Early Morning Spot Urine Sample Research Articles

Urinary phthalate concentrations are associated with total fat mass in Thai children.

Phthalate is one of the endocrine-disrupting chemicals found in many daily consumer products. Chronic exposure to phthalate may associate with obesity and metabolic abnormalities. However, there is limited information showing a direct relationship between phthalate and body compositions. The aim of the study was to determine the association between urinary phthalate concentration and body composition measure among Thai children. A cross-sectional analytic study on urinary phthalate concentrations and body composition in elementary school children, aged 6-13years in Bangkok, was conducted during October 2019 to 2020. Urinary phthalate metabolites; (mono-methyl phthalate-MMP, mono-ethyl phthalate- MEP, mono-buthyl phthalate-MBP, and mono-ethylhexyl phthalate-MEHP), in early morning spot urine samples were measured by liquid chromatography tandem mass spectrometry (LC-MSMS) with a quantitation limit of 1ng/mL. Phthalate exposures were identified through questionnaires. Body composition was measured by Tanita BC-418®. Multivariate logistic regression analysis was performed to determine significant associations. A total of 364 children were enrolled in the study (boy 51.4%). After adjusting for confounders (sex, caregiver educations, family income, BMI-SDS: Body mass index-standard deviation score, TV watching, and exercise frequency), total urinary phthalate concentrations were associated with fat mass 8.24 (0.94, 15.53), trunk percent fat7.69 (3.26, 12.12), arm percent fat 3.69 (0.47, 6.91), arm fat mass 72.88 (1.08, 144.67), and leg fat mass 17.79 (2.37, 33.22). Higher urinary phthalate concentrations were significantly associated with elevated total fat mass among Thai school-aged children. These findings were not mediated through the degree of obesity defined by BMI. These finding emphasized to be careful when being use phthalate-containing products.

Urine protein: Urine creatinine ratio correlation with diabetic retinopathy.

Purpose:To investigate the urine protein (UP) and urine creatinine (UC) ratio in diabetes mellitus and report its influence as a risk factor for the presence and severity of diabetic retinopathy (DR).Methods:In total, 150 diabetic patients presenting to the outpatient department were included. Detailed history with informed consent and ophthalmic examination, including visual assessment, external ocular examination, anterior segment evaluation, dilated fundus examination by slit-lamp biomicroscopy, and indirect ophthalmoscopy, was done. The early morning spot urine sample was used to determine spot urine protein creatinine ratio. Association with hypertension, fasting blood sugar (FBS), and HBA1C (glycosylated Hb) were also noted.Results:Urinary PCR increased with the severity of the diabetic retinopathy (P < 0.001). HbA1c, FBS, and duration of diabetes had a direct correlation with urine PCR. ROC curve analysis showed that the optimal PCR cut-off value for predicting the risk of onset DR was 0.65. Retinopathy progressed with increasing urine PCR. Spot urine PCR strongly correlates with stages of diabetic retinopathy and proteinuria measured in 24-h urine samples.Conclusion:The study showed that urine PCR can be a marker for risk and progression of diabetic retinopathy.

The association of low-grade albuminuria with incident non-alcoholic fatty liver disease and non-invasive markers of liver fibrosis by glycaemia status.

Low-grade albuminuria, as an early marker of endothelial dysfunction and kidney damage, has been recognized as a risk factor for metabolic disorders. Epidemiological studies manifesting the association of low-grade albuminuria with the risk of incident NAFLD and fibrosis were not available. We aimed to investigate the association of low-grade albuminuria with incident NAFLD and fibrosis by glycaemia status. A prospective population-based study was performed in 3308 participants without NAFLD at recruitment. Baseline urinary albumin excretion was obtained by a first-voided early morning spot urine sample. At follow-up visit, incident NAFLD was diagnosed by hepatic ultrasound after excluding alcohol abuse and other cause of hepatic diseases. Fatty liver index (FLI) was employed to reflect liver fat content. Liver fibrosis was evaluated by NAFLD fibrosis score (NFS), fibrosis-4 score (FIB-4) and Hepamet fibrosis score (HFS) respectively. After 4.3years of follow-up, 622 (18.8%) were detected as incident NAFLD. Participants with low-grade albuminuria imposed a 40.4% [1.404 (1.112-1.772)] greater risk on incident NAFLD, and 52.0% [1.520 (1.141-2.026)], 87.4% [1.874 (1.291-2.720)] and 40.4% [1.404 (1.038-1.898)] higher risks on newly onset higher values of FLI, NFS and FIB-4 respectively. The effect of low-grade albuminuria was stronger in the subgroup of non-diabetic population. Low-grade albuminuria was independently associated with incident NAFLD and a higher probability of fibrosis, especially among non-diabetic individuals.

