Micronutrient Intakes and Incidence of Chronic Kidney Disease in Adults: Tehran Lipid and Glucose Study

Serum vitamin C levels and their correlation with chronic kidney disease in adults: a nationwide study

INTRODUCTION

Inflammation and oxidative stress play significant roles in the development of chronic kidney disease (CKD). Given the recognized antioxidant properties of vitamin C, our study aimed to explore the correlation between CKD and serum vitamin C levels.

METHODS

Data were gathered from the 2017-2018 National Health and Nutrition Examination Survey. Participants below 18 years of age, pregnant individuals, those lacking essential data for CKD diagnosis, or individuals with incomplete serum vitamin C data were excluded. Subgroup and weighted multivariable logistic regression analyses were performed to assess the potential correlation between serum vitamin C and CKD.

RESULTS

Our study comprised 4969 participants, revealing an overall CKD prevalence of 15.0%. The results indicated that individuals with reduced serum vitamin C levels were more likely to be male, possess lower educational attainment, have a diminished poverty-income ratio, engage in heavy drinking, and be current smokers. Additionally, they exhibited a higher prevalence of obesity and diabetes. Significantly, participants in the third quartile group experienced a 37.0%, 47.0%, and 46.6% decrease in the risk of developing albuminuria, low estimated glomerular filtration rate (eGFR), and CKD, respectively. Subgroup analysis demonstrated that individuals between 65 and 80 years of age showed a statistically reduced risk of developing CKD and low eGFR when their serum vitamin C levels fell in the third and fourth quartile groups.

CONCLUSIONS

Our findings reveal a correlation between elevated serum vitamin C levels and a decreased risk of developing albuminuria, low eGFR, and CKD. Appropriately increasing serum vitamin C levels may hold promise in protecting renal function, particularly among older individuals.

Adherence to a Healthful Plant-Based Diet and Risk of Chronic Kidney Disease Among Individuals with Diabetes

OBJECTIVE

Chronic kidney disease (CKD) is highly prevalent among people with diabetes. While identifying modifiable risk factors to prevent a decline in kidney function among those living with diabetes is pivotal, there is limited evidence on dietary risk factors for CKD. In this study, we examined the associations between healthy and less healthy plant-based diets (PBDs) and the risk of CKD among those with diabetes, and to identify potential underlying mechanisms.

METHODS

We conducted a prospective analysis among 7,747 UK Biobank participants with prevalent diabetes. Multivariable Cox proportional hazard regression models were used to examine the associations between healthful and unhealthful PBDs and the risk of CKD. Causal mediation analyses were further employed to explore the underlying mechanisms of the observed associations.

RESULTS

Among 7,747 study participants with diabetes, 1,030 developed incident CKD over 10.2 years of follow-up. Higher adherence to a healthy PBD was associated with a 24% lower CKD risk (HRQ4 versus Q1: 0.76 [95%CI: 0.63-0.92], ptrend = 0.002), while higher adherence to an unhealthy PBD was associated with a 35% higher risk (HRQ4 versus Q1: 1.35 [95%CI: 1.11-1.65], ptrend = 0.006). The observed associations were predominantly mediated by markers of body fatness (proportion mediated: 11-25%) and kidney function (23-89%).

CONCLUSIONS

In this prospective cohort study of middle-aged adults with diabetes, adherence to a healthy PBD was associated with lower CKD risk, whereas adherence to an unhealthy PBD was associated with a higher CKD risk. Associations were primarily mediated by markers of lower body fatness and improved kidney function.

Association of dietary manganese intake with new-onset chronic kidney disease in participants with diabetes

BACKGROUND

We explored the association of dietary manganese (Mn) with new-onset chronic kidney disease (CKD) in participants with diabetes on different glycemia control status and potential mechanisms.

METHODS

The study included 7248 adults with diabetes from the UK Biobank who had complete dietary data and were free of CKD at baseline. Dietary information was collected by the online 24-h diet recall questionnaires. The primary outcome was new-onset CKD.

RESULTS

565 (7.8 %) participants developed new-onset CKD during a median follow-up of 11.96 years. Overall, there was a significantly inverse relationship of dietary Mn intake with new-onset CKD in individuals with diabetes at glycated hemoglobin (HbA1c) ≥6.5 % (per SD increment, HR [95%CI]: 0.79 [0.68-0.91]), but not in people with diabetes at HbA1c <6.5 % (per SD increment, HR [95%CI]: 1.07 [0.90-1.29]; P for interaction = 0.004). In individuals with diabetes at HbA1c ≥6.5 %, body mass index and waist circumference significantly mediated the association between dietary Mn intake and new-onset CKD, with mediated proportions of 17.5 % and 17.4 %, respectively.

CONCLUSIONS

Higher dietary Mn intake was significantly associated with a lower new-onset CKD risk in participants with diabetes at poor glycemic control status. The inverse association was mainly mediated by obesity. If further confirmed, our findings underscore the importance of maintaining adequate dietary Mn intake for the primary prevention of new-onset CKD in patients with diabetes, especially those with poor glycemic control.

Association of dietary antioxidant indices with kidney function indicators in patients with type 2 diabetes: a cross-sectional study

This cross-sectional study investigated the relationship between dietary antioxidant indices and kidney function indicators in 240 outpatient adults with type 2 diabetes. Dietary intake was assessed using three 24-h dietary recalls. Dietary total antioxidant capacity (DTAC), dietary antioxidant index (DAI), and dietary antioxidant quality score (DAQS) were obtained. Indicators of kidney function, including serum creatinine, urea, blood urea nitrogen (BUN), and glomerular filtration rate (GFR), were extracted from medical records. After adjustment, the highest DAI tertile had lower serum creatinine (0.98 ± 0.27 vs 1.03 ± 0.32 mg/dL, P < 0.001), reduced urea (30.97 ± 8.75 vs 34.07 ± 14.45 mg/dL, P = 0.005), and higher GFR (85.16 ± 29.43 vs 74.16 ± 22.18 ml/min per 1·73 m2, P < 0.001) compared to the lowest tertile. The results of logistic regression analysis indicated a borderline significant inverse association of serum urea > 20 mg/dl with DTAC (odds ratio (OR):0.28; 95% CI: 0.07-1.09; Ptrend = 0.06). Multivariable linear regression analysis revealed a significant aligned correlation between DAQs and GFR (β: 0.20; P-value: 0.005) and a marginally significant direct relationship between DAI and GFR (β: 0.14; P-value: 0.06). However, no significant association was observed for DTAC with GFR (β:-0.02; P-value: 0.80). Diets with higher antioxidant capacity may be linked to improved kidney function in type 2 diabetes but our results did not support this strongly.

Association between dietary magnesium intake and incident chronic kidney disease: a prospective observational cohort study

BACKGROUND

Although serum magnesium deficiency is linked to higher cardiovascular disease risk, its association with chronic kidney disease (CKD) remains unclear.

OBJECTIVES

This study aimed to evaluate the relationship between dietary magnesium intake and CKD development in adults with clinically normal kidney function.

METHODS

The prospective observational cohort study evaluated 188,510 participants (median age, 57.0 y; female, 54.1%) from the UK Biobank. Dietary magnesium intake was assessed through a 24-h dietary recall questionnaire compromising a list of 206 foods and 32 beverages and categorized into quintiles. The primary outcome was incident CKD diagnosed through International Classification of Diseases-10 and Office of Population Censuses and Surveys 4 codes. Incident CKD, defined as estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2, was also assessed in a subcohort with creatinine follow-up data.

RESULTS

The median magnesium intake amount per person was 323.2 mg/d [interquartile range (IQR): 269.4-382.7 mg/d]. During 1,826,038.1 person-years of follow-up (median: 9.6 y; IQR: 9.3-10.3 y), CKD developed in 5,878 participants. The incidence of CKD was progressively higher in participants with lower magnesium intake (2.8%, 2.8%, 3.0%, 3.2%, and 3.7% in Q5-Q1, respectively). Cox regression analysis revealed that the hazard ratios (HRs) for incident CKD increased in a stepwise manner toward lower magnesium intake quintiles {adjusted HR (95% confidence interval [CI])-Q4: 0.97 (0.89, 1.06); Q3: 1.05 (0.96, 1.14); Q2: 1.12 (1.03, 1.21); Q1: 1.30 (1.20, 1.41)} relative to Q5 (P-linearity < 0.001). Similar results were observed with eGFR-defined CKD outcome [adjusted HR (95% CI)-Q4: 1.09 (0.92, 1.28); Q3: 1.15 (0.98, 1.35); Q2: 1.21 (1.03, 1.42); Q1: 1.41 (1.20, 1.65) relative to Q5; P-linearity < 0.001].

CONCLUSIONS

Lower dietary magnesium intake was associated with higher risk of incident CKD in adults with clinically normal kidney function. Further controlled studies are required to establish the potential benefit of adequate magnesium intake.

Causal relationships between vitamin E and multiple kidney diseases: evidence from trans-ethnic Mendelian randomization study

PURPOSE

The association between vitamin E and the risk of kidney disease is well documented in observational studies, but the role of vitamin E in kidney disease remain inconclusive. Here, we evaluated the causal effect of vitamin E on the risk of multiple kidney diseases, including chronic kidney disease, membranous nephropathy, diabetic nephropathy, IgA nephropathy, and dialysis.

