early renal affection among healthy smokers that may not be discovered by routine renal function tests.

Substance use among adolescents and young adults with chronic kidney disease or kidney failure

Substance use, a significant public health issue, is well described in the adult chronic kidney disease (CKD) population. Knowledge about substance use in the adolescent and young adult (AYA) CKD population such as prevalence, impact on kidney function, medication adherence, and psychosocial well-being remain largely unknown. Awareness of and inquiring about substance use is paramount to providing evidence-based care and preparation to transition to adult-focused health services. The authors in this review identify commonly used substances (alcohol, tobacco, marijuana, etc.) and how they impact kidney function and care of the AYA with CKD or kidney failure. Recommendations for screening and intervention strategies are provided.

Emerging role of air pollution in chronic kidney disease

Chronic kidney disease (CKD), a global disease burden related to high rates of incidence and mortality, manifests as progressive and irretrievable nephron loss and decreased kidney regeneration capacity. Emerging studies have suggested that exposure to air pollution is closely relevant to increased risk of CKD, CKD progression and end-stage kidney disease (ESKD). Inhaled airborne particles may cause vascular injury, intraglomerular hypertension, or glomerulosclerosis through non-hemodynamic and hemodynamic factors with multiple complex interactions. The mechanisms linking air pollutants exposure to CKD include elevated blood pressure, worsening oxidative stress and inflammatory response, DNA damage and abnormal metabolic changes to aggravate kidney damage. In the present review, we will discuss the epidemiologic observations linking air pollutants exposure to the incidence and progression of CKD. Then, we elaborate the potential roles of several air pollutants including particulate matter and gaseous co-pollutants, environmental tobacco smoke, and gaseous heavy metals in its pathogenesis. Finally, this review outlines the latent effect of air pollution in ESKD patients undergoing dialysis or renal transplant, kidney cancer and other kidney diseases. The information obtained may be beneficial for further elucidating the pathogenesis of CKD and making proper preventive strategies for this disease.

Analysis of Active and Passive Tobacco Exposures and Blood Pressure in US Children and Adolescents

Importance

Hypertension is a leading cause of cardiovascular disease in adults; preclinical associations between hypertension and cardiovascular disease are seen in childhood. Nicotine is a known toxin, but its association with pediatric hypertension is unclear.

Objective

To test the hypothesis that tobacco exposure is associated with the presence of elevated blood pressure in US children and adolescents and that this association is dose dependent.

Design, Setting, and Participants

This cross-sectional study used data from the 2007 to 2016 National Health and Nutrition Examination Survey (NHANES), a population-based nationally representative sample of US children and adolescents. Children were eligible if they were aged 8 to 19 years at the time of participation in the main NHANES study. Exclusion criteria included those of the main NHANES study, inability to complete testing, or missing questionnaires. Of the 10 143 participants in NHANES aged 8 to 19 during the study years, 8520 were included in the analysis. Analysis was conducted from October 12, 2019, to July 9, 2020.

Exposures

Tobacco exposure, defined as serum cotinine levels greater than 0.05 µg/L, or reporting living with a smoker or smoking themselves.

Main Outcomes and Measures

Elevated blood pressure, classified as greater than 90% for a child's age, sex, and height according to the 2017 American Academy of Pediatrics Clinical Practice Guidelines. The a priori hypothesis that there is a positive association between tobacco exposure and elevated blood pressure in the study population was tested. Analysis included logistic regression with adjustment for possible confounders. Subgroup and sensitivity analyses were conducted.

Results

A total of 8520 children were included in the analysis, representing 41 million US children. The mean (SD) age of the participants was 13.1 (0.05) years, 51% (95% CI, 49%-52%) were male, and 58% (95% CI, 54%-62%) were non-Hispanic White individuals. Participants with any tobacco smoke exposure were more likely than those without exposure to be older (mean [SD] age, 13.3 [0.07] years vs 12.8 [0.06] years), male (53% [95% CI, 51%-55%] vs 49% [95% CI, 47%-50%]), and non-Hispanic Black individuals (19% [95% CI, 16%-22%] vs 10% [95% CI, 8%-12%]). The odds of having elevated blood pressure was 1.31 (95% CI, 1.06-1.61) for any tobacco exposure after adjustment; odds were similar across subgroups and remained significant in multiple sensitivity analyses.

Conclusions and Relevance

This study suggests that tobacco exposure is associated with elevated blood pressure in US children and adolescents. This modifiable risk factor represents a target for further research into reducing hypertension in children and adolescents.

