Exposure to lead and cadmium of children living in different areas of North-West Germany: results of biological monitoring studies 1982–1986

Summary Between 1982 and 1986 several surveys were carried out to determine the levels of lead and cadmium in blood, urine, and shed deciduous teeth (incisors only) of children living in rural, suburban, urban, and industrial areas of North-West Germany. Blood lead (PbB) and blood cadmium (CdB) were measured in about 4000 children. In rural, suburban and urban areas the median PbB levels vary between 5.5 and 7 g/dl, with 98th percentiles varying between 10 and 13 g/dl. The median CdB levels are between 0.1 and 0.2 g/dl, with 95th percentiles between 0.3 and 0.4 g/l. Children from urban areas have significantly higher PbB levels than children from rural and suburban areas. Regarding CdB no differences could be detected. Children living in areas around lead and zinc smelters, particularly those living very close to the smelters, have substantially increased PbB and CdB levels. Children from lead worker families also have substantially increased PbB and CdB levels. The lead levels in shed milk teeth (PbT) were determined in about 3000 children. In rural, suburban and urban areas the median PbT levels are between 2 and 3 g/g, with 95th percentiles between 4 and 7 g/g. Children from urban areas have significantly higher PbT levels than children from rural and suburban areas. The highest PbT levels (on a group basis) are in children from nonferrous smelter areas. The median levels of lead in urine (PbU) are between 6 and 10 g/g creatinine, with 95th percentiles between 20 and 30 g/g creatinine. Children from polluted areas have higher PbU levels than children from less polluted areas. The median levels of cadmium in urine (CdU) are in the order of 0.1 g/g creatinine, with 95th percentiles being in the range of 0.5 and 1.0 g/g creatinine. Girls have higher CdU levels than boys. There are no differences between groups of children from different areas. Children from lead worker families have higher PbU and CdU levels than otherwise comparable children. The results of the present studies indicate a further decrease of PbB in children from North-West Germany since the CEC blood lead campaigns carried out in 1979 and 1981. The decrease of lead exposure also seems to be reflected by a decrease of tooth lead levels.The studies presented in this communication were supported by the Ministry of Work, Health and Social Affairs and the Ministry of Environment and Agriculture of Nordrhein-West-falen, FRG     

Changes in plasma,liver, and ovary vitellogenin in landlocked atlantic salmon following exposure to sublethal cyanide

Female landlocked Atlantic salmon (Salmo salar Ouananiche) were exposed to 0.005 mg/L hydrogen cyanide (HCN) for 12 days at 7±1°C during late vitellogenesis (October). Plasma vitellogenin and liver and gonad vitellogenin levels were measured by homologous radioimmunoassay (RIA) specifically developed for this species. Results indicated that plasma vitellogenin levels increased in cyanide exposed fish. Vitellogenin levels in the liver did not change relative to control fish suggesting that the increased levels of plasma vitellogenin did not result from a change in synthesis in the liver. Vitellogenin levels declined in the gonad relative to the controls by day 12. Elevated plasma vitellogenin levels along with decreased vitellogenin in the gonads suggest that exposure of female salmon to sublethal HCN during late vitellogenesis inhibits the uptake of vitellogenin at the ovarian level.Marine Sciences Research Laboratory Contribution No. 675.     

Studies on erythrocyte pyrimidine 5′-nucleotidase (P5N) test and its evaluation in workers occupationally exposed to lead

Summary An erythrocyte pyrimidine 5-nucleotidase (P5N) test was performed for 171 workers occupationally exposed to lead. Erythrocyte P5N activity was markedly inhibited by exposure to lead. Among several biological indicators (erythrocyte P5N, -aminolevulinic acid dehydratase (ALAD), protoporphyrin (PROTO), urinary -aminolevulinic acid (ALA), coproporphyrin (COPRO)), the P5N activity had the highest correlation with the concentration of lead in blood (r = – 0.77). A significant inhibition of erythrocyte P5N was found in groups of lead workers with blood-lead levels of more than 10 to 19 g/dl. This P5N inhibition started before any changes occurred in urinary ALA and COPRO. A 45 to 50% inhibition of P5N corresponded to the blood-lead value (50 g/dl) of the BEI recommended by ACGIH. In some lead workers, erythrocyte nucleotides (mainly CTP and UTP) were determined. The data indicated that a marked accumulation of these nucleotides had occurred, and their levels correlated negatively with P5N activity and positively with blood lead.     

