Urinary Markers Research Articles

Interconnected Pathways: Exploring Inflammation, Pain, and Cognitive Decline in Osteoarthritis

The relationship among inflammation, pain, and cognitive decline in osteoarthritis (OA) patients is complex and has not been sufficiently explored; therefore, we undertook this research to evaluate how OA-related inflammation and pain affect cognitive functions, as well as to examine the potential of urinary markers as indicators of these conditions. This study examined fifty OA patients through clinical and cognitive assessments, morphological analyses, urinary biomarkers, and bioinformatics. Morphologically, 24% of patients had moderate to high synovial inflammation, which was significantly correlated with depressive symptoms, pain intensity, and self-reported anxiety. The Montreal Cognitive Assessment indicated minimal decline in most patients but showed negative correlations with age and inflammation severity. Urinary TNF-α and TGF-β1 levels positively correlated with body mass index and pain and synovitis score and immune cell infiltration, respectively. In contrast, cartilage oligomeric matrix protein and C-telopeptides of type II collagen showed inverse correlations with pain duration and cognitive function, respectively. Distinct patient clusters with higher inflammation were identified and were associated with reported pain and depressive symptoms. Urinary TNF-α and TGF-β1 can serve as biomarkers reflecting inflammation and disease severity in OA. This study suggests that synovial inflammation may be linked to mental and cognitive health in some patient cohorts.

Systematic review and meta-analysis of biological variation data of urine albumin, albumin to creatinine ratio and other markers in urine

IntroductionSignificant variations in Biological Variation (BV) estimates have been reported for urine markers. This study aimed to systematically review and critically appraise BV studies for albumin, creatinine, albumin-to-creatinine ratio (ACR), and other urine markers to perform a meta-analysis of eligible studies. MethodsPublications were identified through a systematic search and evaluated using the Biological Variation Data Critical Appraisal Checklist (BIVAC). BIVAC-compliant studies (grades A-C; A being fully compliant) conducted in healthy individuals were included in the meta-analysis, providing within-subject (CVI) and between-subject (CVG) BV estimates with 95% confidence intervals for various sample collection types. ResultsOut of 37 studies evaluated, 16 were included (one grade A, three B, twelve C). No eligible publications were identified for meta-analysis of albumin and ACR. Limited data were available for first-morning urine specimens. A CVI between 15% and 30% was found for most measurands in 24-hour urine samples, while CVI estimates for random urine appeared higher. ConclusionPublished BV studies on urine markers utilized different sample collections and reporting units. Most were considered unfit for use or ineligible for meta-analysis. Given the critical role of urine albumin and ACR in chronic kidney disease risk assessment, there is a need for more BIVAC-compliant studies.

Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial

Abstract Background Heart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) detects many sequenced peptides, for >70% derived from collagens. Purpose UPP and serum fibrosis markers were analysed together in patients at risk of HF with as objective to generate insights into the antifibrotic action of spironolactone. Methods In the open-label HOMAGE trial, patients were randomised to usual therapy combined or not with spironolactone 25-50 mg/d and followed for 9 months (n=290; 23.8% women; median age: 73 years). UPP was done by capillary electrophoresis coupled with mass spectrometry; 1498 urinary peptides with detectable signal in ≥30% of patients were analysed. Serum markers of COL1A1 synthesis (PICP and PICP/CITP) were measured. After rank normalisation of the biomarker distributions, between-group differences in their changes were assessed by multivariable-adjusted models. Correlations between the changes in urinary peptides and in serum PICP and PICP/CITP were compared between groups using Fisher Z transform. Results Among all the urinary peptides, only the changes in collagen fragments remained significantly different (p<0.05) between randomisation groups after accounting for baseline levels, covariables and multiple testing. Compared to the control group, spironolactone reduced 16 of 27 collagen-derived urinary peptides. From baseline to 9 months, serum PICP and the PICP/CITP ratio decreased from 79.0 to 75.4 µg/L and from 21.3 to 18.3, respectively (p≤0.0129), reflecting decreased COL1A1 synthesis. Spironolactone did not affect the correlations between changes in urinary COL1A1 fragments and the serum fibrosis markers. Conclusions Spironolactone downregulated urinary collagen-derived peptides, probably by shrinking the body-wide pool of collagens. Spironolactone did not affect the interaction between urinary and serum fibrosis markers, suggesting that collagen scaffolding is maintained, thereby explaining why some urinary collagen fragments increased. Combining urinary and serum fibrosis biomarkers opens new avenues for discovery of antifibrotic drugs and refines insight in the action of antifibrotic drugs.Figure 1Figure 2

Evaluation of the Effect of an α-Adrenergic Blocker, a PPAR-γ Receptor Agonist, and a Glycemic Regulator on Chronic Kidney Disease in Diabetic Rats.

