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 of unsweetened and sweetened tea consumption with the risk of new-onset chronic kidney disease: Findings from UK Biobank and Coronary Artery Risk Development in Young Adults (CARDIA) study.

Background: The association between tea consumption and chronic kidney disease (CKD) remained inconsistent. We aimed to evaluate the association of tea consumption with new-onset CKD and examine the effects of common additives (milk and sweeteners) and genetic variations in caffeine metabolism on the association. Methods: 176 038 and 3104 participants free of CKD at baseline in the United Kingdom Biobank (UK Biobank) and Coronary Artery Risk Development in Young Adults (CARDIA) study were included, respectively. Dietary information was collected using 24-hour dietary recall questionnaires. The study outcome was new-onset CKD. Results: In the UK Biobank, during a median follow-up of 12.13 years, 3535 (2.01%) participants developed CKD. Compared with tea non-consumers, the risk of new-onset CKD was significantly lower in unsweetened tea consumers (hazard ratio (HR) = 0.84, 95% confidence interval (CI) = 0.76-0.93), but not in sweetened tea consumers (HR = 0.96, 95% CI = 0.85-1.08), regardless of whether milk was added to tea. Accordingly, relative to tea non-consumers, the adjusted HRs (95% CIs) of new-onset CKD for participants who reported drinking unsweetened tea 1.5 or fewer, >1.5 to 2.5, >2.5 to 3.5, >3.5 to 4.5, and >4.5 drinks/d were HR = 0.86, 95% CI = 0.75-0.99; HR = 0.88, 95% CI = 0.78-1.00; HR = 0.83, 95% CI = 0.73-0.94; HR = 0.83, 95% CI = 0.72-0.95; and HR = 0.86, 95% CI = 0.75-0.99. Moreover, the association of unsweetened tea consumption with new-onset CKD was stronger among those with faster genetically predicted caffeine metabolism levels, although the interaction was insignificant (P-value interaction = 0.768). Consistently, in the CARDIA study, compared with tea non-consumers, a significantly lower risk of new-onset CKD was found in unsweetened tea consumers (HR = 0.80, 95% CI = 0.65-0.98) but not in sweetened tea consumers (HR = 0.97, 95% CI = 0.70-1.34). Conclusions: Compared with tea non-consumers, consumption of unsweetened tea, but not sweetened tea, was significantly associated with a lower risk of new-onset CKD, regardless of whether milk was added.

Habitual glucosamine use, APOE genotypes, and risk of incident cause-specific dementia in the older population.

BACKGROUND: The relationship of glucosamine use with incident dementia in the older population remains uncertain. We aimed to evaluate the longitudinal association between habitual glucosamine supplement and the risk of cause-specific dementia and examine the possible effect modifiers on this association. METHODS: The study included 214,945 participants over the age of 60 who had available information on glucosamine use and did not have dementia at baseline in the UK Biobank. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. The primary outcome was incident vascular dementia, incident Alzheimer's disease, and incident frontotemporal dementia, respectively. RESULTS: Over a median follow-up duration of 12 years, 1039, 1774, and 122 participants developed vascular dementia, Alzheimer's disease, and frontotemporal dementia, respectively. Overall, habitual glucosamine use was significantly associated with a lower risk of incident vascular dementia (adjusted HR, 0.82; 95%CI, 0.70-0.96), but not significantly associated with incident Alzheimer's disease (adjusted HR, 1.02; 95%CI, 0.92-1.14) and incident frontotemporal dementia (adjusted HR, 0.95; 95%CI, 0.63-1.43). Moreover, the inverse association between habitual glucosamine use and incident vascular dementia was more pronounced in participants with concomitant supplement of calcium (P-interaction = 0.011), and those without concomitant supplement of zinc (P-interaction = 0.018). However, APOE ε4 dosage and baseline cognitive function did not significantly modify the relationships of glucosamine use with incident vascular dementia or Alzheimer's disease (All P-interactions > 0.05). CONCLUSIONS: Regardless of APOE genotypes and baseline cognitive function, habitual glucosamine use was significantly inversely associated with incident vascular dementia in the older population.

Tea Consumption and New-Onset Acute Kidney Injury: The Effects of Milk or Sweeteners Addition and Caffeine/Coffee.