Effect of lead on cardiac parasympathetic function

Summary A cross-sectional survey was performed on 172 male, lead exposed workers to clarify the effects of lead on the cardiac autonomic nervous system expressed as the decrease of R-R interval variation on an electrocardiogram and to obviate the dose-effect relationship between blood-lead level (Pb-B) and the degree of the decrease. For 132 workers who were exposed to lead for more than one year and whose Pb-B levels were relatively stable (Pb-B variation less than 20 g/dl during recent one year), a significant dose-related decrease of R-R interval variation during deep breathing was observed. Age-adjusted R-R interval variation during deep breathing in those whose Pb-B were 30 g/dl or above was significantly decreased compared with those whose Pb-B levels were 20 g/dl or below. This decrease was observed more clearly in younger workers. These results suggest that an effect on autonomic nervous system expressed as decrease of R-R interval variation during deep breathing might be one of the earliest effects of lead exposure.     

Effects of lead on red blood cell membrane proteins

Summary The effects of lead on red blood cell (RBC) membrane proteins were studied in two groups of workers with different lead exposure levels: Group 1 (6 subjects employed in a battery plant) with a mean blood lead of 40.1 (SD = 3.7) g/100 ml; Group II(5 workers employed in different industries) with a mean blood lead of 60.6 (SD = 8.0) g/100 ml, compared with a control group with mean blood lead of 15.6 (SD = 9.3) g/100 ml. The analysis of RBC membrane polypeptides was carried out by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and by using a densitometer for percentage measurement of the bands corresponding to protein fractions. The results show a very significant decrease in Band 3 (anion channel) and 4.1 in more exposed workers (Group II) only. The effects of lead on RBC membrane proteins seem to be evident at blood-lead levels higher (> 50 g/100 ml) than those previously reported in literature. These results confirm the effects of lead on membrane proteins, even if the exact mechanism, particularly the influence of proteolysis and the meaning of the interference, still needs to be investigated thoroughly.     

Psychological performance of workers with blood-lead concentration below the current threshold limit value

Summary The effects of lead exposure on psychological test performance and subjective feelings of well-being were investigated in 40 exposed workers whose PbB levels had never exceeded 60 g/100 ml and in 20 controls matched for sex, age and educational level. The exposed workers were divided into two groups of 20, with recent PbB levels in the range 45–60 g/100 ml or below 35 g/100 ml. The group of workers with the higher PbB levels showed significantly poorer performance and reported more physical symptoms than the other two groups. These differences were unrelated to socio-demographic and personality characteristics. A principal component analysis suggested that the poorer performance was mainly due to an impairment of general functioning and only to some extent to a deterioration in specific functions, such as verbal reasoning and abstraction. Higher lead concentrations were correlated with poorer performance and a higher number of physical complaints. These results indicate that in exposed workers the threshold for impaired performance lies below the blood-lead concentration of 60 g/100 ml, which is the current threshold limit value (TLV).This study was supported by the Consiglio Nazionale delle Ricerche (CNR, Roma), Gruppo Nazionale Scienze del Comportamento (Grant no. 81.00083.04 and no. 82.02117.04)     

Immunological and enzymatic studies of erythrocytic δ-aminolevulinate dehydratase

Summary The -aminolevulinate dehydratase (ALA.D) quantitative assay on a centrifugal fast analyser showed that subjects whose blood-lead level varies between 30 and 75 tg/100 ml (1.5 to 3.75 M/l) react to blood intoxication by synthesizing de novo an amount of enzyme correlating to blood-lead levels. At higher concentrations, the reactional synthesis occurs very rarely. These results suggest that enzyme is constitutive, but also inductible as soon as its substrate accumulates; this last ability may disappear at high blood-lead levels: a hypothesis is proposed thereafter.     

