Relationship between body mass index and renal function deterioration among the Taiwanese chronic kidney disease population

Association between high-sensitivity C-reactive protein and renal function in Korean adults: A sex-specific analysis of Korea National Health and Nutrition Examination Survey 2015 to 2018 data

This study aimed to investigate the association between high-sensitivity C-reactive protein (hs-CRP) levels, as a surrogate marker of systemic inflammation, and renal function among Korean adults grouped by age, sex, and body mass index. This study analyzed data obtained from the Korea National Health and Nutrition Examination Survey 2015 to 2018, a cross-sectional and nationally representative survey conducted by the Korean Centers for Disease Control and Prevention. Of the 22,451 subjects included in this study, 19,607 (87.3%) and 2844 (12.7%) had normal kidney function and incident chronic kidney disease, respectively. Reduced renal function was more frequently observed in subjects with high hs-CRP levels than in those with low hs-CRP levels (odds ratio [OR], 1.438; 95% confidence interval [CI], 1.234-1.674). In the group aged ≥ 65 years, the odds of reduced renal function were higher among subjects with a high hs-CRP level compared to those with a low hs-CRP level (OR, 1.528; 95% CI, 1.191-1.960). The association between hs-CRP level and renal function was observed only in women (OR, 2.485; 95% CI, 1.779-3.470) and further stratified by age and sex, the odds of reduced renal function were likely higher in women aged ≥ 65 years with a high hs-CRP level (OR, 2.338; 95% CI, 1.622-3.369). Moreover, reduced renal function was more observed in subjects aged ≥ 65 years and those with a body mass index < 25 kg/m2 (OR, 1.502; 95% CI, 1.087-2.075). This study showed that a high hs-CRP level likely contributes to the increased prevalence of reduced renal function. This association may aid the identification of individuals at high risk for reduced renal function, especially elderly women, in clinical or public health practice.

Long-term ozone exposure and mortality in patients with chronic kidney disease: a large cohort study

BACKGROUND

Epidemiologic studies on the effects of long-term exposure to ozone (O3) have shown inconclusive results. It is unclear whether to O3 has an effect on chronic kidney disease (CKD). We investigated the effects of O3 on mortality and renal outcome in CKD.

METHODS

We included 61,073 participants and applied Cox proportional hazards models to examine the effects of ozone on the risk of end-stage renal disease (ESRD) and mortality in a two-pollutants model adjusted for socioeconomic status. We calculated the concentration of ozone exposure one year before enrollment and used inverse distance weighting (IDW) for interpolation, where the exposure was evenly distributed.

RESULTS

In the single pollutant model, O3 was significantly associated with an increased risk of ESRD and all-cause mortality. Based on the O3 concentration from IDW interpolation, this moving O3 average was significantly associated with an increased risk of ESRD and all-cause mortality. In a two-pollutants model, even after we adjusted for other measured pollutants, nitrogen dioxide did not attenuate the result for O3. The hazard ratio (HR) value for the district-level assessment is 1.025 with a 95% confidence interval (CI) of 1.014-1.035, while for the point-level assessment, the HR value is 1.04 with a 95% CI of 1.035-1.045. The impact of ozone on ESRD, hazard ratio (HR) values are, 1.049(95%CI: 1.044-1.054) at the district unit and 1.04 (95%CI: 1.031-1.05) at the individual address of the exposure assessment. The ozone hazard ratio for all-cause mortality was 1.012 (95% confidence interval: 1.008-1.017) for administrative districts and 1.04 (95% confidence interval: 1.031-1.05) for individual addresses.

CONCLUSIONS

This study suggests that long-term ambient O3 increases the risk of ESRD and mortality in CKD. The strategy to decrease O3 emissions will substantially benefit health and the environment.

Metabolic Risk Profile and Graft Function Deterioration 2 Years After Kidney Transplant

Importance

Studies exploring the association of body weight and metabolic status with graft function deterioration (GFD) after kidney transplantation have produced inconsistent findings. Few studies have examined whether metabolically healthy overweight or obesity (MHO) may contribute to GFD.

Objective

To evaluate associations of overweight or obesity and metabolic disorders with GFD in recipients of kidney transplant.

