BACKGROUND: The low accuracy of equations predicting 24-h urinary sodium excretion using a single spot urine sample contributed to the misclassification of individual sodium intake levels. The application of single spot urine sample is limited by a lack of representativity of urinary sodium excretion, possibly due to the circadian rhythm in urinary excretion. This study aimed to explore the circadian rhythm, characteristics, and parameters in a healthy young adult Chinese population as a theoretical foundation for developing new approaches. METHODS: Eighty-five participants (mean age 32.4 years) completed the 24-h urine collection by successively collecting each of the single-voided specimens within 24 h. The concentrations of the urinary sodium, potassium, and creatinine for each voided specimen were measured. Cosinor analysis was applied to explore the circadian rhythm of the urinary sodium, potassium, and creatinine excretion. The excretion per hour was computed for analyzing the change over time with repeated-measures analysis of variance and a cubic spline model. RESULTS: The metabolism of urinary sodium, potassium, and creatinine showed different patterns of circadian rhythm, although the urinary sodium excretion showed non-significant parameters in the cosinor model. A significant circadian rhythm of urinary creatinine excretion was observed, while the circadian rhythm of sodium was less significant than that of potassium. The circadian rhythm of urinary sodium and creatinine excretion showed synchronization to some extent, which had a nocturnal peak and fell to the lowest around noon to afternoon. In contrast, the peak of potassium was observed in the morning and dropped to the lowest point in the evening. The hourly urinary excretion followed a similar circadian rhythm. CONCLUSION It is necessary to consider the circadian rhythm of urinary sodium, potassium, and creatinine excretion in adults while exploring the estimation model for 24-h urinary sodium excretion using spot urine.
Adult ; China ; Circadian Rhythm ; Creatinine ; Humans ; Potassium ; Sodium ; Urine Specimen Collection ; Young Adult

urine instead of 24-hour (hr) urine collection. Nevertheless, the optimal method for assessing daily sodium intake remains unclear.SUBJECTS/METHODS: Fifteen male (age 32.7 ± 6.5 years) participants were offered 3 meals with a total of 9–10 g salt over 24 hours, and 24-hr urine was collected from the second-void urine of the first day to the first-void urine of the second day. Twenty-four-hr urinary sodium (24UNa) was estimated using Tanaka's equation and the Korean formula, and spot urine Na, potassium (K), chloride (Cl), urea nitrogen (UN), creatinine (Cr), specific gravity (SG) and osmolality (Osm) were measured. The ratios of urinary Na to other parameters were calculated, and correlations with total measured 24UNa were identified.RESULTS: Average 24-hr urine volume was 1,403 ± 475 mL, and measured 24UNa was 143.9 ± 42.1 mEq (range, 87.1–239.4 mEq). Measured 24UNa was significantly correlated with urinary Na/UN (r = 0.560, P < 0.01), urinary Na/Osm (r = 0.510, P < 0.01), urinary Na/Cr (r = 0.392, P < 0.01), urinary Na/K (r = 0.290, P < 0.01), 24UNa estimated using Tanaka's equation (r = 0.452, P < 0.01) and the Korean formula (r = 0.414, P < 0.01), age (r = 0.548, P < 0.01), weight (r = 0.497, P < 0.01), and height (r = 0.393, P < 0.01) in all spot urine samples. Estimated 24UNa based on the second-void spot urine of the first day tended to be more closely correlated with measured 24UNa than were estimates from the other spot urine samples. The significant parameters correlated with the second-void urine of the first day were urinary Na/K (r = 0.647, P < 0.01), urinary Na/Cr (r = 0.558, P < 0.05), and estimated 24UNa using Tanaka's equation (r = 0.616, P < 0.05) and the Korean formula (r = 0.588, P < 0.05).CONCLUSIONS: Second-void urine is more reliable than first-void urine for estimating 24UNa. Urinary Na/K in the second-void urine on the first day is significantly correlated with 24UNa. Further studies are needed to establish the most reliable index and the optimal time of urine sampling for predicting 24UNa.]]>
Creatinine ; Humans ; Male ; Meals ; Methods ; Nitrogen ; Osmolar Concentration ; Potassium ; Sodium ; Sodium, Dietary ; Specific Gravity ; Urea ; Urine Specimen Collection