Aims: To explore the relationship between tea consumption and the risk of incident acute kidney injury (AKI) and examine the effects of coffee consumption, genetic variation in caffeine metabolism, and the use of tea additives (milk and sweeteners) on this association. Methods: Using data from the UK Biobank, 498,621 participants who were free of AKI and had information on tea intake were included. Black tea is the main type consumed in this population. Dietary information was collected from standardized and validated Food-Frequency Questionnaire (FFQ). Outcome was incident AKI, determined via primary care data, hospital inpatient data, death register records, or self-reported data at follow-up visits. Results: After a median follow-up period of 12.0 years, 21,202 participants occurred AKI. Overall, there was a reversed J-shaped relation between tea consumption and incident AKI, with an inflection point at 3.5 cup/d (p for nonlinearity < 0.001). The relation was similar among participants with different genetically predicted caffeine metabolism (p-interaction = 0.684), while a more obvious positive association was found between heavy tea consumption and AKI when more coffee was consumed (p-interaction < 0.001). Meanwhile, there was a reversed J-shaped relationship for drinking tea with neither milk nor sweeteners, and a L-shaped association for drinking tea with milk (with or without sweeteners) with incident AKI. However, no significant association was found between drinking tea with sweeteners only and incident AKI. Conclusions: There was a reversed J-shaped relation between tea consumption and incident AKI, suggesting that light to moderate tea consumption, especially adding milk, can be part of a healthy diet.

Associations between Serum 25-hydroxyvitamin D, Sun Exposure Time, Dietary Vitamin D Intake, and New-Onset Acute Kidney Injury among 413,169 UK Adults.

BACKGROUND: The prospective associations of serum 25(OH)D, sun exposure time, and dietary vitamin D with risk of acute kidney injury (AKI) are unclear. OBJECTIVES: We aimed to evaluate the relations of serum 25(OH)D, sun exposure time, and dietary vitamin D intake with new-onset AKI and examine whether genetic susceptibility modified such associations. METHODS: A total of 413,169 participants (mean age was 56.4 y, 47.2% were male) from UK Biobank without prior AKI were included. Sun exposure time was expressed as time spent outdoors. Genetic risk scores were calculated by 263 single nucleotide polymorphisms, which showed significant associations with the estimated glomerular filtration rate. The primary outcome was new-onset AKI. Cox proportional hazards models were used to estimate the HRs and (95% CIs). RESULTS: During a median follow-up duration of 12 y, 16,938 (4.1%) participates developed new-onset AKI. Compared with those with serum 25(OH)D <25 nmol/L, significantly lower risks of new-onset AKI were found between participants with 25(OH)D 25 to <50 nmol/L (adjusted HR: 0.76; 95% CI: 0.73, 0.80), and ≥50 nmol/L (adjusted HR: 0.69; 95% CI: 0.65, 0.72). Moreover, in summer, participants who spent ≥4 h outdoors per day (tertile 3) had a significantly lower risk of new-onset AKI (adjusted HR: 0.90; 95% CI: 0.86, 0.95) than those who spent <2 h outdoors per day (tertile 1). Similar results were found for time spent outdoors in winter. In addition, those in quintile 5 of dietary vitamin D intake showed a lower risk of new-onset AKI (≥4.2 µg/d, adjusted HR: 0.90; 95% CI: 0.82, 0.98) than those in quintile 1 (<1.0 µg/d). Genetic risks of kidney diseases did not significantly modify all the 3 above associations (all P-interactions >0.05). CONCLUSIONS: Serum 25(OH)D concentrations, time spent outdoors, and dietary vitamin D intake were all inversely associated with new-onset AKI, independent of genetic risks for kidney diseases.

Associations of habitual glucosamine supplementation with incident gout: a large population based cohort study.

OBJECTIVES: The association between habitual glucosamine use and incident gout has not been examined in previous studies. We aimed to evaluate the association of habitual use of glucosamine with the risk of gout in general population. METHODS: A total of 436,594 participants (55.4% female) without prior gout at baseline who completed a questionnaire on supplementation use, which included glucosamine, in the UK Biobank were enrolled. Incident gout was recorded from self-report, death register, primary care, and hospital admission data. RESULTS: At baseline, 53,433 (22.1%) females and 30,685 (15.8%) males reported habitual glucosamine use. During a median follow-up period of 12.1 years, 1718 (0.7%) females and 5685 (2.9%) males developed gout. After multivariable adjustment for major risk factors, glucosamine use was associated with a significantly lower risk of incident gout in females (hazard ratio [HR], 0.81, 95% confidence interval [CI], 0.71-0.92), but not in males (HR, 1.05, 95% CI, 0.97-1.13), compared with non-use (P-interaction < 0.001). Among females, the inverse association between glucosamine use and gout was stronger in participants with diuretics use (HR, 0.64, 95% CI, 0.50-0.81) than those without diuretics use (HR, 0.89, 95% CI, 0.77-1.03) (P-interaction = 0.015). Moreover, gout genetic risk scores did not significantly modify the association between glucosamine use and the risk of incident gout in males (P-interaction = 0.548) or females (P-interaction = 0.183). CONCLUSIONS: Habitual glucosamine use to relieve osteoarthritis pain was related to lower risk of gout in females, but not in males.

