Association between smoking and chronic kidney disease: a case control study

Metagenomics and metaproteomics alterations are associated with kidney disease in opisthorchiasis hamsters fed a high-fat and high-fructose diet

BACKGROUND

Opisthorchis viverrini (O. viverrini, Ov) infection and consumption of high-fat and high-fructose (HFF) diet exacerbate liver and kidney disease. Here, we investigated the effects of a combination of O. viverrini infection and HFF diet on kidney pathology via changes in the gut microbiome and host proteome in hamsters.

METHODOLOGY/PRINCIPAL FINDINGS

Twenty animals were divided into four groups; 1) fed a normal diet not infected with O. viverrini (normal group), 2) fed an HFF diet and not infected with O. viverrini (HFF), 3) fed a normal diet and infected with O. viverrini (Ov), and 4) fed an HFF diet and infected with O. viverrini (HFFOv). DNA was extracted from fecal samples and the V3-V4 region of the bacterial 16S rRNA gene sequenced on an Illumina MiSeq sequencing platform. In addition, LC/MS-MS analysis was done. Histopathological studies and biochemical assays were also conducted. The results indicated that the HFFOv group exhibited the most severe kidney injury, manifested as elevated KIM-1 expression and accumulation of fibrosis in kidney tissue. The microbiome of the HFFOv group was more diverse than in the HFF group: there were increased numbers of Ruminococcaceae, Lachnospiraceae, Desulfovibrionaceae and Akkermansiaceae, but fewer Eggerthellaceae. In total, 243 host proteins were identified across all groups. Analysis using STITCH predicted that host proteome changes may lead to leaking of the gut, allowing molecules such as soluble CD14 and p-cresol to pass through to promote kidney disease. In addition, differential expression of TGF-beta-activated kinase 1 and MAP3K7-binding protein 2 (Tab2, involving renal inflammation and injury) are predicted to be associated with kidney disease.

CONCLUSIONS/SIGNIFICANCE

The combination of HFF diet and O. viverrini infection may promote kidney injury through alterations in the gut microbiome and host proteome. This knowledge may suggest an effective strategy to prevent kidney disease beyond the early stages.

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.

Timing of Initiation of Xanthine Oxidase Inhibitors Based on Serum Uric Acid Level Does Not Predict Renoprognosis in Patients with Preserved Kidney Function

Background: Despite recent evidence of remaining possibility that early initiation of xanthine oxidase inhibitors (XOIs) is beneficial in renoprognosis for patients with stage 2 or less chronic kidney disease (CKD), no evidence is available regarding the difference in renoprognosis based on serum uric acid (sUA) levels at the initiation of XOIs among patients with preserved kidney function. Methods: New XOI initiators were divided into quartiles based on baseline sUA. Primary outcome was the composite incidence of a significant estimated glomerular filtration rate (eGFR) decline (≥40% decline in eGFR from baseline or development of eGFR <30 mL/1.73 m2/min) or all-cause death within 5 years. Results: After excluding inapplicable patients, 1170 XOI initiators were analyzed (mean ± standard deviation age: 68 ± 14.3 years; sUA: 10.6 ± 1.15 mg/dL). On overall median [interquartile range (IQR)] follow-up of 824 (342, 1576) days, incidence rate of the primary outcome was 287 per 1000 person-years for 5 years. Although the nonadjusted model showed a dose-response association between baseline sUA level and the outcome, the adjusted model showed no significant association. Adjusted hazard ratios (95% confidence interval) of the second, third, and fourth quartiles of baseline sUA with the composite outcome within 5 years compared to the first quartile were 1.00 (0.78, 1.29), 1.00 (0.80, 1.30), and 1.02 (0.80, 1.32), respectively. Conclusions: Early initiation of XOIs did not predict a significant benefit on renoprognosis even among the population with preserved kidney function. The validity of initiating XOIs with the aim of improving renoprognosis based on sUA is questionable.

Dietary preferences and quality of life among dialysis patients in Pune: a cross-sectional study

BACKGROUND

To assess the dietary preference and quality of life among dialysis patients in Pune.

METHOD

This cross-sectional study was conducted among 127 dialysis patients aged 18-70 through a one-on-one interview to record data on demographic, biochemical, diet preference, and quality of life. The anthropometric and biochemical parameters were recorded with the help of patient reports from the four dialysis centers. A kidney disease quality of life questionnaire was used to assess the quality of life.

RESULT

The mean age of the dialysis patients was (49.1 ± 12.9), comprising of males (104, 81.9%). (63, 49.6%) of the participants belonged to the normal weight category, followed by the underweight category. No association was noted between diet preference and quality of life, but a significant difference between BMI and personal appearance was observed. Serum calcium levels were highest (64.29 ± 1.0) in individuals in the high category of the effect of kidney disease compared to low serum calcium levels (20.89 ± 14.71) in the low category of the same.

CONCLUSION

The present study found that diet preferences were affected due to diet restrictions, but their association with quality of life was not significantly proven. The mean for the disease burden was the lowest, implying poor quality of life among dialysis patients. Therefore, providing nutrition education and counseling for dialysis patients is crucial. A detailed dialysis care plan must address all patient requirements, including medication, dietary changes, modifications, and malnutrition screenings.

Effects of Waterpipe Smoke Exposure on Experimentally Induced Chronic Kidney Disease in Mice

Tobacco smoking is an independent risk factor in the onset of kidney disease. To date, there have been no reports on the influence of waterpipe smoke (WPS) in experimentally induced chronic kidney disease (CKD) models. We studied the effects and mechanisms of actions of WPS on a mouse model of adenine-induced CKD. Mice fed either a normal diet, or an adenine-added diet and were exposed to either air or WPS (30 min/day and 5 days/week) for four consecutive weeks. Plasma creatinine, urea and indoxyl sulfate increased and creatinine clearance decreased in adenine + WPS versus either WPS or adenine + saline groups. The urinary concentrations of kidney injury molecule-1 and adiponectin and the activities of neutrophil gelatinase-associated lipocalin and N-acetyl-β-D-glucosaminidase were augmented in adenine + WPS compared with either adenine + air or WPS groups. In the kidney tissue, several markers of oxidative stress and inflammation were higher in adenine + WPS than in either adenine + air or WPS groups. Compared with the controls, WPS inhalation in mice with CKD increased DNA damage, and urinary concentration of 8-hydroxy-2-deoxyguanosine. Furthermore, the expressions of nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) (ERK and p38) were elevated in the kidneys of adenine + WPS group, compared with the controls. Likewise, the kidneys of adenine + WPS group revealed more marked histological tubular injury, chronic inflammation and interstitial fibrosis. In conclusion, WPS inhalation aggravates kidney injury, oxidative stress, inflammation, DNA damage and fibrosis in mice with adenine-induced CKD, indicating that WPS exposure intensifies CKD. These effects were associated with a mechanism involving NF-κB, ERK and p38 activations.

Chronic kidney disease stage is associated with the number of risk factors in type 2 diabetes patients (STages Of NEphropathy in type 2 diabetes and Heart Failure - STONE HF)

AIMS

To study the association between risk factors and chronic kidney disease (CKD), and characterize medication use in Finnish primary care type 2 diabetes (T2D) patients.

METHODS

Data on clinical characteristics, laboratory measurements, and medications were collected from medical records. The primary outcome measure was notable CKD (stage 3-5, eGFR <60 ml/min/1.73 m2) and/or increased albuminuria. The explanatory variables were individual risk factors and risk factor groups based on their number (0-2, 3-4, 5-6, >7). Spearman's rank correlation coefficient and risk ratio analysis were used to analyze the association between the number of risk factors and CKD stage, and between the number of risk factors and notable CKD, respectively.

RESULTS

Altogether, 1335 patients with T2D in 60 Finnish primary care centers were recruited for this cross-sectional study. Three-quarters of T2D patients had 3 risk factors and 36% had ≥ 5 risk factors. Compared to patients with 0-2 risk factors, patients with 3-4, 5-6, and ≥ 7 risk factors had a 5.5-fold, 9.9-fold, and 15.9-fold risk of notable CKD (p < 0.001), respectively. Heart failure was most strongly associated with notable CKD (risk ratio, 3.7; p < 0.001).