Primary hyperparathyroidism (PHPT) and familial hypocalciuric hypercalcemia (FHH) have significantly different treatment approaches, so physicians must be careful to differentiate these 2 diseases. Herein, we report a 14-year-old female who presented with symptomatic hypercalcemia (12 mg/dL; reference range, 9.2–10.7 mg/dL), elevated intact parathyroid hormone (iPTH) (236 pg/mL; reference range, 9–69 pg/mL), and vitamin D deficiency (6 ng/mL; reference range, ≥ 20 ng/mL). On numerous occasions, her 24-hour urine calcium was more than 4 mg/kg/day, consistent with PHPT, but her fractional excretion of calcium on 24-hour urine collection was consistently below 1%, in line with FHH. ⁹⁹mTc-Sestamibi scan failed to detect any abnormalities. However, a 4-dimensional computed tomography scan of the neck revealed a right superior parathyroid adenoma which was excised with a focused parathyroidectomy. Although the patient’s calcium and iPTH levels normalized, her nonspecific symptoms persisted. This case illustrates both the challenges of differentiating PHPT from FHH and the limitations of a first-line imaging tool in identifying a parathyroid adenoma.
Adolescent ; Calcium ; Female ; Humans ; Hypercalcemia ; Hyperparathyroidism, Primary ; Neck ; Parathyroid Hormone ; Parathyroid Neoplasms ; Parathyroidectomy ; Reference Values ; Urine Specimen Collection ; Vitamin D Deficiency

PURPOSE: The aim of this study was to analyze the association between sodium excretion and obesity for healthy adults in the Gwangju area. METHODS: The participants included 80 healthy adults aged 19 to 69 years in Gwangju. The dietary intake and sodium excretion were obtained using the 24-hour recall method and 24 hour urine collection. The participants were classified into two groups according to the amount of urinary sodium excretion: (≤ 141.75 mmol/dL, > 141.75 mmol/dL). RESULTS: After adjusting for sex, age, smoking history, and income, the high excretion of sodium group was significantly higher for weight, body mass index, body fat mass, percent body fat, visceral fat area (VFA), waist circumference, hip circumference, and WHR. The energy and nutrients intake were significant after adjusting for sex, age, smoking history, and income. The LSE group had a significantly higher fat intake and Na/K intake ratio. The HSE group had significantly higher fiber intake, and K intake. As the amount of urinary sodium excretion increased, the risk of obesity before correction was 3.57 (95% CI: 1.13–11.25) times greater, and the risk of obesity of T3 increased significantly by 3.33 times (95% CI: 1.05–10.59). After correcting for sex and age, the obesity risk of T2 increased significantly by 4.23 times (95% CI: 1.11–16.06), and after correcting for sex, age, smoking history, and income, the obesity risk of T2 increased significantly by 6.81 times (95% CI: 1.44–32.19) the risk of obesity. CONCLUSIONS: An association exists between sodium excretion and obesity in Korean adults. In this study, the high excretion of sodium group was obese and the risk of obesity was higher than the low excretion of sodium group.
Adipose Tissue ; Adult ; Body Weight ; Gwangju ; Hip ; Humans ; Intra-Abdominal Fat ; Methods ; Obesity ; Smoke ; Smoking ; Sodium ; Urine Specimen Collection ; Waist Circumference

PURPOSE: The aim of this study was to analyze the association between sodium excretion and obesity for healthy adults in the Gwangju area. METHODS: The participants included 80 healthy adults aged 19 to 69 years in Gwangju. The dietary intake and sodium excretion were obtained using the 24-hour recall method and 24 hour urine collection. The participants were classified into two groups according to the amount of urinary sodium excretion: (≤ 141.75 mmol/dL, > 141.75 mmol/dL). RESULTS: After adjusting for sex, age, smoking history, and income, the high excretion of sodium group was significantly higher for weight, body mass index, body fat mass, percent body fat, visceral fat area (VFA), waist circumference, hip circumference, and WHR. The energy and nutrients intake were significant after adjusting for sex, age, smoking history, and income. The LSE group had a significantly higher fat intake and Na/K intake ratio. The HSE group had significantly higher fiber intake, and K intake. As the amount of urinary sodium excretion increased, the risk of obesity before correction was 3.57 (95% CI: 1.13–11.25) times greater, and the risk of obesity of T3 increased significantly by 3.33 times (95% CI: 1.05–10.59). After correcting for sex and age, the obesity risk of T2 increased significantly by 4.23 times (95% CI: 1.11–16.06), and after correcting for sex, age, smoking history, and income, the obesity risk of T2 increased significantly by 6.81 times (95% CI: 1.44–32.19) the risk of obesity. CONCLUSIONS: An association exists between sodium excretion and obesity in Korean adults. In this study, the high excretion of sodium group was obese and the risk of obesity was higher than the low excretion of sodium group.
Adipose Tissue ; Adult ; Body Weight ; Gwangju ; Hip ; Humans ; Intra-Abdominal Fat ; Methods ; Obesity ; Smoke ; Smoking ; Sodium ; Urine Specimen Collection ; Waist Circumference