Diabetic nephropathy (DN) is a globally widespread complication of diabetes mellitus (DM). Research indicates that pioglitazone and linagliptin mitigate the risk of DN by reducing inflammation, oxidative stress, and fibrosis. The role of tamsulosin in DN is less studied, but it may contribute to reducing oxidative stress and inflammatory responses. The protective effects of combining pioglitazone, linagliptin, and tamsulosin on the kidneys have scarcely been investigated. This study examines the individual and combined effects of these drugs on DN in Wistar rats. Diabetic rats were treated with tamsulosin, pioglitazone, and linagliptin for six weeks. We assessed food and water intake, estimated glomerular filtration rate (eGFR), histological markers, urea, creatinine, glucose, NF-κB, IL-1, IL-10, TGF-β, and Col-IV using immunofluorescence and qPCR. The DN group exhibited hyperglycaemia, reduced eGFR, and tissue damage. Tamsulosin and linagliptin improved eGFR, decreased urinary glucose, and repaired tissue damage. Pioglitazone and its combinations restored serum and urinary markers and reduced tissue damage. Linagliptin lowered serum creatinine and tissue injury. In conclusion, tamsulosin, linagliptin, and pioglitazone demonstrated renoprotective effects in DN.

Plasma and serum volume remain unchanged following a 12-h fast from food and drink despite changes in blood and urinary hydration markers.

The effect of mild dehydration on plasma and serum volume has not been well established. Furthermore, the ability of urinary and blood biomarkers to monitor small hydration changes have not been solidified. There were two objectives of this research: 1. Determine if mild dehydration affects plasma and serum volume; 2. Determine if mild dehydration can be detected better by urinary or blood biomarkers. 47 subjects were recruited; 10 subjects were removed from the study and 37 subjects (27% male) completed the study. This was a crossover study design such that each subject underwent all protocols in a counterbalanced order. Protocols consisted of 12-h dehydration, 12-h hydration, and control. Neither plasma volume (p = 0.914), plasma volume status (p = 0.649), nor serum volume (p = 0.273) were different among protocols. Body mass (p < 0.001) was lower following the dehydration protocol. Urine color (p < 0.001), urine osmolality (p < 0.001), urine specific gravity (p < 0.001), serum osmolality (p < 0.001), and plasma osmolality (p < 0.001) were all lower following the hydration protocol. Hematocrit (p = 0.842) and hemoglobin concentration (p = 0.558) were not different among protocols. Dehydration did not affect plasma or serum volume. Therefore, a 12-h fast from food and water as done in this study will not likely affect laboratory test results of biomarker concentration. All 3 urinary measures were able to detect changes in hydration status, whereas only 2 blood measures were able to detect changes in hydration status. This may indicate that urinary measures are best at detecting small changes in hydration status.

Bladder Cancer detection by urinary methylation markers GHSR/MAL: a validation study

PurposeAlthough cystoscopy is a reliable tool for detecting bladder cancer, it poses a high burden on patients and entails high costs. This highlights the need for non-invasive and cost-effective alternatives. This study aimed to validate a previously developed urinary methylation marker panel containing GHSR and MAL.MethodsWe enrolled 134 patients who underwent cystoscopy because of hematuria, including 63 individuals with primary bladder cancer and 71 with non-malignant findings. Urine samples were self-collected at home and sent via regular mail. Subsequently, DNA was extracted and the hypermethylation of GHSR and MAL was evaluated using quantitative methylation-specific polymerase chain reaction. The performance of methylation markers was assessed using area-under-the-curve (AUC) analysis and sensitivity and specificity based on pre-established cut-off values.ResultsValidation of the marker panel GHSR/MAL resulted in an AUC of 0.87 at 79% sensitivity and 80% specificity. Sensitivity was comparable to the previous investigation (P > 0.9), though specificity was significantly lower (P = 0.026). Sensitivity was higher for high-grade tumors compared to low-grade tumors (94% vs. 60%, P = 0.002).ConclusionValidation of the GHSR/MAL methylation marker panel on at home collected urine samples confirms its robust performance for bladder cancer detection in a hematuria population, and underscores the diagnostic potential for future clinical application.