CONCLUSIONS

Number of risk factors was strongly associated with advanced-stage CKD.

Reporting chronic kidney disease in Greenland

Background: Chronic kidney disease (CKD) is a major health burden affecting more than 10% of the global population. It is a multifactorial disease with many risk factors attributed lifestyle diseases. The prevalence of CKD in Greenland is unknown; however, the prevalence of risk factors contributing to CKD is increasing.Objectives: To estimate the prevalence of CKD in Greenland.Methods: The study was a cross-sectional register-study including all Greenlandic residents aged ≥20 years with serum creatinine analysis within the last 2 years. We identified those with CKD based on eGFR and UACR and those registered with a CKD diagnosis code. Two limitations of the study are possible lack of data completeness and the reliance of a single time point to report CKD.Results: A total of 2,157 patients were identified with CKD with an age-standardised prevalence of 3.01%. Only 75 patients were registered with a diagnosis code for CKD. Approximately 80% of patients were classified with CKD stages 1-2.Conclusion: This is the first study reporting CKD in Greenland. We found a lower prevalence of CKD than reported by other studies, and a low number of patients correctly diagnosed with CKD. We call for increased awareness and diagnosis coding of CKD in Greenland.

Management of traditional risk factors for the development and progression of chronic kidney disease

Chronic kidney disease (CKD) and its downstream complications (i.e. cardiovascular) are a major source of morbidity worldwide. Additionally, deaths due to CKD or CKD-attributable cardiovascular disease account for a sizeable proportion of global mortality. However, the advent of new pharmacotherapies, diagnostic tools, and global initiatives are directing greater attention to kidney health in the public health agenda, including the implementation of effective strategies that (i) prevent kidney disease, (ii) provide early CKD detection, and (iii) ameliorate CKD progression and its related complications. In this Review, we discuss major risk factors for incident CKD and CKD progression categorized across cardiovascular (i.e. hypertension, dyslipidemia, cardiorenal syndrome), endocrine (i.e. diabetes mellitus, hypothyroidism, testosterone), lifestyle (i.e. obesity, dietary factors, smoking), and genetic/environmental (i.e. CKDu/Mesoamerican nephropathy, APOL1, herbal nephropathy) domains, as well as scope, mechanistic underpinnings, and management.

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.

Factors affecting serum PFAS concentrations among US females with surgically and naturally induced menopause: data from NHANES 2003-2018

Sex hormones influence excretion of the biopersistent per-and polyfluoroalkyl substances (PFAS) in rodents, but such influences in human studies are less clear. Data from National Health and Nutrition Examination Survey (NHANES) for 2003-2018 for US females aged ≥ 20 years who reported having hysterectomy (HYST, N=1064) and who reported being in natural menopause (MENOP, N=1505) were analyzed for associations of ever use of birth control pills, past pregnancies, live births, and other factors with serum concentrations of six per- and polyfluoroalkyl substances (PFAS). For both HYST and MENOP, PFAS concentrations computed as adjusted geometric means (AGM) were higher among those who took female replacement hormone therapy (HRT) compared to nonusers in multivariable adjusted models, for example PFOS in HRT takers (10.70 ng/mL; 95% C.I. 9.46-12.11) vs. 8.70 ng/mL (95% C.I. 8.07-9.37) in nonusers (p<0.01), and PFOA in HRT users was 2.85 ng/mL (95% C.I. 2.53-3.21) vs. 2.44 ng/mL (95% C.I. 2.32-2.36) in nonusers (p=0.01), with similar findings across race/ethnicity stratifications. HYST participants with retained ovaries sometimes had higher serum PFAS than those without ovaries in post-HYST participants not taking HRT, but results had overlapping confidence intervals in all cases and were inconsistent. PFASs were inversely associated with obesity and directly associated with higher SES as reflected in poverty income ratio (PIR) in most cases, yet HRT results for the entire population are robust to adjustments for obesity and PIR. The results suggest the hypothesis that exogenous hormone use, and specifically estrogen hormones, are associated with higher serum PFAS in postmenopausal women. We discuss potential explanations for the findings, including data from other populations that estrogens may delay the onset of kidney disease, a finding which might paradoxically increase serum PFAS among the HRT population to explain some or all of our findings in a menopausal population.

Risk of developing chronic kidney disease in young-onset Type 2 diabetes in Korea

We investigated the risk of developing chronic kidney disease (CKD) in patients with young-onset Type 2 diabetes (YOD, diagnosed age < 40 years). We enrolled 84,384 patients aged 20-64 who started anti-diabetic medication between 2010 and 2011 from the Korea National Health Insurance Sharing Service; patients with Type 1 diabetes or a history of CKD were excluded. Multivariate logistic regression analyses were performed to adjust for YOD-distinct variables and compare the incidence of CKD between YOD and late-onset diabetes (LOD, diagnosed age ≥ 40 years). During the median observation period of 5.16 years (interquartile range: 4.58-5.77 years), 1480 out of 77,039 LOD patients and 34 out of 7345 YOD patients developed CKD. Patients with YOD had distinct baseline characteristics compared with the patients with LOD. The odds ratio of developing CKD in patients with YOD over LOD was 1.70 (95% CI 1.15-2.51) after adjusting clinically distinct variables. The increased CKD odds in YOD compared with LOD was greater in the non-smoking group (OR 2.03, 95% CI 1.26-3.26) than in the smoking group (OR 1.49, 95% CI 0.74-2.98, p = 0.0393 for interaction). Among YOD patients, hypertension (34.76% vs. 64.71%, p = 0.0003), dyslipidemia (46.87% vs. 73.53%, p = 0.0019), and sulfonylurea use (35.54% vs. 52.94%, p = 0.0345) were associated with CKD development. YOD patients have a greater risk of developing CKD than LOD patients after adjusting clinically distinct variables.

Assessing physical inactivity as a risk factor for chronic kidney diseases in Iranian population

OBJECTIVES

Physical inactivity is a major adjustable lifestyle risk factor in renal patients; nevertheless, research on the association of physical activity (PA) with chronic kidney disease (CKD) is unclear.

DESIGN

Cross-sectional.

SETTING

We evaluated the secondary care related to the nephrology specialists.

PARTICIPANTS

We evaluated PA in 3374 Iranian patients with CKD aged ≥18 years. Exclusion criteria were current or prior kidney transplantation, dementia, institutionalisation, expected to start renal replacement therapy or leave the area within study duration, participation in a clinical trial or inability to undergo the informed consent process.

PRIMARY AND SECONDARY OUTCOME

The renal function parameters were measured and compared with PA, assessed by the Baecke questionnaire. Estimated glomerular filtration rate, haematuria and/or albuminuria were used to estimate decreased kidney function and the incidence of CKD. To estimate the relationship between PA and CKD, we used the multinomial adjusted regression models.

RESULTS

In the first model, findings indicate that the patients with the lowest PA score had significantly higher odds of CKD (OR 1.44, 95% CI 1.16 to 1.78; p=0.01), adjustment for age and sex attenuated this relationship (OR 1.25, 95% CI 1.56 to 1.78, p=0.04). Furthermore, adjusting for low-density lipoprotein, high-density lipoprotein, triglyceride, fasting blood glucose, body mass index, waist circumference, waist/hip ratio, coexisting diseases and smoking made this relationship insignificant (OR 1.23, 95% CI 0.97 to 1.55; p=0.076). After adjusting for potential confounders, we found that patients with lower PA have higher odds of CKD stage 2 (OR 1.62, 95% CI 1.13 to 2.32; p=0.008), no association with other CKD stages.

CONCLUSION

These data suggest that physical inactivity contributes to the risk of early CKD, so encouraging patients with CKD to maintain higher PA levels could be used as a simple and useful tool to decrease the risk of disease progression and its related burden.