BACKGROUND: Several epidemiologic studies have suggested that the urine sodium excretion (USE) can be estimated in lieu of performing 24-hour urine collection. However, this method has not been verified in patients with chronic kidney disease (CKD) or in an interventional study. The purpose of this study was to evaluate the usefulness of estimating USE in a prospective low-salt diet education cohort (ESPECIAL). METHODS: A new formula was developed on the basis of morning fasting urine samples from 228 CKD patients in the ESPECIAL cohort. This formula was compared to the previous four formulas in the prediction of 24-hour USE after treatment with olmesartan and low-salt diet education. RESULTS: Most previously reported formulas had low predictability of the measured USE based on the ESPECIAL cohort. Only the Tanaka formula showed a small but significant bias (9.8 mEq/day, P < 0.05) with a low correlation (r = 0.34). In contrast, a new formula showed improved bias (−0.1 mEq/day) and correlation (r = 0.569) at baseline. This formula demonstrated no significant bias (−1.2 mEq/day) with the same correlation (r = 0.571) after 8 weeks of treatment with olmesartan. Intensive low-salt diet education elicited a significant decrease in the measured USE. However, none of the formulas predicted this change in the measured urine sodium after diet adjustment. CONCLUSION: We developed a more reliable formula for estimating the USE in CKD patients. Although estimating USE is applicable in an interventional study, it may be unsuitable for estimating the change of individual sodium intake in a low-salt intervention study.
Bias (Epidemiology) ; Cohort Studies ; Diet ; Diet, Sodium-Restricted* ; Education ; Epidemiologic Studies ; Fasting ; Humans ; Methods ; Prospective Studies ; Renal Insufficiency, Chronic* ; Sodium* ; Urine Specimen Collection

Sodium and potassium intake was assessed on the basis of its respective excretion levels in 24 hr urine samples. However, owing to the inconvenience of collection, we evaluated random spot urine for alternative sodium and potassium excretion markers. We included 250 patients who submitted 24 hr- and spot urine for clinical tests. However, 22 patients who showed 24 hr urine creatinine excretion levels <500 mg/day were excluded, because these samples possibly resulted from incomplete urine collection. Moreover, 24 patients were excluded because of their use of diuretics during the urine collection period. We observed significant correlations between 24 hr urine sodium excretion and both the sodium/creatinine (r=0.34, P<0.0001) and the sodium/specific gravity unit (SGU) ratios (r=0.19, P=0.007) in random urine samples. Similarly, 24 hr urine potassium excretion and both the spot urine potassium/creatinine (r=0.47, P<0.0001) and potassium/SGU ratios (r=0.28, P<0.0001) were significantly correlated. Although the estimated sodium/creatinine and potassium/creatinine ratios showed a significant correlation with 24 hr urine sodium and potassium excretion, respectively, further studies are required to develop a spot urine test for individualized monitoring of sodium and potassium excretion.
Biomarkers/urine ; Creatinine/*urine ; Humans ; Hypertension/pathology/urine ; Potassium/*urine ; Sodium/*urine ; Urinalysis ; Urine Specimen Collection

There has been a long-known association between high dietary sodium intake and hypertension, as well as the increased risk of cardiovascular disease. Reduction of sodium intake is a major challenge for public health. Recently, there have been several controversial large population-based studies regarding the current recommendation for dietary sodium intake. Although these studies were performed in a large population, they aroused controversies because they had a flaw in the study design and methods. In addition, knowledge of the advantages and disadvantages of the methods is essential in order to obtain an accurate estimation of sodium intake. I have reviewed the current literatures on the association between sodium intake and cardiovascular events, as well as the methods for the estimation of sodium intake.
Cardiovascular Diseases ; Hypertension ; Public Health ; Sodium* ; Sodium, Dietary ; Urine Specimen Collection