Gender-biased kidney damage in mice following exposure to tobacco cigarette smoke: More protection in premenopausal females

Multiple clinical studies documented renal damage in chronic cigarette smokers (CS) irrespective of their age and gender. Premenopausal female smokers are known to exert a certain cardiovascular and renal protection with undefined mechanisms. Given the multiple demographic variables within clinical studies, this experimental study was designed to be the first to assess whether gender‐biased CS‐induced kidney damage truly exists between premenopausal female and age‐matched C57Bl6J male mice when compared to their relative control groups. Following 6 weeks of CS exposure, cardiac function, inflammatory marker production, fibrosis formation, total and glomerular ROS levels, and glomerulotubular homeostasis were assessed in both genders. Although both CS‐exposed male and female mice exhibited comparable ROS fold change relative to their respective control groups, CS‐exposed male mice showed a more pronounced fibrotic deposition, inflammation, and glomerulotubular damage profile. However, the protection observed in CS‐exposed female group was not absolute. CS‐exposed female mice exhibited a significant increase in fibrosis, ROS production, and glomerulotubular alteration but with a pronounced anti‐inflammatory profile when compared to their relative control groups. Although both CS‐exposed genders presented with altered glomerulotubular homeostasis, the alteration phenotype between genders was different. CS‐exposed males showed a significant decrease in Bowman's space along with reduced tubular diameter consistent with an endocrinization pattern of chronic tubular atrophy, suggestive of an advanced stage of glomerulotubular damage. CS‐exposed female group, on the other hand, displayed glomerular hypertrophy with a mild tubular dilatation profile suggestive of an early stage of glomerulotubular damage that generally precedes collapse. In conclusion, both genders are prone to CS‐induced kidney damage with pronounced female protection due to a milder damage slope.

Personal exposure to fine particulate matter and renal function in children: A panel study

There is a lack of evidence regarding the association of short-term exposure to fine particulate matter (PM_2.5) with renal function in children and its underlying mechanism. We included 105 children aged 4-13 years from a panel study conducted in Wuhan, China with up to 3 repeated visits across 3 seasons from October 9, 2017 to June 1, 2018. We measured personal real-time PM_2.5 exposure concentration continuously for 72 h preceding each round of health examinations that included serum creatinine and cytokines. Linear mixed-effects models were performed to estimate the effects of PM_2.5 on estimated glomerular filtration rate (eGFR) over various lag times, and a mediation analysis was applied for the role of cytokines in association between PM_2.5 and eGFR. Results showed that personal exposure to PM_2.5 was dose-responsive related to decreased eGFR within lag 2 days. The effect was the strongest at lag 0 day with estimation of -1.69% [95% confidence interval (CI): -2.27%, -1.10%] in eGFR by a 10-μg/m³ increase in PM_2.5, and reached peak at lag 3 h, then declined over time. Such inverse relationships were more evident among children aged 4-6 years, or boys or those who lived proximity to major roadways <300 m. Notably, eGFR still held on to decrease even when PM_2.5 was below Class II Chinese ambient air quality standard at lag 0 day. Moreover, the effect of PM_2.5 on eGFR was significantly reduced in children with high and medium levels of serum chemokine ligand 27 (CCL27), but not in those with low CCL27. Furthermore, CCL27 was positively relevant to PM_2.5, and mediated proportion of CCL27 ranged from 3.75% to 6.61% in relations between PM_2.5 and decreased eGFR over various lag times. In summary, short-term PM_2.5 exposure might be dose-responsive associated with reduced eGFR whereby a mechanism partly involving CCL27 among healthy children.

Associations of melamine and cyanuric acid exposure with markers of kidney function in adults: Results from NHANES 2003-2004

Higher melamine exposure may increase the risk of kidney stone formation and kidney injury in infants, but little is known about the potential nephrotoxic effects of environmental low-dose melamine and its derivative exposure on kidney function of adults in the general population. Our objective was to assess associations between urinary concentrations of melamine and its derivative, cyanuric acid, and kidney function through analyzing the data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004. Information on 298 participants aged ≥20 years was utilized. Urinary melamine and cyanuric acid levels were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (UACR) were calculated to reflect kidney function. Covariate-adjusted creatinine standardization concentrations accounting for sex, race, age, race/ethically, and body mass index, was employed to control potential confounding of kidney function. Multivariable linear regression models were conducted to estimate associations of covariate-adjusted creatinine standardization urinary melamine and cyanuric acid concentrations with eGFR and UACR. Log-binomial regression models were performed to estimate risks of impaired kidney function and hypertension associated with urinary melamine and cyanuric acid levels. The geometric mean values of urinary melamine and cyanuric acid concentrations were 1.51 μg/L [95% confidence interval (CI): 1.21 μg/L, 1.89 μg/L] and 5.86 μg/L (95% CI: 5.34 μg/L, 6.44 μg/L), respectively. The median value of estimated daily intake (EDI) for melamine was 0.06 (ranging from undetectable to 1.11) μg/kg body weight/day calculated by urinary concentration and creatinine excretion accounting for sex and body weight. Adults in the fourth quartile of melamine and cyanuric acid exposure had 0.142 mL/min/1.73 m² (95% CI: -0.271, -0.014) and 0.106 mL/min/1.73 m² (95% CI: -0.020, 0.006) lower eGFR for melamine and cyanuric acid, respectively, compared to participants in the first quartile of exposure with adjustment for potential confounders. To our best knowledge, this is the first study to report associations between melamine and its derivative and kidney function of the U.S. adults from NHANES 2003-2004. The suggestive evidence revealed that individuals with high melamine exposure had lower eGFR than those with low melamine exposure, although no significant association between melamine and cyanuric acid exposure and markers of kidney function was observed. These findings should be interpreted with caution regarding the possible reverse causality.