A new HPLC fluorimetric method to monitor urinary delta-aminolevulinic acid (ALA-U) levels in workers exposed to lead

Summary A new sensitive HPLC method for the determination of urinary delta-aminolevulinic acid (ALA-U) was used to evaluate the relationship between blood-lead (Pb-B) and ALA-U levels in male workers exposed to lead. The differences between the ALA-U levels determined by this method (ALAU-HP) and by a colorimetric method (ALA-U-CL) are discussed. The HPLC method gave values similar to the ALA-U-CL values at high ALA-U level. However, at low blood-lead levels (58 ± 22 g/l, n = 23), the mean ALA-U-HP level corrected by urinary creatinine level was one-third of the corrected ALA-UCL level (0.83 ± 0.14 and 2.4 ± 0.5 mg/g creatinine, respectively). A significant increase of the mean corrected ALA-U-HP level was observed at 162 ± 22 g/l Pb-B (P < 0.05, n = 26), while that of ALA-UCL was observed at 245 ± 30 g/l Pb-B (P < 0.01, n = 37). The regression equation based on the logistic model fitted well to the relationship data between the Pb-B level and the percentage of the subjects with corrected ALA-U-HP above the cut-off point (1.12 mg/g creatinine) and the expected Pb-B level for 50% response was 270 g/l Pb-B, while it did not fit well to the relationship data between Pb-B level and the percentage of the subjects with corrected ALAU-CL above the cut-off point (3.5 mg/g creatinine). The maximum responses for the two sets of corrected ALA-U levels were both observed at 625 ± 25 g/l. The corrected ALA-U level by HPLC method seems to be a useful indicator for biological monitoring of exposure to lead at low levels (< 400 g/l Pb-B = health-based biological limit, WHO) as well as high ones.     

Investigations on neurotoxicity of chemical substances at the workplace

Summary A cross-sectional study was performed in order to investigate the influence of chronic lead-exposure on the peripheral nervous system. We examined 148 male workers of a storage battery manufacturing plant, who had been exposed to lead metal and inorganic lead compounds for 1 to 28 years (mean 11 years). Fifteen workers with non-occupational risks of peripheral neuropathy (former diseases, alcohol abuse, medication) were excluded from the study. The investigation program comprised: case history, physical examination, analyses of blood- and urine-samples and determination of maximal motor, mixed and sensory conduction velocity (NCV) of the ulnar and median nerve of the right forearm. Objectively no worker showed any signs of health effects related to lead exposure. The Biological Monitoring included the determination of (1) Blood-lead level (Pb-B), (2) Free erythrocyte porphyrins (FEP), (3) -Aminolevulinic acid dehydratase (ALA-D) and (4) -Aminolevulinic acid in urine (ALA-U). Further time-weighted-average (TWA)-values of Pb-B were calculated on the basis of several determinations over the period 1975–1981. The following actual (TWA) median values resulted: Pb-B 53 g/dl (54 g/dl), ALA-U 5.6 mg/l (8.4 mg/l), FEP 2.0 mg/l (2.0 mg/l). The Biologischer Arbeitsstoff Toleranz Wert (BAT) of 70 g//dl for Pb-B was exceeded in 15 workers (11%), and of 15 mg/l for ALA-U in 30 cases (23%). In comparison with age-matched controls, the lead workers showed a mild slowing of NCV with mean values between 0.8 and 2.0 m/s. Multiple stepwise regression analyses revealed statistically significant correlations between the four NCV and age as well as Pb-B. There were better correlations by using TWA than actual data of Pb-B. Consideration of the results of the regression analyses, together with an evaluation of the individual neurophysiological status as a function of internal lead exposure, a dose-effect-relationship was found only in the case of Pb-B exceeding 70 g/dl. From our study it is concluded that chronic lead exposure resulting in blood-lead levels of below 70 g/dl is no occupational risk causing a functionally significant slowing of nerve conduction velocities.With Grants from the Deutsche Forschungsgemeinschaft, Bonn (Project no. Va 23/19-1)     

Adjustment of the oral temperature rhythm to a fixed watchkeeping system on board ship

Summary Oral temperature data were collected from 12 members of the crew of an oil tanker at sea. Most of the personnel examined were engaged on watchkeeping duties on a 4 on, 8 off fixed-hours system; the remainder included 3 day-workers. The study commenced after the subjects had been following their particular work schedules continuously for several weeks, thus providing good opportunity for adaptation to them. Observations were made at 4-hourly intervals during waking hours, over a period ranging from 8 to 13 days in individual cases. The form of the mean curves produced by averaging the readings over all days indicated that a reasonable degree of adjustment of the temperature rhythm to the different sleep/wake routines imposed by the work system had occurred. Estimates of rhythm phase and amplitude obtained by single cosinor time series analyses of the sequential data supported this impression. However, further investigations are needed to substantiate these findings, and also to determine how long it takes for the rhythm adjustment process to reach completion in inexperienced workers.Dedicated to Professor G. Hildebrandt on the occasion of his 60th birthday     