METHODS

We conducted a two-sample Mendelian randomization analysis from large-scale trans-ancestry genome-wide association studies to determine whether there was a significant causal relationship between vitamin E and multiple kidney diseases in European, American, and Asian ancestry. Instrumental genetic variants associated with vitamin E were selected, and summary statistic-based methods of inverse variance weighted, MR Egger, weighted median, simple mode, and weighted mode methods were conducted. Pleiotropy and sensitivity were assessed.

RESULTS

We obtained 87 instrumental genetic variants in European ancestry and found no causal relationship between vitamin E and chronic kidney disease, membranous nephropathy, diabetic nephropathy, IgA nephropathy, and dialysis with no heterogeneity and pleiotropy. We obtained 18 instrumental genetic variants in Asian ancestry and vitamin E had no causal relationship with membranous nephropathy, diabetic nephropathy, and IgA nephropathy with no heterogeneity and pleiotropy. In African ancestry, 25 instrumental genetic variants were obtained and no causal relationship was identified with no heterogeneity and pleiotropy.

CONCLUSION

Our study first suggested plausible non-causal associations between vitamin E and multiple kidney diseases among different ancestry.

Association between dietary diversity and chronic kidney disease in community-dwelling older adults

OBJECTIVE

The present study examined whether dietary diversity is associated with chronic kidney disease (CKD) in community-dwelling older Japanese adults.

METHODS

Participants comprised 8,195 older adults (mean age was 74.0 ± 5.6 years; 42.7% were men) in this cross-sectional study. In this study, CKD was defined as estimated Glomerular Filtration Rate (eGFR) < 45 mL/min/1.73 m2. Diet variety was assessed using the Food Frequency Score (FFS) (maximum, 30 points). The FFS assessed the one-week consumption frequency of ten foods (meat, fish/shellfish, eggs, milk, soybean products, green & yellow vegetables, potatoes, fruits, seafood, and fats & oil). Participants with an FFS of 16 or fewer points were defined as having low dietary diversity.

RESULTS

The prevalence of CKD was 376 (4.6%), and the low dietary diversity group had higher prevalence (5.6%) compared with the high and low dietary diversity group (4.3%). Multiple logistic regression analysis revealed low dietary diversity was associated with CKD in older adults (OR 1.30, 95%CI 1.01-1.68). Stratified analysis showed that low dietary diversity was independently associated with CKD (OR 1.43, 95% CI 1.07-1.91) in older adults with hypertension, but not in adults without hypertension (OR 0.94, 95% CI 0.54-1.64).

CONCLUSIONS AND IMPLICATIONS

This cross-sectional study revealed that low dietary diversity was associated with CKD among older adults. Furthermore, low dietary diversity was associated with CKD among older adults with hypertension.

Association Between Plant-based Diet and Kidney Function in Adults

OBJECTIVE

A plant-based diet has both antioxidant and anti-inflammatory properties. Therefore, it is hypothesized that adherence to a plant-based diet may have a positive effect on kidney function. The study aimed to determine the association between the plant-based diet index (PDI) and chronic kidney disease (CKD).

METHODS

This cross-sectional analysis used information from the Ravansar noncommunicable diseases cohort study, which included 9,746 participants between the ages of 35 and 65. By measuring the estimation glomerular filtration rate (eGFR) with the modification of diet in the renal disease equation, CKD was determined. Using a food frequency questionnaire, the PDI was computed based on food intake. To determine odds ratios (ORs), multivariable logistic regression models were utilized.

RESULTS

1,058 (10.86%) participants had CKD (eGFR<60 mL/min/1.73 m2), and the mean PDI was 54.22 ± 6.68. The mean eGFR in the group with a high PDI score was significantly higher than the group with a low PDI score (fourth quartile: 79.20 ± 0.36 vs. first quartile: 72.95 ± 0.31, P < .001). Adherence to a plant-based diet was more prevalent in those with a higher socioeconomic status (P < .001). After adjusting for potential confounders, the odds of CKD in the third and fourth quartiles of PDI were 25% (OR: 0.75; 95% confidence interval: 0.62-0.91) and 39% (OR: 0.61; 95% confidence interval: 0.48-0.78, P trend<.001) lower than the first quartile, respectively.

CONCLUSIONS

The findings of this study suggest that having a plant-based diet may prevent the prevalent CDK. However, further studies with a cohort design are recommended.

Association of ideal cardiovascular health metrics with incident low estimated glomerular filtration rate: More than a decade follow-up in the Tehran Lipid and Glucose Study (TLGS)

AIMS

To evaluate the association between ideal cardiovascular health metrics (ICVHM) and incident low estimated glomerular filtration rate (eGFR) among the Iranian population.

METHODS

The study population included 6927 Iranian adults aged 20-65 years (2942 male) without prevalent low eGFR [i.e., eGFR < 60 ml/min/1.73 m2] and free of cardiovascular disease. The ICVHM was defined according to the 2010 American Heart Association. The multivariable Cox proportional hazards regression analysis was used to calculate the hazard ratios (HRs) of ICVHM both as continuous and categorical variables.

RESULTS

Over the median of 12.1 years of follow-up, we found 1259 incident cases of low eGFR among the study population. In this population, ideal and intermediate categories of body mass index (BMI) and blood pressure (BP) and only the ideal category of fasting plasma glucose (FPG) significantly decreased the risk of developing low eGFR; the corresponding HRs and (95% confidence intervals) were (0.87, 0.77-0.99), (0.84, 0.76-0.99), (0.79, 0.68-0.93), (0.70, 0.60-0.83) and (0.76, 0.64-0.91). Also, one additional ICVHM was associated with a reduced risk of low eGFR for the global (0.92, 0.88-0.97) and biological cardiovascular health (0.88, 0.82-0.93) in these participants. A sensitivity analysis using the interval-censoring approach demonstrated that our method is robust, and results remained essentially unchanged. In a subgroup population with dietary data (n = 2285), we did not find the beneficial impact of having intermediate/ideal categories of nutrition status compared to its poor one on incident low eGFR.

CONCLUSION

We found a strong inverse association between having higher global ICVHM with incident low eGFR among the non-elderly Iranian population; the issue is mainly attributable to normal BP, BMI, and FPG levels.

Relationship of dietary intake of food folate and synthetic folic acid intake from fortified foods with all-cause mortality in individuals with chronic kidney disease

OBJECTIVE

To evaluate the association of the dietary intake of food folate (natural folate) and synthetic folic acid intake from fortified foods with the risk of all-cause mortality and end-stage kidney disease (ESKD) among the chronic kidney disease (CKD) population in regions with folic acid fortification.

METHODS

4028 individuals with established CKD in Chronic Renal Insufficiency Cohort (CRIC) were included. Diet was assessed using a validated diet history questionnaire at the baseline, year 2, and year 4, and nutrient intake, including food folate and folic acid from fortified foods, was estimated using the National Nutrient Database. The outcomes were all-cause mortality and ESKD. The results for all-cause mortality were further validated using the data from National Health and Nutrition Examination Surveys (NHANES).

RESULTS

During a median follow-up of 11.1 years, 1155 deaths and 938 ESKD cases occurred. Compared with the first quartile of food folate intake, the third (HR: 0.74; 95% CI: 0.62, 0.90) and fourth (HR: 0.79; 95% CI: 0.63, 0.98) quartiles had a lower risk of all-cause mortality. Nevertheless, there was no significant association of synthetic folic acid intake from fortified foods with all-cause mortality. Similar results were observed for ESKD. Consistently, in NHANES, food folate intake and serum 5-methyltetrahydrofolate, but not folic acid intake, were inversely associated with all-cause mortality, while serum unmetabolized folic acid was positively associated with all-cause mortality in CKD participants.

CONCLUSIONS

Higher intake of dietary natural folate, but not synthetic folic acid intake from fortified foods, was associated with lower risks of all-cause mortality and ESKD among CKD participants.

Association between dietary vitamin E intake and chronic kidney disease events in US adults: a cross-sectional study from NHANES 2009-2016

Background

The relationship between vitamin E supplementation and the prevalence of chronic kidney disease (CKD) is unclear. We discussed the relationship between vitamin E intake and CKD prevalence and further investigated the effect on different CKD risk strata.

Methods

We ultimately included 20 295 participants from the National Health and Nutrition Examination Survey (NHANES) database from 2009 to 2016. Multiple logistic regression and restricted cubic splines (RCS) were applied to explore the relationship between vitamin E intake and CKD prevalence and risk stratification. Subgroup analysis was applied to assess the stability of the association between vitamin E intake and CKD.

Results

In the CKD prevalence study, we found a negative association between high vitamin E intake and CKD prevalence through an adjusted multiple logistic regression model, the odds ratio (OR) was 0.86 [95% confidence interval (CI) 0.74-1.00; P for trend = .041] and RCS showed a nonlinear negative correlation (P-nonlinear = .0002, <.05). In the CKD risk stratification study, we found that in very high-risk patients, the OR was 0.51 (95% CI 0.32-0.84; P for trend = .006) and the RCS also showed a nonlinear negative correlation (P-nonlinear <.0001, <.05). Subgroup analysis demonstrated that the correlations were stable across populations (P-values >.01 for all interactions).

Conclusion

Dietary vitamin E intake was negatively associated with the prevalence of CKD in US adults. Increased vitamin E intake was a protective factor across CKD risk strata, and as vitamin E intake increased, there was a non-linear downward trend in the proportion progressing to very high-risk CKD.