Cardiovascular Autonomic Function in Normotensive Men with High Salt and Low Salt Intakes

Background and Aim: The autonomic nervous system may play an important role in saltinduced increases in blood pressure (BP). The aim of this study is to assess and compare the heart rate (HR) responses to Valsalva maneuver, deep breathing and standing and BP responses to standing and sustained handgrip between normotensive men with habitual high salt intake (HSI) and low salt intake (LSI). Methods: Twenty-fourty years old normotensive men (n=34; n=17 for HSI and n=17 for LSI) were recruited by collecting 4 early morning spot urine samples. Average estimated 24-hr sodium (Na+) excretion of 4 urine samples of ≥166 mmol/day was regarded as HSI and &lt;115 mmol/day as LSI. Heart rate responses to Valsalva maneuver, deep breathing and standing (parasympathetic function tests) and BP responses to standing and sustained handgrip (sympathetic function tests) were investigated in both groups. Results: Valsalva ratio (VR) [1.64±0.36 (HSI) vs 1.78±0.49 (LSI)], deep breathing difference (DBD) [24.51±9.56 beats/min (HSI) vs 22.93±6.37 beats/min (LSI)] and 30:15 ratio [1.34 (1.12–1.46) (HSI) vs 1.19 (1.13–1.52) (LSI)] were not significantly different in both groups. Systolic blood pressure (SBP) change from lying to standing [-0.67 (-4.00–9.00) mmHg (HSI) vs 0.00 (-3.34–2.34) mmHg (LSI)] was not significantly different between the two groups whereas diastolic blood pressure (DBP) rise in sustained handgrip [18.20±3.49 mmHg (HSI) vs 14.77±4.71 mmHg (LSI)] was significantly higher in the HSI (p=0.022). Conclusion: Cardiovascular sympathetic activity appears to increase in normotensive men with habitual high salt intake.

Normal-to-mildly increased albuminuria predicts the risk for diabetic retinopathy in patients with type 2 diabetes

Albuminuria is closely associated with diabetic retinopathy (DR), but the precise role of the albumin-to-creatinine ratio (ACR) in screening for DR remains to be determined. This study aimed to investigate an ACR threshold for predicting DR in patients with type 2 diabetes. A cross-sectional study was conducted on 1,102 type 2 diabetes patients, aged ≥30 years and recruited from the Korea National Health and Nutrition Examination Survey, 2010–2011. Participants were grouped by stage of DR: mild-to-moderate nonproliferative DR (NPDR), severe NPDR, and proliferative diabetic retinopathy (PDR). An early morning spot urine sample was obtained for ACR measurement. ROC curve analysis revealed that the optimal cut-off value of ACR for predicting DR was 2.26 mg/mmol (20 μg/mg). The prevalence of ACR ≥ 2.26 mg/mmol tended to increase with severity of DR. The risk for DR in patients with ACR ≥ 2.26 mg/mmol was higher than in those with ACR < 2.26 mg/mmol. The risk for severe NPDR and PDR also increased at ACR ≥ 2.26 mg/mmol. Normal-to-mildly increased albuminuria (an ACR of 2.26 mg/mmol) may predict the risk for DR development and progression in patients with type 2 diabetes.

Nonalcoholic fatty liver disease is associated with low-grade albuminuria in Chinese adults (change not displayed)

Nonalcoholic fatty liver disease (NAFLD) was associated with higher risk of cardiovascular disease (CVD). Low-grade albuminuria was recognized as an early indicator of CVD. Epidemiological studies investigating the association between NAFLD and low-grade albuminuria were limited. To determine whether NAFLD is independently associated with the presence of low-grade albuminuria in Chinese adults. A cross-sectional community-based population study was performed in 8270 Chinese adults aged 40 years or older. A first-voided early morning spot urine sample was obtained for urinary albumin and creatinine measurements. The highest quartile of urinary albumin-to-creatinine ratio was defined as low-grade albuminuria, after excluding the participants with micro- or macroalbuminuria. NAFLD was diagnosed by using ultrasonography findings after the exclusion of alcohol abuse and other liver diseases. The prevalence of low-grade albuminuria was significantly higher in participants with NAFLD than in those without NAFLD (33.6% vs. 21.3% in men and 30.4% vs. 22.8% in women, respectively). Multivariate-adjusted logistic regression analysis revealed that NAFLD was significantly associated with increased odds ratio of low-grade albuminuria in men (odds ratio, 1.47; 95% CI, 1.16-1.87) after adjusting for multiple confounders. The significant association was not detected in women. NAFLD was significantly associated with an increased risk of present low-grade albuminuria in middle-aged and elderly Chinese men.