Sex-based differences in myocardial infarction-induced kidney damage following cigarette smoking exposure: more renal protection in premenopausal female mice

The impact of cigarette smoking (CS) on kidney homeostasis in the presence of myocardial infarction (MI) in both males and females remains poorly elucidated. C57BL6/J mice were exposed to 2 weeks of CS prior to MI induction followed by 1 week of CS exposure in order to investigate the impact of CS on kidney damage in the presence of MI. Cardiac hemodynamic analysis revealed a significant decrease in ejection fraction (EF) in CS-exposed MI male mice when compared with the relative female subjects, whereas cardiac output (CO) comparably decreased in CS-exposed MI mice of both sexes. Kidney structural alterations, including glomerular retraction, proximal convoluted tubule (PCT) cross-sectional area, and total renal fibrosis were more pronounced in CS-exposed MI male mice when compared with the relative female group. Although renal reactive oxygen species (ROS) generation and glomerular DNA fragmentation significantly increased to the same extent in CS-exposed MI mice of both sexes, alpha-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) significantly increased in CS-exposed MI male mice, only. Metabolically, nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide riboside-1 (NMRK-1) substantially increased in CS-exposed MI female mice only, whereas sirtuin (SIRT)-1 and SIRT-3 substantially decreased in CS-exposed MI male mice compared with their relative female group. Additionally, renal NAD levels significantly decreased only in CS-exposed MI male mice. In conclusion, MI female mice exhibited pronounced renal protection following CS when compared with the relative male groups.

Influence of Second-Hand Smoke and Prenatal Tobacco Smoke Exposure on Biomarkers, Genetics and Physiological Processes in Children-An Overview in Research Insights of the Last Few Years

Children are commonly exposed to second-hand smoke (SHS) in the domestic environment or inside vehicles of smokers. Unfortunately, prenatal tobacco smoke (PTS) exposure is still common, too. SHS is hazardous to the health of smokers and non-smokers, but especially to that of children. SHS and PTS increase the risk for children to develop cancers and can trigger or worsen asthma and allergies, modulate the immune status, and is harmful to lung, heart and blood vessels. Smoking during pregnancy can cause pregnancy complications and poor birth outcomes as well as changes in the development of the foetus. Lately, some of the molecular and genetic mechanisms that cause adverse health effects in children have been identified. In this review, some of the current insights are discussed. In this regard, it has been found in children that SHS and PTS exposure is associated with changes in levels of enzymes, hormones, and expression of genes, micro RNAs, and proteins. PTS and SHS exposure are major elicitors of mechanisms of oxidative stress. Genetic predisposition can compound the health effects of PTS and SHS exposure. Epigenetic effects might influence in utero gene expression and disease susceptibility. Hence, the limitation of domestic and public exposure to SHS as well as PTS exposure has to be in the focus of policymakers and the public in order to save the health of children at an early age. Global substantial smoke-free policies, health communication campaigns, and behavioural interventions are useful and should be mandatory.

Individual and Environmental Factors Associated with Proteinuria in Korean Children: A Multilevel Analysis

Proteinuria is a significant sign of childhood renal disorders. However, little is known about how sociodemographic and environmental factors are related to the presence of proteinuria among children and adolescents. This paper focuses on the prevalence of proteinuria and its risk factors among children and adolescents. This study conducted a secondary analysis of data from the 2016 Sample Schools Raw Data of Health Examination for School Students (SSRDHESS). Data collected from 27,081 students who had undergone a health screening were analyzed using Chi-square tests, independent t-tests, and multilevel logistic regression analysis. The prevalence of proteinuria was higher in the thin group than in the normal weight group (adjusted odds ratio (aOR) = 1.77; 95% confidence interval (CI) = 1.34–2.33) and lower in the overweight/obese group (aOR = 0.64; 95% CI = 0.51–0.80). Additionally, those in metropolitan and small–medium sized cities had a proteinuria prevalence about 1.5-fold higher than that of those in rural areas (95% CI = 1.08–2.02, 95% CI = 1.19–1.92, respectively). Proteinuria was associated with environmental pollution, including smoking rate, ambient particulate matter and heavy metals in drinking water (aOR = 1.10; 95% CI = 1.01–1.20; aOR = 1.06; 95% CI = 1.01–1.11, aOR = 1.001; 95% CI = 1.0001–1.0015). These results suggest that to improve health management effectiveness, kidney disease prevention efforts for children and adolescents should focus on geographical area and environmental pollution, as well as body weight as individual factors.

Factors associated with serum 25-hydroxyvitamin D concentrations in older people in Europe: the EUREYE study

BACKGROUND/OBJECTIVES

We aimed to describe serum 25-hydroxyvitamin D (25OHD) concentrations in older Europeans and to investigate associations between 25OHD and lifestyle factors, including dietary intake and supplement use.