Design, Setting, and Participants

This multicenter retrospective cohort study was conducted from January 1, 2020, through June 30, 2021, with a follow-up period of 2 years after kidney transplantation. Participants included adult recipients of cadaveric kidney transplant in 4 transplantation centers in China. Participants were classified as 4 metabolic phenotypes according to their BMI and metabolic status. Data were analyzed from July to August 2023.

Exposures

Overweight and obesity were characterized by body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 24 or greater. Metabolic disorder was identified by existence of a minimum of 2 of 4 conditions: hypertension, hyperglycemia, increased triglyceride, and decreased high-density lipoprotein cholesterol.

Main Outcome and Measures

The main outcome was GFD, defined as a decrease in estimated glomerular filtration rate of at least 25% within 6 months to 2 years after transplant.

Results

A total of 1260 adult recipients of cadaveric kidney transplant (mean [SD] age, 43.97 [11.51] years; 755 [59.92%] male) were included in the study, and 127 (10.08%) participants experienced the primary outcome of GFD during follow-up. After accounting for confounding factors in multivariable analyses, overweight or obesity (odds ratio [OR], 1.64; 95% CI, 1.10-2.44; P = .02) and metabolic disorder (OR, 1.71; 95% CI, 1.12-2.63; P = .01) were associated with increased risk of GFD. The MHO subgroup exhibited a greater risk for GFD (OR, 2.37; 95% CI, 1.01-5.57; P = .048) compared with participants who did not have overweight or obesity or metabolic disorder. All components of metabolic disorder, with the exception of elevated triglyceride, were associated with GFD. There was a dose-response association of number of metabolic disorder components (OR per 1 additional condition, 1.40; 95% CI, 1.20-1.63; P < .001) and BMI (OR per 1-unit increase, 1.90; 95% CI, 1.03-1.15; P = .002) with increased risk for GFD. A nonlinear association was observed between BMI and risk of GFD.

Conclusions and Relevance

In this cohort study of recipients of cadaveric kidney transplant, individuals with overweight or obesity or metabolic disorder had a significantly higher risk of experiencing GFD. Individuals with MHO had an elevated risk for graft function deterioration. Additional studies with larger sample size and longer follow-up are necessary to validate our findings.

Geriatric Nutritional Risk Index as a Prognostic Factor for Renal Progression in Patients with Type 2 Diabetes Mellitus

The aim of this study was to evaluate whether the geriatric nutritional risk index (GNRI) is associated with chronic kidney disease (CKD) progression in patients with type 2 diabetes mellitus (DM). In total, 1100 patients with type 2 DM with a follow-up duration > 1 year were included in this longitudinal study. The risk of CKD progression was assessed according to GNRI quartiles. Patients in the lowest GNRI quartile exhibited a significantly lower estimated glomerular filtration rate (eGFR), compared with those in quartile four. Moreover, these patients had poorer glycemic control and lower hemoglobin levels, body mass index, and albumin levels. Additionally, they exhibited a greater annual decline in eGFR. Multivariate logistic regression analysis showed that old age (>60 years), baseline eGFR, the presence of proteinuria, the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and low GNRI were significantly associated with CKD progression. GNRI may serve as a valuable predictive tool for identifying the risk of adverse renal outcomes in patients with type 2 DM. It may potentially serve as a more feasible measure for assessing the nutritional status of these patients, as well as for predicting their clinical outcomes.

Roles of biochemistry data, lifestyle, and inflammation in identifying abnormal renal function in old Chinese

BACKGROUND

The incidence of chronic kidney disease (CKD) has dramatically increased in recent years, with significant impacts on patient mortality rates. Previous studies have identified multiple risk factors for CKD, but they mostly relied on the use of traditional statistical methods such as logistic regression and only focused on a few risk factors.

AIM

To determine factors that can be used to identify subjects with a low estimated glomerular filtration rate (L-eGFR < 60 mL/min per 1.73 m2) in a cohort of 1236 Chinese people aged over 65.

METHODS

Twenty risk factors were divided into three models. Model 1 consisted of demographic and biochemistry data. Model 2 added lifestyle data to Model 1, and Model 3 added inflammatory markers to Model 2. Five machine learning methods were used: Multivariate adaptive regression splines, eXtreme Gradient Boosting, stochastic gradient boosting, Light Gradient Boosting Machine, and Categorical Features + Gradient Boosting. Evaluation criteria included accuracy, sensitivity, specificity, area under the receiver operating characteristic curve (AUC), F-1 score, and balanced accuracy.