The relationship between urodynamic bladder compliance and urinary fibrosis markers in children with neurogenic bladder dysfunction

BackgroundDecreased bladder compliance is an important risk factor for upper urinary tract in children with neurogenic bladder dysfunction (NBD). Urodynamics is the gold standard in determining bladder compliance. ObjectiveTo investigate the relationship between low bladder compliance and urinary fibrosis markers in NBD. Study designSpina bifida patients with NBD, who admitted between March 2021 and July 2021 were included. Patients with low compliant bladders, no renal scar, no recurrent urinary tract infections formed low compliance, LC group. Normal compliance, NC group, was comprised of patients with normocompliant bladders and the same characteristics. Control group (Group C) consisted of patients for outpatient surgery and had no known bladder dysfunction. Compliance was calculated with the formula ΔV/ΔP and a value of under 15 ml/cmH2O was accepted as low. Age, gender, urine density, serum urea, creatinine levels and urodynamic parameters were noted. Urinary type 1, type 3 collagen and its precursor procollagen type 3 and serum type 1 and 3 collagen were determined by ELISA. Results72 patients were included (LC group, n:31, NC group, n:24, C group n:17, mean age 7,39±1,24 years). No significant difference was observed in the comparison of age, gender, urine density and serum urea and creatinine values. No significant difference was observed between the LC and NC groups for urodynamic parameters, except for bladder compliance. Urinary collagen type 1 in LC group (11,71±3,02 ng/ml) was found to be significantly higher than that of the C group (9,45±1,97 ng/ml) (p=0,03). Urinary procollagen type 3 was significantly higher in LC group (103,15±24 ng/ml) when compared to C group (82,42±22,26 ng/ml) (p=0,016). Urinary collagen type 1 level above 9,20 ng/ml was 80,6% sensitive and 70,6% specific and urinary procollagen type 3 level above 78 ng/ml was 87% sensitive and 70,6% specific in predicting low compliance. DiscussionThis study seems to be the first study in the literature to evaluate bladder fibrosis and compliance, biochemically, by measuring urinary collagen levels in NBD. Urinary fibrosis markers are not currently an alternative to urodynamics for bladder compliance, but they may have potential to reduce the need for urodynamics with this indication. ConclusionDetermination of urinary collagen levels may be a marker of bladder wall fibrosis and may indirectly show decreased bladder compliance. It is plausible to say that invasive methods such as urodynamics may be less preferred for defining bladder compliance, instead, urinary biomarkers may have merit for this purpose in the future.

Evaluation of urinary podocin and nephrin as markers of podocyturia in dogs with leishmaniosis

BackgroundRenal disease is the main cause of death in canine leishmaniosis. Detection of an active glomerular injury is important to identify early renal damage and to prevent the development of chronic kidney disease. Podocyturia can indicate renal injury, and podocyte-associated molecules such as podocin and nephrin can be used to identify podocyturia. The purpose of the study was to evaluate urinary podocin and nephrin concentrations in dogs with leishmaniosis as markers of podocyturia.MethodsA total of 35 healthy dogs and 37 dogs with leishmaniosis were enrolled in the study. Dogs with leishmaniosis were classified according to the staging of the International Renal Interest Society (IRIS). Urinary podocin and nephrin concentrations were measured in all dogs with a validated enzyme-linked immunosorbent assay test and normalized to creatinine (uPoC and uNeC, respectively). The demographic, clinical, and laboratory data from both groups were analyzed and compared. Subsequently, the laboratory results were analyzed and compared according to IRIS staging in dogs in IRIS stage I and dogs in IRIS stage II + III + IV. The Pearson’s correlation test evaluated the relationship between urinary markers of podocyturia.ResultsCompared with healthy dogs, lower urinary podocin [median values (IQR): 15.10 (11.75–17.87) ng/ml versus 8.63 (7.08–13.56) ng/ml; P < 0.01] and nephrin [median values (IQR): 3.2 (3.62–5.43) ng/ml versus 2.67 (2.06–3.44) ng/ml; P < 0.01] were found in infected sick dogs. No significant differences were observed in the uPoC and uNeC between the two groups. Urinary nephrin and podocin concentrations were higher in healthy dogs and in dogs in IRIS stage I (both P < 0.05) compared with dogs in IRIS stages II + III + IV. No significant differences were found for uPoC and uNeC between healthy dogs and dogs with leishmaniosis in different IRIS clinical stages.ConclusionsDogs with leishmaniosis had a low concentration of podocin and nephrin in more advanced IRIS clinical stages, when kidney disease was more severe compared with healthy dogs and dogs in IRIS stage I with mild disease. Urinary nephrin was detectable for the first time in healthy non-infected dogs.Graphical