SUBJECTS/METHODS

Men and women aged ≥ 65 years were recruited from seven centres across north to south Europe. Serum 25OHD2 and 25OHD3 concentrations were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 4495 samples and total 25OHD (25OHD2 + 25OHD3) was adjusted for season of blood collection.

RESULTS

The mean (25th, 75th quartile) of seasonally adjusted 25OHD was 46 (34, 65) nmol/L, with the highest concentration of 25OHD in Bergen [61 (49, 79) nmol/L], and the lowest in Paris [36 (24, 57) nmol/L)]. Vitamin D deficiency (25-50 nmol/L) and vitamin D insufficiency (50-75 nmol/L) were found in 41 and 33% of the population, respectively. In multivariable analysis controlled for confounders, seasonally adjusted 25OHD concentrations were significantly (p < 0.05) lower in smokers and participants with self-reported diabetes and higher with increasing dietary vitamin D, and supplement use with fish liver oil, omega-3, and vitamin D. Additionally, in further analysis excluding Bergen, 25OHD was associated with higher intakes of oily fish and increasing UVB exposure. We observed low concentrations of 25OHD in older people in Europe.

CONCLUSIONS

Our findings of the higher 25OHD concentrations in supplement users (omega-3 fish oil, fish liver oil, vitamin D) add to current recommendations to reduce vitamin D deficiency. We were unable to fully assess the role of dietary vitamin D as we lacked information on vitamin D-fortified foods.

Traffic-related air pollution associated with chronic kidney disease among elderly residents in Taipei City

The associations of air pollution with chronic kidney disease (CKD) have not yet been fully studied. We enrolled 8,497 Taipei City residents older than 65 years and calculated the estimated glomerular filtration rate (eGFR) using the Taiwanese Chronic Kidney Disease Epidemiology Collaboration equation. Proteinuria was assessed via dipstick on voided urine. CKD prevalence and risk of progression were defined according to the KDIGO 2012 guidelines. Land-use regression models were used to estimate the participants' one-year exposures to PM of different sizes and traffic-related exhaust, PM_2.5 absorbance, nitrogen dioxide (NO₂), and NO_x. Generalized linear regressions and logistic regressions were used to examine the associations of one-year air pollution exposures with eGFR, proteinuria, CKD prevalence and risk of progression. The results showed that the interquartile range (IQR) increments of PM_2.5 absorbance (0.4 × 10^-5/m) and NO₂ (7.0 μg/m³) were associated with a 1.07% [95% confidence interval (CI): 0.54-1.57] and 0.84% (95% CI: 0.37-1.32) lower eGFR, respectively; such relationships were magnified in subjects who had an eGFR >60 ml/min/1.73 m² or who were non-diabetic. Similar associations were also observed for PM₁₀ and PM_2.5-10. Two-pollutant models showed that PM₁₀ and PM_2.5 absorbance were associated with a lower eGFR. The odd ratios (ORs) of CKD prevalence and risk of progression also increased with exposures to PM_2.5 absorbance and NO_2. In summary, one-year exposures to traffic-related air pollution were associated with lower eGFR, higher CKD prevalence, and increased risk of CKD progression among the elderly population. Air pollution-related impaired renal function was stronger in non-CKD and non-diabetic subjects.

Secondhand smoke and rhinitis

PURPOSE OF REVIEW

The article reviews the most recent literature on the association between secondhand tobacco smoke exposure and rhinitis. The discussion will focus on the biologic links between tobacco exposure and rhinitis symptoms, evaluating this relationship in different populations.

RECENT FINDINGS

Significant associations between tobacco smoke exposure and rhinitis symptoms have been identified in US children and adults. This association is not just a US public health concern, as similar analyses have also recently been performed in other populations. Although pediatric data show a significant trend to greater prevalence of rhinitis with greater levels of secondhand smoke exposure, the adult data on secondhand smoke exposure are less consistent. The exact biological mechanism for these associations is likely multifactorial, but does not appear to be driven by an allergic, IgE-mediated reaction.

SUMMARY

The associations between secondhand tobacco smoke exposure and various upper respiratory inflammatory conditions, including rhinitis, have been observed. The causative biologic mechanisms, however, remain elusive and are a likely target for future research. At this point, evidence points toward nonallergic inflammation as the most likely mechanism. Clearly, further research is necessary before this mechanism is fully established.

Tobacco Use and Smoke Exposure in Children: New Trends, Harm, and Strategies to Improve Health Outcomes

PURPOSE OF REVIEW

Every day in the USA, approximately 4000 adolescents begin smoking and the adolescent brain is particularly susceptible to nicotine addiction. We present current pediatric trends on tobacco use and exposures, various new products used by adolescents, the adverse biological and behavioral effects of tobacco use and exposures, and tobacco control strategies to eliminate tobacco-related illnesses and deaths in the pediatric population.