Urinary Lysosomal Enzyme Activities and Albuminuria in Ghanaian Patients with Type 2 Diabetes Mellitus.

Renal tubular lysosomal enzyme activities like alanine aminopeptidase (AAP) and N-acetyl-β-D-glucosaminidase (NAG) have been shown to increase in patients developing diabetic nephropathy and nephrosclerosis. This study aimed to determine the activities of N-acetyl-β-D-glucosaminidase and alanine aminopeptidase and albumin concentration in urine samples of patients with type 2 diabetes. One hundred and thirty (65 type 2 diabetic and 65 nondiabetic) subjects participated in this study. Blood samples were drawn for measurements of fasting blood glucose, albumin (Alb), lipids, and creatinine (Cr). Early morning spot urine samples were also collected for activities of alanine aminopeptidase (AAP), N-acetyl-β-D-glucosaminidase (NAG), and concentration of albumin (U-Alb) and creatinine (U-Cr). Both NAG/Cr and AAP/Cr were significantly increased in diabetic subjects compared to controls (p < 0.001). There was positive correlation between NAG/Cr and Alb/Cr (r = 0.49, p < 0.001) and between NAG/Cr and serum creatinine (r = 0.441, p < 0.001). A negative correlation was found between NAG/Cr and eGFR (r = −0.432, p < 0.05). 9.3% and 12% of diabetics with normoalbuminuria had elevated levels of AAP/Cr and NAG/Cr, respectively. We conclude that measuring the urinary enzymes activities (NAG/Cr and AAP/Cr) could be useful as a biomarker of early renal involvement in diabetic complications.

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Objective: Serum uric acid (UA) has been associated with metabolic syndrome (MetS) and urine albumin/creatinine ratio (ACR). We questioned whether UA and ACR are associated in pre-metabolic individuals, and whether this association is modified by any component variable of the metabolic syndrome. Design and method: In a cross-sectional survey of a representative Czech population (n = 3612) aged 25–64 years, urinary albumin and creatinine excretion were determined in an early morning spot urine sample and ACR was calculated. Components of MetS were defined using the joint statement of IDF, NHBLI, AHA, WHF, IAS, and IASO. Individuals presenting with 1 or 2 components were defined as pre-metabolic. Individuals with urinary albumin excretion bellow the detection limit of 1 mg (n = 594), diabetes treated with glucose lowering medication (n = 122), current use of inhibitors of xanthine oxidase (n = 95) and incomplete data (n = 135) were excluded from this analysis. This resulted in 2666 individuals in total. Results: Six hundred and sixty-five (25%) individuals presented without any component of MetS, and 1248 (46.8%) individuals with 1 or 2 components. In individuals free of any component of MetS, there was no association between UA and ln-ACR. In pre-metabolic individuals, UA significantly correlated with ln-ACR in men (n = 639; standardized beta (SB) 0.091; p = 0.022) and in women (n = 609; SB 0.122; p = 0.003). After multivariate adjustment, UA was independently associated with ln-ACR (SB 0.058; p = 0.004), age (SB -0.247; p < 0.001), gender (SB -0.568; p < 0.001), waist-to-height ratio (SB 0.247; p < 0.001), ln-triglycerides (SB 0.087; p = 0.001), estimated glomerular filtration rate (SB -0.425; p < 0.001), and current use of diuretics (SB 0.054; p = 0.008). An independent interaction of ln-ACR with diastolic blood pressure (DBP), (p = 0.023) in relation to UA was present. In individuals with DBP over the median of 81 mmHg (n = 611), there was independent association between ln-ACR and UA (SB 0.094; p = 0.004), whereas no association between the two variables (SB 0.038; p = 0.176) was present in individuals with DBP bellow or equal to 81 mmHg (n = 637). Conclusions: Uric acid is independently associated with albumin/creatinine ratio in individuals with pre-metabolic syndrome. This association appears to be largely modified by diastolic blood pressure.