Relationship between inhibition of erythrocyte pyrimidine 5′-nucleotidase activity and biological response for porphyrin metabolism in workers occupationally exposed to lead

Summary A rapid determination of erythrocyte pyrimidine 5-nucleotidase (P5N) activity in lead workers was carried out using a high-performance liquid chromatograph (HPLC). The P5N activity had a good negative correlation with the concentration of lead in blood (PbB) ranging from 16 to 96 g/dl (r = -0.82, n = 77). Further, the P5N was compared with other biological parameters: erythrocyte -aminolevulinic acid dehydratase (ALAD) activity, erythrocyte protoporphyrin (PROTO), urinary -aminolevulinic acid (ALA) and urinary coproporphyrin (COPRO).The correlation coefficients between P5N and ALAD, log PROTO, log ALA, and log COPRO were 0.59, –0.72, –0.65, and –0.61, respectively. On the other hand, the normal value of P5N obtained from 72 healthy subjects was 11.9 ± 2.1 units; ol uridine/h/g Hb (mean ± SD), indicating that the lower limit of 95% confidence interval for normal P5N was about 8 units. When P5N was cut off at 8 units in 77 lead workers, the validity (sensitivity + specificity) for PbB 40 g/dl, PbB 60 gg/dl, erythrocyte PROTO 150 g/dl RBC, urinary ALA 6 mg/l, and urinary COPRO 150 g/l was 1.66, 1.76, 1.57, 1.68, and 1.60, respectively. From these results, it was confirmed that the erythrocyte P5N test is suitable for the biological monitoring of exposure to lead in a wide range, and its activity is useful in predicting the disturbance of porphyrin metabolism induced by lead.     

Assessment of thyroid,testes, kidney and autonomic nervous system function in lead-exposed workers

Summary The objective of the study was to assess whether moderate occupational exposure to lead may be associated with early changes in potential target organs (thyroid, testes, kidney, autonomic nervous system). Workers exposed to lead in a lead acid battery factory (n = 98; mean blood lead 51 g/dl, range 40–75 g/dl) and 85 control workers were examined. None of the indicators of kidney function (in urine: retinol-binding protein, ₂-microglobulin, albumin,N-acetyl--d-glucosaminidase; in serum: creatinine, ₂-microglobulin), endocrine function (follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, thyroxine, triiodothyronine) and autonomic nervous system (R-R interval variations on the electrocardiogram) were correlated with lead exposure (blood lead or duration of exposure) or showed significantly different mean values between the exposed group and controls. These results and an assessment of the published data suggest that compliance with the Directive of the Council of the European Communities on lead exposure (health surveillance in workers whose lead in blood exceeds 40 g/dl and removal from exposure when blood lead exceeds 70–80 g/dl) would prevent the occurrence of significant biological changes in the majority of lead-exposed workers.     

Assessment of exposure to lead of the general population in the French community through biological monitoring

Summary The aim of the council directive of 29 March 1977 of the European Community (1) is the screening for non-work-related lead exposure levels in the general populations of European (member) countries. In France, such testing was carried out in eight metropolitan areas (having more than 500000 inhabitants), another eight critical areas surrounding industrial emission sources and one area (Vosges) having a high level of lead contamination in the water. In view of the reference values (maximum 35 g/ dl in an individual blood sample) adopted by the directive, the situation is most serious in the area where the exposure is due to the lead contamination in the water. Individuals here run a seven times greater risk of exceeding the 35 g/dl blood-lead limit relative to urban populations where the lead comes mostly from vehicle emissions into the atmosphere (i.e. 9.3% of the blood-lead values of the Vosgian sample exceed 35 pg/dl; 3.5% for the industrial complexes which deal with lead and 1.4% for the urban zone). While these vehicle exhausts are the subject of much current concern, in perspective, the problem of lead pipe contaminated drinking water appears to be of far greater importance.     

