Urinary Chromium Excretion Research Articles

Urinary excretion of chromium as an indicator of exposure to trivalent chromium sulphate in leather tanning.

Two workers exposed to trivalent chromium sulphate in a leather tannery had high concentrations of chromium in the urine. The concentration of chromium showed a workshift-related diurnal fluctuation, but it was remarkably high even after a vacation, indicating accumulation of chromium in the body. The concentrations of chromium in the workplace air, as collected on filters using standard techniques, were below 30 micrograms/m3. The chromium in the air was present in the form of large droplets not collected by the standard techniques. In the blood stream, chromium was transported exclusively in the plasma. No absorption of chromium through the skin could be detected. Absorption from the gastrointestinal tract was calculated to explain the findings.

Chromium intake and urinary chromium excretion of trauma patients

Glucose metabolism is altered after trauma and those factors that affect glucose metabolism often affect chromium (Cr) metabolism and excretion. To ascertain whether urinary Cr excretion is affected by the elevated serum glucose and other factors associated with trauma, the serum glucose and urinary Cr and Creatinine (Cre) excretion of seven severely traumatized patients were determined. The Cr concentration of intravenous (IV) fluids administered was determined and approximate Cr intake calculated. For all patients, urinary Cr concentration was high in the initial sample collected within 24 h of admission (10.3 ± 2.5 ng/mL, mean ± SEM) and decreased significantly (P < 0.05) by 42 h (2.0 ±0.6 ng/mL). The mean urinary Cr concentration 42 h following admission was 10 times greater than the urinary Cr concentration of normal, healthy subjects (0.2 ± 0.02 ng/mL). There was no significant change in urinary Cre concentration within 42 h of admission, therefore the ratio of urinary Cr to Cre (ng Cr:mg Cre) also decreased. Serum glucose concentration was elevated at admission (170 ± 18 mg/dL, mean ± SD) and decreased to 145 ± 10 mg/dL by 48 h post-admission. The intravenous fluids, dextrose and NaCl, were the lowest in Cr of the samples tested, range 0.02 to 0.20 ng/mL; lactated Ringer's solution, with or without dextrose, contained 10-20 times more Cr and plasma protein fraction contained approximately 32 ng/mL. The mean calculated Cr intake for the first 24 h postadmission was 37.1 µg/d, significantly greater (P < 0.01) than intake from 24 to 48 h (0.12 µg/d) and 48-72 h (1.63 µg/d). The IV intake of Cr varied for trauma patients depending on fluids required during treatment, but for all patients the relatively high IV Cr intake was rapidly excreted in the urine. These data demonstrate that urinary Cr concentration is elevated several-fold within 24 h of trauma and that Cr contents of intravenous fluids administered in the days immediately following injury vary dramatically. The effects of trauma alone on Cr excretion are difficult to assess because of the variable intake of Cr from IV fluids.

Biological monitoring of occupational exposure to different chromium compounds at various valency states.

Chromium concentrations in the air were measured in seven different workroom environments, where exposure to water soluble hexavalent or trivalent compounds was expected. Urinary excretion of chromium was measured before and after the same arbitrarily chosen working day. End-of-shift urinary chromium and its increase above pre-exposure levels were closely related to the concentration of water soluble chromium (VI) in the air. The values corresponding to 50 micrograms m-3 in the air, which is the current threshold limit value in most countries, were 29.8 and 12.2 micrograms g-1 of creatinine, respectively. Urinary chromium in workers exposed to water insoluble chromates or to water soluble chromic (III) sulphate was definitely higher than that observed in subjects not occupationally exposed to chromium compounds, but it cannot be recommended as short-term exposure test for evaluation of the job-related hazard.