Misclassification of iodine intake level from morning spot urine samples with high iodine excretion among Inuit and non-Inuit in Greenland

Iodine nutrition is commonly assessed from iodine excretion in urine. A 24 h urine sample is ideal, but it is cumbersome and inconvenient. Hence, spot urine samples with creatinine to adjust for differences in void volume are widely used. Still, the importance of ethnicity and the timing of spot urine samples need to be settled. We, thus, collected 104 early morning spot urine samples and 24 h urine samples from Inuit and non-Inuit living in Greenland. Diet was assessed by a FFQ. Demographic data were collected from the national registry and by questionnaires. Iodine was measured using the Sandell-Kolthoff reaction, creatinine using the Jaffe method and para-amino benzoic acid by the HPLC method for the estimation of completeness of urine sampling and compensation of incomplete urine samples to 24 h excretion. A population-based recruitment was done from the capital city, a major town and a settlement (n 36/48/20). Participants were seventy-eight Inuit and twenty-six non-Inuit. The median 24 h iodine excretion was 138 (25th-75th percentile 89-225) μg/97 (25th-75th percentile 72-124) μg in Inuit/non-Inuit (P= 0.030), and 153 (25th-75th percentile 97-251) μg/102 (25th-75th percentile 73-138) μg (P= 0.026) when including compensated iodine excretion. Iodine excretion in 24 h urine samples increased with a rising intake of traditional Inuit foods (P= 0.005). Iodine excretion was lower in morning spot urine samples than in 24 h urine samples (P< 0.001). This difference was associated with iodine intake levels (P< 0.001), and was statistically significant when the iodine excretion level was above 150 μg/24 h. In conclusion, the iodine intake level was underestimated from morning spot urine samples if iodine excretion was above the recommended level.

Variability in Kidney Stone Incidence Between Black and White South Africans: AGT Pro11Leu Polymorphism Is Not a Factor

Kidney stone disease is rare in the South African black (B) population and more prevalent in the white (W) population. Genetic studies have not previously examined this anomaly. The AGT Pro11Leu polymorphism in the alanine:glyoxylate aminotransferase (AGT) enzyme has been suggested as possibly playing a role in the pathogenesis of idiopathic calcium oxalate kidney stones. The present study was undertaken to investigate whether differences occur in the frequency of this polymorphism in subjects of both race groups. Healthy B (n=60) and W (n=60) male subjects each provided early morning spot urine, blood, and buccal cell samples. The AGT Pro11Leu locus was amplified using the polymerase chain reaction and polymorphism was genotyped using a restriction fragment length polymorphism. There was no difference in the frequency of the AGT Pro11Leu polymorphism, and the major allele (C) was present at a frequency of 0.82 in B and 0.83 in W. Thus, the most common genotype homozygous normal CC genotype was observed at similar frequencies in both groups (0.68 and 0.65 in B and W, respectively), as were the heterozygous CT genotype (CT) and the homozygous variant TT genotype (TT) genotypes (0.33 & 0.02 and 0.28 & 0.03 in B and W, respectively). Neither urinary oxalate nor any other component in the two groups was correlated with the frequency of the AGT Pro11Leu polymorphism. Our data imply that the AGT Pro11Leu polymorphism is not directly responsible for the low incidence of stone formation in B. We conclude that other factors must be instrumental in protecting the B population from urolithiasis.

Urinary Concentration of Monocyte Chemoattractant Protein-1 in Idiopathic Glomerulonephritis: A Long-Term Follow-Up Study

BackgroundMonocyte chemoattractant protein-1 (MCP-1), which is up regulated in kidney diseases, is considered a marker of kidney inflammation. We examined the value of urine MCP-1 in predicting the outcome in idiopathic glomerulonephritis.MethodsBetween 1993 and 2004, 165 patients (68 females) diagnosed with idiopathic proteinuric glomerulopathy and with serum creatinine <150 µmol/L at diagnosis were selected for the study. Urine concentrations of MCP-1 were analyzed by ELISA in early morning spot urine samples collected on the day of the diagnostic kidney biopsy. The patients were followed until 2009. The progression rate to end-stage kidney disease was calculated using Kaplan–Meier survival analysis. End-stage kidney disease (ESKD) was defined as the start of kidney replacement therapy during the study follow-up time.ResultsPatients with proliferative glomerulonephritis had significantly higher urinary MCP-1 excretion levels than those with non-proliferative glomerulonephritis (p<0.001). The percentage of patients whose kidney function deteriorated significantly was 39.0% in the high MCP-1 excretion group and 29.9% in the low MCP-1 excretion group. However, after adjustment for confounding variables such as glomerular filtration rate (GFR) and proteinuria, there was no significant association between urine MCP-1 concentration and progression to ESKD, (HR = 1.75, 95% CI = 0.64–4.75, p = 0.27).ConclusionOur findings indicate that progression to end-stage kidney disease in patients with idiopathic glomerulopathies is not associated with urine MCP-1 concentrations at the time of diagnosis.