Effect of occupational mercury exposure on plasma lysosomal hydrolases

Summary The activities of three plasma lysosomal hydrolases, -galactosidase, -glucuronidase and -N-acetylglucosaminidase, were studied in 20 workers exposed to metallic mercury vapor in a chlorine alkali plant and in 10 nonexposed referents. The urinary excretion and blood levels of mercury were determined on the day of study, and the history of mercury exposure was reviewed from the records of mercury concentrations in urine and blood over periods of up to 133 months. The average levels of -N-acetylglucosaminidase and -glucuronidase were higher in the plasma of exposed workers, but the difference was not significant. No significant positive correlation was seen between lyosomal enzyme activities and cumulative long-term exposure to mercury. It is concluded that measurement of plasma lysosomal hydrolase-activities is not of great value in the biological monitoring of workers exposed to low concentrations of metallic mercury vapor.In line with published data, the concentration of mercury showed a clearcut diurnal variation in nonexposed persons, persons currently exposed and persons with a history of past exposure. The excretion rate of mercury remained constant throughout the day.     

Health-related quality of life in a rare disease: Hereditary hemorrhagic telangiectasia (HHT) or Rendu–Osler–Weber Disease

The levels of the health-related quality of life (HR-QoL) were analyzed in hereditary hemorrhagic telangiectasia (HHT) patients. The Short Form-36 Health Survey (SF-36) was administered to 50 HHT patients and scores were compared to a cohort of 2301 normal subjects. Clinical variables were patient age, illness duration, number of epistaxis episodes in the previous year and hemoglobin levels. Physical functioning, physical role limitations, bodily pain, social functioning, emotional role limitations and the physical component scores were lower among females. In multivariable analyses increasing age was related to lower physical functioning (P<0.04), physical role limitations (P<0.008), bodily pain (P<0.05) and emotional role limitations (P<0.01), while higher hemoglobin levels improved physical functioning(€P<0.03). The number of epistaxis episodes was negatively associated with physical role limitations (€P<0.009), vitality (P<0.002), social functioning (P<0.001), physical component summary (€P<0.001) and bodily pain (P<0.01). Illness duration was negatively related to the mental component summary (P<0.004). HHT patients had a lower HR-QoL with respect to normal controls in all domains except for bodily pain. Females had lower scores for several domains. Epistaxis was the most important clinical variable.     

Assessment of occupational exposure to 4,4′-methylene-bis-(2-chloroaniline) “MOCA” by a new sensitive method for biological monitoring

Summary A new specific and sensitive method for the urinary determination of 4,4-methylene-bis-(2-chloroaniline) (MOCA), a known carcinogen in rats, mice and dogs, has been developed. After a brief study on rats to determine some peculiarities in MOCA urinary excretion, this method was used to assess occupational exposure in French industrial firms. Both the manufacture of MOCA and its use as a curing agent in the production of polyurethane elastomers were surveyed. MOCA excretion levels were distributed from non-detectable (<0.5 g/l) up to 1600 g/l. Concentrations of N-acetyl metabolites, when present, were largely lower than MOCA levels. The results seemed to reflect workers' overall exposure fairly. Preventive measures following analytical determinations often led to an obvious lowering of excretion levels.     

Cyanide and thiocyanate levels in blood and urine of workers with low-grade exposure to cyanide

Summary The concentrations of free cyanide in the blood and in the urine, and the levels of free thiocyanate (oxidized to cyanide and distilled) as well as total thiocyanate (directly determined and quite unspecific) were determined in the urine of 140 volunteers.There were four main categories of volunteers: (i) non-smokers, not exposed to cyanide in the atmosphere, (ii) smokers, not exposed to cyanide, (iii) non-smokers, exposed to various levels of cyanide in their occupation, and (iv) smokers who were also exposed to cyanide.The cyanide concentration in the blood did not show a clear relationship to either smoking or moderate occupational exposure; the levels were found to lie between 2.0 and 15.0 g of free cyanide per 100 ml of blood, with an average of 5.4 g for all categories of volunteers.It was found that the individual concentrations of free CN and CNS in the urine varied considerably and could not be used for detecting undue chronic exposure to cyanide at the concentrations encountered in the atmosphere. The average values, on the other hand, varied in a regular pattern for each of the four categories listed above. The influence of smoking had a far greater effect on the values obtained than the influence of atmospheric cyanide.Because of the great variations caused by other factors, concentrations of CN and CNS in the urine are not appropriate tools for individual routine control of minor occupational exposure to cyanides. However, non-smokers exposed to moderate cyanide levels in the air, and any individual exposed to high cyanide levels show higher than average values of CN and CNS in their urine.The cyanide values reported in this paper may be useful for the evaluation of analytical results from individual cases where poisoning from cyanide in the atmosphere is suspected.     