Untargeted Metabolomics to Characterize the Urinary Chemical Landscape of E-Cigarette Users

The health and safety of using e-cigarette products (vaping) have been challenging to assess and further regulate due to their complexity. Inhaled e-cigarette aerosols contain chemicals with under-recognized toxicological profiles, which could influence endogenous processes once inhaled. We urgently need more understanding on the metabolic effects of e-cigarette exposure and how they compare to combustible cigarettes. To date, the metabolic landscape of inhaled e-cigarette aerosols, including chemicals originated from vaping and perturbed endogenous metabolites in vapers, is poorly characterized. To better understand the metabolic landscape and potential health consequences of vaping, we applied liquid chromatography-mass spectrometry (LC-MS) based nontargeted metabolomics to analyze compounds in the urine of vapers, cigarette smokers, and nonusers. Urine from vapers (n = 34), smokers (n = 38), and nonusers (n = 45) was collected for verified LC-HRMS nontargeted chemical analysis. The altered features (839, 396, and 426 when compared smoker and control, vaper and control, and smoker and vaper, respectively) among exposure groups were deciphered for their structural identities, chemical similarities, and biochemical relationships. Chemicals originating from e-cigarettes and altered endogenous metabolites were characterized. There were similar levels of nicotine biomarkers of exposure among vapers and smokers. Vapers had higher urinary levels of diethyl phthalate and flavoring agents (e.g., delta-decalactone). The metabolic profiles featured clusters of acylcarnitines and fatty acid derivatives. More consistent trends of elevated acylcarnitines and acylglycines in vapers were observed, which may suggest higher lipid peroxidation. Our approach in monitoring shifts of the urinary chemical landscape captured distinctive alterations resulting from vaping. Our results suggest similar nicotine metabolites in vapers and cigarette smokers. Acylcarnitines are biomarkers of inflammatory status and fatty acid oxidation, which were dysregulated in vapers. With higher lipid peroxidation, radical-forming flavoring, and higher level of specific nitrosamine, we observed a trend of elevated cancer-related biomarkers in vapers as well. Together, these data present a comprehensive profiling of urinary biochemicals that were dysregulated due to vaping.

Phosphate induces inflammation and exacerbates injury from cigarette smoke in the bronchial epithelium

An elevation in serum phosphate-also called hyperphosphatemia-is associated with reduced kidney function in chronic kidney disease (CKD). Reports show CKD patients are more likely to develop lung disease and have poorer kidney function that positively correlates with pulmonary obstruction. However, the underlying mechanisms are not well understood. Here, we report that two murine models of CKD, which both exhibit increased serum levels of phosphate and fibroblast growth factor (FGF) 23, a regulator of phosphate homeostasis, develop concomitant airway inflammation. Our in vitro studies point towards a similar increase of phosphate-induced inflammatory markers in human bronchial epithelial cells. FGF23 stimulation alone does not induce a proinflammatory response in the non-COPD bronchial epithelium and phosphate does not cause endogenous FGF23 release. Upregulation of the phosphate-induced proinflammatory cytokines is accompanied by activation of the extracellular-signal regulated kinase (ERK) pathway. Moreover, the addition of cigarette smoke extract (CSE) during phosphate treatments exacerbates inflammation as well as ERK activation, whereas co-treatment with FGF23 attenuates both the phosphate as well as the combined phosphate- and CS-induced inflammatory response, independent of ERK activation. Together, these data demonstrate a novel pathway that potentially explains pathological kidney-lung crosstalk with phosphate as a key mediator.

A prediction model of CKD progression among individuals with type 2 diabetes in the United States

BACKGROUND

CKD progression among individuals with T2D is associated with poor health outcomes and high healthcare costs, which have not been fully studied. This study aimed to predict CKD progression among individuals with diabetes.

METHOD

Using ACCORD trial data, a time-varying Cox model was developed to predict the risk of CKD progression among patients with CKD and T2D. CKD progression was defined as a 50 % decline, or 25 mL/min/1.73 m² decline in eGFR from baseline, doubling of the serum creatinine, or onset of ESKD. A list of candidate variables included demographic characteristics, physical exam results, laboratory results, medical history, drug use, and healthcare utilization. A stepwise algorithm was used for variable selection. Model performance was evaluated by Brier score and C-statistics. Confidence intervals (CI) were calculated using a bootstrap method. Decomposition analysis was conducted to assess the predictor contribution. Generalizability was assessed on patient-level data of the Harmony Outcome trial and CRIC study.

RESULTS

A total of 6982 diabetes patients with CKD were used for model development, with a median follow-up of 4 years and 3346 events. The predictors for CKD progression included female sex, age at T2D diagnosis, smoking status, SBP, DBP, HR, HbA1c, alanine aminotransferase (ALT), eGFR, UACR, retinopathy event, hospitalization. The model demonstrated good discrimination (C-statistics 0.745 [95 % CI 0.723-0.763]) and calibration (Brier Score 0.0923 [95 % CI 0.0873-0.0965]) performance in the ACCORD data. The most contributing predictors for CKD progression were eGFR, HbA1c, and SBP. The model demonstrated acceptable discrimination and calibration performance in the two external data.

CONCLUSION

For high-risk patients with both diabetes and CKD, the tool as a dynamic risk prediction of CKD progression may help develop novel strategies to lower the risk of CKD progression.

Prediction of incident chronic kidney disease in a population with normal renal function and normo-proteinuria

Regarding the irreversible clinical course of chronic kidney disease, identifying high-risk subjects susceptible to Chronic Kidney Disease (CKD) has an important clinical implication. Previous studies have developed risk prediction models identifying high-risk individuals within a group, including those who may have experienced minor renal damage, to provide an opportunity for initiating therapies or interventions at earlier stages of CKD. To date, there were no other studies developed a prediction model with quantitative risk factors to detect the earliest stage of CKD that individuals with normal renal function in the general population may experience. We derived 11,495,668 individuals with an estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m2 and normo-proteinuria, who underwent health screening ≥2 times between 2009 and 2016 from the prospective nationwide registry cohort. The primary outcome was the incident CKD, defined by an eGFR <60 mL/min/1.73 m2. Sex-specific multivariate Cox regression models predicting the 8-year incident CKD risk were developed. The performance of developed models was assessed using Harrell's C and the area under the receiver operating characteristics curve (AUROC) with 10-fold cross-validation. Both men and women, who met the definition of incident CKD, were older and had more medical treatment history in hypertension and diabetes. Harrell's C and AUROC of the developed prediction models were 0.82 and 0.83 for men and 0.79 and 0.80 for women. This study developed sex-specific prediction equations with reasonable performance in a population with normal renal function.

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.

High prevalence of chronic kidney disease and its related risk factors in rural areas of Northeast Thailand

In Thailand, chronic kidney disease (CKD) screening was reported in 2009 with an overall prevalence of 17.5% and the highest at 22.2% in the northeastern region. This study aimed to find out CKD prevalence of the Kidney Disease Improving Global Outcomes criteria and their related risk factors in the rural community. A population-based study was conducted in the rural sub-districts of northeastern Thailand. Data of socio-demographic status, lifestyle, underlying diseases, blood pressure, and body mass index were recorded. Blood and urine analysis was conducted along with ultrasonography of kidneys. Specimen collection and analyses were repeated after 3 months, and the factors associated with CKD were studied by logistic regression analysis. A total of 2205 participants with a mean age of 57.8 ± 11.7 years and female predominance (66.7%) completed the study. The prevalence of CKD was 26.8%, i.e., stages 1 (7.3%); stage 2 (9.0%); stage 3a (6.0%); stage 3b (2.8%); stage 4 (1.4%); and stage 5 (0.3%). Hypertension, diabetes mellitus, and renal stones were the major underlying diseases. Only 3.5% of the participants were aware of having CKD. An increase in age, male, unemployment, current smoking, diabetes, hypertension, underweight, anemia, hyperuricemia, and leukocytosis were significantly associated factors with the disease. The study revealed that CKD has developed as a significant public health problem in rural northeastern Thailand and one out of every four people has CKD. Therefore, early interventions are essential for the proper management and prevention of CKD.