Association between serum vitamin C and chronic kidney disease among adults in NHANES, 2017-2018

OBJECTIVE

The current study evaluated the relationship between serum vitamin C and chronic kidney disease.

METHODS

The database from the National Health and Nutrition Examination Survey (NHANES, 2017-2018) was used to perform a cross-sectional study. Multivariate logistic regression was performed to analyze the relationship between serum vitamin C and chronic kidney disease (CKD), and stratified analysis by sex was performed to assess whether there were sex differences in the association between serum vitamin C and CKD.

RESULTS

Before stratified analysis, multivariate logistic regression showed that serum vitamin C was negatively associated with CKD in all models (All OR > 1, P< 0.05), the risk of CKD decreased by one quantile increase in serum vitamin C (P for trend< 0.001) and low vitamin C status was associated with a higher risk of CKD (All OR > 1, P< 0.05). Stratified analyses by sex showed that the association between serum vitamin C and CKD remained negative in men, but not in women.

CONCLUSION

There were a negative correlation between serum vitamin C and CKD, low levels of vitamin C were associated with a higher risk of CKD, and these associations were only found in men, but not in women.

The association between dietary micronutrient patterns and odds of diabetic nephropathy: A case-control study

Uncontrolled diabetes can lead to diabetic nephropathy (DN). The aim of the study was to investigate the relationship between different dietary micronutrient patterns and risk of DN in women. This was a case-control study. One hundred and five patients had DN (defined as urinary mg of albumin per gram of creatinine ≥30 mg/g) were chosen as the case and 105 women without DN were chosen as control. Dietary intakes were assessed by a semi-quantitative food frequency questionnaire. Principal component analysis with varimax rotation was used to derive the micronutrient patterns. Patterns were divided into two groups of lower and higher than median. Logistic regression was used to discern and find the odds ratio (ORs) of DN, and its 95% confidence interval (CI) based on the micronutrient patterns in crude and adjusted model. Three patterns which were included, (1) mineral patterns such as chromium, manganese, biotin, vitamin B6, phosphorus, magnesium, selenium, copper, zinc, potassium, and iron, (2) water-soluble vitamin patterns such as vitamin B5, B2, folate, B1, B3, B12, sodium and C, and (3) fat-soluble vitamin patterns such as calcium, vitamin K, beta carotene, alpha tocopherol, alpha carotene, vitamin E, and vitamin A, were extracted. An inverse relationship was found between risk of DN and following mineral patterns and fat-soluble vitamin patterns in adjusted model (ORs = 0.51 [95% CI 0.28-0.95], p = .03) and (ORs = 0.53 [95% CI 0.29-0.98], p = .04), respectively. No relationship was seen between water-soluble vitamin patterns and risk of DN in crude and adjusted model but the significance was decreased in adjusted model. The risk of DN was 47% decreased after high adherence of fat-soluble vitamin patterns. In addition, we saw a 49% decrease of risk of DN in high adherence group of mineral patterns. The findings confirm that renal-protective dietary patterns can reduce risk of DN.

Relationships of beans intake with chronic kidney disease in rural adults: A large-scale cross-sectional study

Background and aims

Dietary factors play an important role in the development of chronic kidney disease (CKD). However, evidence on the relationship of beans consumption with CKD remains limited and inconclusive, especially in the middle-and low-income populations. The current study aimed to investigate the relationships of beans intake with indicators of kidney injury and CKD prevalence in rural adults.

Methods

A total of 20,733 rural adults from the Henan Rural Cohort Study in 2018–2022 were included. The total beans intake was collected using a validated food frequency questionnaire. Indicators of kidney injury and CKD was determined by the estimated glomerular filtration rate and the urinary albumin to creatinine ratio. Generalized linear regression and logistic regression models were applied to estimate the relationship of beans intake with continuous and dichotomized indicators of renal function, respectively.

Results

Of the 20,733 participants, 2,676 (12.91%) subjects were identified as CKD patients. After adjusting for potential confounders, participants in the higher quartiles of beans intake had a lower prevalence of CKD (odds ratio and 95% confidence interval, OR (95%CI); Q2: 0.968(0.866–1.082); Q3: 0.836(0.744–0.939); Q4: 0.854(0.751–0.970)) and albuminuria (Q2: 0.982(0.875–1.102); Q3: 0.846(0.750–0.954); Q4: 0.852 (0.746–0.973)), compared with the Q1. Per 50 g/day increment in beans intake was significantly associated with a 5 and 4% decreased prevalence of albuminuria and CKD, respectively. These inverse relationships were also significant in the subgroups of men, elder, and high-income participants (p &lt; 0.05).

Conclusion

Dietary beans intake was inversely associated with the prevalence of albuminuria and CKD in rural adults, suggesting that promoting soy food intake might help reduce the occurrence of CKD in rural adults.

Magnesium in Kidney Function and Disease-Implications for Aging and Sex-A Narrative Review

Magnesium (Mg) has a vital role in the human body, and the kidney is a key organ in the metabolism and excretion of this cation. The objective of this work is to compile the available evidence regarding the role that Mg plays in health and disease, with a special focus on the elderly population with chronic kidney disease (CKD) and the eventual sex differences. A narrative review was carried out by executing an exhaustive search in the PubMed, Scopus, and Cochrane databases. Ten studies were found in which the role of Mg and sex was evaluated in elderly patients with CKD in the last 10 years (2012-2022). The progression of CKD leads to alterations in mineral metabolism, which worsen as the disease progresses. Mg can be used as a coadjuvant in the treatment of CKD patients to improve glomerular filtration, but its use in clinical applications needs to be further characterized. In conclusion, there's a need for well-designed prospective clinical trials to advise and standardize Mg supplementation in daily clinical practice, taking age and sex into consideration.

Beneficial and adverse effects of vitamin E on the kidney

This article reviews the beneficial and adverse effects of high-dose vitamin E supplementation on the vitamin E status and renal function in human and rodent studies. The high doses of vitamin E, which can cause renal effects, were compared to upper limits of toxicity (UL) as established by various authorities worldwide. In recent mice studies with higher doses of vitamin E, several biomarkers of tissue toxicity and inflammation were found to be significantly elevated. In these biomarker studies, the severity of inflammation and the increased levels of the biomarkers are discussed together with the need to re-evaluate ULs, given the toxic effects of vitamin E on the kidney and emphasizing oxidative stress and inflammation. The controversy in the literature about vitamin E effects on the kidney is mainly caused by the dose-effects relations that do not give a clear view, neither in human nor animals studies. In addition, more recent studies on rodents with new biomarkers of oxidative stress and inflammation give new insights into possible mechanisms. In this review, the controversy is shown and an advice given on the vitamin E supplementation for renal health.

Inverse Association Between Baseline Plasma Selenium Concentrations and Risks of Renal Function Decline in Hypertensive Adults

BACKGROUND

The kidney has the highest level of selenium (Se) in the body, but the role of plasma Se in chronic kidney disease is uncertain.

OBJECTIVE

We aimed to investigate the longitudinal association between baseline plasma Se and renal function decline in adults with hypertension and to explore possible effect modifiers.

METHODS

This was a post hoc analysis of 935 men and women with hypertension aged 40 to 75 years from a folic-acid intervention trial (the China Stroke Primary Prevention Trial) in China. The baseline plasma Se was analyzed both as a continuous variable and as tertiles. The primary outcome was a rapid decline in renal function, defined as a mean decline in the estimated glomerular filtration rate of ≥ 5 mL/(min × 1.73 m2) per year.

RESULTS

The median follow-up duration from baseline to outcome was 4.4 years. After multivariate adjustment, there was an inverse association between plasma Se and a rapid decline in renal function (per 10-unit increment; OR: 0.85; 95% CI: 0.73, 0.99). When the baseline plasma Se was assessed as tertiles, compared to the lowest tertile (<74.5 μg/L), a lower trend of the primary outcome was found in the second tertile (74.5 to < 89.4 μg/L; OR: 0.60; 95% CI: 0.34, 1.07) and the highest tertile (89.4 to <150 μg/L; OR: 0.42; 95% CI: 0.22, 0.80; Ptrend = 0.006). Furthermore, the Se-renal association was more pronounced among participants with folic acid treatment or with a higher baseline folate concentration (both Pinteraction values < 0.05).

CONCLUSIONS

In this sample of Chinese adults with hypertension, baseline plasma Se concentrations were inversely associated with the risk of renal function decline. The China Stroke Primary Prevention Trial was registered at clinicaltrials.gov as NCT00794885.

Dietary vitamin E and tocopherol isoforms and incident chronic kidney disease: A 30-y follow-up study from young adulthood to midlife

BACKGROUND

The relationship of dietary vitamin E intake with incident chronic kidney disease (CKD) was not clear as yet. We aimed to examine the associations of dietary total vitamin E and tocopherol isoforms intakes with incident CKD in a 30-year follow-up study from young adulthood to midlife.

METHODS

A total of 4038 American adults aged 18-30 years and without reduced estimated glomerular filtration rate (eGFR) were enrolled from Coronary Artery Risk Development in Young Adults study. Diet was evaluated by a validated dietary-history questionnaire at baseline, and after 7 and 20 years later. The study outcome was incident CKD, defined as an eGFR<60 mL/min/1.73 m² or a urinary albumin to creatinine ratio ≥30 mg/g.