RECENT FINDINGS

Twelve-20% of women continue to smoke during pregnancy. New research reveals cognitive differences and behavior-control disorders are seen in elementary school children from prenatal and postnatal exposures. Traditional cigarette smoking has decreased in adolescents; novel and appealing tobacco products have captured their attention, particularly electronic cigarettes, and rates double and often triple from middle to high school. Children with asthma and those living in multi-housing units have higher rates of secondhand smoke exposure than non-asthmatics and children living in single-home dwellings. There is no "safe or risk-free" level of tobacco use or exposure. Tobacco use and exposure in childhood and adolescence must be decreased using evidenced-based strategies to improve child health.

Age-dependent sensitivity of the mouse kidney to chronic nicotine exposure

BackgroundMany adolescents are exposed to nicotine via smoking, e-cigarette use, or second-hand smoke. Nicotine-induced renal oxidative stress and its long-term consequences may be higher in adolescents than in adults because of intrinsic factors in the adolescent kidney.MethodsAdolescent and adult male C57Bl/6J mice were subjected to 2 or 200 μg/ml nicotine, which closely emulates passive or active smoking, respectively, for 4 weeks. Extent of nicotine exposure (cotinine content), oxidative stress (HNE), renal function (creatinine), tubular injury (KIM-1), and pretreatment renal levels of select pro-oxidant (p66shc) and antioxidant (Nrf2/MnSOD) genes were determined. Impact of p66shc overexpression or Nrf2/MnSOD knockdown on low-/high-dose nicotine-induced oxidative stress was determined in cultured renal proximal tubule cells.ResultsDespite similar plasma/renal cotinine levels, renal HNE and KIM-1 contents were higher in adolescents compared with those in adults, whereas renal function was unaltered after passive or active smoking-equivalent nicotine exposure. Pretreatment levels of p66shc were higher, whereas Nrf2/MnSOD levels were lower in the adolescent kidney. In agreement with this, overexpression of p66shc or knockdown of Nrf2/MnSOD augmented nicotine-induced ROS production in renal proximal tubule cells.ConclusionChronic nicotine exposure incites higher oxidative stress in the adolescent than in adult kidney because of a pre-existent pro-oxidant milieu.

Non-Traditional Risk Factors of Albuminuria in the Pediatric Population: A Scoping Review

The presence of albumin in urine has been used for more than four decades as a marker of renal and cardiovascular damage. Most of the information on this marker is related to adults. The prevalence of albuminuria in the pediatric population has been reported as being 2.2-12.8% in some countries. Most research in this field is related to albuminuria and diseases, such as diabetes and hypertension. Using the methodology described by Arksey and O'Malley in 2005, a scoping review was carried out to show that the presence of albumin in urine in the pediatric population might be associated with environmental, demographic, congenital, infectious, and non-infectious factors. The information collected is supported by 74 references present in PubMed. The results reveal the multiple causes associated with albuminuria in the pediatric population. This information can be very useful for clinical practice by adding knowledge about albuminuria behavior in children.

Environmental exposures and pediatric kidney function and disease: A systematic review

BACKGROUND

Environmental chemical exposures have been implicated in pediatric kidney disease. No appraisal of the available evidence has been conducted on this topic.

METHODS

We performed a systematic review of the epidemiologic studies that assessed association of environmental exposures with measures of kidney function and disease in pediatric populations. The search period went through July 2016.

RESULTS

We found 50 studies that met the search criteria and were included in this systematic review. Environmental exposures reviewed herein included lead, cadmium, mercury, arsenic, fluoride, aflatoxin, melamine, environmental tobacco, bisphenol A, dental procedures, phthalates, ferfluorooctanoic acid, triclosan, and thallium/uranium. Most studies assessed environmental chemical exposure via biomarkers but four studies assessed exposure via proximity to emission source. There was mixed evidence of association between metal exposures, and other non-metal environmental exposures and pediatric kidney disease and other kidney disease biomarkers. The evaluation of causality is hampered by the small numbers of studies for each type of environmental exposure, as well as lack of study quality and limited prospective evidence.

CONCLUSION

There is a need for well-designed epidemiologic studies of environmental chemical exposures and kidney disease outcomes.

Tobacco Control and Treatment for the Pediatric Clinician: Practice, Policy, and Research Updates

Tobacco use is the leading cause of preventable death in the United States, and exposure to tobacco smoke harms children from conception forward. There is no safe level of tobacco exposure. Although overall smoking rates have declined, the advent of new products, such as electronic cigarettes, threatens to perpetuate nicotine addiction without clear health benefits. In addition to reviewing traditional and new tobacco products, we discuss the unique role that pediatricians should play in tobacco treatment and control efforts. New policies and technologies can empower pediatric clinicians and pediatric health care systems to help parent smokers quit, and new policies outside of the health care setting might help prevent smoking initiation as well as improve cessation treatments. Future research is needed to continue to study the consequences of tobacco use exposure as well as the best ways to help patients and parents stop tobacco use.

