Casual Urine Specimens Research Articles

Association between sodium and potassium excretion estimated from spot urine and socioeconomic status among primary school children and their mothers in Okinawa, Japan.

Hypertension is the greatest and the most preventable risk factor for cardiovascular disease. Excessive sodium (Na) intake and insufficient potassium (K) intake have been identified as risk factors for hypertension. Socioeconomic status (SES) may be related to diet quality. In Japan, few studies have examined the relationship between urinary Na and K excretion and SES in adults, and there are no studies in children. In 2014, 1944 children (1382 households) in all public elementary schools in Yaese town, Okinawa, Japan were recruited to participate in a study. Casual urine specimens were collected to estimate 24-h urinary Na and K excretion and urinary Na/K ratio. Mother's educational background and household incomes were assessed and used as indicators of SES. A total of 236 pairs of children and their mothers were analyzed in this study. Urinary Na and K excretion were not significantly related to educational levels of mothers and household incomes in children. On the other hand, in mothers, lower household income group had higher 24-h estimated urinary Na excretion and urinary Na/K ratio than other groups. There was no significant difference between urinary excretion and educational levels in mothers. Household income disparities in urinary levels seen in mothers were not seen in children. There may be some factors that moderate the dietary inequalities in children.

A Method for Estimating 24-Hour Urinary Sodium Excretion by Casual Urine Specimen in Chinese Hypertensive Patients.

High salt intake is a known risk factor of hypertension, which in turn increases the risk of stroke and cardiovascular diseases. The aim of this study was to develop and evaluate a method for predicting 24-hour urinary sodium excretion (UNa24h) using casual urine specimens in Chinese hypertensive patients. A total of 966 patients with hypertension were included from 8 provinces across China. A UNa24h prediction model (Sun_C method) was developed for males and females using linear regression based on age, weight, sodium concentration in the spot urine (UNaspot), and creatinine concentration in the spot urine (UCrspot). The data were split into the training (70%) and testing (30%) sets to, respectively, develop and evaluate the Sun_C method. Compared with the Kawasaki, INTERSALT, and Tanaka methods, Sun_C method achieved a low and consistent mean bias (1.1 mmol/d) within the range from 106 to 212 mmol/d of UNa24h (equivalent to NaCl intake of 6-12 g/d). In addition, the Sun_C method showed no significant difference between the measured and estimated UNa24h in a paired t-test (P = 0.689). At individual level, Sun_C method had 79.8% of individuals at the cutoff under ±30% level. Sun_C method may prove a reasonable method to estimate the daily dietary sodium intakes (particularly in the range of 6-12 g/d of NaCl) in Chinese hypertensive patients using spot urine measurements. As the amount of data increases in the future, the performance of our formulae will be further improved.

Protocol for a Case-Control Study to Investigate the Association of Pellagra With Isoniazid Exposure During Tuberculosis Preventive Treatment Scale-Up in Malawi.

Background: Pellagra is caused by niacin (vitamin B3) deficiency and manifested by a distinctive dermatitis. Isoniazid is critical for treating tuberculosis globally and is a component of most regimens to prevent tuberculosis. Isoniazid may contribute to pellagra by disrupting intracellular niacin synthesis. In 2017, Malawian clinicians recognized a high incidence of pellagra-like rashes after scale-up of isoniazid preventive treatment (IPT) to people living with HIV (PLHIV). This increase in pellagra incidence among PLHIV coincided with a seasonal period of sustained food insecurity in the region, which obscured epidemiological interpretations. Although isoniazid has been implicated as a secondary cause of pellagra for decades, no hypothesis-driven epidemiological study has assessed this relationship in a population exposed to isoniazid. We developed this case-control protocol to assess the association between large-scale isoniazid distribution and pellagra in Malawi.Methods: We measure the relative odds of having pellagra among isoniazid-exposed people compared to those without exposure while controlling for other pellagra risk factors. Secondary aims include measuring time from isoniazid initiation to onset of dermatitis, comparing niacin metabolites 1-methylnicotinamide (1-MN), and l-methyl-2-pyridone-5-carboxamide (2-PYR) in urine as a proxy for total body niacin status among subpopulations, and describing clinical outcomes after 30-days multi-B vitamin (containing 300 mg nicotinamide daily) therapy and isoniazid cessation (if exposed). We aim to enroll 197 participants with pellagra and 788 age- and sex-matched controls (1:4 ratio) presenting at three dermatology clinics. Four randomly selected community clinics within 3–25 km of designated dermatology clinics will refer persons with pellagra-like symptoms to one of the study enrollment sites for diagnosis. Trained study dermatologists will conduct a detailed exposure questionnaire and perform anthropometric measurements. A subset of enrollees will provide a casual urine specimen for niacin metabolites quantification and/or point-of-care isoniazid detection to confirm whether participants recently ingested isoniazid. We will use conditional logistic regression, matching age and sex, to estimate odds ratios for the primary study aim.Discussion: The results of this study will inform the programmatic scale-up of isoniazid-containing regimens to prevent tuberculosis.