RESULTS

During a 30-year follow-up, 642 (15.9%) participants developed incident CKD. Overall, there was a L-shaped relationship between dietary total vitamin E intake and incident CKD (P for non-linearity<0.001). When total vitamin E intake was assessed as quartiles, compared with those in the first quartile (<4.35 mg α-TE/1000 kcal), the adjusted HRs (95%CI) of incident CKD for participants in the fourth quartile (≥9.61 mg α-TE/1000 kcal) was 0.55 (0.40, 0.75). Moreover, higher intakes of beta-tocopherol and gamma-tocopherol were significantly associated with a lower incident CKD. Higher intake of delta-tocopherol was significantly related to a higher incident CKD. And there was no obvious association of alpha-tocopherol intake with incident CKD.

CONCLUSIONS

There were inverse associations of total vitamin E, beta-tocopherol and gamma-tocopherol intakes, a positive association of delta-tocopherol intake, and no obvious association of alpha-tocopherol intake, with incident CKD among American adults.

Folate intake and incident chronic kidney disease: a 30-year follow-up study from young adulthood to midlife

BACKGROUND

The relation of long-term dietary folate intake with incident chronic kidney disease (CKD) remains uncertain.

OBJECTIVES

We aimed to investigate the association between dietary folate intake and incident CKD in a 30-y follow-up study from young adulthood to midlife.

METHODS

A total of 4038 American adults aged 18-30 y and without reduced estimated glomerular filtration rate (eGFR) were enrolled in 1985-1986 and monitored until 2015-2016 in the CARDIA (Coronary Artery Risk Development in Young Adults) study. Diet was assessed by a validated dietary history questionnaire at baseline, in 1992-1993, and in 2005-2006. The primary outcome was incident CKD, defined as an eGFR <60 mL · min-1 · 1.73 m-2 or a urinary albumin to creatinine ratio (ACR) ≥30 mg/g. The secondary outcomes included 1) incident decreased eGFR, defined as an eGFR <60 mL · min-1 · 1.73 m-2, and 2) incident albuminuria, defined as an ACR ≥30 mg/g.

RESULTS

During the follow-up, 642 (15.9%) participants developed CKD. Overall, there was a significant L-shaped relation of dietary folate with incident CKD after adjustment for potential confounders. Compared with the lowest quintile of total folate intake, the multivariable-adjusted HRs (95% CIs) in quintiles 2-5 for incident CKD were 0.69 (0.56, 0.85), 0.35 (0.27, 0.45), 0.34 (0.26, 0.45), and 0.39 (0.30, 0.51), respectively. Similar results were found for the secondary outcomes. Moreover, the L-shaped association was confirmed in a subset of the cohort (n = 1462) with serum folate measured at baseline, in 1992, and in 2000.

CONCLUSIONS

Higher folate intake in young adulthood was longitudinally associated with a lower incidence of CKD later in life. Additional studies are warranted to establish the causal inference.

Prospective associations between a priori dietary patterns adherence and kidney function in an elderly Mediterranean population at high cardiovascular risk

Purpose

To assess the association between three different a priori dietary patterns adherence (17-item energy reduced-Mediterranean Diet (MedDiet), Trichopoulou-MedDiet and Dietary Approach to Stop Hypertension (DASH)), as well as the Protein Diet Score and kidney function decline after one year of follow-up in elderly individuals with overweight/obesity and metabolic syndrome (MetS).

Methods

We prospectively analyzed 5675 participants (55–75 years) from the PREDIMED-Plus study. At baseline and at one year, we evaluated the creatinine-based estimated glomerular filtration rate (eGFR) and food-frequency questionnaires-derived dietary scores. Associations between four categories (decrease/maintenance and tertiles of increase) of each dietary pattern and changes in eGFR (ml/min/1.73m²) or ≥ 10% eGFR decline were assessed by fitting multivariable linear or logistic regression models, as appropriate.

Results

Participants in the highest tertile of increase in 17-item erMedDiet Score showed higher upward changes in eGFR (β: 1.87 ml/min/1.73m²; 95% CI: 1.00–2.73) and had lower odds of ≥ 10% eGFR decline (OR: 0.62; 95% CI: 0.47–0.82) compared to individuals in the decrease/maintenance category, while Trichopoulou-MedDiet and DASH Scores were not associated with any renal outcomes. Those in the highest tertile of increase in Protein Diet Score had greater downward changes in eGFR (β: − 0.87 ml/min/1.73m²; 95% CI: − 1.73 to − 0.01) and 32% higher odds of eGFR decline (OR: 1.32; 95% CI: 1.00–1.75).

Conclusions

Among elderly individuals with overweight/obesity and MetS, only higher upward change in the 17-item erMedDiet score adherence was associated with better kidney function after one year. However, increasing Protein Diet Score appeared to have an adverse impact on kidney health. Trial Registration Number: ISRCTN89898870 (Data of registration: 2014).

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02838-7.

Associations between dietary patterns and stages of chronic kidney disease

BACKGROUND

Studies have revealed that patients with chronic kidney disease (CKD) have dietary patterns different from those of the general population. However, no studies have compared the dietary patterns of between patients with early-stages (stages 1-3a) and late-stages (stages 3b-5) of CKD. Our objective was to investigate the associations between dietary patterns in early and late-stage CKD.

METHODS

We analyzed 4480 participants with CKD at various stages based on the data recorded between 2007 and 2016 from the database of the American National Health and Nutrition Examination Survey.

RESULTS

In total, 3683 and 797 participants had early and late-stage CKD, respectively. Through principal components analysis, the dietary intake dimension was reduced from 63 variables to 3 dietary patterns. We adopted logistic regression for analysis. The three dietary patterns are as follows: (1) saturated fatty acids and mono-unsaturated fatty acids (MUFA); (2) vitamins and minerals; and (3) cholesterols and polyunsaturated fatty acids (PUFA). These 3 patterns explained > 50% of dietary nutrient intake. Results indicated that among participants with dietary patterns 2 (vitamins and minerals) and 3 (cholesterols and PUFA), those with low intakes were more likely to have late-stage CKD. The odds ratios for patterns 2 and 3 were 1.74 (95% CI: 1.21-2.50) and 1.66 (95% CI: 1.13-2.43), respectively.

CONCLUSIONS

This study revealed that intakes of vitamins and minerals and cholesterols and PUFA were associated with the stages of CKD.

Nutritional and dietary interventions to prolong renal allograft survival after kidney transplantation

PURPOSE OF REVIEW

Diet plays an important role in slowing progression of chronic kidney disease in native and transplanted kidneys. There is limited evidence on the association on dietary intake with renal allograft function. Mechanisms of major nutrients and dietary patterns with focusing on a plant-based diet related to kidney transplant health and longevity are reviewed.

RECENT FINDINGS

High dietary protein intake may adversely affect renal allograft. Low protein plant-focused diets such as Dietary Approaches to Stop Hypertension, plant-dominant low-protein diet and Mediterranean diets appear associated with favorable outcomes in slowing renal allograft function decline. The mechanism may be related to a change in renal hemodynamic by decreasing glomerular hyperfiltration from low dietary protein intake and plant-based ingredients. Recent observational studies of association between dietary protein intake and kidney allograft outcomes are conflicting. Although strong evidence is still lacking, a low protein diet of 0.6-0.8 g/kg/day with at least 50% of the protein source from plant-based components in kidney transplant recipients with stable kidney allograft function should be considered as the dietary target.

SUMMARY

Dietary intervention with low-protein plant-focused meals may improve outcomes in kidney transplant recipients, but the evidence remains limited and further studies are warranted.

High Dietary Diabetes Risk Reduction Score Is Associated with Decreased Risk of Chronic Kidney Disease in Tehranian Adults

AIM

In the current study, we examined the association of dietary diabetes risk reduction score (DDRRS) with chronic kidney disease (CKD) among an Iranian adult population.

METHODS

We followed up 2076 ≥20-year-old participants of the Tehran Lipid and Glucose Study (2006-2008), who were initially free of CKD for 5.98 years. The dietary diabetes risk reduction score was calculated based on scoring eight components, including cereal fiber, nuts, coffee, polyunsaturated fatty acids-to-saturated fatty acids ratio, glycemic index, sugar-sweetened beverages, trans fatty acids, and red and processed meat using a valid and reliable 168-item food frequency questionnaire. CKD was defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m². A Cox proportional hazard regression model was used to assess the association between the quartiles of DDRRS and CKD incidence.

RESULTS

Mean ± SD age of the study population (53% women) was 37.6 ± 12.61 years. During 5.98 years of follow-up, 357 incident cases of CKD were reported. The median (25-75 interquartile range) of DDRRS was 20 (18-22). After adjustment for age, sex, smoking status, total energy intake, body mass index, hypertension, diabetes, eGFR, and physical activity, individuals in the highest versus lowest quartile of DDRRS were 33% less likely to have CKD (HR: 0.67; 95% CI: 0.48-0.96, P for trend: 0.043).

CONCLUSION

The present study's findings suggest that greater adherence to a dietary pattern with a higher score of DDRRS may be associated with a lower risk of CKD incident.

Relationship between carbohydrate-to-fat intake ratio and the development of chronic kidney disease: A community-based prospective cohort study

BACKGROUND & AIMS

It is well-known that high protein intake is associated with renal hyperfiltration and faster renal function decline, but the association of other macronutrients, carbohydrate and fat, with development of chronic kidney disease (CKD) is still inconclusive. Therefore, we aimed to examine the relationship between fat-to-carbohydrate intake ratio (F/C ratio) and incident CKD.