Effect of SGLT2 Inhibitor Therapy on Urinary Podocyte Markers in Diabetic Kidney Disease

Effect of SGLT2 Inhibitor Therapy on Urinary Podocyte Markers in Diabetic Kidney Disease

Effect of brown alga kurome (Ecklonia Cava ssp. Kurome) supplementation on urinary oxidative stress markers and advanced glycation end products

Effect of brown alga kurome (Ecklonia Cava ssp. Kurome) supplementation on urinary oxidative stress markers and advanced glycation end products

Effects of Bardoxolone Methyl on Urinary Proximal Tubular Markers: A Subanalysis of the TSUBAKI Study

Effects of Bardoxolone Methyl on Urinary Proximal Tubular Markers: A Subanalysis of the TSUBAKI Study

90 - Effect of botulinum neurotoxin A bladder injections on urinary markers associated with inflammation and urinary infections: a study in patients with neurogenic detrusor overactivity associated incontinence.

90 - Effect of botulinum neurotoxin A bladder injections on urinary markers associated with inflammation and urinary infections: a study in patients with neurogenic detrusor overactivity associated incontinence.

Podocyte-Derived Vesicles as Urinary Markers of Kidney Function

Podocyte-Derived Vesicles as Urinary Markers of Kidney Function

Lung-Kidney Axis in Cystic Fibrosis: Early Urinary Markers of Kidney Injury Correlate with Neutrophil Activation and Worse Lung Function.

Adult people with cystic fibrosis (PwCF) have a higher risk of end-stage kidney disease than the general population. The nature and mechanism of kidney disease in CF are unknown. This study quantifies urinary kidney injury markers and examines the hypothesis that neutrophil activation and lung infection are associated with early kidney injury in CF. Urinary total protein, albumin, and markers of kidney injury and neutrophil activation, normalized to creatinine, as well as urinary immune cells, were quantified in CF (n = 48) and healthy (n = 33) cohorts. Infection burden and chronicity were defined by sputum culture and serum titers of anti-bacterial antibodies. PwCF had increased urinary protein levels, consisting of low-molecular-weight tubular injury markers, independent of glomerular filtration rate (eGFR). This finding suggests subclinical renal injury processes. Urinary analysis of the CF cohort identified different associations of urinary injury markers with aminoglycoside exposure, lung function, and neutrophil activation. High urinary KIM-1 levels and increased prevalence of neutrophils among urine immune cells correlated with decreased lung function in PwCF. The relationship between tubular injury and decreased lung function was most prominent in patients harboring chronic Pseudomonas aeruginosa infection. Increased urinary tubular injury markers in PwCF suggest early subclinical renal injury not readily detected by eGFR. The strong association of high urinary KIM-1 and neutrophils with diminished lung function and high Pseudomonas aeruginosa burden suggests that pulmonary disease may contribute to renal injury in CF.

Urinary proteomic signature of mineralocorticoid receptor antagonism by spironolactone: evidence from the HOMAGE trial

ObjectiveHeart failure (HF) is characterised by collagen deposition. Urinary proteomic profiling (UPP) followed by peptide sequencing identifies parental proteins, for over 70% derived from collagens. This study aimed to refine...

Improving the Determination of Carbon Isotope Ratios of Endogenous Steroids Found in Human Serum.

