Cross-sectional association between fish consumption and albuminuria: the European Prospective Investigation of Cancer-Norfolk Study

Associations of meat, fish and seafood consumption with kidney function in middle-aged to older Chinese: a cross-sectional study based on the Guangzhou Biobank Cohort Study

OBJECTIVE

To examine the associations of red meat, poultry, fish and seafood and processed meat consumption with kidney function in middle-aged to older Chinese.

DESIGN

A cross-sectional study based on the Guangzhou Biobank Cohort Study.

SETTING

Community-based sample.

PARTICIPANTS

9768 participants (2743 men and 7025 women) aged 50+ years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was estimated glomerular filtration rate (eGFR) derived from the Chinese-specific equation based on the Modification of Diet in Renal Disease (MDRD) equation (c-aGFR). eGFR derived from the original isotope-dilution mass spectrometry-traceable MDRD study equation, and prevalent chronic kidney disease (CKD) defined as c-aGFR<60 mL/min/1.73 m2 were considered the secondary outcomes.

RESULTS

After adjusting for sex, age, body mass index, education, occupation, family income, smoking status, alcohol use, physical activity, daily energy intake, self-rated health and chronic disease history (diabetes, hypertension and dyslipidaemia), compared with processed meat consumption of 0-1 portion/week, those who consumed ≥3 portions/week had lower c-aGFR (β=-2.74 mL/min/1.73 m2, 95% CI=-4.28 to -1.20) and higher risk of prevalent CKD (OR=1.40, 95% CI=1.09 to 1.80, p<0.0125). Regarding fish and seafood consumption, the associations varied by diabetes (p for interaction=0.02). Fish and seafood consumption of ≥11 portions/week, versus 0-3 portions/week, was non-significantly associated with higher c-aGFR (β=3.62 mL/min/1.73 m2, 95% CI=-0.06 to 7.30) in participants with diabetes, but was associated with lower c-aGFR in normoglycaemic participants (β=-1.51 mL/min/1.73 m2, 95% CI=-2.81 to -0.20). No significant associations of red meat or poultry consumption with c-aGFR nor prevalent CKD were found. Similar results were found for meat, fish and seafood consumption with eGFR.

CONCLUSIONS

Higher processed meat, fish and seafood consumption was associated with lower kidney function in normoglycaemic participants. However, the associations in participants with diabetes warrant further investigation.

A Randomized, Double-Blind, Placebo-Controlled Clinical Trial of an Omega-3 Fatty Acid Supplement in Patients With Predialysis Chronic Kidney Disease

OBJECTIVE

Omega-3 fatty acids may reduce albuminuria and cardiovascular risk factors in patients with chronic kidney disease (CKD). We aimed to assess the effects of omega-3 fatty acid supplementation on albuminuria, blood pressure, pulse wave velocity, and inflammatory markers in patients with CKD.

METHODS

Patients with CKD and a urine albumin excretion of at least 30 mg/g creatinine were supplemented for 3 months with 3,666 mg/day of docosahexaenoic and eicosapentaenoic acids or a corn oil supplement. The study was double blind. At baseline, 6 weeks, and 12 weeks, fasting blood and morning spot urine samples were obtained. Blood pressure, carotid intima media thickness, and pulse wave velocity were measured. The main outcome measure was a reduction of ≥20% in urine albumin.

RESULTS

One hundred patients were randomized (50 received omega-3 fatty acids and 50 received corn oil). Four patients who received omega-3 fatty acids and 5 who received vegetable oil were lost to follow-up. In patients receiving omega-3 fatty acids, the omega-3 index increased from 3.08 (2.32-3.81) to 5.48 (3.045-7.04) percent. A 20% reduction in urine albumin excretion was observed in 13 participants of the control group and 19 participants of omega-3 group (Fisher's exact P = .274). However, the supplement had a significant and positive effect on pulse wave velocity and triglyceride level.

CONCLUSION

An omega-3 fatty acid supplement of 3,666 mg/day did not modify urine albumin excretion in patients with CKD but did improve pulse wave velocity and serum triglyceride levels.

Low linolenic and linoleic acid consumption are associated with chronic kidney disease in patients with type 2 diabetes

Aim

This cross-sectional study aimed to assess the association of the fat content in the diet with Diabetic Kidney Disease (DKD) in patients with type 2 diabetes.