METHODS

We included 9226 subjects from the Korean Genome and Epidemiology Study. The subjects were divided into two groups depending on 1 g protein intake per ideal body weight per day. Primary exposure was the F/C ratio defined as calorie intake of fat/calorie intake of fat and carbohydrate. The primary outcome was the development of CKD, which was defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m² and/or proteinuria (≥1+).

RESULTS

During a median follow-up duration of 11.4 years, 778 (8.4%) CKD events occurred. Subjects in the lowest F/C ratio tertile had faster eGFR decline rate than other tertiles. In multivariable Cox analysis, a significantly higher CKD risk was observed in the lowest tertile when protein intake > 1 g/kg/day (hazard ratio [HR] for T1 (<16.1%) vs. T3 (>21.5%), 1.38; 95% confidence interval [CI], 1.03-1.84; P = 0.031). In sensitivity analysis, subjects maintained low F/C ratio diet (<16.1%) during 4 years showed higher risk of subsequent CKD development than those maintained high F/C ratio diet (≥16.1%; HR, 1.70; 95% CI, 1.10-2.63; P = 0.018). In cubic spline analysis, CKD risk was sharply increased in F/C ratio <16.1%, but the risk was nearly constant in F/C ratio ≥16.1%.

CONCLUSIONS

A diet with a low F/C ratio was associated with increased risk of CKD in the general population. Therefore, it is necessary to limit excessive high carbohydrate and low fat intake to prevent CKD development in this population.

Association of Metabolic Syndrome and Chronic Kidney Disease in Moroccan Adult Population

Background: Metabolic syndrome (MetS) is a cluster of cardiovascular risk factors that may promote the development of chronic kidney disease (CKD). The aim of this research was to determine the prevalence of MetS and its components and, to study their association with CKD among Moroccan adult population living in an agricultural province. Materials and Methods: The study involved 210 adult participants of 18 and over years, of both sexes, sampled from urban and rural areas of Sidi Bennour province in Morocco. Systolic and diastolic blood pressure, weight, height, and waist circumference were measured and body mass index (BMI) was calculated. Blood total cholesterol, triglycerides, glucose, and serum creatinine were determined. Subsequent glomerular filtration rate (GFR) was estimated by the modification of diet in renal disease formula and the CKD was defined by an estimated GFR (eGFR) <60 mL/min/1.73 m². The diagnosis of MetS was based on the National Cholesterol Education Program/Adult Treatment Panel (NCEP ATP III) report. Results: The mean age of the participants was 54.18 ± 13.45 years, the prevalence of MetS and CKD were 38% and 4.4%, respectively. Abdominal obesity was the strongest risk factor of MetS among the studied population (71%), followed by increased fasting plasma glucose (40.5%), high blood pressure (35.2%), hypercholesterolemia (31.0%), and hypertriglyceridemia (23.8%). The prevalence of these comorbid factors increased with age (P = 0.000), BMI (P = 0.000), and decreased with education level (P = 0.012). The presence of MetS was significantly associated with decreased eGFR (P = 0.022), hence the prevalence of CKD was markedly greater in subjects with MetS than those without. Conclusions: Our finding indicates that MetS is a serious public health problem in the study population and that its individual components are involved in decreasing the eGFR and the progression of renal dysfunction. The study results support the need of the development of a strategy to control and prevent worsening of the MetS individual components and development of CKD.

Kidney Adaptations Prevent Loss of Trace Elements in Wistar Rats with Early Metabolic Syndrome

Metabolic syndrome (MetS) represents a cluster of related metabolic abnormalities, including central obesity, hypertension, dyslipidemia, hyperglycemia, and insulin resistance. These metabolic derangements present significant risk factors for chronic kidney disease that carries to loss of essential micronutrients, which accelerates comorbidity apparition. The work aimed was to evaluate the trace element homeostasis regarding morphological adaptations and renal function in MetS early-onset. Fifty male Wistar rats were divided into two groups: (a) control group and (b) hypercaloric diet group that developed MetS early-onset after 3 months. Classical zoometric parameters do not show changes; however, biochemical modifications were observed such as hyperglycemia, protein glycation, insulin resistance, dyslipidemia, hyperinsulinemia, and hypoadiponectinemia. MetS early-onset group observed renal structural modifications, but no functional changes. The structural modifications observed were minimal glomerular injury, glomerular basement membrane thickening, as well as mesangial and tubular cells that showed growth and proliferation. In serum and kidney (cortex and medulla), the concentrations of Zn, Fe, Cr, Mg, Mn, Cu, Co, and Ni were no differences between the experimental groups, but excretory fractions of these were lower in the hypercaloric diet group. In conclusion, MetS early-onset coexist renal structural modification and a hyperreabsorptive activity of essential trace elements that avoid its loss; thus, the excretory fraction of oligo-elements could be used a biomarker of early renal injury caused by metabolic diseases in the clinical practice.

Dietary Micronutrients and Risk of Chronic Kidney Disease: A Cohort Study with 12 Year Follow-Up

We investigated the association between dietary micronutrient intakes and the risk of chronic kidney disease (CKD) in the Ansan-Ansung study of the Korean Genome and Epidemiologic Study (KoGES), a population-based prospective cohort study. Of 9079 cohort participants with a baseline estimate glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m² and a urine albumin to creatinine ratio (UACR) <300 mg/g and who were not diagnosed with CKD, we ascertained 1392 new CKD cases over 12 year follow-up periods. The risk of CKD according to dietary micronutrient intakes was presented using hazard ratios (HRs) and 95% confidence intervals (95% CIs) in a full multivariable Cox proportional hazard models, adjusted for multiple micronutrients and important clinico-epidemiological risk factors. Low dietary intakes of phosphorus (<400 mg/day), vitamin B2 (<0.7 mg/day) and high dietary intake of vitamin B6 (≥1.6 mg/day) and C (≥100 mg/day) were associated with an increased risk of CKD stage 3B and over, compared with the intake at recommended levels (HR = 6.78 [95%CI = 2.18–21.11]; HR = 2.90 [95%CI = 1.01–8.33]; HR = 2.71 [95%CI = 1.26–5.81]; HR = 1.83 [95%CI = 1.00–3.33], respectively). In the restricted population, excluding new CKD cases defined within 2 years, an additional association with low folate levels (<100 µg/day) in higher risk of CKD stage 3B and over was observed (HR = 6.72 [95%CI = 1.40–32.16]). None of the micronutrients showed a significant association with the risk of developing CKD stage 3A. Adequate intake of micronutrients may lower the risk of CKD stage 3B and over, suggesting that dietary guidelines are needed in the general population to prevent CKD.

Gender difference in the association of dietary intake of antioxidant vitamins with kidney function in middle-aged and elderly Japanese

Dietary intake modification is important for the treatment of chronic kidney disease (CKD); however, little is known about the association between dietary intake of antioxidant vitamins and kidney function based on gender difference. We examined the relationship of dietary intake of antioxidant vitamins with decreased kidney function according to gender in Japanese subjects. This population-based, cross-sectional study included 936 Japanese participants with the age of 40 years or older. A validated brief self-administered diet history questionnaire was used to measure dietary intakes of vitamin E and its four isoforms, vitamin A and vitamin C. Decreased kidney function was defined as estimated glomerular filtration rate <60 ml/min/1·73 m2. A total of 498 (53·2 %) of the study participants were women. Mean age was 62·4 ± 11·3 years. Overall, 157 subjects met the criteria of decreased kidney function. In the fully adjusted model, a high vitamin E intake is inversely associated with decreased kidney function in women (odds ratio, 0·886; 95 % confidence interval, 0·786-0·998), whereas vitamin E intake was not associated with decreased kidney function (odds ratio, 0·931; 95 % confidence interval, 0·811-1·069) in men. No significant association between dietary intake of vitamins A and C and decreased kidney function was observed in women and men. Higher dietary intake of vitamin E was inversely associated with decreased kidney function in middle-aged and older women, and the result may provide insight into the more tailored dietary approaches to prevent CKD.

Dietary patterns and chronic kidney disease risk: a systematic review and updated meta-analysis of observational studies

BACKGROUND

A number of studies have reported the association between dietary patterns and the risk of chronic kidney disease (CKD), however a consistent perspective hasn't been established to date. Herein, we conducted this systematic review and meta-analysis of observational studies to assess the association between dietary patterns and CKD.

METHODS

MEDLINE, EBSCO and references from eligible studies were searched for relevant articles published up to 9 May 2020 that examined the association of common dietary patterns and CKD. The heterogeneity among studies was assessed by Cochran's Q test and I² methods.

RESULTS

Seventeen eligible studies, involving 149,958 participants, were included in our systematic review and meta-analysis. The highest compared with the lowest category of healthy dietary pattern was significantly associated with a lower risk of CKD (OR=0.69; CI: 0.57, 0.84; P=0.0001). A higher risk of CKD was shown for the highest compared with the lowest categories of Western-type dietary pattern (OR=1.86; CI: 1.21, 2.86; P=0.005). There were evidence of a lower risk of CKD in the highest compared with the lowest categories of light-moderate drinking pattern (OR=0.76; CI: 0.71, 0.81; P< 0.0001) and heavy drinking pattern (OR=0.67; CI: 0.56, 0.80; P< 0.0001).