Hypoxia: The Force that Drives Chronic Kidney Disease

In the United States the prevalence of end-stage renal disease (ESRD) reached epidemic proportions in 2012 with over 600,000 patients being treated. The rates of ESRD among the elderly are disproportionally high. Consequently, as life expectancy increases and the baby-boom generation reaches retirement age, the already heavy burden imposed by ESRD on the US health care system is set to increase dramatically. ESRD represents the terminal stage of chronic kidney disease (CKD). A large body of evidence indicating that CKD is driven by renal tissue hypoxia has led to the development of therapeutic strategies that increase kidney oxygenation and the contention that chronic hypoxia is the final common pathway to end-stage renal failure. Numerous studies have demonstrated that one of the most potent means by which hypoxic conditions within the kidney produce CKD is by inducing a sustained inflammatory attack by infiltrating leukocytes. Indispensable to this attack is the acquisition by leukocytes of an adhesive phenotype. It was thought that this process resulted exclusively from leukocytes responding to cytokines released from ischemic renal endothelium. However, recently it has been demonstrated that leukocytes also become activated independent of the hypoxic response of endothelial cells. It was found that this endothelium-independent mechanism involves leukocytes directly sensing hypoxia and responding by transcriptional induction of the genes that encode the β2-integrin family of adhesion molecules. This induction likely maintains the long-term inflammation by which hypoxia drives the pathogenesis of CKD. Consequently, targeting these transcriptional mechanisms would appear to represent a promising new therapeutic strategy.

Association between perfluoroalkyl acids and kidney function in a cross-sectional study of adolescents

BACKGROUND

Perfluoroalkyl acids are synthetic compounds widely used in industrial and commercial applications. Laboratory studies suggest that these persistent and bioaccumulative chemicals produce oxidant stress and damage glomerular endothelial cells, raising concern regarding the impact of these compounds on renal function.

METHODS

We performed cross-sectional analyses of data 1960 participants aged 12-19 years of the 2003-2010 National Health and Nutrition Examination Surveys. PFAA exposure was assessed using levels of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid, and perfluorohexane sulfonic acid. Primary study outcomes were estimated glomerular filtration rate (eGFR) and serum uric acid.

RESULTS

While adjusting for demographics, cotinine, prehypertension, insulin resistance, body mass index, and hypercholesterolemia, adolescents in the highest PFOA and PFOS quartile had a lower eGFR, 6.84 mL/min/1.73 m(2) (95% CI: 2.19 to 11.48) and 9.69 mL/min/1.73 m(2) (95 % CI: -4.59 to 14.78), respectively, compared to the lowest quartile. Highest PFOA and PFOS quartiles were also associated with 0.21 mg/dL (95% CI: 0.056 to 0.37) and 0.19 mg/dL (95% CI: 0.032 to 0.34) increases in uric acid, respectively.

CONCLUSIONS

PFAAs are associated with a reduction in kidney function and increased uric acid levels in otherwise healthy adolescents. Reverse causation and residual confounding could explain the results. Our study results confirm and amplify previous findings, though longitudinal studies examining prenatal and childhood biomarkers in relationship with robust measures of childhood renal function are needed.

Public Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco use and tobacco smoke exposure are among the most important health threats to children, adolescents, and adults. There is no safe level of tobacco smoke exposure. The developing brains of children and adolescents are particularly vulnerable to the development of tobacco and nicotine dependence. Tobacco is unique among consumer products in that it causes disease and death when used exactly as intended. Tobacco continues to be heavily promoted to children and young adults. Flavored and alternative tobacco products, including little cigars, chewing tobacco, and electronic nicotine delivery systems are gaining popularity among youth. This statement describes important evidence-based public policy actions that, when implemented, will reduce tobacco product use and tobacco smoke exposure among youth and, by doing so, improve the health of children and young adults.

Clinical Practice Policy to Protect Children From Tobacco, Nicotine, and Tobacco Smoke

Tobacco dependence starts in childhood. Tobacco exposure of children is common and causes illness and premature death in children and adults, with adverse effects starting in the womb. There is no safe level of tobacco smoke exposure. Pediatricians should screen for use of tobacco and other nicotine delivery devices and provide anticipatory guidance to prevent smoking initiation and reduce tobacco smoke exposure. Pediatricians need to be aware of the different nicotine delivery systems marketed and available.Parents and caregivers are important sources of children's tobacco smoke exposure. Because tobacco dependence is a severe addiction, to protect children's health, caregiver tobacco dependence treatment should be offered or referral for treatment should be provided (such as referral to the national smoker's quitline at 1-800-QUIT-NOW). If the source of tobacco exposure cannot be eliminated, counseling about reducing exposure to children should be provided.Health care delivery systems should facilitate the effective prevention, identification, and treatment of tobacco dependence in children and adolescents, their parents, and other caregivers. Health care facilities should protect children from tobacco smoke exposure and tobacco promotion. Tobacco dependence prevention and treatment should be part of medical education, with knowledge assessed as part of board certification examinations.

Allergic Sensitization, Rhinitis and Tobacco Smoke Exposure in US Adults

INTRODUCTION

Tobacco exposure has been linked with sinonasal pathology and may be associated with allergic sensitization. This study evaluates the association between exposure to active smoking or secondhand smoke (SHS) and the prevalence of rhinitis and allergic sensitization in the US adult population.