RESULTS

A trend of increasing AUC of each was observed from Model 1 to Model 3 and reached statistical significance. Model 3 selected uric acid as the most important risk factor, followed by age, hemoglobin (Hb), body mass index (BMI), sport hours, and systolic blood pressure (SBP).

CONCLUSION

Among all the risk factors including demographic, biochemistry, and lifestyle risk factors, along with inflammation markers, UA is the most important risk factor to identify L-eGFR, followed by age, Hb, BMI, sport hours, and SBP in a cohort of elderly Chinese people.

Association between weight-adjusted-waist index and chronic kidney disease: a cross-sectional study

AIMS

We aimed to investigate the potential association between weight-adjusted-waist index (WWI) and chronic kidney disease (CKD).

DESIGN AND METHODS

This research examined data collected from the National Health and Nutrition Examination Survey (NHANES) spanning from 1999 to 2020. CKD was defined as the low estimated glomerular filtration rate (eGFR) or the existence of albuminuria (urinary albumin-to-creatinine ratio (ACR) ≥ 30mg/g). Low-eGFR was described as eGFR < 60 mL/min/1.73m2. The associations between WWI with CKD, albuminuria, and low-eGFR were examined using generalized additive models and weighted multivariable logistic regression models. We also analyzed the associations of other obesity indicators with CKD, albuminuria, and low-eGFR, including body mass index (BMI), waist-to-height ratio (WHtR), waist circumference(WC), height, and weight. The receiver operating characteristic (ROC) curves were used to assess and compare their diagnostic abilities.

RESULTS

Males made up 48.26% of the total 40,421 individuals that were recruited. The prevalences of CKD, albuminuria, and low-eGFR were 16.71%, 10.97%, and 7.63%, respectively. WWI was found to be positively linked with CKD (OR = 1.42; 95% CI: 1.26, 1.60). A nonlinear connection between WWI and CKD was found using smooth curve fitting. Additionally, a higher prevalence of albuminuria is linked to a higher level of WWI (OR = 1.60; 95% CI: 1.40, 1.82). Different stratifications did not substantially influence the connection between WWI and CKD, albuminuria, and low-eGFR, according to subgroup analysis and interaction tests. We observed higher height was related to higher low-eGFR prevalence (OR = 1.05; 95% CI: 1.03, 1.06). ROC analysis revealed that WWI had the best discrimination and accuracy for predicting CKD and albuminuria compared to other obesity indicators (BMI, WHTR, WC, height and weight). In addition, height had the highest area under the curve (AUC) value for predicting low-eGFR.

CONCLUSION

WWI is the best obesity indicator to predict CKD and albuminuria compared to other obesity indicators (BMI, WHTR, WC, height, and weight). WWI and CKD and albuminuria were found to be positively correlated. Furthermore, height had the strongest ability to predict low-eGFR. Therefore, the importance of WWI and height in assessing kidney health in US adults should be emphasized.

The Triglyceride-Glucose Index is Independently Associated with Chronic Kidney Disease in the Geriatric Population, Regardless of Obesity and Sex

BACKGROUND

Insulin resistance (IR) negatively affects several risk factors of chronic kidney disease (CKD). This cross-sectional study investigated whether the triglyceride-glucose (TyG) index, which reflects IR, was independently associated with CKD in a geriatric population, regardless of obesity and sex.

METHODS

The analysis included 7,326 individuals (2,864 males and 4,462 females) aged ≥60 years. Non-obesity or obesity was evaluated using a body mass index cutoff of 25 kg/m2. The TyG index was calculated as ln [triglyceride concentration (mg/dL)×fasting plasma glucose concentration (mg/dL)]/2. All participants were categorized into three groups according to TyG tertiles. Moderate-to-severe CKD (MSCKD) was defined as an estimated glomerular filtration rate (eGFR) of <45.0 mL/min/1.73 m2.