Persistent Microalbuminuria in Human Immunodeficiency Virus Infected Children in Kano, Nigeria

Microalbuminuria has been reported to be a precursor of HIV related renal disease, which if detected early and coupled with appropriate intervention may slow or retard the progress of the disease. One hundred and seventy-eight HIV infected children aged 15 years and below were recruited from the Paediatric Infectious Disease Clinic of Aminu Kano Teaching Hospital (AKTH), Kano, to determine the prevalence of persistent microalbuminuria using the albumin creatinine ratio (ACR). Early morning urine samples and spot urine samples were analyzed using a dipstick specific for microalbumin. Those who tested positive had their samples reanalyzed in the laboratory using immunometric assay and Jaffe reaction method for albumin and creatinine, respectively. Patients that had ACR of 30–300 mg/g were said to have microalbuminuria and had their urine samples retested after 6 to 8 weeks. Twelve children (6.7%) had persistent microalbuminuria and had a mean age of 7.5 ± 3.3 years, with a male to female ratio of 1 : 1. There was no significant relationship between the finding of microalbuminuria and age, sex, duration of infection, and the use of highly active antiretroviral therapy. Periodic screening for microalbuminuria using albumin specific dipstick should be considered for children with HIV infection.

Low-grade albuminuria is associated with peripheral artery disease in Chinese diabetic patients

BackgroundIncreasing studies have suggested that albuminuria might be an important risk factor for peripheral artery disease (PAD). However, studies focusing on the association between low-grade albuminuria and PAD are limited. It would be of great interest to elucidate the association between low-grade albuminuria and PAD in diabetic subjects. MethodsA cross-sectional study was conducted in 1386 diabetic subjects (age ≥ 40 years) with normal urinary albumin levels from Shanghai, China. A first voided early morning spot urine sample was obtained for urinary albumin and creatinine measurements. Subjects were divided into three groups according to sex-specific cutoff points of urinary albumin–creatinine ratio (UACR) tertiles. Subjects in the upper tertile of UACR were classified as having low-grade albuminuria. PAD was defined by ankle–brachial index (ABI) <0.9 or >1.4. ResultsOverall, 106 (7.7%) of the study population had PAD. The prevalence of PAD in tertile 3 of UACR was higher than the prevalence in tertile 2 and tertile 1 (10.2%, 6.4% and 6.4%, respectively; P < 0.05). A fully adjusted logistic regression analysis revealed that compared with subjects in tertile 1 of normal UACR, those in tertile 3 had 1.7-fold increased risk for the presence of PAD. ConclusionsIn diabetic patients, high normal UACR level, which is below the current cutoff point of microalbuminuria, was associated with the increased prevalence of PAD. It suggested that low-grade albuminuria might be an early marker for the detection of PAD in diabetic patients.

Nightshift work job exposure matrices and urinary 6-sulfatoxymelatonin levels among healthy Chinese women.

Six-sulfatoxymelatonin (aMT6s) is a primary urinary metabolite of melatonin. We examined the association between aMT6s levels and shift work estimated by a job exposure matrix (JEM) among healthy participants of the Shanghai Women's Health Study. Creatinine-adjusted aMT6s levels were measured in the urine samples of 300 women and related to JEM shift work categories. Adjusted geometric means of aMT6s levels from urine samples collected before 08:00 hours were lower among persons holding nighttime shift work jobs. The adjusted aMT6s levels (ng/mg creatinine) were 8.36 [95% confidence intervals (95% CI) 4.47-15.6], 6.37 (95% CI 3.53-11.5), 6.20 (95% CI 3.33-11.5), 3.81 (95% CI 2.02-7.19), and 3.70 (95% CI 1.92-7.11) from the lowest (never held a shift work job) to the highest (current job likely involved all-night shift work) shift work JEM scores (P=0.05). Our results indicate that nightshift work JEM scores were significantly and inversely associated with aMT6s levels in early morning spot urine samples collected between 07:00-08:00 hours.