Iodine Nutrition and the Prevalence Status of Thyroid Nodules in the Population: a Cross-sectional Survey in Heilongjiang Province, China.

The aim of this study was to determine the iodine nutritional status and the epidemiological characteristics of thyroid nodules (TNs) in the adult population of Heilongjiang Province. From December 2017 to December 2018, a total of 3661 adults aged 20-70years were selected through probability proportional to size (PPS) sampling for a cross-sectional survey. During the field epidemiological investigation, each participant received a questionnaire survey and thyroid ultrasonography examination. The iodine concentrations in casual urine specimens and household edible salt were measured. The household coverage of iodized salt was 86.56%. The median urinary iodine concentration (MUIC) in the adult population in Heilongjiang Province was 161.57μg/L (25th-75th percentile: 100.35-245.15μg/L). The prevalence of TNs was 36.88%, and the prevalence in females was significantly higher than that in males (41.25% vs 32.50%, χ2 = 11.841, P < 0.01). The prevalence of TNs increased with age (χ2trend = 49.80, P < 0.001). The prevalence of multiple TNs increased with age (χ2trend = 48.709, P < 0.001). There was no significant difference in the MUIC between healthy control group and those with TNs (Z = - 1.386, P = 0.166). The female, age (40-49 age group, 50-59 age group, 60-70 age group), BMI (obesity, overweight), history of hypertension, history of diabetes, and smoking history were all independent risk factors that affected the occurrence of TNs. The iodine nutritional status of the adult population in Heilongjiang Province was adequate. The prevalence of TNs was higher in middle-aged and elderly women, so these individuals should be the focus of the prevention and treatment of thyroid nodule disease.

Socioeconomic Status Associated With Urinary Sodium and Potassium Excretion in Japan: NIPPON DATA2010.

BackgroundAlthough socioeconomic status (SES) may affect food and nutrient intakes, few studies have reported on sodium (Na) and potassium (K) intakes among individuals with various SESs in Japan. We investigated associations of SES with Na and K intake levels using urinary specimens in a representative Japanese population.MethodsThis was a cross-sectional study of 2,560 men and women (the NIPPON DATA2010 cohort) who participated in the National Health and Nutrition Survey Japan in 2010. Casual urine was used to calculate estimated excretion in 24-hour urinary Na (E24hr-Na) and K (E24hr-K). The urinary sodium-to-potassium (Na/K) ratio was calculated from casual urinary electrolyte values. An analysis of covariance was performed to investigate associations of aspects of SES, including equivalent household expenditure (EHE), educational attainment, and job category, with E24hr-Na, E24hr-K, and the Na/K ratio for men and women separately. A stratified analysis was performed on educational attainment and the job category for younger (<65 years) and older (≥65 years) participants.ResultsIn men and women, average E24hr-Na was 176.2 mmol/day and 172.3, average E24hr-K was 42.5 and 41.3, and the average Na/K ratio was 3.61 and 3.68, respectively. Lower EHE was associated with a higher Na/K ratio in women and lower E24hr-K in men and women. A shorter education was associated with a higher Na/K ratio in women and younger men, and lower E24hr-K in older men and women.ConclusionLower EHE and a shorter education were associated with a lower K intake and higher Na/K ratio estimated from casual urine specimens in Japanese men and women.