Determination of chromium in human milk, serum and urine by electrothermal atomic absorption spectrometry without preliminary ashing

In the present study a Perkin-Elmer 5000 atomic absorption spectrometer equipped with a tungsten—iodide lamp for improved background correction at the 357.9 nm chromium absorption line and an HGA 500 graphite furnace were employed for the direct determination of chromium in human serum, milk and urine. The method of standard additions was used: 0.25–0.75 ng Cr was added to 1 ml samples. Except for urine samples, a dilution of 1 + 1 to 1 + 2 with H 2O was necessary in order to obtain correct calibration curves. The average concentration of chromium in all the samples of normal subjects was less than 0.5 ng Cr ml −1. The day-to-day variation for all of the pooled samples was around 10% (relative standard deviation). For urine, the accuracy of the method was tested by comparing the results of another laboratory for the same two round robin samples. Excellent agreement was found between the present method and those of the other laboratory that had used isotope dilution—mass spectrometry and continuum source wavelength modulated echelle—atomic absorption spectrometry to define the chromium concentration in the samples. The detection limit of the method, 0.05 ng Cr ml −1 for urine and serum and 0.1 ng Cr ml −1 for human milk, was sufficient for the biological fluids analyzed. The method was employed for the determination of chromium in 24-h urine samples of maturity onset diabetics supplemented with 20 or 200 μg Cr 3+ d −1 for six weeks. It was shown that the 24-h urinary chromium excretion accurately indicates the daily dietary chromium intake of these patients.

Effect of Inorganic chromium supplementation on glucose tolerance, insulin response, and serum lipids in noninsulin-dependent diabetics

A placebo-controlled double-blind cross-over study was carried out to assess the effect of chromium supplementation (200 µg trivalent chromium daily for 6 wk) on glucose tolerance, insulin response, long-term diabetic control, and serum lipids in 10 noninsulin-dependent diabetics aged 37 to 68 yr. After chromium supplementation 24-h urinary chromium excretion showed a 9-fold increase indicating a positive chromium balance in the subjects. There was no significant difference between chromium supplementation and placebo periods in glucose tolerance and in fasting or 2-h postglucose serum insulin levels but the 1-h postglucose serum insulin level was slightly lower on chromium supplementation than on the placebo (55 ± 9.0 versus 64 ± 11; p < 0.01, paired t test). Serum total cholesterol and triglycerides and their high-density, low-density, and very low-density lipoprotein subfractions showed no change after chromium supplementation as compared to the placebo period.

Urinary arsenic, chromium, and copper levels in workers exposed to arsenic-based wood preservatives.

Urinary excretion of arsenic, chromium, and copper in workers exposed to arsenic-based wood preservatives was examined to evaluate occupational exposure to these chemicals. Spot urine samples were collected from 89 wood treaters and a comparison group of 232 individuals with no known exposure to arsenicals. The results of urinalysis revealed that the wood treaters averaged 103 micrograms arsenic/L while the comparison group averaged 74 micrograms arsenic/L. The mean urinary chromium and copper levels of the wood treaters were 41 micrograms chromium/L and 191 micrograms copper/L compared with 63 micrograms chromium/L and 221 micrograms copper/L for the comparison group. Covariance analysis of urinary arsenic level between the exposed and comparison groups revealed that the adjusted mean arsenic levels of the exposed population (78 to 122 micrograms arsenic/L) were significantly higher than that of the comparison group (72 micrograms arsenic/L). The adjusted mean urinary arsenic levels of these wood treaters, however, were within published normal limits. Analysis of covariance allowed comparison of group means after statistical adjustments for possible confounding variables such as seafood intake and age. The results indicate that urinary arsenic values can provide a useful index of occupational exposure to chromated copper arsenate wood preservatives, when the effects of dietary arsenic are controlled statistically.

Effects of Chromium Supplementation on Urinary Cr Excretion of Human Subjects and Correlation of Cr Excretion with Selected Clinical Parameters

Daily urinary chromium (Cr) excretion of 15 healthy free-living female subjects was 0.20 ± 0.03 µg (mean ± SEM) and nearly identical for 27 male subjects, 0.17 ± 0.02 µg. Minimum Cr absorption calculated from urinary Cr excretion was about 0.4 percent. Increasing intake fivefold by Cr supplementation led to a nearly fivefold increase in Cr excretion suggesting that the extent of absorption of supplemental inorganic chromium was similar to that from normal dietary sources. Correlations between 24-hour Cr excretion and urine volume, age, total creatinine and body weight were not found. Urinary Cr concentration of samples obtained following a morning void correlated with creatinine and Cr concentration following a glucose challenge but not with serum glucose, insulin, lipid parameters, age or body weight. Similar results were obtained for urine samples obtained from subjects during Cr supplementation. These results suggest that urinary Cr excretion does not appear to be a meaningful indicator of Cr status but is a meaningful indicator of Cr intake and that the absorption of supplemental inorganic Cr was similar to that of Cr from normal dietary sources.