Low-Grade Albuminuria Is Associated with Carotid Intima-Media Thickness in Chinese Type 2 Diabetic Patients

Low-grade albuminuria was reported to be associated with cardiovascular risk factors. Our present study showed a significant association between low-grade urinary albumin-to-creatinine ratio (ACR) and elevated carotid intima-media thickness (CIMT) in type 2 diabetic patients. The objective of this study is to evaluate the association between low-grade albuminuria and CIMT in type 2 diabetic patients. A cross-sectional study was performed in 760 type 2 diabetic patients (age range, 29-76 yr) with normoalbuminuria from Shanghai, China. A first-voided early morning spot urine sample was obtained for urinary albumin and creatinine measurements. CIMT was measured using high-resolution B-mode ultrasonography. CIMT, as well as body mass index, glycated hemoglobin A1c, systolic and diastolic blood pressure, and serum triglycerides, progressively increased across the sex-specific quartiles of ACR (all P < 0.05). Compared with the patients in the lowest quartile, those in the third and the highest quartiles had significantly higher levels of CIMT (0.87 and 0.91 vs. 0.79 mm, P = 0.0025 and <0.0001, respectively). A fully adjusted logistic regression analysis revealed that compared with the patients in the lowest quartile of ACR, those in the third and the highest quartiles had 1.98- to 2.76-fold increased risk of elevated CIMT. In type 2 diabetic patients, slightly elevated ACR level, which was below the current cutoff point of microalbuminuria, was associated with higher CIMT after adjustments of conventional cardiovascular risk factors. The results implied that low-grade albuminuria might be an early marker for the detection of cardiovascular disease in type 2 diabetic patients.

Prevalence of the metabolic syndrome among patients with type 2 diabetes mellitus in urban North-Central Nigeria.

Background: In most people with glucose intolerance or type 2 diabetes mellitus (DM), there is a multiple set of risk factors that commonly appear together forming what is now known as the ‘Metabolic Syndrome’ (MS). This ‘clustering’ of metabolic abnormalities that occur in the same individual appear to confer substantial additional cardiovascular risk. There has been no report on the MS among patients with type 2 DM in urban North-central Nigeria. Objective: The objective of this study was to determine the prevalence of the MS among urban North-central Nigerians with type 2 DM and to describe the frequency of the syndrome’s components. Methods: Six hundred and thirty four (634) patients with type 2 diabetes attending the out-patient clinic of the Diabetes Screening and Care Centre, Jos, Nigeria were screened for the MS. A brief history was obtained and their anthropometric indices and blood pressure were measured. Fasting venous plasma samples were analyzed for lipids. Early morning spot urine samples were obtained for estimation of microalbuminuria using the Bayer DCA 2000® machine. The diagnosis of MS was made based on the new International Diabetes Federation (IDF) definition. Results: Of the 634 patients enrolled with mean (standard deviation/SD) age 54.2(9.1) years, 56% were females. The prevalence of MS was 63.6% (74.5% in males and 54.9% in females, p

Spot Urine Osmolality/Creatinine Ratio in Healthy Humans

Background: Spot urine albumin/creatinine ratio is a reliable estimate of 24-hour urine albumin excretion. In a pilot study, we observed that the spot urine osmolality/creatinine ratio (U_osm/U_cr) in healthy adults is reproducible. Therefore, we postulated that U_osm/U_cr of a spot urine sample may give an overall estimate of urinary excretion of solutes, renal concentrating ability and body hydration status. Method: Early morning spot urine samples were collected from healthy humans, frozen and analyzed in batches to establish spot U_osm/U_cr and its variation in relation to sex, age, body weight and height. Results: Two hundred and twenty-nine healthy volunteers participated. They were stratified into seven age groups: (a) 1.5–5, (b) >5–10, (c) >10–20, (d) >20–30, (e) >30–45, (f) >45–60, and (g) >60 years. Fifteen males and 15 females were allocated to each age category. A spot urine sample was collected from all subjects in the morning after the first void and was analyzed for osmolality and creatinine. The influence of age, sex, body weight and height on spot U_osm/U_cr was investigated using multiple linear regression. Only height showed a significant correlation (R² = 0.02). Further analysis after excluding the 1.5–5 years age group revealed no significant correlation between age, sex, body weight and height and the U_osm/U_cr ratio. Conclusion: Spot U_osm/ U_cr of healthy humans is a consistent index in steady state and needs no correction for sex, age and body weight above the age of 5 years.