METHODS

Cross-sectional study in 4,339 adults aged 20-85 in the National Health and Nutrition Examination Survey, 2005-2006. Never smoking was defined as reported lifetime smoking less than 100 cigarettes and serum cotinine levels <10ng/ml, while active smoking was defined as self-reported smoking or serum cotinine concentrations > 10 ng/mL. Self-reported rhinitis was based on symptoms during the past 12 months, and allergen sensitization was defined as a positive response to any of the 19 specific IgE antigens tested.

RESULTS

Almost half of the population (43%) had detectable levels of IgE specific to at least one inhaled allergen and 32% reported a history of rhinitis. After multivariate adjustment, there was a statistically significant association between the highest serum cotinine tertile and rhinitis in active smokers (OR 1.42; 95%CI 1.00-2.00). The association between active smoking and rhinitis was stronger in individuals without allergic sensitization (OR 2.47; 95%CI 1.44-4.23). There was a statistically significant association between increasing cotinine tertiles and decreased odds of inhaled allergen sensitization (p-trend <.01).

CONCLUSION

Tobacco smoke exposure was associated with increased prevalence of rhinitis symptoms, but not with allergic sensitization. The results indicate that the relationship between tobacco smoke exposure and sinonasal pathology in adults may be independent of allergic sensitization.

Cellular and Molecular Mechanisms of Chronic Kidney Disease with Diabetes Mellitus and Cardiovascular Diseases as Its Comorbidities

Chronic kidney disease (CKD), diabetes mellitus (DM), and cardiovascular diseases (CVD) are complex disorders of partly unknown genesis and mostly known progression factors. CVD and DM are the risk factors of CKD and are strongly intertwined since DM can lead to both CKD and/or CVD, and CVD can lead to kidney disease. In recent years, our knowledge of CKD, DM, and CVD has been expanded and several important experimental, clinical, and epidemiological associations have been reported. The tight cellular and molecular interactions between the renal, diabetic, and cardiovascular systems in acute or chronic disease settings are becoming increasingly evident. However, the (patho-) physiological basis of the interactions of CKD, DM, and CVD with involvement of multiple endogenous and environmental factors is highly complex and our knowledge is still at its infancy. Not only single pathways and mediators of progression of these diseases have to be considered in these processes but also the mutual interactions of these factors are essential. The recent advances in proteomics and integrative analysis technologies have allowed rapid progress in analyzing complex disorders and clearly show the opportunity for new efficient and specific therapies. More than a dozen pathways have been identified so far, including hyperactivity of the renin-angiotensin (RAS)-aldosterone system, osmotic sodium retention, endothelial dysfunction, dyslipidemia, RAS/RAF/extracellular-signal-regulated kinase pathway, modification of the purinergic system, phosphatidylinositol 3-kinase (PI 3-kinase)-dependent signaling pathways, and inflammation, all leading to histomorphological alterations of the kidney and vessels of diabetic and non-diabetic patients. Since a better understanding of the common cellular and molecular mechanisms of these diseases may be a key to successful identification of new therapeutic targets, we review in this paper the current literature about cellular and molecular mechanisms of CKD.

Allergic sensitization, rhinitis, and tobacco smoke exposure in U.S. children and adolescents

BACKGROUND

Childhood tobacco exposure has been linked with sinonasal pathology, and may be associated with allergic sensitization. This study evaluates the association between exposure to active smoking or secondhand smoke (SHS) and the prevalence of rhinitis and allergic sensitization in the U.S. pediatric population.

METHODS

Cross-sectional study in 2714 children and adolescents aged 6 to 19 in the National Health and Nutrition Examination Survey (NHANES), 2005-2006. Active smoking was defined as self-reported smoking or serum cotinine concentrations >10 ng/mL. SHS was defined as nonactive smokers who reported living with ≥1 smokers or had serum cotinine ≥0.011 ng/mL. Self-reported rhinitis was based on symptoms during the past 12 months, and allergen sensitization was defined as a positive response to any of the 19 specific immunoglobulin E (IgE) antigens tested.

RESULTS

About half of the population (54%) had detectable levels of IgE specific to at least 1 of the tested allergens, and 25% reported a history of rhinitis. After multivariate adjustment, an increased prevalence rate ratio (PRR) of self-reported rhinitis was seen in individuals in the highest cotinine tertile among active smokers (PRR, 1.73; 95% confidence interval [CI], 1.23 to 2.43), with a significant trend between increasing cotinine levels in individuals exposed to either secondhand smoke or active smoking (p = 0.05 for both analyses). Significantly less food allergen sensitization was observed in participants in the highest cotinine tertile of secondhand smoke (PRR, 0.61; 95% CI, 0.43 to 0.85).

CONCLUSION

Tobacco smoke exposure was associated with increased prevalence of rhinitis symptoms, but decreased prevalence of allergic sensitization. The results highlight the complex relationship between tobacco exposure and sinonasal pathology.