Relationship of several serum folate forms with kidney function and albuminuria: cross-sectional data from the National Health and Nutrition Examination Surveys (NHANES) 2011-2018.

We aim to examine the relation of several folate forms (5-methyltetrahydrofolate (5-mTHF), unmetabolised folic acid (UMFA) and MeFox) with kidney function and albuminuria, which remained uncertain. The cross-sectional study was conducted in 18 757 participants from National Health and Nutrition Examination Survey 2011-2018. The kidney outcomes were reduced estimated glomerular filtration rate (eGFR) (<60 ml/min/1·73 m2), microalbuminuria (albumin:creatinine ratio (ACR) of 30-299 mg/g) and macroalbuminuria (ACR ≥ 300 mg/g). Overall, there were significant inverse associations between serum 5-mTHF and kidney outcomes with significant lower prevalence of reduced eGFR (OR, 0·71; 95 % CI: 0·57, 0·87) and macroalbuminuria (OR, 0·65; 95 % CI: 0·46, 0·91) in participants in quartiles 3-4 (v. quartiles 1-2; both Pfor trend across quartiles <0·05). In contrast, there were significant positive relationship between serum UMFA and kidney outcomes with significant higher prevalence of reduced eGFR in participants in quartiles 2-4 (v. quartile 1; OR, 2·12; 95 % CI: 1·45, 3·12; Pfor trend <0·001) and higher prevalence of macroalbuminuria in participants in quartile 4 (v. quartiles 1-3; OR, 1·46; 95 % CI: 1·06, 2·01; Pfor trend <0·001). However, there was no significant associations of 5-mTHF and UMFA with microalbuminuria. In addition, there were significant positive relationships of serum MeFox with reduced eGFR, microalbuminuria and macroalbuminuria (all Pfor trend <0·01). In conclusion, higher 5-mTHF level, along with lower UMFA and MeFox level, was associated with lower prevalence of kidney outcomes, which may help counsel future clinical trials and nutritional guidelines regarding the folate supplement.

Habitual Fish Oil Supplementation and Incident Chronic Kidney Disease in the UK Biobank.

BACKGROUND: To explore the relation of habitual fish oil use with the risk of chronic kidney diseases (CKD). METHODS: 408,023 participants (54.2% female) without prior CKD and with completed information regarding their consumption of major food groups and fish oil in the UK Biobank were enrolled. Fish oil use and dietary intakes were assessed by touch screen questionnaire and food frequency questionnaire, respectively. Incident CKD was recorded from hospital inpatient records. RESULTS: At baseline, 128,843 (31.6%) participants reported taking fish oil supplements. During a median follow-up period of 12.0 years, a total of 10,782 (2.6%) participants developed CKD. With adjustments for important confounders, habitual fish oil use was associated with a significantly lower hazard of incident CKD (hazard ratio [HR], 0.90; 95% confidence interval [CI], 0.87-0.95), compared with non-use. Consistently, participants reporting ≥2 servings/week of oily fish (HR, 0.86; 95% CI, 0.79-0.94) and nonoily fish (HR, 0.86; 95% CI, 0.77-0.97) consumption had a lower hazard of incident CKD compared to those reporting no consumption ever. Additionally, among the 97,914 participants with data on plasma fatty acid, there were significant inverse relationships of plasma omega-3 polyunsaturated fatty acid (PUFA) (per SD increment, HR, 0.89, 95% CI, 0.84-0.94) and eicosatetraenoic acid (per SD increment, HR, 0.91, 95% CI, 0.87-0.96) with incident CKD. CONCLUSIONS: Habitual fish oil use was associated with a lower hazard of CKD, which was further confirmed by the consistent inverse relations between fish consumption and circulating omega-3 PUFA concentration with incident CKD.

Aerobic removal of iodinated contrast medium by nano-sized zero-valent iron: A combination of oxidation and reduction.

The removal performance and mechanisms of diatrizoate (DTA), a typical iodinated contrast medium, from water by nano-sized zero-valent iron (nZVI) under aerobic conditions were investigated in this study. Reactive oxygen species (ROS) and transformation products were detected with electron spin resonance and liquid chromatography electrospray ionization tandem mass spectrometry, respectively. Furthermore, the effects of several operational parameters on DTA removal were illustrated. The results showed that nZVI had a much higher DTA removal ability compared to microscale zero-valent iron (mZVI) in the presence of oxygen. Moreover, the detection of ROS and I- as well as the analysis of intermediate products suggested a combination of oxidation and reduction pathways for DTA removal by nZVI under aerobic conditions. Additionally, a high dosage of nZVI and acidic conditions led to the enhancement of DTA removal, while nZVI aging, as well as chloride and nitrate ions in the solution, had negative effects on the degradation of DTA by nZVI in the presence of oxygen.