Shared exposure liability of type 2 diabetes and other chronic conditions in the UK Biobank

AIMS

To investigate whether the cumulative exposure risks of incident T2D are shared with other common chronic diseases.

RESEARCH DESIGN AND METHODS

We first establish and report the cross-sectional prevalence, cross-sectional co-prevalence, and incidence of seven T2D-associated chronic diseases [hypertension, atrial fibrillation, coronary artery disease, obesity, chronic obstructive pulmonary disease (COPD), and chronic kidney and liver diseases] in the UK Biobank. We use published weights of genetic variants and exposure variables to derive the T2D polygenic (PGS) and polyexposure (PXS) risk scores and test their associations to incident diseases.

RESULTS

PXS was associated with higher levels of clinical risk factors including BMI, systolic blood pressure, blood glucose, triglycerides, and HbA1c in individuals without overt or diagnosed T2D. In addition to predicting incident T2D, PXS and PGS were significantly and positively associated with the incidence of all 7 other chronic diseases. There were 4% and 8% of individuals in the bottom deciles of PXS and PGS, respectively, who were prediabetic at baseline but had low risks of T2D and other chronic diseases. Compared to the remaining population, individuals in the top deciles of PGS and PXS had particularly high risks of developing chronic diseases. For instance, the hazard ratio of COPD and obesity for individuals in the top T2D PXS deciles was 2.82 (95% CI 2.39-3.35, P = 4.00 × 10-33) and 2.54 (95% CI 2.24-2.87, P = 9.86 × 10-50), respectively, compared to the remaining population. We also found that PXS and PGS were both significantly (P < 0.0001) and positively associated with the total number of incident diseases.

CONCLUSIONS

T2D shares polyexposure risks with other common chronic diseases. Individuals with an elevated genetic and non-genetic risk of T2D also have high risks of cardiovascular, liver, lung, and kidney diseases.

Chronic kidney disease and its health-related factors: a case-control study

BACKGROUND

Chronic kidney disease (CKD) is a non-communicable disease that includes a range of different physiological disorders that are associated with abnormal renal function and progressive decline in glomerular filtration rate (GFR). This study aimed to investigate the associations of several behavioral and health-related factors with CKD in Iranian patients.

METHODS

A hospital-based case-control study was conducted on 700 participants (350 cases and 350 controls). Logistic regression was applied to measure the association between the selected factors and CKD.

RESULTS

The mean age of cases and controls were 59.6 ± 12.4 and 58.9 ± 12.2 respectively (p = 0.827). The results of multiple logistic regression suggested that many factors including low birth weight (OR yes/no = 4.07, 95%CI: 1.76-9.37, P = 0.001), history of diabetes (OR yes/no = 3.57, 95%CI: 2.36-5.40, P = 0.001), history of kidney diseases (OR yes/no = 3.35, 95%CI: 2.21-5.00, P = 0.001) and history of chemotherapy (OR yes/no = 2.18, 95%CI: 1.12-4.23, P = 0.02) are associated with the risk of CKD.

CONCLUSIONS

The present study covered a large number of potential risk/ preventive factors altogether. The results highlighted the importance of collaborative monitoring of kidney function among patients with the above conditions.

Association of Diabetes Mellitus and Alcohol Abuse with Cancer: Molecular Mechanisms and Clinical Significance

Diabetes mellitus (DM), one of the metabolic diseases which is characterized by sustained hyperglycemia, is a life-threatening disease. The global prevalence of DM is on the rise, mainly in low- and middle-income countries. Diabetes is a major cause of blindness, heart attacks, kidney failure, stroke, and lower limb amputation. Type 2 diabetes mellitus (T2DM) is a form of diabetes that is characterized by high blood sugar and insulin resistance. T2DM can be prevented or delayed by a healthy diet, regular physical activity, maintaining normal body weight, and avoiding alcohol and tobacco use. Ethanol and its metabolites can cause differentiation defects in stem cells and promote inflammatory injury and carcinogenesis in several tissues. Recent studies have suggested that diabetes can be treated, and its consequences can be avoided or delayed with proper management. DM has a greater risk for several cancers, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer. The incidence of cancer is significantly higher in patients with DM than in those without DM. In addition to DM, alcohol abuse is also a risk factor for many cancers. We present a review of the recent studies investigating the association of both DM and alcohol abuse with cancer incidence.

Risk factors associated with albuminuria in Rwanda: results from a STEPS survey

BACKGROUND

Non-communicable diseases (NCDs) are a growing burden which affects every part of the world, including developing countries. Chronic kidney disease (CKD) has varied etiology which can result from or complicate other NCDs such as diabetes and cardiovascular diseases. The growing prevalence of NCDs coupled with the increasing age in most developing countries, has seen a marked increase of CKD in these settings. CKD has been described as "the most neglected NCD" and greatly affects the quality of life of patients. It also places a huge economic burden on societies. However, few epidemiological data exist, particularly in sub-Saharan Africa. Assessment of the prevalence of albuminuria as a marker of kidney damage and CKD progression and its main risk factors was thus needed in Rwanda.

METHODS

This study analyzed data collected during the first STEPwise approach to NCD risk factor Surveillance (STEPS) survey in Rwanda, conducted from 2012 to 2013, to assess the prevalence of albuminuria. A multistage cluster sampling allowed to select a representative sample of the general population. Furthermore, descriptive, as well as univariable analyses and multiple logistic regression were performed to respond to the research question.

RESULTS

This survey brought a representative sample of 6,998 participants, among which 4,384 (62.65%) were female. Median age was 33 years (interquartile range, IQR 26-44), and over three quarters (78.45%) lived in rural areas. The albuminuria prevalence was 105.9 per 1,000 population. Overall, semi-urban and urban residency were associated with lower odds of CKD (odds ratio, OR 0.36, CI 0.23-0.56, p<0.001 and OR 0.34, CI 0.23-0.50, p<0.001, respectively) than rural status. Being married or living with a partner had higher odds (OR 1.44 (CI 1.03-2.02, p=0.031) and OR 1.62 (CI 1.06-2.48, p=0.026), respectively) of CKD than being single. Odds of positive albuminuria were also greater among participants living with human immunodeficiency virus (HIV) (OR 1.64, CI 1.09- 2.47, p=0.018). Gender, age group, smoking status and vegetable consumption, body mass index (BMI) and hypertension were not associated with albuminuria.

CONCLUSION

The albuminuria prevalence was estimated at 105.9 per 1,000 in Rwanda. Rural residence, partnered status and HIV positivity were identified as main risk factors for albuminuria. Increased early screening of albuminuria to prevent CKD among high-risk groups, especially HIV patients, is therefore recommended.

A Link between Chronic Kidney Disease and Gut Microbiota in Immunological and Nutritional Aspects

Chronic kidney disease (CKD) is generally progressive and irreversible, structural or functional renal impairment for 3 or more months affecting multiple metabolic pathways. Recently, the composition, dynamics, and stability of a patient's microbiota has been noted to play a significant role during disease onset or progression. Increasing urea concentration during CKD can lead to an acceleration of the process of kidney injury leading to alterations in the intestinal microbiota that can increase the production of gut-derived toxins and alter the intestinal epithelial barrier. A detailed analysis of the relationship between the role of intestinal microbiota and the development of inflammation within the symbiotic and dysbiotic intestinal microbiota showed significant changes in kidney dysfunction. Several recent studies have determined that dietary factors can significantly influence the activation of immune cells and their mediators. Moreover, dietary changes can profoundly affect the balance of gut microbiota. The aim of this review is to present the importance and factors influencing the differentiation of the human microbiota in the progression of kidney diseases, such as CKD, IgA nephropathy, idiopatic nephropathy, and diabetic kidney disease, with particular emphasis on the role of the immune system. Moreover, the effects of nutrients, bioactive compounds on the immune system in development of chronic kidney disease were reviewed.