RESULTS

In males and females with or without obesity, a trend test showed a decreasing tendency in the eGFR from the lowest to highest TyG tertiles. Males without obesity and females with obesity in the middle and highest tertiles of the TyG index were 2.342 and 2.393, and were 2.313 and 3.516 times more likely to have MSCKD, respectively. Those with or without obesity in the highest tertile of the TyG index were 1.736 and 2.374 times more likely to have MSCKD, respectively.

CONCLUSION

Geriatric populations with an increased TyG index have a high risk of MSCKD regardless of obesity and sex. Our findings suggest that increased IR is associated with CKD in the geriatric population independent of obesity and sex.

Lipid accumulation product, visceral adiposity index and risk of chronic kidney disease

BACKGROUND

Lipid accumulation product (LAP) and visceral adiposity index (VAI) are novel, non-imaging markers of visceral adiposity that are calculated by using body mass index (BMI), waist circumference (WC) and serum lipid concentrations. We hypothesized that LAP and VAI are more strongly associated with adverse kidney outcomes than BMI and WC.

METHODS

Using data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, we used multivariable logistic regression to evaluate associations of LAP, VAI, BMI and WC with incident chronic kidney disease (CKD), (incident eGFR < 60 ml/min/1.73m2 and > 25% decline).

RESULTS

Among the overall cohort of 27,550 participants, the mean baseline age was 65 years; 54% were women; and 41% were African American. After a median of 9.4 years (IQR 8.6, 9.9) of follow-up, a total of 1127 cases of incident CKD were observed. Each two-fold higher value of VAI (OR 1.12, 95% CI 1.04, 1.20), LAP (OR 1.21, 95% CI 1.13, 1.29), WC (OR 2.10, 95% CI 1.60, 2.76) and BMI (OR: 2.66, 95% CI 1.88, 3.77), was associated with greater odds of incident CKD.

CONCLUSIONS

LAP and VAI as measures of visceral adiposity are associated with higher odds of incident CKD but may not provide information beyond WC and BMI.

Use of the Visceral Adiposity Index as an Indicator of Chronic Kidney Disease in Older Adults: Comparison with Body Mass Index

The visceral adiposity index (VAI) was recently introduced to quantify visceral fat accumulation and dysfunction. This cross-sectional study explored whether the VAI is associated with chronic kidney disease (CKD) in older adults and compared its utility with that of body mass index (BMI) for predicting CKD. In total, 7736 older adults (3479 men and 4257 women) aged ≥ 60 years were divided into normal, mild, and moderate-to-severe CKD groups. Associations of the VAI and BMI with CKD were compared among the groups, and cut-off points for moderate-to-severe CKD (MSCKD) were established. While the VAI could discriminate among all of the groups, the BMI could not. The severity of CKD was more strongly associated with the VAI than BMI. The odds ratios indicated that, in the fully adjusted model, the VAI was a significant predictor of MSCKD in both men and women, while the BMI was a significant predictor only in men. For the VAI, the area under the receiver operating characteristic curve values for men and women were 0.631 (cut-off point: ≥2.993) and 0.588 (≥4.001), compared with 0.555 (≥25.335) and 0.533 (≥24.096) for BMI, respectively. Taken together, the findings suggest that the VAI is associated with CKD and represents a better indicator for the disease than BMI.

Higher Neutrophil-To-Lymphocyte Ratio Was Associated with Increased Risk of Chronic Kidney Disease in Overweight/Obese but Not Normal-Weight Individuals