Trends in children's exposure to second-hand smoke in the INMA-Granada cohort: an evaluation of the Spanish anti-smoking law

The smoke-free legislation implemented in Spain in 2006 imposed a partial ban on smoking in public and work places, but the result did not meet expectations. Therefore, a more restrictive anti-smoking law was passed five years later in 2011 prohibiting smoking in all public places, on public transport, and the workplace. With the objective of assessing the impact of the latter anti-smoking legislation on children's exposure to second-hand smoke (SHS), we assessed parent's smoking habits and children's urine cotinine (UC) concentrations in 118 boys before (2005-2006) and after (2011-2012) the introduction of this law. Repeated cross-sectional follow-ups of the "Environment and Childhood Research Network" (INMA-Granada), a Spanish population-based birth cohort study, at 4-5 years old (2005-2006) and 10-11 years old (2011-2012), were designed. Data were gathered by ad-hoc questionnaire, and median UC levels recorded as an objective indicator of overall SHS exposure. Multivariable logistic regression was used to examine the association between parent's smoking habits at home and SHS exposure, among other potential predictors. An increase was observed in the prevalence of families with at least one smoker (39.0% vs. 50.8%) and in the prevalence of smoking mothers (20.3% vs. 29.7%) and fathers (33.9% vs. 39.0%). Median UC concentration was 8.0ng/mL (interquartile range [IQR]: 2.0-21.8) before legislation onset and 8.7ng/mL (IQR: 2.0-24.3) afterwards. In the multivariable analysis, the smoking status of parents and smoking habits at home were statistically associated with the risk of SHS exposure and with UC concentrations in children. These findings indicate that the recent prohibition of smoking in enclosed public and workplaces in Spain has not been accompanied by a decline in the exposure to SHS among children, who continue to be adversely affected. There is a need to target smoking at home in order to avoid future adverse health effects in a population that has no choice in the acceptance or not of SHS exposure-derived risk.

Tobacco and the pediatric chronic kidney disease population

Tobacco use and exposure are preventable causes of morbidity and mortality. Whereas the impact of this public health issue is well described in adults with kidney disease, its role in the pediatric chronic kidney disease (CKD) population is largely unknown. This review discusses the prevalence of tobacco use and exposure in children with CKD, updates the reader on how tobacco affects the kidney, and presents intervention strategies relevant to this patient population.

Nicotine signaling and progression of chronic kidney disease in smokers

The deleterious health effects of cigarette smoking are far reaching, and it remains the most important modifiable risk factor for improving overall morbidity and mortality. In addition to being a risk factor for cancer, cardiovascular disease and lung disease, there is strong evidence, both from human and animal studies, demonstrating a role for cigarette smoking in the progression of chronic kidney disease (CKD). Clinical studies have shown a strong correlation between cigarette smoking and worsening CKD in patients with diabetes, hypertension, polycystic kidney disease, and post kidney transplant. Nicotine, in addition to its role in the addictive properties of cigarette smoking, has other biological effects via activation of non-neuronal nicotinic acetylcholine receptors (nAChRs). Several nAChR subunits are expressed in the normal kidney and blockade of the α7-nAChR subunit ameliorates the effects of nicotine in animal models of CKD. Nicotine increases the severity of renal injury in animal models including acute kidney injury, diabetes, acute nephritis and subtotal nephrectomy. The renal effects of nicotine are also linked to increased generation of reactive oxygen species and activation of pro-fibrotic pathways. In humans, nicotine induces transitory increases in blood pressure accompanied by reductions in glomerular filtration rate and effective renal plasma flow. In summary, clinical and experimental evidence indicate that nicotine is at least in part responsible for the deleterious effects of cigarette smoking in the progression of CKD. The mechanisms involved are the subject of active investigation and may result in novel strategies to ameliorate the effects of cigarette smoking in CKD.

Evaluation of pediatricians' adherence to tobacco prevention, control, and treatment guidelines before and after an educational outreach program

BACKGROUND

Tobacco use is the world's leading single preventable cause of death. Because children exposed to second- and third-hand smoke are at risk for smoke-related morbidity, pediatricians have an obligation to address tobacco use in their practices. The purpose of this study was to measure physician adherence to the American Academy of Pediatrics' guidelines on tobacco prevention, control, and treatment before and after the implementation of an educational outreach program.

METHODS

Charts were randomly selected from pediatric clinics before and after the educational outreach. The intervention consisted of a review of the guidelines and available tools physicians could implement into their practices. We measured the rates of adherence to the guidelines before and after the educational outreach.

RESULTS

We analyzed 213 charts (116 pre- and 97 posteducation). The proportion of families screened for tobacco smoke exposure was comparable between the pre- and postintervention groups (67.2% vs 59.8%, P=0.317). The postintervention group had a higher proportion of counseling compared to the preintervention group (51.5% vs 31.9%, P<0.05). We found no statistically significant change in the rate of screening or referral to smoking cessation services.

CONCLUSION

Current guidelines to reduce tobacco use are underutilized. Educational outreach may increase the rate of counseling. Physician acceptance of guidelines is urgently needed to affect the tobacco epidemic.