Evaluation of Serum Cyclooxygenase, Hepcidin Levels in Acute Renal Injury (AKI) Patients Following Cardiac Catheterization

Background

Acute kidney damage is a severe condition common in patients who have undergone heart surgery (catheterization) and secondary injury is also referred to as being synonymous with surgery. The goal of this research is to determine the rate of cyclooxygenase and hepcidin levels in patients with acute renal injury (AKI) following cardiac catheterization.

Methods

The study is performed on (81) patients (64 males and 17 females) aged 40-75 years. Data from most patients are reported in the form of age, gender, and smoking background questionnaire.

Results

The results indicate a significant increase in serum levels of cyclooxygenase and hepcidin levels in patients with severe renal insufficiency after cardiac catheterization by (79%) males versus (21%) females.

Conclusion

In this study, improved risk prediction could enhance patient monitoring and treatment after surgery, direct patient treatment and decision making, and enhance participation in AKI interventional trials.

Racial Health Disparity and COVID-19

Abstract

The infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and resultant coronavirus diseases-19 (COVID-19) disproportionally affects minorities, especially African Americans (AA) compared to the Caucasian population. The AA population is disproportionally affected by COVID-19, in part, because they have high prevalence of underlying conditions such as obesity, diabetes, and hypertension, which are known to exacerbate not only kidney diseases, but also COVID-19. Further, a decreased adherence to COVID-19 guidelines among tobacco smokers could result in increased infection, inflammation, reduced immune response, and lungs damage, leading to more severe form of COVID-19. As a result of high prevalence of underlying conditions that cause kidney diseases in the AA population coupled with tobacco smoking make the AA population vulnerable to severe form of both COVID-19 and kidney diseases. In this review, we describe how tobacco smoking interact with SARS-CoV-2 and exacerbates SARS-CoV-2-induced kidney diseases including renal failure, especially in the AA population. We also explore the role of extracellular vesicles (EVs) in COVID-19 patients who smoke tobacco. EVs, which play important role in tobacco-mediated pathogenesis in infectious diseases, have also shown to be important in COVID-19 pathogenesis and organ injuries including kidney. Further, we explore the potential role of EVs in biomarker discovery and therapeutics, which may help to develop early diagnosis and treatment of tobacco-induced renal injury in COVID-19 patients, respectively.

Graphical Abstract

Community-based screening to determine the prevalence, health and nutritional status of patients with CKD in rural and peri-urban Bangladesh

Background:

Studies have labelled chronic kidney disease (CKD) among the adult population in urban Bangladesh. To address knowledge gaps on CKD, we aimed to generate data on prevalence, health and nutrition of CKD individuals living in rural and peri-urban Bangladesh.

Methods:

Participants were recruited from the Mirzapur Demographic Surveillance System by age-stratified random sampling. We screened participants by measuring serum creatinine and urine albumin to creatinine ratio, and collected socio-demographic, lifestyles and health information (phase I). After 3 months (phase II), we repeated the urine and blood tests as per the Kidney Disease Outcomes Quality Initiative guidelines. The glomerular filtration rate was calculated using the CKD Epidemiology Collaboration equation.

Results:

Among 928 participants, 872 completed the study. In phase I, probable CKD cases were 281 (32.2%); in phase II, confirmed cases were 192 (22.0%) (stage 1, 4.0%; stage 2, 11.8%; stage 3, 5.5%; stage 4, 0.6%; stage 5, 0.1%). In multivariable analysis, associated factors for prevalent CKD included aged ⩾60 years [adjusted odds ratio (aOR) 5.02; 95% confidence interval (CI) 1.85–13.65], hypertension (aOR 3.08; 95% CI 2.07–4.59), diabetes (aOR 2.52; 95% CI 1.60–3.96), presence of red blood cell in urine (aOR 3.20; 95% CI 1.71–5.98) and anemia (aOR 2.50; 95% CI 1.63–3.84).

Conclusions:

This is the first ever research on CKD prevalence in rural and peri-urban Bangladesh and recorded about 22%, which is higher than urban settings. Monitoring systems are needed to evaluate the overall burden and to mitigate risk factors with an emphasis on the rural and peri-urban population.

Cross-sectional study of diabetes kidney disease in the Eastern Cape, South Africa

Diabetes mellitus (DM) is an independent risk factor for the development of kidney disease. This study assesses the prevalence and determinants of asymptomatic kidney disease in individuals with DM attending health facilities in OR Tambo district, Eastern Cape, South Africa.In this cross-sectional analysis, medical data of 327 individuals receiving care for DM in primary health care centers in OR Tambo district, Eastern Cape between June and November 2013 were reviewed. Significant kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m in accordance with the guidelines of the Society of Endocrinology, Metabolism and Diabetes of South Africa (2017).One-quarter of the 327 participants (n = 80) had significant kidney disease. Female sex [odds ratio (OR) = 5.2; 95% confidence interval (95% CI) 1.2-23.5], never used alcohol (OR = 13.4; 95% CI 2.5-72.1), hypertension (OR = 16.2; 95% CI 2.0-130.0), triglyceride (TG)/high-density lipoprotein (HDL) ratio (OR = 1.2; 95% CI 1.0-1.5), current smoker (OR = 1127.9; 95% CI 162.9-7808.9), former smoker (OR = 13.3; 95% CI 4.1-41.4), and longer duration of diabetes (OR = 4.6; 95% CI 1.6-13.0) were the independent determinants of significant kidney disease among the participants. A significant dose--effect relationship exists between renal disease and smoking status (P < .0001), duration of DM (P < .001), glycemic status (P = .025), and body mass index (P = .003).There is a high rate of undiagnosed kidney disease in this setting, which was independently associated with female sex and presence of other cardiovascular risk factors. Strategic interventions targeting screening and monitoring of renal functions in individuals with DM are urgently needed in this region.

Coffee Consumption is Associated with a Decreased Risk of Incident Chronic Kidney Disease: A Systematic Review and Meta-analysis of Cohort Studies

BACKGROUND

Recent studies have suggested a renal protective effect of coffee consumption against development of chronic kidney disease (CKD) although the results remain inconclusive. This systematic review and meta-analysis aimed to comprehensively investigate this association by summarizing all available data.

METHODS

A systematic review was performed using MEDLINE and EMBASE database from inception to November 2019 to identify all cohort studies that compared the risk of developing CKD after index date among coffee-drinkers versus non-drinkers. Pooled risk ratio and 95% confidence interval (CI) were calculated using random-effect, generic inverse-variance method of DerSimonian and Laird.

RESULTS

A total of 4 cohort studies comprising of 25,849 participants met the inclusion criteria and were analyzed in the meta-analysis. The meta-analysis found a significantly decreased risk of incident CKD among coffee-drinkers compared with non-drinkers with the pooled risk ratio of 0.87 (95% CI, 0.81-0.95; I² of 57%). The funnel plot of this study was relatively symmetric and was not indicative of publication bias CONCLUSIONS: A significant association between coffee consumption and a lower risk of incident CKD was demonstrated in this study.

Increased Acid-Producing Diet and Past Smoking Intensity Are Associated with Worse Prognoses Among Breast Cancer Survivors: A Prospective Cohort Study

Current dietary guidelines do not consider cancer survivors’ and past smokers’ low capacity to regulate their acid–base balance. People with a low capacity to regulate their acid–base balance are more susceptible to acid-producing diets. We studied a cohort of 2950 early stage breast cancer survivors who provided dietary information at baseline and during follow-up. We assessed the intakes of acid-producing diets via two commonly used dietary acid load scores: potential renal acid load (PRAL) and net endogenous acid production (NEAP). We assessed past smoking intensity by pack-years of smoking. After an average of 7.3 years of follow-up, there were 295 total deaths, 249 breast cancer-specific deaths, and 490 cases of recurrent breast cancer. Increased intakes of dietary acid load and pack-years of smoking were each independently and jointly associated with increased total mortality and breast cancer-specific mortality; tests for trends and overall associations were statistically significant for NEAP and marginally significant for PRAL. Compared to women in the lowest tertile of NEAP and pack-year of smoking = 0, women in the highest tertile of NEAP and pack-years of smoking >15 had the greatest increased risk of total mortality (HR = 3.23, 95%CI 1.99–5.26). Further, dietary acid scores were associated with increased breast cancer recurrence among women with pack-years of smoking >0 but not in those with pack-years of smoking = 0 (p values for interactions <0.05). Our study provides valuable evidence for adding dietary acid load scores to dietary guidelines for breast cancer survivors and developing specific guidelines for past smokers among these survivors.