Background: Inflammation has been proposed to play potential roles in the development and progression of chronic kidney disease (CKD). We evaluated the relationship of neutrophil-to-lymphocyte ratio (NLR), a systemic inflammation marker, with CKD in normal-weight and overweight/obese adults. Methods: This cross-sectional study included 2846 apparently healthy adults who underwent a health examination between August 2000 and April 2002. Normal-weight was defined as a body mass index (BMI, kg/m2) of 18.5−24, while overweight/obesity was defined as a BMI of ≥24. CKD was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2. Logistic and linear regression analysis was performed to explore the NLR−CKD relationship. Results: Of the 2846 participants (1777 men and 1069 women), there were 348 CKD individuals (12.3%), with 262 (14.7%) men and 86 (8%) women. A total of 1011 men (56.9%) and 408 women (38.2%) were overweight or obese. Compared with the normal-weight participants, CKD prevalence was higher in the overweight/obese women (6.1% vs. 11.3%, p = 0.002), but not in the overweight/obese men (14.5% vs. 14.9%, p = 0.793). CKD percentages in the NLR quartile groups were 9.4%, 11.5%, 15.4%, and 22.7% in men (p < 0.0001) and 6.4%, 7.1%, 10.5%, and 8.2% in women (p = 0.2291). After adjustment for confounders, each increment of one unit of NLR was associated with a higher CKD risk in the overweight/obese men (adjusted odds ratio (OR) = 1.37, 95% confidence interval (CI) = 1.03−1.82, p = 0.03) and women (adjusted OR = 1.77, 95% CI = 1.08−2.90, p = 0.023), whereas NLR was not associated with CKD in normal-weight men or women. Further, in the overweight/obese participants with an eGFR of 50−70 mL/min/1.73 m2, univariable linear regression analysis revealed a significant negative correlation between NLR and eGFR for men (p = 0.004) and women (p = 0.009). Conclusions: It was found that higher NLR was associated with an increased CKD risk in overweight/obese but not in normal-weight men and women in an adult health examination dataset. Our study suggests a role of NLR for CKD prediction in overweight/obese individuals.

Association between Body Mass Index and Renal Outcomes Modified by Chronic Kidney Disease and Anemia: The Obesity Paradox for Renal Outcomes

Obesity-related nephropathy is associated with renal function progression. However, some studies have associated a high body mass index (BMI) with improved renal outcomes—this is referred to as the obesity paradox for renal outcomes, especially in relation to advanced chronic kidney disease (CKD). Central obesity can explain the obesity paradox in all-cause mortality. However, whether obesity or central obesity is associated with renal outcomes (renal replacement therapy or a 50% decline in the estimated glomerular filtration rate) in patients with advanced CKD remains unclear. Our study included 3605 Asian patients with CKD stages 1−5 divided into six groups according to their BMI (between 15 and 35 kg/m2). Through linear regression, BMI was positively associated with hemoglobin and albumin at CKD stages 4 and 5. In the competing risk Cox regression model, a high BMI (27.5−35 kg/m2) was associated with renal outcomes at CKD stages 1−3, but not stages 4 and 5. A high BMI was associated with renal outcomes in patients with hemoglobin ≥11 g/dL, but not <11 g/dL. A high waist-to-hip ratio was not associated with renal outcomes. We conclude that the CKD stage and anemia may explain the obesity paradox in renal outcomes in patients with CKD.

Obesity, Weight Loss, Lifestyle Interventions, and Autosomal Dominant Polycystic Kidney Disease

Obesity remains a growing public health concern in industrialized countries around the world. The prevalence of obesity has also continued to rise in those with chronic kidney disease. Epidemiological data suggests those with overweight and obesity, measured by body mass index, have an increased risk for rapid kidney disease progression. Autosomal dominant polycystic kidney disease causes growth and proliferation of kidney cysts resulting in a reduction in kidney function in the majority of adults. An accumulation of adipose tissue may further exacerbate the metabolic defects that have been associated with ADPKD by affecting various cell signaling pathways. Lifestyle interventions inducing weight loss might help delay disease progression by reducing adipose tissue and systematic inflammation. Further research is needed to determine the mechanistic influence of adipose tissue on disease progression.

Association between metabolic syndrome components and chronic kidney disease among 37,533 old Chinese individuals

Background

Chronic kidney disease (CKD) has become a worldwide health problem among aging populations. However, epidemiological information on Chinese elderly people with CKD is still lacking. This study aimed to investigate the epidemiological features and associated risk factors of CKD in aging population in China.

Methods

In this cross-sectional study, a total of 37,533 individuals aged ≥ 65 years were enrolled in Binhai from January to December 2018. The crude and standardized prevalence of CKD were calculated. Associations of metabolism-related indicators with CKD were examined using univariate and multivariate analyses.

Results

The overall prevalence of CKD was 17.7% (95% confidence interval 17.3–18.1%) in this Chinese elderly population. The prevalence was 17.5% among men (95% CI 17.0–18.1%) and 17.8% among women (95% CI 17.3–18.4%). The mean eGFR was 84.22 (SD ± 12.87) mL/min/1.73 m², with the median value higher for women than for men.