Methodology

Patients from the Diabetes research clinic at Hospital de Clínicas de Porto Alegre (Brazil) were consecutively recruited. The inclusion criterion was the diagnosis of type 2 diabetes. The exclusion criteria were as follows: body mass index >40 kg/m², heart failure, gastroparesis, diabetic diarrhea, dietary counseling by a registered dietitian during the previous 12 months, and inability to perform the weighed diet records (WDR). The dietary fatty acids (saturated, monounsaturated and polyunsaturated) consumption was estimated by 3-day WDR. Compliance with the WDR technique was assessed by comparison of protein intake estimated from the 3-day WDR and from the 24-h urinary nitrogen output performed on the third day of the WDR period. The presence of DKD was defined as urinary albumin excretion (UAE) ≥ 30 mg / 24 h or/and glomerular filtration rate (eGFR) <60 ml/min/1.73 m². Urinary albumin was measured twice and eGFR was estimated by using the CKD-EPI equation.

Results

A total of 366 patients were evaluated; of these, 33% (n = 121) had DKD. Multivariate analysis showed that the intake of linolenic acid was negatively associated with DKD (OR = 0.57; 95% CI 0.35–0.93; P = 0.024), adjusted for gender, smoking, cardiovascular disease, ACE inhibitors and/or angiotensin receptor blocker use, systolic blood pressure, fasting plasma glucose and HDL cholesterol. In a separate model, similar results were observed for linoleic acid, adjusting to the same co-variables (OR = 0.95; 95% CI 0.91–0.99; P = 0.006).

Conclusion

The lower intake of polyunsaturated fatty acids, especially linolenic and linoleic acid, is associated with chronic kidney disease in patients with type 2 diabetes.

Recent findings on the effects of marine-derived n-3 polyunsaturated fatty acids on urinary albumin excretion and renal function

Albuminuria (this includes microalbuminuria and macroalbuminuria) and reduced glomerular filtration rate are present not only in high-risk populations, but also in the general population. These manifestations of renal disease are associated with an increased risk of cardiovascular disease and may reflect subclinical vascular disease. Long-chain n-3 polyunsaturated fatty acids have been vigorously studied for their potential cardioprotective effects. These fatty acids reduce the levels of serum lipids, blood pressure, inflammation, and endothelial dysfunction, all of which are associated with albuminuria and renal impairment; therefore, marine-derived n-3 fatty acids may potentially play a role in their prevention. This report reviews the recent findings relating marine-derived n-3 fatty acids to urinary albumin excretion and renal function and their risk factors. Although some evidence suggests that marine-derived n-3 fatty acids are associated with a lower incidence of albuminuria in diabetes, there is inadequate evidence supporting their role in glomerular filtration.

Factors affecting levels of urinary albumin excretion in the general population of Spain: the Di@bet.es study

The present study was undertaken to examine the prevalence of urinary ACR (albumin/creatinine ratio) >30 mg/g and the associated clinical and environmental factors in a representative sample of the population of Spain. Di@bet.es study is a national, cross-sectional population-based survey conducted in 2009-2010. Clinical, metabolic, socio-demographic, anthropometric data and information about lifestyle habit were collected. Those subjects without KDM (known diabetes mellitus) were given an OGTT (oral glucose tolerance test). Albumin and creatinine were measured in a urinary sample and ACR was calculated. The population prevalence of ACR >30 mg/g was 7.65% (adjusted for sex and age). The prevalence of ACR >30 mg/g increased with age (P<0.001). Subjects with carbohydrate metabolism disorders had a greater prevalence of ACR >30 mg/g but after being adjusted for age, sex and hypertension, was significant only in those subjects with UKDM (unknown diabetes mellitus) {OR (odd ratio), 2.07 [95% CI (confidence interval), 1.38-3.09]; P<0.001] and KDM [OR, 3.55 (95% CI, 2.63-4.80); P<0.001]. Prevalence of ACR >30 mg/g was associated with hypertension [OR, 1.48 (95% CI, 1.12-1.95); P=0.001], HOMA-IR (homoeostasis model assessment of insulin resistance) [OR, 1.47 (95% CI, 1.13-1.92); P≤0.01], metabolic syndrome [OR, 2.17 (95% CI, 1.72-2.72); P<0.001], smoking [OR, 1.40 (95% CI, 1.06-1.83); P≤0.05], physical activity [OR, 0.68 (95% CI, 0.54-0.88); P≤0.01] and consumption of fish [OR, 0.38 (95% CI, 0.18-0.78); P≤0.01]. This is the first study that reports the prevalence of ACR >30 mg/g in the Spanish population. The association between clinical variables and other potentially modifiable environmental variables contribute jointly, and sometimes interactively, to the explanation of prevalence of ACR >30 mg/g. Many of these risk factors are susceptible to intervention.