Urinary chromium excretion of human subjects: effects of chromium supplementation and glucose loading

The utilization of inorganic chromium by free-living human subjects was studied in 76 volunteers (male, 48; female, 28) who were supplemented with 200 micrograms of inorganic chromium as chromic chloride or a placebo tablet for 3 months in a double-blind, cross-over experiment. For all subjects, initial mean +/- SEM urinary chromium (Cr) level was 0.20 +/- 0.01 (range, 0.05 to 0.58) ng/ml and did not differ by sex. Initial chromium/creatinine ratio (Cr/Ct) was 0.15 +/- 0.01 (range 0.03 to 0.36) ng Cr/mg creatinine for females and was significantly lower, 0.10 +/- 0.01 (range 0.03 to 0.36) for males. Mean urinary Cr level increased to 1.0 +/- 0.12 after 2 and to 1.13 +/- 0.08 ng/ml after 3 months' supplementation. The Cr/Ct ratio increased to 0.69 +/- 0.10 for females and to 0.50 +/- 0.04 for males after 2 months' supplementation; values were similar after 3 months. An increase in urinary Cr excretion in response to a glucose load was demonstrated for nonsupplemented normal free-living subjects but not for subjects supplemented daily with trivalent chromium. Urinary Cr excretion after a glucose challenge was not predictable and did not depend on Cr status.

Effect of exercise (running) on serum glucose, insulin, glucagon, and chromium excretion.

Chromium is involved in normal glucose metabolism. To test whether chromium is also associated with the exercise-induced increases in glucose utilization, urinary chromium excretion, serum glucose, insulin, and glucagon of nine male runners (23-46 yr) were evaluated. Blood samples were taken prior to, immediately following, and 2 h after a strenuous 6-mile run. Urine samples were also taken at these times, and total daily urine collections were made the day of the run and the following day. Mean serum glucose for all runners immediately after running was 185 +/- 19 mg/dl compared with 90 +/- 1 mg/dl (mean +/- SE) prior to running. Mean serum glucagon immediately after running was significantly elevated compared with that observed prior to or 2 h after running; serum insulin levels were not altered significantly. Mean urinary chromium concentration was increased nearly five-fold 2 h after running; similar results were obtained when chromium concentration was expressed per mg of creatinine. Total daily urinary Cr excretion was approximately two times higher the day of running compared with the following nonrun day. Daily urinary excretion of sodium, potassium, and calcium were measured to determine if exercise had a general nonspecific effect on renal function; daily urinary excretion of these was not changed by exercise. These data demonstrate that accompanying the exercise-induced changes associated with increased glucose utilization, there is a significant increase in chromium excretion.

Urinary chromium excretion during pregnancy and its relationship with intravenous glucose loading

This study was conducted to investigate the changes in urinary chromium excretion in the different stages of pregnancy and the effect of intravenous glucose tolerance test on urinary excretion of chromium in late pregnancy. Urine samples were collected from pregnant women cross-sectionally and longitudinally in different stages of pregnancy. Urinary chromium excretion before and after intravenous glucose tolerance test was also determined in nine women in their 3rd trimester of pregnancy. The results can be summarized as: 1) mean chromium/creatinine ratio in urine increased significantly with advancing pregnancy, 2) in late pregnancy, with the exception of one subject, urinary chromium/creatinine ratio showed a decrease after intravenous glucose tolerance test. The results obtained in this study have led us to conclude that the habitual dietary intake does not meet the increased chromium requirement and that prophylaxis may be of benefit and appears to be advisable in pregnancy.

The effect of glucose loading on urinary excretion of chromium in normal adults, in individuals from diabetic families and in diabetics

This study was designed to investigate the effect of oral glucose tolerance tests (OGTT) on urinary chromium excretion in normal individuals, in individuals belonging to diabetic families, and in diabetics. The results can be summarized as: 1) eight of the 10 normal adults showed a significant increase both in terms of chromium per minute and chromium/creatinine (Cr/Cre) ratio after OGTT, and the difference between the mean values before and after OGTT was significant, 2) Of the 13 individuals from diabetic families, only five increased their chromium excretion and chromium/creatinine ratio after the glucose challenge (39%). However, the mean values for the group before and after OGTT remained statistically unchanged, 3) three of eight overt diabetic subjects (38%) showed moderate increase in chromium excretion and Cr/Cre ratio after OGTT, but the mean values were not effected. The creatinine values in urine remained constant before and after OGTT in all groups. These results suggest that a positive Cr/Cre response is more likely to occur in groups of normals than in groups of diabetics, and in individuals from diabetic families.