Conclusion

Our study shows a high prevalence of CKD among Chinese elderly population. Aging, pre-HTN, HTN, elevated triglyceride, and FBG were associated with the risk of CKD. More attention should be paid to metabolic diseases to prevent CKD in the elderly.

Early triggers of moderately high-fat diet-induced kidney damage

Most of the obesity murine models inducing renal injury use calorie-enriched foods, where fat represents 60% of the total caloric supply, however, this strategy doubles the standard proportion of fat ingestion in obese patients. Therefore, it is crucial to study the impact of a high-fat intake on kidney physiology that resembles common obesity in humans to understand the trigger mechanisms of the long-term consequences of overweight and obesity. In this study, we analyzed whether chronic feeding with a moderately high fat diet (MHFD) representing 45% of total calories, may induce kidney function and structural injury compared to C57BL/6 mice fed a control diet. After 14 weeks, MHFD induced significant mice obesity. At the functional level, obese mice showed signs of kidney injury characterized by increased albuminuria/creatinine ratio and higher excretion of urinary biomarkers of kidney damage. While, at the structural level, glomerular hypertrophy was observed. Although, we did not detect renal fibrosis, the obese mice exhibited a significant elevation of Tgfb1 mRNA levels. Kidney damage caused by the exposure to MHFD was associated with greater oxidative stress, renal inflammation, higher endoplasmic reticulum (ER)-stress, and disruption of mitochondrial dynamics. In summary, our data demonstrate that obesity induced by a milder fat content diet is enough to establish renal injury, where oxidative stress, inflammation, ER-stress, and mitochondrial damage take relevance, pointing out the importance of opportune interventions to avoid the long-term consequences associated with obesity and metabolic syndrome.

Population Pharmacokinetic Analysis and Dosing Optimization Based on Unbound Daptomycin Concentration and Cystatin C in Nonobese Elderly Patients with Hypoalbuminemia and Chronic Kidney Disease

PURPOSE

This study evaluated the population pharmacokinetics of daptomycin in nonobese elderly patients with hypoalbuminemia and chronic kidney disease (CKD) using the glomerular filtration rate estimated from cystatin C (eGFRcys) and estimated its optimal dose.

METHODS

We performed population pharmacokinetic analysis of the unbound concentrations of daptomycin. The probability of target attainment of 90% for achieving an area under the concentration-time curve of unbound daptomycin at steady state/ minimum inhibitory concentration ratio of ≥66.6 was stochastically simulated.

RESULTS

In the population pharmacokinetic analysis of 25 patients aged ≥65 years, the two-compartment model using eGFRcys and age as covariates of clearance in central compartment of unbound daptomycin were optimal. The unbound fraction rate (fu) was 0.05-0.14. According to the Monte Carlo simulation, the optimal doses for patients with eGFRcys of 20-60 mL/min and aged 65-95 years were calculated as 200-500 mg q24h.

CONCLUSION

These results suggest that establishing the dose using total concentrations may result in under- or overestimation caused by alterations in fu. The optimal dose for nonobese elderly patients with hypoalbuminemia and CKD depends on eGFRcys and age, and a standard dose may be insufficient for some patients.

Investigations of Kidney Dysfunction-Related Gene Variants in Sickle Cell Disease Patients in Cameroon (Sub-Saharan Africa)

Background

Renal dysfunctions are associated with increased morbidity and mortality in sickle cell disease (SCD). Early detection and subsequent management of SCD patients at risk for renal failure and dysfunctions are essential, however, predictors that can identify patients at risk of developing renal dysfunction are not fully understood.

Methods

In this study, we have investigated the association of 31 known kidney dysfunctions-related variants detected in African Americans from multi-ethnic genome wide studies (GWAS) meta-analysis, to kidney-dysfunctions in a group of 413 Cameroonian patients with SCD. Systems level bioinformatics analyses were performed, employing protein-protein interaction networks to further interrogate the putative associations.