Abstract P333: Repeated Measurementof Casual Urine Na/K Ratio May Provide Useful Information to Screen Early Stage Chronic Kidney Disease Patients With Higher Sodium and Lower Potassium Intake

Objective: Lowering sodium-to-potassium ratio has been reported to benefit people for hypertension prevention and control in epidemiological studies. Four to seven repeated measurements of casual urine sodium-to-potassium ratio is known to provide high correlation and good agreement quality with less bias to estimate 7-day 24-hour urinary Na/K ratio in normotensive and hypertensive individuals. However, little is known about urinary Na/K ratio in patients with chronic kidney disease (CKD). The aim of this study was to clarify the relationship of the repeated measurement of casual and 24-hour urinary sodium-to-potassium ratio in patients with CKD. Design and Method: A total of 61 inpatients with CKD, 31 in stage 1-3 (eGFR ≥ 30 ml/min/1.73m 2 ) and 30 in stage 4-5 (eGFR &lt; 30 ml/min/1.73m 2 ), aged 20 to 85 under low-sodium diet (NaCl 6 g/day) were recruited in Okayama University hospital. Sodium-to-potassium ratio in casual urine at 4 points/day (first void after rising, each urine after breakfast, lunch or dinner) for 2 days and 2-day 24-hr urine at the same day were measured. Correlation and the quality of agreement by Bland and Altman between casual urine and 24-hour urine samples were analyzed. Results: Mean 24-hour Na and K excretion was lower in participants in stage 4-5 (Na: 87.5 mmol/24h, K: 18.8 mmol/24h) than in participants in stage 1-3 (Na: 99.0 mmol/24h, K: 26.1 mmol/24h), whereas mean 24-hour urine Na/K ratio was higher in participants in stage 4-5 (5.1) than in participants in stage 1-3 (4.1). Casual urine Na/K ratio was strongly correlated with 2-day 24-hour urinary Na/K ratio by sampling 2 casual urine specimens per day for 2 days in participants in stage 1-3 (r = 0.69-0.78), but not in stage 4-5 (r = 0.12-0.19). The bias for mean Na/K ratio between 2-day 24-hour urine and sampling 2 casual urine per day for 2 days in participants in stage 1-3 ranged from -0.86 to 0.16, and the quality of agreement for the mean of this casual urine sampling was similar to that of all 8 points of casual urine samples for estimating 2-day 24-hour values. Conclusion: Repeated casual urine Na/K ratio measurement may provide good estimate of 24-hour urine Na/K ratio, in stage 1-3 CKD patients as well as normotensive and hypertensive people; however, not in stage 4-5 CKD patients.

Diurnal variation of urinary sodium-to-potassium ratio in free-living Japanese individuals

High sodium-to-potassium ratios are associated with elevated blood pressure levels and an increased risk of cardiovascular diseases. We aimed to determine whether urinary sodium-to-potassium ratios fluctuate diurnally during the day to understand measured values of casual urinary sodium-to-potassium ratios. A total of 13,277 casual urine specimens were collected under free-living conditions from 122 Japanese normotensive and hypertensive individuals. Participants collected all casual urine samples in aliquot tubes, reported urine volumes and the time at each voiding for 10–22 days. Then, specimens were classified into hourly data. Diurnal patterns of urinary sodium-to-potassium ratios and urinary concentrations of sodium and potassium were evaluated. Overall mean values of hourly urinary sodium-to-potassium ratios were highest (4.1–5.0) in the early morning, lower (3.3–3.8) in the daytime and higher (4.0–4.4) toward evening hours. The mean urinary sodium and potassium concentrations were the lowest (90–110 and 24–32 mmol l−1, respectively) during the early morning and higher (110–140 and 35–43 mmol l−1, respectively) after mid-morning. Diurnal variability of potassium concentrations was larger than for sodium concentrations. Diurnal variations in urinary sodium-to-potassium ratios were comparable between normotensive and hypertensive individuals, between hypertensive individuals with and without antihypertensive medications, and among age and gender-specific subgroups. Overall mean hourly urinary sodium-to-potassium ratios fluctuated diurnally under free-living conditions and were higher during the morning and evening and lower during the daytime compared with 24-h urinary sodium-to-potassium ratios. Diurnal variation in urinary sodium-to-potassium ratios should be considered to understand actual daily dietary levels and avoid over- and under-estimation in clinical practice.

Four to seven random casual urine specimens are sufficient to estimate 24-h urinary sodium/potassium ratio in individuals with high blood pressure.