CONCLUSIONS

The results of this systematic review and meta-analysis show that a healthy dietary pattern and alcohol drinking were associated with lower risk of CKD, whereas a Western-type dietary pattern was associated with higher risk of CKD.

Association of vitamin D status with liver and kidney disease: A systematic review of clinical trials, and cross-sectional and cohort studies

Abstract. Background: Vitamin D deficiency (VDD) is a major public health problem. There are few comprehensive systematic reviews about the relationship between Vitamin D status and liver and renal disease in Iran.

Methods: We systemically searched the following databases: Web of Science; PubMed; Cochrane Library; Scopus; Science Direct; Google Scholar and two Iranian databases (Scientific Information Database (SID) and IranMedex) up until November 2017 to identify all randomized control trials (RCTs), case control, cross-sectional and cohort studies investigating the association between vitamin D and any form of liver or kidney disease.

Results: Vitamin D insufficiency, or deficiency (VDD), is highly prevalent in Iran, reports varying between 44.4% in Isfahan to 98% in Gorgan. There is also a high prevalence of VDD among patients with liver or kidney disease, and the administration of vitamin D supplements may have beneficial effects on lipid profile, blood glucose, liver function and fatty liver disease, and bone health. Low serum vitamin D levels are related with abnormalities in these laboratory and clinical parameters.

Conclusion: VDD is prevalent in patients with chronic liver or renal disease in Iran. There appear to be several beneficial effects of vitamin D supplementation in vitamin D deficient patients with liver or kidney disease.

Modifiable Lifestyle Factors for Primary Prevention of CKD: A Systematic Review and Meta-Analysis

BACKGROUND

Despite increasing incidence of CKD, no evidence-based lifestyle recommendations for CKD primary prevention apparently exist.

METHODS

To evaluate the consistency of evidence associating modifiable lifestyle factors and CKD incidence, we searched MEDLINE, Embase, CINAHL, and references from eligible studies from database inception through June 2019. We included cohort studies of adults without CKD at baseline that reported lifestyle exposures (diet, physical activity, alcohol consumption, and tobacco smoking). The primary outcome was incident CKD (eGFR<60 ml/min per 1.73 m²). Secondary outcomes included other CKD surrogate measures (RRT, GFR decline, and albuminuria).

RESULTS

We identified 104 studies of 2,755,719 participants with generally a low risk of bias. Higher dietary potassium intake associated with significantly decreased odds of CKD (odds ratio [OR], 0.78; 95% confidence interval [95% CI], 0.65 to 0.94), as did higher vegetable intake (OR, 0.79; 95% CI, 0.70 to 0.90); higher salt intake associated with significantly increased odds of CKD (OR, 1.21; 95% CI, 1.06 to 1.38). Being physically active versus sedentary associated with lower odds of CKD (OR, 0.82; 95% CI, 0.69 to 0.98). Current and former smokers had significantly increased odds of CKD compared with never smokers (OR, 1.18; 95% CI, 1.10 to 1.27). Compared with no consumption, moderate consumption of alcohol associated with reduced risk of CKD (relative risk, 0.86; 95% CI, 0.79 to 0.93). These associations were consistent, but evidence was predominantly of low to very low certainty. Results for secondary outcomes were consistent with the primary finding.

CONCLUSIONS

These findings identify modifiable lifestyle factors that consistently predict the incidence of CKD in the community and may inform both public health recommendations and clinical practice.

The Role of Disturbed Mg Homeostasis in Chronic Kidney Disease Comorbidities

Some of the critical mechanisms that mediate chronic kidney disease (CKD) progression are associated with vascular calcifications, disbalance of mineral metabolism, increased oxidative and metabolic stress, inflammation, coagulation abnormalities, endothelial dysfunction, or accumulation of uremic toxins. Also, it is widely accepted that pathologies with a strong influence in CKD progression are diabetes, hypertension, and cardiovascular disease (CVD). A disbalance in magnesium (Mg) homeostasis, more specifically hypomagnesemia, is associated with the development and progression of the comorbidities mentioned above, and some mechanisms might explain why low serum Mg is associated with negative clinical outcomes such as major adverse cardiovascular and renal events. Furthermore, it is likely that hypomagnesemia causes the release of inflammatory cytokines and C-reactive protein and promotes insulin resistance. Animal models have shown that Mg supplementation reverses vascular calcifications; thus, clinicians have focused on the potential benefits that Mg supplementation may have in humans. Recent evidence suggests that Mg reduces coronary artery calcifications and facilitates peripheral vasodilation. Mg may reduce vascular calcification by direct inhibition of the Wnt/β-catenin signaling pathway. Furthermore, Mg deficiency worsens kidney injury induced by an increased tubular load of phosphate. One important consequence of excessive tubular load of phosphate is the reduction of renal tubule expression of α-Klotho in moderate CKD. Low Mg levels worsen the reduction of Klotho induced by the tubular load of phosphate. Evidence to support clinical translation is yet insufficient, and more clinical studies are required to claim enough evidence for decision-making in daily practice. Meanwhile, it seems reasonable to prevent and treat Mg deficiency. This review aims to summarize the current understanding of Mg homeostasis, the potential mechanisms that may mediate the effect of Mg deficiency on CKD progression, CVD, and mortality.

Dietary Sodium Intake and Health Indicators: A Systematic Review of Published Literature between January 2015 and December 2019

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.

Undiagnosed chronic kidney disease and its associated risk factors in an agricultural Moroccan adult's population

INTRODUCTION

Chronic kidney disease is among the major non-communicable diseases with increasing prevalence. This study aimed to estimate the prevalence of chronic kidney disease and its associated risk factors among Moroccan population sample from Sidi Bennour province.

METHODS

An observational, descriptive and analytical study was conducted in an agricultural community of Morocco. A sample of 182 subjects aged 18 or older, randomly selected from the province health care centers. The information on the participants was collected using a structured questionnaire, blood samples were collected and the serum creatinine was determined. Subsequent glomerular filtration rate (eGFR) was estimated by the modification of diet in renal disease formula and the chronic kidney disease was defined by an eGFR<60 mL/min/1.73 m².

RESULTS

The participants mean age was 53.58±12.06 years, with a sex ratio of 0.30 and the prevalence of chronic kidney disease was 4.4%. The risk factors associated with chronic kidney disease were age, hypertension, and nephrotoxic treatment, that are significantly correlated with renal impairment (P=0.006 for age, P=0.008 for hypertension and P=0.001 for nephrotoxic medication used respectively).

CONCLUSIONS

The study data show that chronic kidney disease should be of important consideration in any strategy to address non-communicable diseases and associated risk factors.

Magnesium: An old player revisited in the context of CKD-MBD

Chronic kidney disease (CKD) is associated with a wide number of abnormalities in mineral metabolism. Often, these alterations are the leading players in the development of comorbidities associated with CKD, which are risk factors of mortality. In this context, mineral and bone disorder associated with CKD (CKD-MBD) are highlighted, connecting bone, renal, and cardiovascular disorders. Many studies have been led to propose strategies to avoid, reduce, or slow down CKD-MBD progression using different compositions of metallic elements-based P binders such as aluminum, magnesium, or calcium. Magnesium, the aim of this review, has been used by nephrologists to treat CKD-MBD with a variable acceptation due mainly to different results on bone homeostasis. Nowadays, we have new evidence about the efficacy of magnesium supplementation on vascular calcification, renal function, and bone disorders, suggesting potential beneficial effects of Magnesium in the management of CKD-MBD.

Association between dietary patterns and chronic kidney disease in a middle-aged Chinese population

OBJECTIVE

To explore the relationship between dietary patterns and risk of chronic kidney disease (CKD) in Chinese adults aged 45-59 years.

DESIGN

Dietary data were collected using a semi-quantitative FFQ. Factor analysis was used to identify the major dietary patterns. Logistic regression models were applied to clarify the association between dietary patterns and the risk of CKD.

SETTING

The present study population was a part of the population-based Nutrition and Health Study performed in the city of Hangzhou, Zhejiang Province, eastern China.

PARTICIPANTS

A total of 2437 eligible participants (45-59 years) were enrolled in the present cross-sectional study from June 2015 to December 2016.

RESULTS

Three major dietary patterns were identified: 'traditional southern Chinese', 'Western' and 'grains-vegetables' patterns, collectively accounting for 25·6 % of variance in the diet. After adjustment for potential confounders, participants in the highest quartile of the Western pattern had greater odds for CKD (OR = 1·83, 95 % CI 1·21, 2·81; P < 0·05) than those in the lowest quartile. Compared with the lowest quartile of the grains-vegetables pattern, the highest quartile had lower odds for CKD (OR = 0·84, 95 % CI 0·77, 0·93; P < 0·05). In addition, there was no significant association between the traditional southern Chinese pattern and risk of CKD (P > 0·05).

CONCLUSIONS

Our results suggest that the Western pattern is associated with an increased risk, whereas the grains-vegetables pattern is associated with a reduced risk for CKD. These findings can guide dietary interventions for the prevention of CKD in a middle-aged Chinese population.