Active Smoking is Associated with Lower Dialysis Adequacy in Prevalent Dialysis Patients

BACKGROUND:

Dialysis adequacy measured by single pool Kt/V (spKt/V) lower than 1.2 or urea reduction rate (URR) lower than 65% is associated with a significant increase in patient mortality rate. Patients’ adherence to the medical treatment is crucial to achieve recommended targets for spKt/V. Smoking is a recognized factor of non-adherence.

AIM:

In this study we sought to assess the association of active smoking and dialysis adequacy.

METHODS:

A total of 134 prevalent dialysis patients from one dialysis center were included in an observational cross-sectional study. Clinical, laboratory and dialysis data were obtained from medical charts in previous 6 months. The number of missed, on purpose interrupted or prematurely terminated dialysis sessions was obtained. Dialysis adequacy was calculated as spKt/V and URR. Patients were questioned about current active smoking status. T-test and Chi-Square test were used for comparative analysis of dialysis adequacy with regard to smoking status.

RESULTS:

The majority of patients declared a non-smoking status (100 (75%)) and 34 (25%) were active smokers. Male gender, younger age and shorter dialysis vintage were significantly more often present in the active smokers ((9 (26%) vs 25 (73%), p = 0.028; 57.26 ± 12.59 vs 50.15 ± 14.10, p = 0.012; 118.59 ± 76.25 vs 88.82 ± 57.63, p = 0.030)), respectively. spKt/V and URR were significantly lower and Kt/V target was less frequently achieved in smokers ((1.46 ± 0.19 vs. 1.30 ± 0.021, p = 0.019; 67.14 ± 5.86 vs. 63.64 ± 8.30, p = 0.002; 14 (14%) vs. 11 (32%), p = 0.023), respectively. Shorter dialysis sessions, larger ultra filtrations and higher percentage of missed/interrupted dialysis session on patients’ demand were observed in smokers (4.15 ± 0.30 vs. 4.05 ± 0.17, p = 0.019; 3.10 ± 0.78 vs. 3.54 ± 0.92, p = 0.017; 25 (0.3%) vs. 48 (1.8%), p = 0.031), respectively.

CONCLUSION:

Active smokers, especially younger men, achieve lower than the recommended levels for dialysis adequacy. Non-adherence to treatment prescription in smokers is a problem to be solved. Novel studies are recommended in patients on dialysis, to further elucidate the association of dialysis adequacy with the active smoking status.

Associations between Dietary Acid Load and Biomarkers of Inflammation and Hyperglycemia in Breast Cancer Survivors

Metabolic acidosis can lead to inflammation, tissue damage, and cancer metastasis. Dietary acid load contributes to metabolic acidosis if endogenous acid-base balance is not properly regulated. Breast cancer survivors have reduced capacities to adjust their acid-base balance; yet, the associations between dietary acid load and inflammation and hyperglycemia have not been examined among them. We analyzed data collected from 3042 breast cancer survivors enrolled in the Women's Healthy Eating and Living (WHEL) Study who had provided detailed dietary intakes and measurements of plasma C-reactive protein (CRP) and hemoglobin A1c (HbA1c). Using a cross-sectional design, we found positive associations between dietary acid load and plasma CRP and HbA1c. In the multivariable-adjusted models, compared to women with the lowest quartile, the intakes of dietary acid load among women with the highest quartile showed 30-33% increases of CRP and 6-9% increases of HbA1c. Our study is the first to demonstrate positive associations between dietary acid load and CRP and HbA1c in breast cancer survivors. Our study identifies a novel dietary factor that may lead to inflammation and hyperglycemia, both of which are strong risk factors for breast cancer recurrence and comorbidities.

Risk of Kidney Dysfunction from Polypharmacy among Older Patients: A Nested Case-Control Study of the South Korean Senior Cohort

Polypharmacy, the concurrent use of multiple medicines, could increase the risk of kidney dysfunction among older adults because it likely burdens the aging kidneys to excrete multiple pharmaceutical ingredients and their metabolites. This study aimed to examine the relation between polypharmacy and kidney dysfunction among older patients. A nested case-control study was conducted using the National Health Insurance Service - Senior Cohort (NHIS-SC, 2009-2013), representative of the Korean senior population. It consisted of all health insurance claims linked to records of mandatory health examination. Kidney dysfunction was defined as having an eGFR lower than 60, with a decline rate of 10% or more compared to the baseline eGFR. Polypharmacy was defined based on daily counts of pharmaceutical ingredients during one year prior to the case's event date. It was classified into polypharmacy (five to 10 ingredients) and excessive polypharmacy (10 or more ingredients). After matching case and control groups based on a range of potential confounders, conditional logistic regression was performed incorporating adjustments on disease-specific, medication-specific, and lifestyle-related risk factors. The matching resulted in 14,577 pairs of cases and controls. Exposure to polypharmacy was significantly associated with increase in the risk of kidney dysfunction; i.e., crude model (polypharmacy: OR = 1.572, 95% CI = 1.492-1.656; excessive polypharmacy: OR = 2.069, 95% CI = 1.876-2.283) and risk adjustment model (polypharmacy: OR = 1.213, 95% CI = 1.139-1.292; excessive polypharmacy: OR = 1.461, 95% CI = 1.303-1.639). The significant associations were robust across different definitions of kidney dysfunction. These findings inform healthcare providers and policy makers of the importance of polypharmacy prevention to protect older adults from kidney dysfunction.

Beclin-1 regulates cigarette smoke-induced kidney injury in a murine model of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), associated with cigarette smoke-induced (CS-induced) emphysema, contributes significantly to the global health care burden of disease. Although chronic kidney disease (CKD) may occur in patients with COPD, the relationship between COPD and CKD remains unclear. Using a murine model of experimental COPD, we show that chronic CS exposure resulted in marked kidney injury and fibrosis, as evidenced by histological and ultrastructural changes, altered macrophage subpopulations, and expression of tissue injury, fibrosis, and oxidative stress markers. CS induced mitochondrial dysfunction, and increased autophagic flux in kidney tissues and in kidney tubular epithelial (HK-2) cells, as determined by LC3B turnover assays. Mice heterozygous for Beclin-1 (Becn1+/-) were protected from the development of kidney tissue injury and renal fibrosis in response to CS exposure, and displayed impaired basal and inducible mitochondrial turnover by mitophagy. Interestingly, CS caused a reduction of Beclin-1 expression in mouse kidneys and kidney tubular epithelial cells, attributed to increased autophagy-dependent turnover of Beclin-1. These results suggest that Beclin-1 is required for CS-induced kidney injury and that reduced levels of Beclin-1 may confer renoprotection. These results identify the kidney as a target for CS-induced injury in COPD and the Beclin-1-dependent autophagy pathway as a potential therapeutic target in CKD.

Deleting Death and Dialysis: Conservative Care of Cardio-Vascular Risk and Kidney Function Loss in Chronic Kidney Disease (CKD)

The uremic syndrome, which is the clinical expression of chronic kidney disease (CKD), is a complex amalgam of accelerated aging and organ dysfunctions, whereby cardio-vascular disease plays a capital role. In this narrative review, we offer a summary of the current conservative (medical) treatment options for cardio-vascular and overall morbidity and mortality risk in CKD. Since the progression of CKD is also associated with a higher cardio-vascular risk, we summarize the interventions that may prevent the progression of CKD as well. We pay attention to established therapies, as well as to novel promising options. Approaches that have been considered are not limited to pharmacological approaches but take into account lifestyle measures and diet as well. We took as many randomized controlled hard endpoint outcome trials as possible into account, although observational studies and post hoc analyses were included where appropriate. We also considered health economic aspects. Based on this information, we constructed comprehensive tables summarizing the available therapeutic options and the number and kind of studies (controlled or not, contradictory outcomes or not) with regard to each approach. Our review underscores the scarcity of well-designed large controlled trials in CKD. Nevertheless, based on the controlled and observational data, a therapeutic algorithm can be developed for this complex and multifactorial condition. It is likely that interventions should be aimed at targeting several modifiable factors simultaneously.