Results

Up to 61% of these patients had micro-albuminuria, 2.4% proteinuria, 71% glomerular hyperfiltration, and 5.9% had renal failure. Six variants are significantly associated with the two quantifiable phenotypes of kidney dysfunction (eGFR and crude-albuminuria): A1CF-rs10994860 (P = 0.02020), SYPL2-rs12136063 (P = 0.04208), and APOL1 (G1)-rs73885319 (P = 0.04610) are associated with eGFR; and WNT7A-rs6795744 (P = 0.03730), TMEM60-rs6465825 (P = 0.02340), and APOL1 (G2)-rs71785313 (P = 0.03803) observed to be protective against micro-albuminuria. We identified a protein-protein interaction sub-network containing three of these gene variants: APOL1, SYPL2, and WNT7A, connected to the Nuclear factor NF-kappa-B p105 subunit (NFKB1), revealed to be essential and might indirectly influence extreme phenotypes. Interestingly, clinical variables, including body mass index (BMI), systolic blood pressure, vaso-occlusive crisis (VOC), and haemoglobin (Hb), explain better the kidney phenotypic variations in this SCD population.

Conclusion

This study highlights a strong contribution of haematological indices (Hb level), anthropometric variables (BMI, blood pressure), and clinical events (i.e., vaso-occlusive crisis) to kidney dysfunctions in SCD, rather than known genetic factors. Only 6/31 characterised gene-variants are associated with kidney dysfunction phenotypes in SCD samples from Cameroon. The data reveal and emphasise the urgent need to extend GWAS studies in populations of African ancestries living in Africa, and particularly for kidney dysfunctions in SCD.

Population Estimates of GFR and Risk Factors for CKD in Guatemala

INTRODUCTION

Chronic kidney disease (CKD) is an emerging public health priority in Central America. However, data on the prevalence of CKD in Guatemala, Central America's most populous country, are limited, especially for rural communities.

METHODS

We conducted a population-representative survey of 2 rural agricultural municipalities in Guatemala. We collected anthropometric data, blood pressure, serum and urine creatinine, glycosylated hemoglobin, and urine albumin. Sociodemographic, health, and exposure data were self-reported.

RESULTS

We enrolled 807 individuals (63% of all eligible, 35% male, mean age 39.5 years). An estimated 4.0% (95% confidence interval [CI] 2.4-6.6) had CKD, defined as an estimated glomerular filtration rate (eGFR) less than 60 ml/min per 1.73 m2. Most individuals with an eGFR below 60 ml/min per 1.73 m2 had diabetes or hypertension. In multivariable analysis, the important factors associated with risk for an eGFR less than 60 ml/min per 1.73 m2 included a history of diabetes or hypertension (adjusted odds ratio [aOR] 11.21; 95% CI 3.28-38.24), underweight (body mass index [BMI] <18.5) (aOR 21.09; 95% CI 2.05-217.0), and an interaction between sugar cane agriculture and poverty (aOR 1.10; 95% CI 1.01-1.19).

CONCLUSIONS

In this population-based survey, most observed CKD was associated with diabetes and hypertension. These results emphasize the urgent public health need to address the emerging epidemic of diabetes, hypertension, and CKD in rural Guatemala. In addition, the association between CKD and sugar cane in individuals living in poverty provides some circumstantial evidence for existence of CKD of unknown etiology in the study communities, which requires further investigation.

Association between body mass index and estimated glomerular filtration rate in patients with chronic kidney disease of unknown aetiology in Sri Lanka

Chronic kidney disease of unknown aetiology (CKDu), which is widespread in the North Central Province (NCP) of Sri Lanka, is not associated with commonly known factors such as diabetes, hypertension, and glomerulonephritis. The pathogenicity of CKDu is not well understood, but people with a low body mass index (BMI) and mineral and nutrient deficiencies are more vulnerable to develop CKDu. To understand this situation, the relationship between BMI and the estimated glomerular filtration rate (eGFR) was investigated in people with CKDu in comparison with unaffected age-matched control groups in disease-endemic areas of the NCP. This community-based cross-sectional study was performed in Medirigiriya in the Polonnaruwa district of Sri Lanka, which has one of the highest densities of patients with CKDu. The data for identifying demographic factors and the relationship between CKDu and BMI were investigated by using a validated survey questionnaire. Findings indicated that the group with the highest number of people affected with CKDu (i.e. eGFR of less than 60 mL/min/1.73 m²) had the lowest BMI compared to those with normal eGFR. The majority affected were male farmers. The severity of the disease was inversely associated with BMI values and had a higher prevalence of smoking and alcohol consumption. In addition, those who consume water from household dug wells had significantly lower eGFR (p < 0.0001). A linear regression analysis revealed a significant positive association between lower eGFR and lower BMI (p < 0.001). We hypothesised that the low BMI in those with CKDu may have increased susceptibility to develop CKDu, in the presence of exposure to multiple nephrotoxins and adverse conditions.