Relationship between dietary intake and microalbuminuria: findings from the Takahata study

BACKGROUND

Although several studies have investigated the relationship between dietary nutrient intake and microalbuminuria, no study of an Asian population has been reported. The present study investigates the relationship between dietary intake and microalbuminuria in a general Japanese population.

METHODS

We analyzed 675 men and 924 women who did not have diabetes. Participants who had a urinary albumin-to-creatinine ratio (UACR) ≥300 mg/g, who did not complete a questionnaire regarding food frequency and who did not provide complete urine measurements were excluded. Nutrient intake was assessed by validated food frequency questionnaire. Microalbuminuria was defined as UACR ≥30 mg/g. The relationship between dietary nutrient intake and microalbuminuria was examined using a multiple logistic regression model adjusted for age, total energy intake, body mass index, smoking status, systolic blood pressure and use of antihypertensive medication.

RESULTS

No significant association was observed among the men. The multiple adjusted odds ratios (95% confidence interval) of having microalbuminuria per 1 standard deviation increase in total protein (%kcal), animal protein (%kcal), animal protein (g/day), animal fat, niacin, carbohydrate and β-cryptoxanthin among the women were 1.33 (1.07-1.66), 1.35 (1.09-1.66), 1.42 (1.08-1.88), 1.29 (1.05-1.59), 1.28 (1.04-1.57), 0.73 (0.58-0.92) and 0.76 (0.59-0.996), respectively. The multiple adjusted odds ratio (95% confidence interval) of having microalbuminuria in the highest quintile of n-3 polyunsaturated fatty acids compared with the lowest was 2.16 (1.03-4.54).

CONCLUSION

Less animal protein and more β-cryptoxanthin in the diet might help to prevent microalbuminuria. Prospective studies including controlled trials are required to confirm this conclusion.

Association between fish consumption and nephropathy in American Indians--the Strong Heart Study

OBJECTIVE

The present study examined the association between fish consumption and nephropathy in American Indians.

METHODS

In the family cohort of the Strong Heart Study, we investigated 2,261 participants with baseline examination between 2001 and 2003 and follow-up examination between 2006 and 2008. The average follow-up period was 5.4 years. We defined fish consumption as the sum of dietary intake of tuna, fried fish, and nonfried fish obtained from a validated food frequency questionnaire. Nephropathy was defined as microalbuminuria (urinary albumin-creatinine ratio [ACR]: 30 to 299 mg/g), macroalbuminuria (urinary ACR: ≥ 300 mg/g), or an estimated glomerular filtration rate of <60 mL/min/1.73 m(2). Using regression models, we examined the association between fish consumption measured at baseline and 2 outcomes in nephropathy present at follow-up, albuminuria, or renal impairment, and change in urinary ACR or estimated glomerular filtration rate between baseline and follow-up examinations.

RESULTS

The prevalence of microalbuminuria, macroalbuminuria, and renal impairment was 13%, 3%, and 4%, respectively. The fish items consumed by the participants were predominantly deep-fried. We found no associations between fish consumption and any measure of nephropathy after adjusting for demographic, clinical, lifestyle, and dietary factors.

CONCLUSIONS

Dietary intake of predominantly fried fish was not associated with a lower risk of nephropathy in American Indians.

CUBN is a gene locus for albuminuria

Identification of genetic risk factors for albuminuria may alter strategies for early prevention of CKD progression, particularly among patients with diabetes. Little is known about the influence of common genetic variants on albuminuria in both general and diabetic populations. We performed a meta-analysis of data from 63,153 individuals of European ancestry with genotype information from genome-wide association studies (CKDGen Consortium) and from a large candidate gene study (CARe Consortium) to identify susceptibility loci for the quantitative trait urinary albumin-to-creatinine ratio (UACR) and the clinical diagnosis microalbuminuria. We identified an association between a missense variant (I2984V) in the CUBN gene, which encodes cubilin, and both UACR (P = 1.1 × 10(-11)) and microalbuminuria (P = 0.001). We observed similar associations among 6981 African Americans in the CARe Consortium. The associations between this variant and both UACR and microalbuminuria were significant in individuals of European ancestry regardless of diabetes status. Finally, this variant associated with a 41% increased risk for the development of persistent microalbuminuria during 20 years of follow-up among 1304 participants with type 1 diabetes in the prospective DCCT/EDIC Study. In summary, we identified a missense CUBN variant that associates with levels of albuminuria in both the general population and in individuals with diabetes.