Cigarette smoking reduced renal function deterioration in hypertensive patients may be mediated by elevated homocysteine

Elevated homocysteine (HCY) and smoking are both important risk factors for hypertensive patients. However, whether they have crossing effect on renal function deterioration of hypertensive patients and what is the underlying mechanism are unclear. In the present study, 3033 participants diagnosed as essential hypertension with estimated glomerular filtration rate (eGFR)> 30 ml/min/1.73 m² from southern China were enrolled in this cross-sectional study. We collected the demographic and clinical data. In addition, the mediation effects were analyzed. The results showed that, comparing with non-smokers, smokers had significant higher levels of HCY (13.10 (11.20−16.87) vs. 11.00 (8.90−13.40) umol/L, P < 0.001) and lower eGFR (79.71 (66.83−91.05) vs. 82.89 (69.80−95.85) ml/min/1.73m², P < 0.001). HCY levels and smoking were independently associated with decreased eGFR. Meanwhile, eGFR levels were significantly negatively correlated with HCY (P < 0.001), and this correlation might be stronger in current smokers. Current smoker consuming over 20 cigarettes per day would accelerate early renal function deterioration (OR = 1.859, P = 0.019). The mediation effects analysis further showed that the association between smoking and renal function deterioration was mediated by HCY. And elevated HCY was accounted for 56.94% of the estimated causal effect of smoking on renal function deterioration in hypertensive patients. Our findings indicated that cigarette smoking was associated with renal function deterioration in hypertensive patients, and the association between cigarette smoking and renal function deterioration was probably mediated by elevated HCY. Therefore, HCY-lowering therapy may be beneficial for renal function deterioration in hypertensive smoking patients.

Duration-dependent effects of nicotine exposure on growth and AKT activation in human kidney epithelial cells

Exposure to nicotine is known to cause adverse effects in many target organs including kidney. Epidemiological studies suggest that nicotine-induced kidney diseases are prevalent worldwide. However, the impact of duration of exposure on the nicotine-induced adverse effects in normal kidney cells and the underlying molecular mechanism is still unclear. Hence, the objective of this study was to evaluate both acute and long-term effects of nicotine in normal human kidney epithelial cells (HK-2). Cells were treated with 1 and 10 µM nicotine for acute and long-term duration. The result of cell viability showed that the acute exposure to 1 µM nicotine has no significant effect on growth. However, the 10 µM nicotine caused significant decrease in the growth of HK-2 cells. The long-term exposure resulted in significantly increased cell growth in both 1 and 10 µM nicotine-treated groups. Analysis of cell cycle and expression of marker genes related to proliferation and apoptosis further confirmed the effects of nicotine. Additionally, the analysis of growth signaling pathway revealed the decreased level of pAKT in cells with acute exposure whereas the increased level of pAKT in long-term nicotine-exposed cells. This suggests that nicotine, through modulating the AKT pathway, controls the duration-dependent effects on the growth of HK-2 cells. In summary, this is the first report showing long-duration exposure to nicotine causes increased proliferation of human kidney epithelial cells through activation of AKT pathway.

Location-Specific Oral Microbiome Possesses Features Associated With CKD

INTRODUCTION

Chronic kidney disease (CKD), a progressive loss of renal function, can lead to serious complications if underdiagnosed. Many studies suggest that the oral microbiota plays important role in the health of the host; however, little is known about the association between the oral microbiota and CKD pathogenesis.

METHODS

In this study, we surveyed the oral microbiota in saliva, the left and right molars, and the anterior mandibular lingual area from 77 participants (18 with and 59 without CKD), and tested their association with CKD to identify microbial features that may be predictive of CKD status.

RESULTS

The overall oral microbiota composition significantly differed by oral locations and was associated with CKD status in saliva and anterior mandibular lingual samples. In CKD patients, we observed a significant enrichment of Neisseria and depletion of Veillonella in both sample types and a lower prevalence of Streptococcus in saliva after adjustment for other comorbidities. Furthermore, we detected a negative association of Neisseria and Streptococcus genera with the kidney function as measured by estimated glomerular filtration rate. Neisseria abundance also correlated with plasma interleukin-18 levels.

CONCLUSION

We demonstrate the association of the oral microbiome with CKD and inflammatory kidney biomarkers, highlighting a potential role of the commensal bacteria in CKD pathogenesis. A better understanding of the interplay between the oral microbiota and CKD may help in the development of new strategies to identify at-risk individuals or to serve as a novel target for therapeutic intervention.

Associations of smoking with cardiometabolic profile and renal function in a Romanian population-based sample from the PREDATORR cross-sectional study

BACKGROUND

The impact of smoking on morbidity is well known, but in Romania, limited data are available regarding the smoking prevalence and relationship with cardiometabolic profile and kidney function.

OBJECTIVES

To assess the association of smoking with cardiometabolic traits and kidney function, in a Romanian population-based sample from the PREDATORR study.

METHODS

PREDATORR was an epidemiological cross-sectional study. Between 2012 and 2014, participants were randomly selected from the lists of general practitioners and enrolled if they were aged 20 to 79 years, born and living in the past 10 years in Romania. Sociodemographic and lifestyle characteristics were collected through interviewer-administered questionnaires.

RESULTS

Overall, 2704 participants were included in the analysis, 18% of them being current smokers and 30.8% former smokers. Current smokers compared to non-smokers had higher total cholesterol (220.6 ± 50.4 versus 213.9 ± 86.8 mg/dl, P = 0.017), LDL-cholesterol (137.8 ± 45.2 versus 130.7 ± 83.7 mg/dl, P = 0.004) and glomerular filtration rate (96.9 ± 16.8 versus 90.7 ± 19.1 ml/min/1.73 m2, P <0.001) in women and higher triglycerides (170.7 ± 129.8 versus 144.3 ± 94.2 mg/dl, P = 0.007), glomerular filtration rate (97.6 ± 17 versus 90.3 ± 18 ml/min/1.73 m2, P < 0.001) and lower HDL-cholesterol (48 ± 15.5 versus 50.4 ± 14.1 mg/dl, P = 0.002) in men. Active smoking was associated with hypercholesterolaemia [OR: 1.40 (95% CI: 1.01-1.96), P = 0.04] and low HDL-cholesterolaemia [OR: 1.39 (95% CI: 1.01-1.91), P = 0.04] and negatively associated with overweight/obesity [OR: 0.67 (95% CI: 0.48-0.94), P = 0.02]. Male former smokers had higher prevalence of abdominal obesity (82.4% versus 76.4%, P = 0.02), hypertriglyceridaemia (43.6% versus 35.6%, P = 0.01), hypertension (64% versus 56.4%, P = 0.01) and ischaemic vascular disease (40.5% versus 30.9%, P = 0.003) than male non-smokers.

CONCLUSION

The PREDATORR study showed a high prevalence of smoking in the adult Romanian population providing data on the association of smoking with cardiometabolic traits.

The Associations of Endotoxemia With Systemic Inflammation, Endothelial Activation, and Cardiovascular Outcome in Kidney Transplantation

OBJECTIVE

Cardiovascular disease is the leading cause of death in kidney transplant recipients (KTRs), yet incompletely accountable by traditional risk factors. Inflammation is an unconventional cardiovascular risk factor, with gut-derived endotoxemia potentially driving inflammation and endothelial disease. Comparable data are lacking in kidney transplantation. This study investigated the associations of endotoxemia with inflammation, endothelial activation, and 5-year cardiovascular events in KTRs. Determinants of endotoxemia were also explored.