This study was done to clarify the optimal number and type of casual urine specimens required to estimate urinary sodium/potassium (Na/K) ratio in individuals with high blood pressure. A total of 74 individuals with high blood pressure, 43 treated and 31 untreated, were recruited from the Japanese general population. Urinary sodium, potassium and Na/K ratio were measured in both casual urine samples and 7-day 24-h urine samples and then analyzed by correlation and Bland–Altman analyses. Mean Na/K ratio from random casual urine samples on four or more days strongly correlated with the Na/K ratio of 7-day 24-h urine (r=0.80–0.87), which was similar to the correlation between 1 and 2-day 24-h urine and 7-day 24-h urine (r=0.75–0.89). The agreement quality for Na/K ratio of seven random casual urine for estimating the Na/K ratio of 7-day 24-h urine was good (bias: −0.26, limits of agreements: −1.53–1.01), and it was similar to that of 2-day 24-h urine for estimating 7-day 24-h values (bias: 0.07, limits of agreement: −1.03 to 1.18). Stratified analyses comparing individuals using antihypertensive medication and individuals not using antihypertensive medication showed similar results. Correlations of the means of casual urine sodium or potassium concentrations with 7-day 24-h sodium or potassium excretions were relatively weaker than those for Na/K ratio. The mean Na/K ratio of 4–7 random casual urine specimens on different days provides a good substitute for 1–2-day 24-h urinary Na/K ratio for individuals with high blood pressure.

Six random specimens of daytime casual urine on different days are sufficient to estimate daily sodium/potassium ratio in comparison to 7-day 24-h urine collections

The objective of this study was to determine the optimal number and type of casual (spot) urine specimens required to estimate an individual's urinary sodium/potassium (Na/K) ratio. A total of 48 participants, 25 men and 23 women, aged between 25 and 59 years, was recruited from healthy volunteers. The Na/K ratio in each casual urine and 7-day 24-h urine sample was measured. Correlation analysis and the quality of agreement by the Bland and Altman method between casual urine and 24-h urine were analyzed. The mean Na/K ratio of 7-day 24-h urine was 4.3. The mean Na/K ratio of six random specimens of daytime (collected between 09 and 17 hours) casual urine correlated most strongly with the Na/K ratio of 7-day 24-h urine (r=0.87). The bias for the mean Na/K ratio between 7-day 24-h urine and daytime casual urine was almost negligible (0.03), and the quality of agreement for the mean of the six random, daytime casual urine specimens on different days was similar to that of the 2-day 24-h urine samples for estimating 7-day 24-h values. Our findings show that the mean Na/K ratio of six random daytime casual urine specimens on different days was a good substitute for the 2-day 24-h urine Na/K ratio.

Abstract MP78: Relationship Between Casual Urinary Sodium/potassium Ratio And 24-h Urinary Sodium/potassium Ratio: The Intersalt Study

Objective: High dietary sodium (Na) and low dietary potassium (K) intakes are associated with adverse blood pressure levels and excess risks of cardiovascular diseases. The Sodium/potassium (Na/K) ratio is a composite index of Na and K. Recently, we found Na/K ratio of casual urine is useful for estimating 24-h urinary Na/K ratio in healthy Japanese participants. However, this finding has not been validated in different ethnic groups. Our aim was to assess the utility across and within populations of casual (spot) urine specimens to estimate 24-h urinary Na/K ratio using data from the International Cooperative Study on Salt, Other Factors, and Blood Pressure (INTERSALT). Methods: The INTERSALT study collected standardized data on casual urinary Na and K concentrations, and also on timed 24-h urinary Na and K excretion for 10,079 men and women ages 20-59 years from 52 population samples in 32 countries. Pearson correlation coefficients and agreement quality analysis (by the Bland-Altman method) were computed for Na/K ratio of casual urine against 24-h urinary Na/K ratio. Results: Overall mean value of Na/K ratio in 24-h urine collections was 3.24. 24-h urinary Na/K ratio and Na/K ratio of casual urine across the 52 population samples were highly correlated: r=0.96 (overall), r=0.96 (men), r=0.95 (women), r=0.94 (ages 20-29), r=0.94 (ages 30-39), r=0.95 (ages 40-49) and r=0.95 (ages 50-59). 24-hour urinary Na/K ratio and Na/K of casual urine across the 10,079 individuals had moderately strong correlations: r=0.69 (overall), r=0.70 (men), r=0.68 (women), r=0.58 (white), r=0.47 (black), r=0.81 (Amerindian), r=0.70 (Asian Indian), r=0.64 (east-Asian), r=0.70 (other ethnicities), r=0.58 (with anti-hypertensive medication use) and r=0.72 (without anti-hypertensive medication use). The bias estimate with the Bland-Altman method, defined as the difference between Na/K of 24-h urine collection and casual urine, was approximately 0.4 across both populations and individuals, independent of age, gender and anti-hypertensive medication use across the 52 population samples. Bias estimates across population samples were 0.39 (overall), 0.42 (men), 0.36 (women), 0.32 (ages 20-29), 0.41 (ages 30-39), 0.37 (ages 40-49) and 0.46 (ages 50-59). Bias estimates for the 10,079 individuals were 0.40 (overall), 0.42 (men), 0.37 (women), 0.33 (white), 0.69 (black), 0.04 (Amerindian), 0.22 (Asian Indian), 0.65 (east-Asian), 0.31 (other ethnicities), 0.45 (with anti-hypertensive medication use) and 0.38 (without anti-hypertensive medication use). Conclusions: These findings indicate that casual urine Na/K ratio is a useful, low-burden, low-cost method alternative to 24-h urine collection for estimation of urinary Na/K ratio across populations of various ethnicities. It is also applicable to individual urinary Na/K ratio.