Dietary intake of eicosapentaenoic and docosahexaenoic acid and diabetic nephropathy: cohort analysis of the diabetes control and complications trial

OBJECTIVE

To investigate the association between dietary n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFAs) and the degree and development of albuminuria in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We analyzed longitudinal data from 1,436 participants in the Diabetes Control and Complications Trial. We defined the average intake of eicosapentaenoic and docosahexaenoic acid from diet histories. Urinary albumin excretion rates (UAERs) were measured over 24 h; incident albuminuria was considered the first occurrence of an UAER >40 mg/24 h sustained for >or=1 year in normoalbuminuric individuals. RESULTS In a mean follow-up of 6.5 years, we observed a lower mean UAER (difference 22.7 mg/24 h [95% CI 1.6-43.8)]) in the top versus the bottom third of dietary n-3 LC-PUFAs, but we found no association with incident albuminuria.

CONCLUSIONS

Dietary n-3 LC-PUFAs appear inversely associated with the degree but not with the incidence of albuminuria in type 1 diabetes. These findings require further investigation in prospective studies.

Fish-oil supplement has neutral effects on vascular and metabolic function but improves renal function in patients with Type 2 diabetes mellitus

AIMS

Increased dietary fish-oil consumption is associated with a reduced risk of coronary heart events and has pronounced effects on dyslipidaemia. However, the effects of fish-oil supplement on vascular function and metabolic profile in patients with Type 2 diabetes mellitus (DM) are unclear.

METHODS

In a double-blind placebo-controlled trial, we randomized 97 Type 2 DM patients without prior cardiovascular disease to fish-oil (4 g/day, n = 49) or olive-oil (with equivalent calories, as placebo, n = 48) supplements for 12 weeks. Assessment of vascular function with brachial artery flow-mediated dilation (FMD) and circulating levels of endothelial progenitor cells (EPCs), and metabolic parameters, high-sensitivity C-reactive protein (hsCRP), oxidative stress markers and renal function were examined before and after the supplement.

RESULTS

Despite a significant reduction in serum triglycerides (-0.47 mmol/l, P < 0.01), 12-week supplement of fish oil did not improve vascular function as determined by FMD (+0.16%, P = 0.83) and circulating EPC count (+4 cells/microl, P = 0.78). Furthermore, fish-oil supplement did not have any significant treatment effects on hsCRP, oxidative stress, low- and high-density lipoprotein and glycated haemoglobin (HbA(1c)) (all P > 0.05). In contrast, serum creatinine was lower (-4.5 micromol/l, P = 0.01) in fish-oil-treated patients as compared with control subjects.

CONCLUSIONS

This study demonstrated that 12 weeks of fish-oil supplement had no significant beneficial effect on vascular endothelial function, but improved renal function without changes in endothelial function, metabolic profiles, blood pressure, inflammation or oxidative stress in patients with Type 2 DM.

The effect of n-3 long-chain polyunsaturated fatty acid supplementation on urine protein excretion and kidney function: meta-analysis of clinical trials

BACKGROUND

Chronic kidney disease is a major worldwide problem. Although epidemiologic and experimental studies suggest that n-3 long-chain polyunsaturated fatty acid (n-3 LCPUFA) supplementation may prevent or slow the progression of kidney disease, evidence from clinical trials is inconsistent.

OBJECTIVE

The objective was to combine evidence from controlled clinical trials to assess the effect of n-3 LCPUFA supplementation on the change in urine protein excretion (UPE) and on glomerular filtration rate (GFR).

DESIGN

We performed a meta-analysis of clinical trials that tested the effect of n-3 LCPUFA supplementation on UPE, a marker of kidney damage, and on GFR, a marker of kidney function. A random-effects model was used to pool SD effect size (Cohen's d) across studies.

RESULTS

Seventeen trials with 626 participants were included in the meta-analysis. Most trials focused on patients with a single underlying diagnosis: IgA nephropathy (n = 5), diabetes (n = 7), or lupus nephritis (n = 1). The dose of n-3 LCPUFAs ranged from 0.7 to 5.1 g/d, and the median follow-up was 9 mo. In the pooled analysis, there was a greater reduction in UPE in the n-3 LCPUFA group than in the control group: Cohen's d for all trials was -0.19 (95% CI: -0.34, -0.04; P = 0.01). In a patient with 1 g UPE/d , this corresponds to a reduction of 190 mg/d. Effects on GFR were reported in 12 trials. The decline in GFR was slower in the n-3 LCPUFA group than in the control group, but this effect was not significant (0.11; 95% CI: -0.07, 0.29; P = 0.24).

CONCLUSIONS

In our meta-analysis, use of n-3 LCPUFA supplements reduced UPE but not the decline in GFR. However, small numbers of participants in trials, different methods of assessing proteinuria and GFR, and inconsistent data reporting limit the strength of these conclusions. Large, high-quality trials with clinical outcomes are warranted.