Greater Dietary Inflammatory Index score is associated with higher likelihood of chronic kidney disease

Chronic kidney disease (CKD) is described as a progressive alteration of kidney function, resulting from multiple factors, including behaviours. We investigated the association of the Dietary Inflammatory Index (DII®) with prevalent CKD in adult Americans. National Health and Nutrition Examination Survey participants with measured data on kidney function markers from 2005 to 2012 were included in this study. Prevalent CKD was based on an estimated glomerular filtration rate (eGFR) <60 ml/min per 1·73 m2 or urinary albumin/creatinine≥30 mg/g. Energy-adjusted DII (E-DIITM) scores were calculated from 24-h dietary recalls. Statistical analyses accounted for the survey design and sample weights. We included 21 649 participants, with 1634 (6·8 %) having prevalent CKD. Participants with high E-DII scores had greater BMI, fasting blood glucose and systolic blood pressure, and were more likely to be diabetic or hypertensive (all P<0·001) compared with those with lower E-DII scores. In regression models adjusted for age, sex, race, fasting blood glucose, blood pressure, BMI, hypertension and diabetes status, mean eGFR significantly decreased across increasing quartiles of E-DII, whereas serum uric acid level and log urinary albumin:creatinine ratio significantly increased (all P<0·001). Prevalent CKD increased from 5·3 % in the lowest to 9·3 % in the highest E-DII quartile (P=0·02). In multivariable-adjusted logistic regression models, the odds of prevalent CKD were 29 % higher in the highest compared with the lowest E-DII quartile. Pro-inflammatory diet is associated with declining kidney function and high prevalence of CKD. Dietary changes that reduce inflammation have a potential to prevent CKD.

Plant-Based Diets and Incident CKD and Kidney Function

BACKGROUND AND OBJECTIVES

The association between plant-based diets, incident CKD, and kidney function decline has not been examined in the general population. We prospectively investigated this relationship in a population-based study, and evaluated if risk varied by different types of plant-based diets.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Analyses were conducted in a sample of 14,686 middle-aged adults enrolled in the Atherosclerosis Risk in Communities study. Diets were characterized using four plant-based diet indices. In the overall plant-based diet index, all plant foods were positively scored; in the healthy plant-based diet index, only healthful plant foods were positively scored; in the provegetarian diet, selected plant foods were positively scored. In the less healthy plant-based diet index, only less healthful plant foods were positively scored. All indices negatively scored animal foods. We used Cox proportional hazards models to study the association with incident CKD and linear mixed models to examine decline in eGFR, adjusting for confounders.

RESULTS

During a median follow-up of 24 years, 4343 incident CKD cases occurred. Higher adherence to a healthy plant-based diet (HR comparing quintile 5 versus quintile 1 [HRQ5 versus Q1], 0.86; 95% confidence interval [95% CI], 0.78 to 0.96; P for trend =0.001) and a provegetarian diet (HRQ5 versus Q1, 0.90; 95% CI, 0.82 to 0.99; P for trend =0.03) were associated with a lower risk of CKD, whereas higher adherence to a less healthy plant-based diet (HRQ5 versus Q1, 1.11; 95% CI, 1.01 to 1.21; P for trend =0.04) was associated with an elevated risk. Higher adherence to an overall plant-based diet and a healthy plant-based diet was associated with slower eGFR decline. The proportion of CKD attributable to lower adherence to healthy plant-based diets was 4.1% (95% CI, 0.6% to 8.3%).

CONCLUSIONS

Higher adherence to healthy plant-based diets and a vegetarian diet was associated with favorable kidney disease outcomes.

Dietary pattern and incidence of chronic kidney disease among adults: a population-based study

Background & Aims

Although dietary patterns have been linked to chronic diseases such as cardiovascular disease, sparse data are available for a relationship between dietary patterns and incident chronic kidney disease (CKD) in West Asian populations. The aim of this study was to evaluate the association of population-based dietary pattern with the risk of incident CKD after 6.1 years of follow-up.

Methods

At baseline, habitual dietary intakes of 1630 participants of the Tehran Lipid and Glucose Study (TLGS) who were free of CKD was assessed by a valid and reliable food-frequency questionnaire. The following three major dietary patterns were identified using a principal components analysis: Lacto-vegetarian dietary pattern, traditional Iranian dietary pattern, and high fat, high sugar dietary pattern. Estimated glomerular filtration rate (eGFR) was calculated, using the Modification of Diet in Renal Disease (MDRD) Study equation and CKD was defined as eGFR < 60 mL/min/1.73m². Odds ratio (OR) using multivariable logistic regression was calculated for the association of incident CKD with the extracted dietary patterns.

Results

After adjusting for age, sex, smoking, total energy intake, physical activity, body mass index, diabetes, and hypertension the OR for participants in the highest compared with those in the lowest tertile of the lacto-vegetarian dietary pattern was 0.57 (95% confidence interval [CI]: 0.41 to 0.80, P-trend = 0.002). In contrast, the high fat, high sugar dietary pattern was positively associated with the incidence of CKD (OR for the third tertile compared with first tertile: 1.46; 95% CI: 1.03-2.09; P-trend = 0.036). Traditional Iranian dietary pattern was not associated with incident CKD.

Conclusion

The high fat, high sugar dietary pattern was associated with significantly increased (46%) odds of incident CKD, whereas a lacto-vegetarian dietary pattern may be protective against the occurrence of CKD by 43%.

A higher ratio of refined grain to whole grain is associated with a greater likelihood of chronic kidney disease: a population-based study

A growing number of studies suggest that diet and renal function are related. However, little is known about the link between both whole grain (WG) and refined grain (RG) consumption and kidney function parameters. Thus, we investigated the association of WG and RG with urinary albumin to creatinine ratio (ACR) and prevalent chronic kidney disease (CKD). Data from participants of the National Health and Nutrition Examination Surveys (NHANES) from 2005 to 2010 were collected. Estimated glomerular filtration rate (eGFR) was calculated by the CKD Epidemiology Collaboration equation. Survey design and sample weights were taken into consideration for statistical analyses. Finally, we included 16 325 participants from NHANES, 6·9 % of whom had prevalent CKD. In models adjusted for age, sex, race, fasting blood glucose, blood pressure, adiposity, hypertension and diabetes status, mean eGFR significantly increased across increasing quartiles of WG (Q1: 88·2 v. Q4: 95·4 ml/min per 1·73 m2, P&lt;0·001), whereas it significantly decreased across increasing quartiles of RG (Q1: 97·2 v. Q4: 88·4 ml/min per 1·73 m2, P&lt;0·001). Furthermore, serum uric acid levels and ACR significantly decreased across quartiles of WG (both P&lt;0·001). In multivariable-adjusted logistic regression models, the likelihood of prevalent CKD was 21 % lower in the highest WG quartile compared with the lowest one. In conclusion, our results shed light on the beneficial impact of WG on kidney function and CKD, whereas RG is adversely associated with eGFR.

Nutrition and Diabetes, Cardiovascular and Chronic Kidney Diseases: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

The high prevalence of chronic diseases can be prevented or managed by specific changes in lifestyle patterns of individuals of which dietary factors is emphasized. The objective of this study was to review all findings of the Tehran Lipid and Glucose Study regarding validity and reliability of food frequency questionnaire (FFQ), evaluating dietary quality and association of dietary factors in relation to diabetes, dysglycemia, cardiovascular (CVD) and chronic kidney disease (CKD).

EVIDENCE ACQUISITION

Related documents were searched through PubMed and Scopus databases, in English language from 2000 to 2017. Finally, 52 relevant documents were eligible for inclusion in this review.

RESULTS

The FFQ proved to be an acceptable tool for assessing nutrient and food group intakes and rank individuals accurately according to the levels of their dietary intakes. After 8 years of follow-up, the western dietary pattern (DP) was fairly stable but there was instability of traditional Iranian DP. DPs of over two-thirds of Tehranian populations were not in accordance with the dietary recommendations. Higher dietary scores of variety and healthy DPs were also associated with reduced odds of dysglycemia. The main dietary factor related to increased risk of CVD in our population was western DP. Patterns of amino acid intakes may contribute to the development of CVD. Higher intakes of several micronutrients and macronutrients, DPs and some vegetables decrease the risk of CKD. In conclusion DPs of most Tehranian adults need improvement.

CONCLUSIONS

This review showed that higher adherence to healthy food choices was associated with reduced odds of dysglycemia and CVD. Dietary sources of renal-protective nutrients should be encouraged among the general population.

Validity of predictive equations for 24-h urinary potassium excretion based on timing of spot urine collection among adults: the MESA and CARDIA Urinary Sodium Study and NHANES Urinary Sodium Calibration Study

Background

24-h urine collections are the suggested method to measure daily urinary potassium excretion (uK) but are costly and burdensome to implement.

Objective

This study tested how well existing equations with the use of spot urine samples can estimate 24-h uK and if accuracy varies by timing of spot urine collection, age, race, or sex.

Design

This cross-sectional study used data from 407 participants aged 18-39 y from the Washington, DC area in 2011 and 554 participants aged 45-79 y from Chicago in 2013. Spot urine samples were collected in individual containers for 24 h, and 1 for each timed period (morning, afternoon, evening, and overnight) was selected. For each selected timed spot urine, 24-h uK was predicted through the use of published equations. Difference (bias) between predicted and measured 24-h uK was calculated for each timed period and within age, race, and sex subgroups. Individual-level differences were assessed through the use of Bland-Altman plots and correlation tests.