Increase in the amount of erythrocyte δ-aminolevulinic acid dehydratase in workers with moderate lead exposure

Summary The amount of ALA-D in human erythrocytes was determined directly by radioimmunoassay or calculated from the restored activity assayed in the presence of zinc and dithiothreitol, and a good correlation was observed between the RIA-based and the restored activity-based amounts.The RIA-based amount of ALA-D in the blood of 10 normal individuals (blood lead levels of 5.6 ± 2.3 g/100 ml: mean ± SD) and 19 lead-exposed workers (blood lead levels of 41.2 ± 10.2 g/100 ml) was 54.1 ± 11.8 g/ml blood and 92.3 ± 20.6 g/ml blood, respectively, indicating an apparent increase of the enzyme amount in lead-exposed workers.A significant increase in the amount of erythrocyte ALA-D calculated from the restored activity in lead-exposed workers was observed even in the low blood lead level of 10–20 g/100 ml, resulting in the range of blood lead level 20–40 g/100 ml. No significant difference was observed in hematocrit and hemoglobin content between lead-exposed and non-exposed groups. These observations suggested that the increase of erythrocyte ALA-D in lead exposure was not due to anemia, which might result in the increase of young erythrocytes in peripheral blood.This increase in the amount of ALA-D in human erythrocytes might be a result of the function to overcome the inhibition of the enzyme in bone marrow cells during lead exposure, and these findings may throw light on the danger to human health of low-level lead toxicity.Abbreviations ALA-D -Aminolevulinic acid dehydratase or 5-Amnoevulinic acid hydro-lyase, EC 4.2.1.24 - ALA -Aminolevulinic acid - Rc Reticulocyte - RIA Radioimmunoassay - DTT Dithiothreitol Supported in parts by Science Research Fund of the Ministry of Education, Science and Culture of Japan and by Research Grant of Fujiwara Foundation of Kyoto University     

Biological and environmental monitoring of occupational exposure of pharmaceutical plant workers to methotrexate

Summary The exposure of 11 pharmaceutical plant workers to methotrexate (MTX) was studied. Personal air samples were taken during the different manufacturing processes: drug compounding, vial filling, and tablet preparation. The uptake of MTX was established by the determination of MTX in urine. MTX was analyzed using the fluorescence polarization immunoassay (FPIA), a method that is frequently used for monitoring serum levels in patients treated with MTX. The FPIA method was modified in such a way that MTX could be measured quickly and efficiently in air and urine samples. MTX was detected in air samples of all workers except for those involved in the vial filling process (range: 0.8–182 g/m³; median: 10 g/m³). The highest concentrations were observed for workers weighing MTX (118 and 182 g/m³). MTX was detected in urine samples of all workers. The mean cumulative MTX excretion over 72–96 h was 13.4 g MTX-equivalents (range: 6.1–24 g MTX-equiva g MTX-equivalents (range: 6.1–24 g MTX-equivalents). lents). A significantly lower background level of 10.2 g A significantly lower background level of 10.2 g MTX-equivalents was measured in urine of 30 control persons (range: 4.9–21 g MTX-equivalents).     

Comprehensive pediatric primary care vs traditional care in an israeli population: Their influence on pediatric emergency room use and hospitalization

Emergency room (ER) utilization and hospitalization were studied as indicators of the impact of improvements in pediatric primary care services in an Israeli development town, Ofakim, population 12,000. One of the two pediatric services was upgraded in 1976 through the introduction of pediatric faculty, integration of preventive and curative services and conversion of the medical records to a problem-oriented format ( experimental clinic B ). The primary care system remained unchanged in the second clinic ( traditional clinic A ). During 1980, ER utilization by the B clinic population was 9.3/100 compared with 17.6/100 for the A clinic population. Fifty two percent of the B clinic population patients reaching the ER were hospitalized compared with 25% of A clinic patients.The lower ER utilization rate represents a significant saving for the health services, and educational interventions are suggested from the study. Analysis of ER utilization data seems to offer useful information for overall planning and monitoring of ambulatory services for a community.Corresponding author.