Effectiveness of zinc protoporphyrin/heme ratio for screening iron deficiency in preschool-aged children

Hemoglobin and zinc protoporphyrin (ZPP) tests are commonly used to screen for iron deficiency, but little research has been done to systematically evaluate the sensitivity and specificity of these two tests. The goal of this study was to evaluate the effectiveness of zinc protoporphyrin/heme (ZPP/H) ratio as a point-of-service screening test for iron deficiency among preschool-aged children by comparing the sensitivity and specificity of hemoglobin, ZPP/H ratio, and serum ferritin (SF). Also completed were assessments for the prevalence of anemia, iron deficiency (ID), and iron deficiency anemia (IDA) with indicators of ferritin models. This study was carried out with 95 children ages 3 to 6 y. Anthropometric measurements were assessed, and blood samples were analyzed for hemoglobin, SF, transferrin saturation (TS), and ZPP. Anemia was common and the prevalences of anemia, ID, and IDA were 14.7%, 12.6%, and 5.2%, respectively. The ZPP/H ratio was strongly and significantly correlated with hemoglobin. And ZPP/H ratio was a more sensitive test for ID than hemoglobin or SF measurement, correctly identifying more than twice as many iron-deficient children (sensitivity of 91.7%, compared to 41.7% for hemoglobin and SF). However, ZPP/H ratio had lower specificity (60.2%, compared to 89.1% for hemoglobin or 96.4% for SF) and resulted in the false identification of more subjects who actually were not iron deficient than did hemoglobin or SF. Low hemoglobin concentration is a late-stage indicator of ID, but ZPP/H ratio can detect ID at early stages and can be performed easily at a relatively low cost. Therefore, ZPP/H ratio can serve as a potential screening test for pre-anemic iron deficiency in community pediatric practices.

Effect of Cumulative Blood Lead and Cumulative Blood ZPP as Lead Body Burden on Renal Lead Biomarkers / 대한산업의학회지

OBJECTIVE: To evaluate the possibility of cumulative blood lead and blood ZPP as surrogates of lead body burden and to investigate their association with renal function as an index of lead body burden. METHODS: The study subjects comprised 678 lead workers with past blood lead and blood ZPP data from their employment. Cumulative blood and ZPP were calculated by accumulating the every year mean value of both indices from the new employment since 1983. To assess the cumulative data of lead workers who started their lead work before 1983, the years before 1983 were simulated with the first available data from 1983. Study variables for lead body burden were tibia bone lead and DMSA chelatable lead, whereas those for current lead biomarkers were blood lead and blood ZPP. BUN and serum creatinine were selected as clinical renal biomarkers, while NAG (N-acetyl-D-glucosamine) and RBP (Retinol binding protein) were selected as early renal biomarkers. RESULTS: The association between cumulative blood lead and blood ZPP with tibia bone lead was statistically significant with determinant coefficients (r(2)) of 0.72 and 0.567, respectively, and their relationships were better explained by the curvilinear regression model. In multiple regression analysis of current lead biomarkers on the renal biomarkers after controlling for possible confounders (age, sex, job duration, smoking and drinking status), blood lead was associated only with log-transformed NAG, whereas blood ZPP was associated with 3 other renal biomarkers. On the other hand, in multiple regression analysis of biomarkers of lead body burden on renal biomarkers after controlling for possible confounders (age, sex, job duration, smoking and drinking status), cumulative blood ZPP and tibia bone lead were associated with all 4 renal function biomarkers, whereas cumulative blood lead and DMSA chelatable lead were associated with 3 renal biomarkers except BUN. CONCLUSION: Cumulative blood and ZPP were demonstrated to be good surrogates of lead burden. Furthermore, the cumulative blood ZPP was confirmed to have a better association than the cumulative blood lead.

A cohort study on blood zinc protoporphyrin concentration of workers in storage battery factory / 예방의학회지