The determination of serum concentrations of testosterone (T) and 4-androstenedione (A4) was implemented into the steroidal module of the Athlete Biological Passport in 2023. Monitoring T, A4, and the ratio of T/A4 in a longitudinal manner enables the detection of the misuse of low-dose T administrations especially in female athletes, whereas urinary markers of the steroid profile may not be influenced significantly. In contrast to the urinary steroid profile, knowledge on confounding factors regarding serum concentrations of T and A4 is yet comparably scarce, and corroborating exogenous sources of the target analytes by isotope ratio mass spectrometry (IRMS) is desirable. In a recent study, it was demonstrated that carbon isotope ratios (CIRs) of serum steroids can be determined if analyte concentrations permit. The therein-employed method utilized 2D-GC/IRMS, and only a limited number of potential endogenous reference compounds were available. The here-presented approach uses complementary analyte purification strategies, addressing previous limitations. A high-performance liquid chromatography cleanup was developed and fully validated for serum steroids in order to enable all doping control laboratories to potentially implement this method alongside existing protocols for urinary steroids. Besides the already-investigated endogenous steroids cholesterol, dehydroepiandrosterone sulfate, androsterone sulfate, and epiandrosterone sulfate, two additional steroids were included in the test menu, namely, pregnenolone sulfate and 5-androstene-3β,17β-diol sulfate. Serum steroid concentrations down to 25 ng/mL were found to allow robust CIR determinations, and a reference population encompassing 124 male and female athlete samples was investigated to enable the calculation of population-based thresholds for all relevant steroid combinations.

Association of Angiotensin Converting Enzyme (insertion\deletion) and Angiotensin II Type 1 Receptor (A1166C) gene polymorphisms with diabetic nephropathy in Iraqi type 2 diabetic patients

Renin-angiotensin-aldosterone system abnormalities are the most prevalent cause of renal hemodynamic abnormalities, and candidate genes in this system are involved in the etiology of diabetic nephropathy (DN). A polymorphism in the angiotensin converting enzyme (ACE) gene I(insertion)\D(deletion) has been correlated to plasma ACE levels. Furthermore, the Angiotensin II Type 1 Receptor AGT1R (A1166C) expression pattern is highly related to nephropathy. The objectives of this study involved evaluating the frequency of the ACE (I/D) and AGT1R (A1166C) gene polymorphisms and investigating the association of these polymorphism with the development of DN in Iraqi patients with Type 2 diabetes mellitus (T2DM) and evaluating the levels of several urinary and serum markers in relation to studied polymorphisms. This is a cross-sectional study that included 161 T2DM patients whom were divided into two groups: T2DM with DN(included 98 patients) and normalbuminuric T2DM (included 63 patients). ACE gene polymorphism analysis revealed that the D allele was far more prevalent in DN patients compared to normalbuminuric patients (60.2% vs. 50.8%), while the I allele frequency was 39.8% in DN and 49.2% in normoalbuminuric patients. In addition, DN patients carrying the DD genotype had higher serum kidney injury molecule 1 (KIM1), serum cystatin C (CysC), and HbA1C and lower glomerular filtration rate (GFR) compared to ID+II genotypes. For AGT1R (A1166C), both DN and normalbuminuric patients had a comparable high prevalence of the AA genotype, followed by the AC genotype, while the CC genotype had been seen only in 3 patients. In conclusion, among the studied T2DM patients, individuals with DD genotype had higher frequency of DN and had 2-fold risk for DN compared to II genotype which had the lowest risk for DN. Also the current study shows that the A1166C polymorphisms of AGT1R distribution frequency were similar for both study groups with higher frequency for A allele compared to C allele and not associated with risk of DN in Iraqi T2DM Keywords: Angiotensin Converting Enzyme (I\D) gene polymorphism, Angiotensin II Type 1 Receptor (A166C) gene polymorphisms, Cystatin C, Diabetic nephropathy, Kidney injury molecule1.

Human phase-I metabolism of three synthetic cannabinoids bearing a cumyl moiety and a cyclobutyl methyl or norbornyl methyl tail: Cumyl-CBMEGACLONE, Cumyl-NBMEGACLONE, and Cumyl-NBMINACA.