Abstract P362: Validation of a Simple Method to Estimate Populational 24-h Urinary Sodium Excretion Based on a Casual Urine Specimen in an Adult Danish Population

Background: Tanaka et al (J Hum Hypert 2002; 16: 97-103) developed a simple method to estimate populational 24-h urinary sodium excretion using a casual urine specimen. However, this method was developed and validated in a Japanese population and thus this method might not be valid in populations that differ markedly from this population. Hypothesis: We assessed the hypothesis that the 24 hour urinary sodium excretion can be estimated from a casual spot urine using the Tanaka prediction method in a Danish general population. Methods: Overall 473 Danish individuals provided both a 24h urine collection and a spot urine sample. Data were collected in the Danthyr study (248 women aged 25-30 years and 60-65 years) and the Inter99 study (102 men and 113 women aged 30-60 years), respectively. Only participants with complete 24h urine collection (validated by the PABA method) were included. We compared the estimated daily sodium excretion through 24h urine (the gold standard) with the predicted 24 h sodium excretion from a causal urine specimen, using the Tanaka prediction method. Results: The predicted median 24 h sodium excretion (median [5 and 95 percentile]) was 8.6 gram [3.7;17.5] compared with a median measured 24 h sodium excretion of 8.9 [5.4; 13:1]. The mean (sd) residual (measured minus predicted 24 h sodium excretion) was 0.08 (3.7). The correlation (Spearman) between predicted and measured 24 h sodium excretion was 0.39 and the R 2 was 0.17. The proportion of individuals classified in the same or adjacent quintiles was 67%. Gross misclassification was found for 3% of the individuals. However, a Bland-Altman plot indicated a tendency of underestimation the sodium excretion for individuals with a high level of sodium excretion (&gt;14 g per day). Conclusion: The Tanaka prediction model gives a reasonable estimate of sodium intake in a Danish population using casual spot urines. However, the validation study showed a tendency of underestimation of the sodium intake for individuals with a high sodium excretion (&gt;14 g per day).

The ratio of urine albumin to creatinine used in screening for albuminuria among the middle-aged and elderly at high-risk for diabetes in an urban community with casual and morning urine specimens

Objective To compare the value of clinical application of the ratio of urine albumin to creatinine (ACR) in the community-dwelled middle-aged and elderly at high-risk for diabetes in screening for albuminuria with casual and morning urine specimens. Methods Totally, 443 middle-aged and elderly people (234 men and 209 women) at high-risk for diabetes, with an average age of (59±8) years, were recruited from Changfeng Community of Shanghai in screening for albuminuria with casual and morning urine specimens collected on the same day, as well as another two morning urine specimens collected at an interval of two weeks, for determination of urine ACR. Albuminuria was defined as ACR equal to or more than 30 mg (albumin)/g (creatinnine) in two or more of the three urine specimens collected. Results Overall prevalence of albuminuria was 6. 3% ( 28/443 ) in the middle-aged and elderly according to diagnostic standard mentioned above, significantly higher in casual urine specimens than in morning urine specimens (14. 9% vs. 5.9%, P 0. 05). Specificity and negative predictive value (NPV) of casual urine specimens was significantly lower than those of morning urine specimens (90.6% vs. 100.0%, and 40.9% vs. 100.0%, respectively, P<0.05). The optimal cut-off value of ACR by casual urine specimens was 40. 0 mg/g in screening for albuminuria, based on receiver operating characteristic (ROC) curve, with sensitivity of 96. 4%, specificity 95.2%, PPV 57.5% and NPV 99. 8%. The middle-aged and elderly with negative albuminuria in morning urine but positive in casual urine had more risk factors for cardiovascular and chronic kidney diseases than those with negative albuminuria in both morning and casual urine specimens. Conclusions Morning urine specimen is better than casual urine for albuminuria screening in the middle-aged and elderly people with risk factors for diabetes in urban community, but casual urine used in screening for albuminuria is very convenient for collection. It is suggested that urine ACR of 40. 0 mg/g be used as an optimal cut-off value for casual urine in albuminuria screening among them. Key words: Albuminuria; Mass screening; Diagnosis services