Urinary chromium excretion, diurnal changes, and relationship to creatinine excretion in healthy and sick individuals of different ages

Since urine is the main excretory pathway for chromium, this study was conducted to compare in normal individuals the daily urinary chromium excretion with a 4 hr sample, to investigate diurnal fluctuations of urinary chromium and age-dependent relationship between urinary chromium and creatinine excretion. The results can be summarized as 1) there was no significant difference between the observed 24 hr chromium excretion and 24 hr excretion calculated from the one 4 hr samples, 2) a diurnal variation was observed when urinary excretion was expressed as chromium per minute, but no time-related variation could be established when chromium/creatinine (Cr/Cre) ratios in samples from three different periods of the same day were compared, although a significant positive correlation existed between urinary chromium and creatinine concentration, 3) the Cr/Cre ratio was found to be age-dependent, 4) in malnourished children the Cr/Cre ratio was very high and significantly different from that of normal infants, 5) This ratio for the eight diabetics was found to be significantly higher when compared with normal adults. On the basis of these results, it is suggested that morning 4 hr urinary chromium reflects the daily chromium excretion and that the Cr/Cre ratio of single urine samples obtained during this period is a reliable criterion in the evaluation of chromium nutrition of individuals in different conditions, provided that the influence of age is taken into consideration.

Urinary excretion of chromium and nickel among electroplaters and pigment industry workers.

The urinary excretion of chromium and nickel among workers of some small electroplating-polishing and paint-pigment industries was investigated to ascertain the occupational exposures to the two metals, used extensively in these trades. The workers were also clinically examined for any symptoms of metal poisoning. The excretion of chromium was very high in all the exposed subjects and that of nickel considerably high in some of the workers, compared to unexposed subjects. However, there was no definite co-relation between excretion of metals and the duration of the exposures, though most significant metal excretions were observed at the longest period of occupational exposure.

Chromium and its Relation to Carbohydrate Metabolism

Chromium is an essential nutrient and can be expected to be effective only in the treatment or prevention of a deficiency. Chromium occurs in numerous foods in the form of a complex with nicotinic acid and, possibly, three amino acids. This complex is called glucose tolerance factor. In this form, chromium is better absorbed, it is excreted almost exclusively via the urine. Therefore, the measurement of daily urinary chromium excretion is a promising tool for the diagnosis of gross abnormalities in chromium metabolism in animals and man.

Renal excretion of trace elements: chromium and copper.

SummaryThe ingestion by normal adults of a standard oral glucose load (75 g) resulted in a significant decrease of the fasting rate of urinary excretion of the trace metal chromium. This effect was not accompanied by any significant parallel change in GFR. Copper excretion rate was not significantly changed by the glucose load. In contrast with the effect of a glucose load, diuresis, induced by a water load, increased the excretion rate of both chromium and copper by more than 100%. The increases in metal excretion with diuresis were not attributable to increased GFR.Observations on the renal excretion of chromium and copper in the dog showed that tubular reabsorption of chromium and copper was greater than 98% in normal fasting conditions. In dogs receiving intravenous infusions of hypotonic saline and of vasopressin, a marked correlation was obtained between urine flow rate, the chromium and copper excretion rates, and also the fraction of the filtered loads of the metals excreted. However, tubular reab...

Urinary Excretion of 51Cr From Labeled Erythrocytes

The urinary excretion of radioactive chromium ( 51 Cr) can be used as an index of erythrocyte survival, using washed erythrocytes labeled with 51 Cr, in a study period of four days. This method also appears to be a better index of erythrocyte destruction than the conventional erythrocyte survival measurement because the 51 Cr activity in the urine is a function only of the rate of in vivo destruction and elution of labeled erythrocytes, and data obtained from excretion of 51 Cr show virtually no dispersion from a simple exponential curve. The dose can be decreased to 10 microcuries or less and the amount of labeled blood injected can be as little as 1 ml. This method has a potential for use in in vivo compatibility testing of donor blood.