Results

For all equations, regardless of the timing of spot urine, mean bias was usually significantly different than 0. No one prediction equation was unbiased across all sex, race, and age subgroups. With the use of the Kawasaki and Tanaka equations, 24-h uK was overestimated at low levels and underestimated at high levels, whereas observed differential bias with the Mage equation was in the opposite direction. Depending on prediction equation and timing of urine sample, 61-75% of individual 24-h uKs were misclassified among 500-mg incremental categories from <1500 to ≥3000 mg. Correlations between predicted and measured 24-h uK were poor to moderate (0.19-0.71).

Conclusion

Because predicted 24-h uK accuracy varies by timing of spot urine collection, published prediction equations, and within age-race-sex subgroups, study results making use of predicted 24-h uK in association with health outcomes should be interpreted with caution. It is possible that a more accurate prediction equation can be developed leading to different results.

Food Patterns are Associated with Likelihood of CKD in US Adults

We investigated the association between dietary patterns and prevalent chronic kidney diseases (CKD), in participants of the 2005–2012 US National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2012, who had measured data on dietary intake and kidney function. Analyse of covariance (ANCOVA) and logistic regression models were employed to account for the survey design and sample weights. A total of 21,649 eligible participants (634 with and 20,015 without prevalent CKD) were included in the final analysis. Three food patterns together explained 50.8% of the variance of the dietary nutrients consumption. The first food pattern was representative of a diet containing high levels of saturated and mono-unsaturated fatty acids; the second food pattern comprised vitamins and trace elements; and the third food pattern was mainly representative of polyunsaturated fatty acids. The odd of prevalent CKD decreased across increasing quarters of vitamins and trace elements, so that the top quarter was associated with a 53% (95%CI: 42–62%) lower odds of CKD in age, sex and race adjusted logistic regression models. These results suggest that vitamins and trace elements intake are associated with lower risk of prevalent CKD.

Association between Dietary Mineral Intake and Chronic Kidney Disease: The Health Examinees (HEXA) Study

Few studies have explored the association between mineral intake and chronic kidney disease (CKD). A cross-sectional analysis investigated the association between mineral intake (calcium, phosphorus, sodium, potassium, iron, and zinc) and CKD using the Health Examinee (HEXA) cohort of the Korean Genome and Epidemiologic Study (KoGES). For 159,711 participants, mineral intake was assessed by a food frequency questionnaire. CKD was defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73 m². Dietary intake of each mineral was divided into quartiles and the quartile including recommended dietary allowance (RDA) or adequate intake (AI) of each mineral was used as a reference. We assessed the association between the quartile of mineral intakes and CKD using polytomous logistic regression models. The lowest quartiles of phosphorus (≤663.68 mg/day, odds ratio [OR] = 1.64, 95% confidence interval [CI]: 1.25–2.15), potassium (≤1567.53 mg/day, OR = 1.87, 95% CI: 1.27–2.75), iron (≤6.93 mg/day, OR = 1.53, 95% CI: 1.17–2.01), and zinc (≤5.86 mg/day, OR = 1.52, 95% CI: 1.02–2.26) were associated with higher odds for advanced CKD compared with the references. The present study suggests that an inadequate intake of some minerals may be associated with CKD occurrence in the general population. Due to the reverse causation issue in this cross-sectional study design, further longitudinal prospective studies are needed in order to prove the results.

Magnesium and Progression of Chronic Kidney Disease: Benefits Beyond Cardiovascular Protection?

Experimental and clinical studies have demonstrated that magnesium deficiency leads to hypertension, insulin resistance, and endothelial dysfunction, and is associated with an increased risk of cardiovascular events. Given that cardiovascular disease and CKD share similar risk factors, the low magnesium status may also contribute to CKD progression. In fact, lower serum magnesium levels and lower dietary magnesium intake are associated with an increased risk of incident CKD and progression to end-stage kidney disease. Because these associations are independent of traditional risk factors, other pathways might be involved in the relationship between magnesium deficiency and the risk of CKD progression. Recent evidence has shown that magnesium suppresses phosphate-induced vascular calcification. Magnesium impairs the crystallization of calcium phosphate-more specifically, the maturation of calciprotein particles. Considering that phosphate overload causes kidney damage, magnesium might counteract the phosphate toxicity to the kidney, as in the case of vascular calcification. This hypothesis is supported by an in vitro observation that magnesium alleviates proximal tubular cell injury induced by high phosphate. Potential usefulness of magnesium as a treatment option for phosphate toxicity in CKD should be further investigated by intervention studies.

Dietary fibre intake in relation to the risk of incident chronic kidney disease

The purpose of this study was primarily to evaluate the association of total fibre intake with the risk of incident chronic kidney disease (CKD). We also evaluated the association of dietary fibre from fruits, vegetables, cereals and legumes with the incidence of CKD in a population-based prospective study. We followed up 1630 participants of the Tehran Lipid and Glucose Study for 6·1 years, who were initially free of CKD. Baseline diet was assessed by a valid and reliable FFQ. Estimated glomerular filtration rate (eGFR) was calculated, using the Modification of Diet in Renal Disease Study equation, and CKD was defined as eGFR <60 ml/min per 1·73 m2. OR using multivariable logistic regression was reported for the association of incident CKD with tertiles of dietary fibre intake. After adjustment for age, sex, smoking, total energy intake, physical activity, diabetes and using angiotensin-converting-enzyme inhibitor, the OR for subjects in the highest compared with the lowest tertile of total fibre intake was 0·47 (95 % CI 0·27, 0·86). In addition, for every 5 g/d increase in total fibre intake, the risk of incident CKD decreased by 11 %. After adjusting for potential confounders, OR for participants in the highest compared with the lowest tertile of fibre from vegetables was 0·63 (95 % CI 0·43, 0·93) and from legumes it was 0·68 (95 % CI 0·47, 0·98). We observed inverse associations between total fibre intake and risk of incident CKD, which demonstrate that high fibre intake, mainly from legumes and vegetables, may reduce the occurrence of CKD.

Dietary Magnesium and Kidney Function Decline: The Healthy Aging in Neighborhoods of Diversity across the Life Span Study

BACKGROUND

Prior studies suggest that certain aspects of the diet related to magnesium intake, such as dietary acid load, protein intake and dietary patterns rich in fruits and vegetables, may impact kidney disease risk. We hypothesized that lower dietary magnesium intake would be prospectively associated with more rapid kidney function decline.

METHODS

Among participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span study with estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2 at baseline (2004-2009), dietary magnesium intake was calculated from two 24-hour dietary recalls. Rapid decline was defined as ≥3% eGFR decline per year.

RESULTS

Median (25th-75th percentile) dietary magnesium intake was 116 (96-356) mg/1,000 kcal. Among 1,252 participants, those with lower dietary magnesium intake were younger, and were more likely to be African-American men. A total of 177 participants (14.1%) experienced rapid eGFR decline over a median follow-up of 5 years. Lower dietary magnesium intake was significantly associated with a greater odds of rapid eGFR decline (OR for tertile 1 vs. 3: 2.02, 95% CI 1.05-3.86, p value for trend across tertiles = 0.02) in analyses adjusted for sociodemographics (age, sex, race, education level, health insurance status, poverty status), kidney disease risk factors (smoking status, diabetes, hemoglobin A1c, hypertension, body mass index), baseline eGFR and dietary factors (total energy intake; diet quality; dietary intake of fiber, sodium, calcium, potassium and phosphorus).

CONCLUSIONS

In this urban population, lower dietary magnesium intake was independently associated with greater odds of rapid kidney function decline.

Dietary Habits and Risk of Kidney Function Decline in an Urban Population

OBJECTIVE

Explore the association between following a Dietary Approaches to Stop Hypertension (DASH)-accordant diet and kidney end points among urban adults.

DESIGN

Prospective cohort study.

SETTING

Healthy Aging in Neighborhoods of Diversity across the Life Span study.

SUBJECTS

A total of 1,534 urban dwelling participants of the Healthy Aging in Neighborhoods of Diversity across the Life Span study with a baseline estimated glomerular filtration rate (eGFR) ≥60 mL/minute/1.73 m².

INTERVENTION

DASH diet accordance determined via a score based on nine target nutrients.

MAIN OUTCOME MEASURE

Rapid kidney function decline (eGFR decline >3 mL/minute/1.73 m² per year), incident chronic kidney disease (CKD) (follow-up eGFR <60 mL/minute/1.73 m²), and eGFR decline >25%.

RESULTS

Participants' mean age was 48 years, and 59% were African-American. Median DASH score was 1.5 (range, 0-8). Over a median of 5 years, 13.4% experienced rapid eGFR decline, including 15.2% among participants not following a DASH-accordant diet (score ≤1) and 12.0% with higher accordance (score >1) (P = .08). Outcomes varied by hypertension status. In multinomial logistic regression models, following adjustment for sociodemographic and clinical factors, including total energy intake, low DASH diet accordance was associated with rapid eGFR decline among participants with hypertension (risk ratio, 1.68; 95% confidence interval: 1.17-2.42) but not among those without hypertension (risk ratio, 0.83; 95% confidence interval: 0.56-1.24; P interaction .001). There was no statistically significant association between DASH diet accordance and incident CKD or eGFR decline >25%. Results were similar when DASH diet accordance was analyzed in tertiles.

CONCLUSIONS

Among urban adults, low accordance to a DASH-type diet was not associated with incident CKD, but was associated with higher risk of rapid eGFR decline among those with hypertension, yet not among those without hypertension. Further study of dietary patterns as a potential target for improving kidney outcomes among high-risk populations is warranted.