Microalbuminuria is a negative correlate for cognitive function in older adults with peripheral arterial disease: results from the U.S. National Health and Nutrition Examination Survey 1999–2002

Microalbuminuria (MA) has been increasingly identified as a marker of cardiovascular risk. Although poor cognitive function has been implicated as a sequelae of increased cardiovascular burden, little is known about the association between MA and cognitive function. Population-based cross-sectional study. National Health and Nutrition Examination Survey 1999-2002 in the USA. 2049 noninstitutionalized adults (>/=60 years) with nonmissing values in cognitive test, urinary albumin-to-creatinine ratio (UACR) and ankle-brachial blood pressure index (ABPI) was analysed. Participants with UACR >300 microg mg(-1) were excluded. The UACR, in the unit of microg mg(-1), was calculated by dividing the urinary albumin value by the urinary creatinine concentration. MA was defined as UACR between 30 and 300 microg mg(-1). Cognitive function was measured by a 2-min Digit Symbol Substitution Test (DSST). Peripheral artery disease (PAD) was defined as an ABPI <0.9 in either leg. Overall speaking, MA was inversely associated with DSST score after controlling for age, sex, race, body mass index and educational level (regression coefficient = -2.8, P = 0.002). There was an effect modification of PAD on the association between MA and the DSST score. Amongst participants with PAD, the DSST score for those with MA was lower than those without MA (beta = -6.3, P = 0.003) after multivariate adjustment. Moreover, participants with PAD in the highest quartile of UACR had significantly lower DSST score compared to those in the lowest quartile (beta = -8.7, P = 0.001). There was no association between MA and cognitive function amongst participants without PAD. We observed an additive effect of MA and PAD on DSST score. Participants with both MA and PAD had a lower mean DSST score compared to those without both conditions (beta = -6.2, P = 0.003). The presence of MA or a higher level of urinary albumin excretion was inversely associated with cognitive function in participants with PAD.

Metals in urine and peripheral arterial disease.

Exposure to metals may promote atherosclerosis. Blood cadmium and lead were associated with peripheral arterial disease (PAD) in the 1999–2000 National Health and Nutrition Examination Survey (NHANES). In the present study we evaluated the association between urinary levels of cadmium, lead, barium, cobalt, cesium, molybdenum, antimony, thallium, and tungsten with PAD in a cross-sectional analysis of 790 participants ≥40 years of age in NHANES 1999–2000. PAD was defined as a blood pressure ankle brachial index < 0.9 in at least one leg. Metals were measured in casual (spot) urine specimens by inductively coupled plasma–mass spectrometry. After multivariable adjustment, subjects with PAD had 36% higher levels of cadmium in urine and 49% higher levels of tungsten compared with noncases. The adjusted odds ratio for PAD comparing the 75th to the 25th percentile of the cadmium distribution was 3.05 [95% confidence interval (CI), 0.97 to 9.58]; that for tungsten was 2.25 (95% CI, 0.97 to 5.24). PAD risk increased sharply at low levels of antimony and remained elevated beyond 0.1 μg/L. PAD was not associated with other metals. In conclusion, urinary cadmium, tungsten, and possibly antimony were associated with PAD in a representative sample of the U.S. population. For cadmium, these results strengthen previous findings using blood cadmium as a biomarker, and they support its role in atherosclerosis. For tungsten and antimony, these results need to be interpreted cautiously in the context of an exploratory analysis but deserve further study. Other metals in urine were not associated with PAD at the levels found in the general population.