Synthetic cannabinoid receptor agonists (SCRAs) continue to show high prevalence on the new psychoactive substances drug market. Around 2019-2020, new SCRAs bearing a cumyl moiety emerged: Cumyl-CBMEGACLONE and Cumyl-NBMEGACLONE, carrying a cyclobutyl methyl (CBM) and a norbornyl methyl moiety (NBM) attached to the γ-carbolinone core. These were followed by Cumyl-NBMINACA, the indazole carboxamide analog of Cumyl-NBMEGACLONE. The study aimed at evaluating the human phase-I metabolism of these compounds and at identifying suitable urinary markers to prove their consumption. After enzymatic hydrolysis, 14 authentic urine samples (eight for Cumyl-CBMEGACLONE, four for Cumyl-NBMEGACLONE, and two for Cumyl-NBMINACA) were analyzed by liquid chromatography-quadrupole time-of-flight mass spectrometry. Results were compared with in vitro metabolites generated by pooled human liver microsomes incubation. Fifteen human phase-I metabolites were identified for Cumyl-CBMEGACLONE, nine for Cumyl-NBMEGACLONE, and thirteen for Cumyl-NBMINACA. The main in vivo metabolites were built by monohydroxylation, dihydroxylation, or trihydroxylation. The following urinary biomarkers are suggested for detecting the consumption of the investigated SCRAs: products of monohydroxylation at the CBM and at the core for Cumyl-CBMEGACLONE; two products of monohydroxylation at the norbonyl methyl tail for Cumyl-NBMEGACLONE; and metabolites built by dihydroxylation at the NBM substructure and by an additional hydroxylation at the cumyl moiety for Cumyl-NBMINACA.

The administration route of indigestible gut permeability markers modulates urinary marker recovery in calves

Indigestible gut permeability markers are used to assess gut integrity and can be administered to calves via a milk meal (MM) or orally pulsed (OP). This study investigated how marker administration route (ADM_R) affects the estimation of gut permeability in relation to MR fat inclusion. Thirty-two male Holstein calves were blocked based on their arrival sequence at the facility. Within each block of 4 calves, calves were randomly assigned to one of 2 treatments (n = 16/ treatment): a MR high in lactose (HL) and a MR high in fat (HF). During the first 5 d, calves were fed 6.0 L/d followed by 7.0 L/d offered in 2 meals per day at 15% solids. To evaluate gut permeability, indigestible markers (lactulose, D-mannitol, and chromium (Cr)-EDTA) were administered in 2 periods, on Tuesday and Thursday in the third week after arrival. Within each block, calves with different MR treatments were randomly assigned to a different marker ADM_R order: MM in the first period and OP in the second (n = 16) or the opposite order (n = 16). Thus, one block of 4 calves included all combinations of MR and ADM_R. Following marker administration, urine was collected over 2 sampling periods: the first from 0 to 6 h and the second from 6 to 24 h. Measurements included weekly BW and daily MR intake and fecal scoring. Intake, growth, and fecal consistency were not affected by dietary treatments nor by ADM_R. The urinary recovery of lactulose was greater in calves fed HF during the 6–24 h and the overall 24-h collection period. Consistently, D-mannitol recovery tended to be greater in calves fed HF during the 24-h collection. With OP administration, the urinary recovery of all markers was greater between 0 and 6 h, whereas in the 6–24 h period, the recovery of lactose and D-mannitol were lower. Over 24-h of collection, Cr-EDTA recovery was greater with OP. No interaction between ADM_R and MR composition was detected. This suggests that both ADM_R were equivalent in assessing the effects of dietary interventions on gut permeability. However, different ADM_R affected the trajectory and time spent by the markers in each section of the gut.

Factors associated with water consumption measured using the stable isotope techniques among Japanese adults: a cross-sectional study.

While some dietary guidelines have established daily water requirements for adults, those for older adults are not well defined. Factors associated with water turnover (WT), indicating water requirements and preformed water (PW), referring to fluids consumed from food and beverages, remain poorly understood. Therefore, we aimed to investigate these factors in Japanese adults. This cross-sectional study included 57 participants aged 54-85 years, living in Fukuoka City, Japan. The WT and PW were measured using the doubly labelled water (DLW) methods from August 2015 to September 2015. Dietary intake and physical activity were evaluated using a 3-day dietary record (DR) and a validated triaxial accelerometer, respectively. Fasting blood and urine samples, as well as environmental conditions, were assessed using a validated technique. We evaluated the variables for predicting water consumption by using a multivariate generalised linear model, with forward stepwise selection using these covariates. The median WT and PW were 2842 ml/day and 2227 ml/day, respectively. In the multivariate model, WT (R2 = 0.629) and PW (R2 = 0.621) were moderately predicted by variables such as sex, body weight, moderate-to-vigorous physical activity, water consumption estimated by DR, urinary aldosterone and osmolality, creatinine clearance and wet-bulb globe temperature. The PW estimates from DR were ~40% lower than those from DLW method, despite a significant correlation between the values. WT and PW are associated not only with lifestyle and environmental factors but also with urinary markers and kidney function. These findings provide useful insights into the differences in each individual's water requirement.