PURPOSE: Catheter urine (CATH-U) and suprapubic aspiration (SPA) are reliable urine collection methods for confirming urinary tract infections (UTI) in infants. However, noninvasive and easily accessible collecting bag urine (CBU) is widely used, despite its high contamination rate. This study investigated the validity of CBU cultures for diagnosing UTIs, using CATH-U culture results as the gold standard. METHODS: We retrospectively analyzed 210 infants, 2- to 24-month-old, who presented to a tertiary care hospital's pediatrics department between September 2008 and August 2013. We reviewed the results of CBU and CATH-U cultures from the same infants. RESULTS: CBU results, relative to CATH-U culture results (> or =104 colony-forming units [CFU]/mL) were widely variable, ranging from no growth to > or =105 CFU/mL. A CBU cutoff value of > or =105 CFU/mL resulted in false-positive and false-negative rates of 18% and 24%, respectively. The probability of a UTI increased when the CBU bacterial count was > or =105/mL for all infants, both uncircumcised male infants and female infants (likelihood ratios [LRs], 4.16, 4.11, and 4.11, respectively). UTIs could not be excluded for female infants with a CBU bacterial density of 104-105 (LR, 1.40). The LRs for predicting UTIs based on a positive dipstick test and a positive urinalysis were 4.19 and 3.11, respectively. CONCLUSION: The validity of obtaining urine sample from a sterile bag remains questionable. Inconclusive culture results from CBU should be confirmed with a more reliable method.
Bacterial Load ; Catheters ; Child, Preschool ; Female ; Humans ; Infant* ; Male ; Matched-Pair Analysis* ; Pediatrics ; Retrospective Studies ; Stem Cells ; Tertiary Healthcare ; Urinalysis ; Urinary Tract Infections* ; Urine Specimen Collection*

PURPOSE: To report a case of multiple endocrine neoplasia type 2B (MEN 2B) diagnosed early based on conjunctival neuroma. CASE SUMMARY: A 15-year-old female presented with red eye and conjunctival mass in both eyes. A 5 x 5 mm-sized yellowish conjunctival mass adjacent to the limbus was observed in her right eye and a 3 x 3 mm-sized mass in her left eye. Excisional biopsy was performed and the patient was diagnosed with conjunctival neuroma. Other abnormalities were not found on the ophthalmic examination, but she had characteristic appearances such as thickened upper eyelid, mild telecanthus and nodular edematous upper lip. She was transferred to the Endocrinology Department for systemic evaluation in consideration of multiple endocrine neoplasia. Abdominal pelvic computed tomography and a 24-hr urine collection analysis showed asymptomatic pheochromocytoma. Thyroid ultrasonography and fine-needle biopsy revealed medullary thyroid carcinoma. Finally, MEN type 2B was confirmed by using a RET mutation gene test. CONCLUSIONS: Thyroid carcinoma can occur in MEN 2B in combination with pheochromocytoma and mucosal neuroma. Thickened corneal nerve fiber and perilimbal conjunctival mass have been regarded as ophthalmologic characteristics of MEN 2B and may be accompanied by telecanthus, thickened upper eyelid and marfanoid habitus. A biopsy of the mass is required for pathological diagnosis. Medullary thyroid carcinoma is the most significant clinical component of MEN 2B syndrome and thyroidectomy is indicated. MEN 2B may be a rare syndrome, but its consequences are serious and the ophthalmologist may play a lifesaving role in its diagnosis.
Adolescent ; Biopsy ; Biopsy, Fine-Needle ; Diagnosis ; Early Diagnosis* ; Endocrinology ; Eyelids ; Female ; Humans ; Lip ; Male ; Multiple Endocrine Neoplasia ; Multiple Endocrine Neoplasia Type 2b* ; Nerve Fibers ; Neuroma* ; Pheochromocytoma ; Thyroid Gland ; Thyroid Neoplasms ; Thyroidectomy ; Ultrasonography ; Urine Specimen Collection