Increasing Sensitivity of Blood Pressure to Dietary Sodium and Potassium With Increasing Age: A Population Study Using Casual Urine Specimens

In a population of 887 men and 1159 women aged 40 to 89 years in southern California, age adjusted systolic and diastolic blood pressures correlated significantly with sodium/potassium ratios estimated from casual urine samples. The relationship was apparent over the whole range of blood pressures and urinary electrolyte excretions. An age gradient was apparent for systolic pressure in both men and women, the regression slope for blood pressure versus sodium/potassium ratio being steeper with increasing age. The regression slope overall was approximately 4 mm Hg systolic and 1 mm Hg diastolic pressure increase per unit increase in sodium/potassium (mmol/mmol) ratio. The use of casual urine samples in assessing the blood pressure and sodium/potassium relationship should not be prematurely dismissed. Evidence from this and other studies suggests the relationship between blood pressure and electrolyte intake in the population may be more dynamic than previously believed, and also more marked in the old, who are at the greatest risk for cardiovascular disease. A reduction in the age-related increase in blood pressure has considerable implications for the prevention of cardiovascular disease.

The prognostic significance of proteinuria: The Framingham study

Despite considerable clinical experience with proteinuria, its prognostic meaning in the ambulatory general population is poorly documented. From a 16-year study of 5209 men and women in the Framingham cohort it is evident that proteinuria, even in casual urine specimens, carries substantial risk with the mortality rate increased threefold. Proteinuria was three times as common in hypertensive persons and also occurred to excess in diabetic patients and in persons with cardiac enlargement. In the absence of these factors, proteinuria was so uncommon that its risk could not be accurately assessed. Among persons with these associated risk factors, those with proteinuria have higher death rates than those without proteinuria. In men, overall mortality and cardiovascular mortality rates remained significantly increased even when other contributors to risk were taken into account. Proteinuria in the ambulatory general population is not a benign condition and carries a serious prognosis. It appears to reflect widespread vascular damage.

Plasma Renin Activity: A Method for Rapid Screening by Radioimmunoassay and a Comparison of Two Commercially Available Kits

Abstract Twenty to thirty percent of patients with essential hypertension have subnormal plasma renin activity (PRA) and lower incidences of stroke and myocardial infarction. NaCl intake influences PRA, which should thus be compared with 24-h urinary sodium excretion. Because such specimens are difficult to collect accurately, we investigated the relation between PRA and sodium in casual (i.e., untimed) urine specimens and found none. However, PRA and urinary Na/creatinine ratio are inversely correlated for casual specimens. This method is useful for screening individuals whose salt intake is low. Mean PRA, measured by the Schwarz-Mann procedure, was 0.62 ± 0.12 (SD) ng/ml per hour for 59 normotensive volunteers, 35% lower by the Squibb procedure.

LACK OF CORRELATION BETWEEN URINARY IODINE AND DIETARY IODINE IN GOITROUS CHILDREN.

Because of difficulties of direct measurement of dietary iodine intake during the course of endemic goiter studies, investigators have used urinary iodine excretion as an index of dietary iodine intake. In those studies, the urinary excretion of iodine has been either (a) measured directly by determining the iodine content of 24-hour urine collections, or (b) estimated from the ratio of urinary iodine concentration to urinary creatinine concentration (iodine/creatinine ratio) in casual urine specimens. The assumptions on which such procedures have been based—namely, that the average daily total iodine excretion (urinary plus fecal) is equal to iodine intake (i.e., iodine balance) and that fecal excretion of iodine is negligible relative to urinary iodine excretion—have not been fully validated.

New Rapid Test for Pheochromocytoma

A new chromatoelectrophoretic urine test based on the quantitative assay of normetanephrine (NM), metanephrine (M), and 3-methoxy-4-hydroxyphenylglycol (G) in a casual urine specimen was used to detect pheochromocytomas. Urine specimens from 40 patients with pheochromocytoma, 50 normotensive subjects, and 25 primary benign hypertensive subjects were analyzed for NM, M, and G using the chromoelectrophoretic test, and the results compared with other tests for pheochromocytoma based on the urinary assay for 3-methoxy-4-hydroxymandelic acid (VMA). Correct results were obtained in all specimens with the chromatoelectrophoretic test as opposed to several equivocal results with the tests that analyze for VMA.

The Use of Casual Urine Specimens in the Evaluation of the Excretion Rates of Thiamine, Riboflavin and N1-Methylnicotinamide

The Use of Casual Urine Specimens in the Evaluation of the Excretion Rates of Thiamine, Riboflavin and N1-Methylnicotinamide