DESIGN AND METHODS

This is a single-center cross-sectional study with prospective follow-up from a prevalent cohort of 128 KTRs.

MAIN OUTCOME MEASURES

Demographic, nutritional and clinical predictors of inflammation (high-sensitivity C-reactive protein [hsCRP]), endothelial activation (sE-selectin), and endotoxemia (endotoxin) were assessed. Follow-up data on 5-year cardiovascular event rates were collected.

RESULTS

Endotoxemia (P = .03), reduced 25-hydroxyvitamin D (P = .04), high fructose intake (P < .001), decreased fiber intake (P < .001), and abdominal obesity (P = .002) were independently associated with elevated hsCRP. In turn, endotoxemia (P = .007) and increasing hsCRP (P = .02) were both independently associated with raised sE-selectin. Furthermore, endotoxemia predicted increased cardiovascular event rate (P = .02), independent of hsCRP and a global measure of cardiovascular risk estimated by a validated algorithm of 7-year risk for major adverse cardiac events in kidney transplantation. Determinants of endotoxemia included reduced 25-hydroxyvitamin D (P < .001), hypertriglyceridemia (P < .001), increased fructose intake (P = .01), and abdominal obesity (P = .01).

CONCLUSIONS

Endotoxemia in KTRs contributes to inflammation, endothelial activation, and increased cardiovascular events. This study highlights the clinical relevance of endotoxemia in KTRs, suggesting future interventional targets.

Risk factors for chronic kidney disease among patients at Olabisi Onabanjo University Teaching Hospital in Sagamu, Nigeria: A retrospective cohort study

BACKGROUND

Chronic kidney disease (CKD) is common and often goes undetected and undiagnosed until the disease is well advanced and kidney failure is imminent. It is estimated that approximately 36 million Nigerians suffer from different stages of CKD, as one in seven Nigerians has kidney disease.

METHODS

This research was a retrospective cohort study of 150 cases and 300 controls. Selection of subjects was by a retrospective review of records of in-patients from 2010-2013 in a state teaching hospital. Data was analyzed using Chi-square at 5% level of significance.

RESULTS

Majority of subjects were between ages 20 - 29 years. The mean (SD) age of the cases was 40.6 (14.4) and controls was 38.6 (15.8). Ninety (60%) of the cases and 212(70.7%) of the controls were males (p= 0.023). Almost 87% of the cases and 42% of the controls ingest herbal concoction. Use of bleaching substances was more among the cases 20(13.4%) compared with the controls 2(0.7%), ( p= 0.001). Eight (5.3%) of the cases had family history of CKD while only 1(0.3%) of the control had similar history (p= 0.001). There were more cases (10.7%) with diabetic mellitus compared with the controls (2.7%), (p= 0.001). The number of cases with high blood pressure was more than the number of controls, (p-value <0.001). Sixty-four percent of the cases had history of chronic use of analgesic compared with 10.3% of the controls (p < 0.001).

CONCLUSIONS

CKD is mostly found among men in their productive age, who were either diabetic or hypertensive with history of ingestion of herbal concoction and chronic use of analgesic. Individual should engage in regular medical check, modify their life style while government and health care providers increase awareness and campaign on the causes and risk factors of CKD.

Reducing the costs of chronic kidney disease while delivering quality health care: a call to action

The treatment of chronic kidney disease (CKD) and of end-stage renal disease (ESRD) imposes substantial societal costs. Expenditure is highest for renal replacement therapy (RRT), especially in-hospital haemodialysis. Redirection towards less expensive forms of RRT (peritoneal dialysis, home haemodialysis) or kidney transplantation should decrease financial pressure. However, costs for CKD are not limited to RRT, but also include nonrenal health-care costs, costs not related to health care, and costs for patients with CKD who are not yet receiving RRT. Even if patients with CKD or ESRD could be given the least expensive therapies, costs would decrease only marginally. We therefore propose a consistent and sustainable approach focusing on prevention. Before a preventive strategy is favoured, however, authorities should carefully analyse the cost to benefit ratio of each strategy. Primary prevention of CKD is more important than secondary prevention, as many other related chronic diseases, such as diabetes mellitus, hypertension, cardiovascular disease, liver disease, cancer, and pulmonary disorders could also be prevented. Primary prevention largely consists of lifestyle changes that will reduce global societal costs and, more importantly, result in a healthy, active, and long-lived population. Nephrologists need to collaborate closely with other sectors and governments, to reach these aims.

Smoking has no impact on survival and it is not associated with ACE gene I/D polymorphism in hemodialysis patients

INTRODUCTION

The relationship between smoking and mortality in patients on hemodialysis is controversial. Earlier studies showed that the insertion/deletion (I/D) polymorphism of the ACE gene might have an effect on mortality. The aim of this study was to test the impact of smoking on survival and whether this association was influenced by ACE gene I/D polymorphism in patients on maintenance hemodialysis.

PARTICIPANTS AND METHODS

In this prospective, multicenter cohort study we analyzed 709 prevalent patients on maintenance hemodialysis. Patients were allocated into groups based on their smoking habit. Outcome data were collected during the 144-month follow-up period. Outcomes of current smokers and lifelong non-smokers were compared. In order to control for interactions between predictor variables, we also identified 160 matched pairs for further sub-analysis.

RESULTS

The vast majority of patients (67%) were non-smokers, followed by current smokers (22.2%) and ex-smokers (9.8%). Smoking had no impact on survival in the matched pair analysis ( p = 0.99). After adjustment for ACE I/D polymorphism and other co-variates, smoking had no effect on survival.

CONCLUSION

Our data suggest that smoking has no impact on survival; neither is it associated with ACE gene I/D polymorphism in hemodialysis patients.

Air pollution and urinary n-acetyl-B-glucosaminidase levels in residents living near a cement plant

Background

To identify adverse renal effects due to air pollution derived from a cement plant in Korea. Urinary n-acetyl-B-glucosaminidase (U-NAG) levels in residents living near a cement plant were compared to those in a group who lived farther away from the plant.

Methods

From June to August 2013 and from August to November 2014, laboratory tests for U-NAG and heavy metal were conducted on 547 study participants. Based on the level of air pollution exposure, subjects were divided into the “less exposed group,” (LEG) which consisted of 66 persons who lived more than 5 km away from the cement plant, the “more exposed group from the rural area” (MEG-R), which consisted of 272 persons, and the “more exposed group from downtown area” (MEG-D), which consisted of 209 persons who lived within a 1 km radius of the cement plant. U-NAG levels >5.67 U/L were defined as “higher U-NAG” levels. We compared the prevalence of higher U-NAG levels and estimated the adjusted odds ratio (OR) by air pollution exposure using a chi-square test and multiple logistic regression analysis. Further, we estimated the interaction between air pollution exposure and heavy metal exposure in renal toxicity.

Results

The OR of higher U-NAG levels by MEG-D and MEG-R compared to LEG was 2.13 (95 % CI 0.86–4.96) and 4.79 (95 CI 1.65–10.01), respectively. Urinary cadmium (U-Cd), urinary mercury (U-Hg), age, occupation, hypertension, and diabetes had a significant association with higher U-NAG levels. However, blood lead (B-Pb), sex, and smoking were not associated with higher U-NAG. Especially, concurrent exposure to heavy metals (U-Hg or/and U-Cd) and air pollution had an additive adverse effect. In the group with both 4^th quartile heavy metal exposure (U-Cd or/and U-Hg) and air pollution exposure, the OR in MEG-R and MEG-D was 6.49 (95 % 1.42–29.65) and 8.12 (95 % CI 1.74–37.92), respectively, after adjustment for age, occupation, hypertension, diabetes.

Conclusions

U-NAG levels seem to be affected by air pollution exposure as well as age, hypertension, diabetes, and even low levels of cadmium and low levels of mercury. Moreover, concurrent exposure to heavy metals and air pollution can have additive cytotoxic renal effects.