Twenty-four Hour and Spot Urine Metabolic Evaluations: Correlations Versus Agreements

To investigate the correlations and agreements between the solute/creatinine ratios from the 24-hour and early morning spot urine samples for metabolic evaluation in stone-formers given the various pitfalls with the 24-hour urinary metabolic evaluation in stone-formers. 30 urinary stone-formers out of an initial 62 recruited provided a complete 24-hour urine and early morning spot urine samples for metabolic evaluation. Pearson correlation and Bland and Altman Test were used to assess the correlations and agreements. Significant correlations were established between the 24-hour urinary solute excretions and the corresponding early morning spot urine solute/creatinine ratios for calcium, magnesium, urate, potassium, oxalate, citrate, and the Differential Gibb's free energy value of calcium oxalate DG(CaOx) values. However, all these solute/creatinine measurements between the 24-hour and early morning spot urine samples were judged to be not within the acceptable limits based on the estimated "limit of agreement" by the Bland and Altman Test of Agreement. Diurnal circadian rhythm and postprandial excretion surge are thought to be responsible for the disagreements. Thus, the early morning spot urine is not suitable to be used interchangeably to replace the 24-hour urine collection in the evaluation of urinary metabolic abnormalities in stone-formers. A good correlation does not translate to an agreement between the 2 measurements.

Microalbuminuria and Cardiovascular Autonomic Dysfunction Are Independently Associated With Cardiovascular Mortality: Evidence for Distinct Pathways

OBJECTIVEMicroalbuminuria is associated with cardiovascular mortality, particularly among individuals with type 2 diabetes, but the mechanisms underlying this association are not completely understood. Microalbuminuria is known to be associated with cardiovascular autonomic dysfunction (C-AD), and C-AD in turn is associated with cardiovascular mortality. The purpose of this study, therefore, was to investigate whether C-AD can explain the relationship between microalbuminuria and cardiovascular mortality.RESEARCH DESIGN AND METHODSWe studied 490 individuals from a population-based cohort of individuals aged 50–75 years who were followed for a median period of 13.6 years. Microalbuminuria was defined as an albumin-to-creatinine ratio ≥2.0 mg/mmol in an early-morning spot-urine sample. Ten parameters reflecting different aspects of cardiovascular autonomic function were measured and compiled into a total score of C-AD (mean of separate z scores). The association between C-AD and microalbuminuria was estimated by multiple linear regression, and relative risks (RRs) for cardiovascular mortality were estimated by Cox proportional hazards analyses.RESULTSAfter adjustments for age, sex, glucose tolerance status, and other risk factors, C-AD was associated with microalbuminuria (β = 0.16 [95% CI 0.01–0.33]), and both microalbuminuria (RR 2.09 [1.07–4.08]) and C-AD (1.74 [1.04–2.89]) were associated with cardiovascular mortality. These associations did not change after further mutual adjustment for C-AD (2.13 [1.09–4.17]) or microalbuminuria (1.76 [1.05–2.94]), respectively.CONCLUSIONSBoth microalbuminuria and C-AD are independently associated with cardiovascular mortality, and the excess mortality attributable to microalbuminuria cannot be explained by C-AD.

Screening techniques for detecting chronic kidney disease

As patients with impaired kidney function are at increased risk not only for progressive renal function loss, but also for cardiovascular disease, it is of importance to have accurate techniques to screen patients for the presence of an impaired kidney function. Glomerular filtration rate can in mass screenings best be evaluated using a formula based upon a serum creatinine measurement and anthropometric parameters. The Cockcroft-Gault and Modification of Diet in Renal Disease (MDRD) formulas are mostly used. Both are easy to use, but have their limitations. Interpreting the results of such glomerular filtration rate estimates requires a good knowledge of these limitations. Urinary albumin excretion can best be measured from 24 h urine collections. As these collections are difficult to perform, however, an early morning spot urine sample for the measurement of urinary albumin concentration can be applied as preselection for screening purposes. Mass screening for early kidney function impairment, expressed by an impaired glomerular filtration rate or elevated urinary albumin excretion, may help to detect patients at increased cardiac and renal risk. This can best be done using formulas to estimate glomerular filtration rate and by measuring urinary albumin loss.