The relationship between body mass index and blood pressure in patients undergoing chronic hemodialysis: A reverse epidemiology in Jakarta, Indonesia

In the general population, obesity is positively correlated with hypertension. On the other hand, there was hypothesis of "reverse epidemiology" in the relationship between body mass index (BMI) and blood pressure (BP) of hemodialysis (HD) patients. This study aimed to investigate the "reverse epidemiology" of the relationship between the two variables in Jakarta, Indonesia. Cross-sectional study was conducted at Cipto Mangunkusumo Hospital, Koja District Hospital, and Cengkareng District Hospital in July 2018. Total sampling was performed with a total of 525 HD patients aged >18 years. All data were analyzed from the medical records. Of 525 patients, 27.4% were obese. The post hoc analyses showed that obese patients had significantly lower post-HD systolic BP (P = 0.006) and diastolic BP (P = 0.004) than the normal-weight patients. The Chi-square analyses showed that the overweight group [odds ratio (OR) = 0.53; 95% confidence interval (CI) 0.31-0.87; P = 0.011] and the obese group (OR = 0. 63; 95% CI 0.400.97; P= 0.038) had significant protective effect (OR <1) on the post-HD hypertension. Being obese was a strong predictor for reduced BP (coefficient β = -0.02; P = 0.031). BMI is inversely associated with BP in patients undergoing chronic HD.

Association of kidney function-related dietary pattern, weight status, and cardiovascular risk factors with severity of impaired kidney function in middle-aged and older adults with chronic kidney disease: a cross-sectional population study

Background

Chronic Kidney Disease (CKD), characterized by impaired kidney function, affects over 1.5 million individuals in Taiwan. Cardiovascular disease (CVD) is commonly found in patients with CKD, and the increased prevalence of obesity can have some implications for the risk of both CKD and CVD. Since diet plays an important role in the development of obesity, CVD and CKD, our study was designed to investigate the association of kidney function-related dietary pattern with weight status, cardiovascular risk factors, and the severity of impaired kidney function in middle-aged and older adults in Taiwan.

Methods

A total of 41,128 participants aged 40 to 95 years old with an estimated glomerular filtration rate (eGFR) less than 90 mL/min/1.73 m² and proteinuria were recruited from Mei Jau Health Institute between 2008 and 2010. The kidney function-related dietary pattern was identified using reduced rank regression (RRR) and was known as high consumption of preserved or processed food, meat, organ meats, rice/flour products, and, low consumption of fruit, dark-colored vegetables, bread, and beans. A multivariable logistic regression analysis was used to identify the association of weight status and cardiovascular risk factors with moderately/severely impaired kidney function (eGFR < 60 mL/min/1.73 m²) and the association of dietary pattern with the outcomes aforementioned.

Results

Moderately/severely impaired kidney function participants were heavier and had higher abnormality of cardiovascular risk factors compared with those with mildly impaired kidney function. Weight status (OR = 1.28, 95% CI 1.12–1.45, P <  0.001 for obesity) and cardiovascular risk factors (OR = 1.52, 95% CI 1.31–1.77, P <  0.001 for high total cholesterol/HDL-C ratio and OR = 1.56, 95% CI 1.41–1.72, P <  0.001 for hypercalcemia) were positively associated with increased risk of moderately/severely impaired kidney function. The kidney function-related dietary pattern was correlated with overweight or obese (OR = 2.07, 95% CI 1.89–2.27, P <  0.01) weight status, increased cardiovascular risk by 10–31%, and the risk of moderately/severely impaired kidney function (OR = 1.15, 95% CI 1.02–1.29, P <  0.05).

Conclusions

The RRR-derived kidney function-related dietary pattern, characterized by high intake of processed and animal foods and low intake of plant foods, predicts the risks for developing cardiovascular disease and moderately/severely impaired kidney function among middle-aged and older adults.

Electronic supplementary material

The online version of this article (10.1186/s12937-019-0452-4) contains supplementary material, which is available to authorized users.