OBJECTIVE: This study explored whether thyroglobulin and thyroid disease prevalence rates were higher in pregnant Chinese women with a median urinary iodine concentration of 100-149 µg/L, compared with those with a median urinary iodine concentration of 150-249 μg/L maintained through sustainable universal salt iodization. METHODS: This was a cross-sectional study in which 812 healthy pregnant women were enrolled to collect samples of their household edible salt, urine, and blood during their routine antenatal care in the 18 counties in Fujian Province, China. The levels of salt iodine concentration, urinary iodine concentration (UIC), free triiodothyronine (FT3), free thyroid hormone (FT4), thyroid-stimulating hormone (TSH), thyroglobulin (Tg), thyroid peroxidase antibody and thyroglobulin antibody were assessed during the routine antenatal care visits. RESULTS: The median UIC (mUIC) in pregnant women was 130.8 μg/L (interquartile range = 91.5-198.1 μg/L) in the counties with an mUIC of 100-149 μg/L (Group I), and 172.0 μg/L (interquartile range = 123.5-244.4 μg/L) in the counties with an mUIC of 150-249 μg/L (Group II). Goiter prevalence and thyroid nodule detection rates showed no difference between Group I and Group II ( P > 0.05). Except for FT4 values, the TSH, FT4, FT3, Tg and Tg values > 40 (μg/L) and the thyroid diseases prevalence rate (TDR) showed no significant differences between Group I and Group II ( P > 0.05), whether or not iodine supplementation measures were taken. CONCLUSION Compared with an mUIC of 150-249 μg/L, not only there was no difference in thyroid morphology, but also the Tg value, rate of Tg values > 40 µg/L, and TDR were not higher in pregnant women in the counties with an mUIC of 100-149 μg/L achieved through sustainable universal salt iodization in Fujian Province, China.
Female ; Humans ; Pregnancy ; Cross-Sectional Studies ; Iodine/urine* ; Pregnant Women ; Sodium Chloride, Dietary ; Thyroglobulin ; Thyroid Gland ; Thyrotropin ; East Asian People

Objective: To investigate the associations between 24-hour urinary sodium excretion (24hUNaE) and all-cause mortality in adult Northern Chinese population. Methods: Data from this study were derived from the prospective urban and rural epidemiology (PURE) study in north China. Baseline information of all participants were obtained by face to face interview through trained research staffs based on questionnaires, and morning fasting urine samples of participants were collected to estimate 24hUNaE and 24-hour potassium excretion (24hUKE). Multivariable frailty Cox regression models were used to explore the association between 24hUNaE (<3.00, 3.00-3.99, 4.00-4.99, 5.00-5.99 and ≥6 g/d) and all-cause death. Results: A total of 27 310 participants were included in this study. The mean 24hUNaE was (5.84±1.73) g/d. After a median follow-up of 8.8 years, 1 024 participants died (3.7%), including 390 cardiovascular related deaths and 591 non-cardiovascular related deaths. The cause of death of the remaining patients could not be determined. Using 24hUNaE level of 4.00-4.99 g/d as the reference group, after fully adjustment, 24hUNaE ≥6.00 g/d was associated with an increased risk of all-cause death (HR=1.24, 95%CI: 1.02-1.49) and cardiovascular related death (HR=1.39, 95%CI: 1.02-1.88). 24hUNaE<3.00 g/d was associated with increased risk of all-cause mortality (HR=1.38, 95%CI: 0.96-1.99). There was no significant association between 24hUNaE and non-cardiovascular related death. Furthermore, using the combination of 24hUNaE 4.00-4.99 g/d and 24hUKE≥2.11 g/d as the reference group, the highest risk occurred in participants with the combination of low sodium (<3.00 g/d) and low potassium (<2.11 g/d). Conclusion: 24hUNaE equal or higher than 6 g/d or lower than 3 g/d is associated with increased risk of all-cause mortality and cardiovascular related death in Northern Chinese population. Besides, moderate sodium intake in combination with increased potassium intake might reduce the risk of all-cause death.
Humans ; Adult ; Sodium/urine* ; Prospective Studies ; Potassium/urine* ; China/epidemiology* ; Proportional Hazards Models ; Cardiovascular Diseases/epidemiology*

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

sodium intake has been evaluated based on spot 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

BACKGROUND: Estimates of daily sodium (Na) and potassium (K) excretion were explicitly biased when using equations for adults. We aimed to develop equations to estimate them using overnight urine from Japanese children and adolescents. METHODS: The subjects comprised 70 students aged 10.49-15.76 years: validation group, n = 34; and verification group, n = 36. Each subject performed two operations of overnight spot urine (U RESULTS: In validation, we formulated Na excretion (mg d CONCLUSION We obtained validated equations to estimate daily Na and K excretion with accessible variables such as Na, K, and Cr concentrations of overnight urine, body height and weight, and age for children and adolescents. When using the obtained equations, caution should be paid to small but definite biases and measurement errors.
Adolescent ; Child ; Creatinine/urine* ; Female ; Humans ; Japan ; Male ; Potassium/urine* ; Sodium/urine*

BACKGROUND: Before iodination of Swedish table salt in 1936, iodine deficiency resulting in goitre and hypothyroidism was common. Sweden has become iodine sufficient, as shown in a national survey in 2007, proving its iodination fortification programme effective for the general population. The objective of this study was to collect drinking water from water treatment plants nationally and test if water iodine concentration (WIC) correlated to urinary iodine concentration (UIC) of school-aged children in a national survey 2007 to former goitre frequency in 1929 and to thyroid volume data in 2007. METHODS: In 2012, 166 treatment plants, located in 57% (166 of 290) of all Swedish municipalities, were asked to collect drinking water samples of approximately 10 ml. In 2007, tap water samples of the same volume were collected from 30 randomly selected schools for the national survey. Analysis of WIC was done in both treatment plants in 2012 (n = 166) and tap water in 2007 (n = 30). The correlation of WIC to the children's UIC and thyroid volume after iodination was tested based on data from the national survey in 2007. The association of WIC to former goitre frequency was tested based on pre-iodination data, derived from a map of goitre frequency drawn in 1929. RESULTS: The median WIC from water treatment plants was 4.0 μg/L (range 0-27 μg/L). WIC was similar in coastal and inland areas, for both ground and surface water. WIC correlated with historical goitre areas and was lower in the goitre areas than in non-goitre areas (p < 0.001). WIC in the same municipalities as the schools correlated with the UIC of children (p < 0.01), but not with their thyroid volume. CONCLUSIONS WIC still contributes to iodine nutrition in Sweden, but iodination overrides the goitre effect.
Adolescent ; Child ; Drinking Water ; chemistry ; Female ; Food, Fortified ; analysis ; Goiter ; epidemiology ; history ; History, 20th Century ; History, 21st Century ; Humans ; Iodine ; analysis ; urine ; Male ; Sodium Chloride, Dietary ; analysis ; Sweden ; epidemiology ; Thyroid Gland ; anatomy & histology

Adult ; China ; Female ; Humans ; Iodine ; administration & dosage ; urine ; Maternal Nutritional Physiological Phenomena ; Nutritional Status ; Pregnancy ; Sodium Chloride, Dietary ; Urinalysis ; methods

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