To investigate the effectiveness of the interventions in working environment and personal hygiene for the occupational exposure to the lead, the blood zinc protoporphyrin(ZPP) concentrations of 131 workers ( 100 exposed subjects and 31 controls ) of a newly established battery factory were analyzed. They were measured in every 3 months up to 18 months. Air lead concentration (Pb-A) of the workplaces was also checked for 3 times in 6 months interval from August 1987. Environmental intervention included the local exhaust ventilation and vacuum cleaning of the floor. Intervention of the personal hygiene included the daily change of clothes, compulsory shower after work and hand washing before meal, prohibition of cigarette smoking and food consumption at the work site and wearing mask. Mean blood ZPP concentration of the controls was 16.45+/-4.83 microgram/dashliter at the preemployment examination and slightly increased to 17.77+/-5.59 microgram/dashliter after 6 months. Mean blood ZPP concentration of the exposed subjects who were employed before the factory was in operation (Group A) was 17.36+/-5.20 microgram/dashliter on employment and it was increased to 23.00+/-13.06 microgram/dashliter after 3 months. The blood ZPP concentration was increased to 27.25+/-6.40 microgram/dashliter on 6 months (p<0.01) after the employment which was 1 month after the initiation of intervention program. It did not increase thereafter and ranged between 25.48 microgram/dashliter and 26.61 microgram/dashliter in the subsequent 4 results. Mean blood ZPP concentration of the exposed subjects who were employed after the factory had been in operation but before the intervention program was initiated (Group B) was 14.34+/-6.10 microgram/dashliter on employment and it was increased to 28.97+/-7.14 microgram/dashliter (p<0.01) in 3 months later(1 month after the intervention). The values of subsequent 4 tests were maintained between 26.96 microgram/dashliter and 27.96 microgram/dashliter. Mean blood ZPP concentration of the exposed subjects who were employed after intervention program had been started (Group C) was 21.34+/-5.25 microgram/dashliter on employment and it was gradually increased to 23.37+/-3.86 microgram/dashliter (p<0.01) after 3 months, 23.93+/-3.64 microgram/dashliter after 6 months, 25.50+/-3.01 microgram/dashliter (p<0.01) after 9 months, and 25.50+/-3.10 microgram/dashliter after 12 months. Workplaces were classified into 4 parts according to Pb-A. The Pb-A of part I, the highest areas, were 0.365 microgram/m4, and after the intervention the levels were decreased to 0.216 microgram/m4 and 0.208 microgram/m4 in follow-up test. The Pb-A of part II which was resulted in lower value than part I was decreased from 0.232 microgram/m4 to 0.148 microgram/m4, and 0.120 microgram/m4 after the intervention. The Pb-A of part III was tested after the intervention and resulted in 0.124 microgram/m4 in January 1988 and 0.081 microgram/m4 in August 1988. The Pb-A of part IV was also tested after the intervention and resulted in 0.110 microgram/m4 in August 1988. There was no consistent relationship between Pb-A and blood ZPP concentration. The blood ZPP concentration of the group A and B workers in the part of the highest Pb-A were lower than those of the workers in the parts of lower Pb-A. The blood ZPP concentration of the workers in the part of the lowest Pb-A increased more rapidly. The blood ZPP concentration of the group C workers was the highest in part III. These findings suggest that the intervention in personal hygiene is more effective than environmental intervention, and it should be carried out from the first day of employment and to both the exposed subjects, blue color workers and the controls, white color workers.

Occupational Lead Exposure of Storage Battery Industry Workers in Korea / 대한산업의학회지

In order to investigate the level of lead absorption of lead workers and to evaluate the effect of blood lead on blood zinc protoporphyrin (ZPP) and prevalence of lead related symptoms, 1,782 lead workers(male: 1,506, female: 276) from 8 storage battery industries were studied. Selected variables as indices of lead exposure were blood lead, blood ZPP, and hemoglobin (HB). Fifteen questionnaires of lead related symptoms were provided to all lead workers and filled up by themselves and confirmed by medical doctors. Personal variables such as age, work duration, smoking and drinking habits were also collected. The results were follows : 1. While the mean blood lead of lead workers of all lead companies was 31.0+/-3.0 ug/100ml (male: 31.5+/-2.9 ug/100ml, female: 27.9+/-3.3 ug/100m1), the mean blood ZPP of all lead workers was 66.7+/-4.1 ug/100ml (male: 59.6+/-3.3, female: 105.3+/-3.0 ug/100ml). The mean hemoglobin of male lead workers was 15.7+/-.3 gm/100ml and that of female lead workers was 13.0+/-.3 gm/100ml. 2. The percentage of lead workers whose blood lead was over 60.0 ug/100m1 and 40.0-59.9 ug/100ml was 2.81 % and 19.08 %, respectively. On the other hand, the percentage of lead workers whose blood ZPP was over 150 ug/100ml and 100-149 ug/100ml was 5.89 % and 8.31 %, respectively. 3. The slopes of simple linear regression of blood lead (independent variable) and blood ZPP in female lead workers was significantly steeper than that of male lead workers. The slope of storage battery industries with better working condition in terms of low air concentration of lead were less steeper than those with poor working condition with high mean air concentration of lead. 4. Stepwise multiple regression analysis, using overall symptom prevalence as a dependent variables, blood lead, blood ZPP, hemoglobin, age, work duration, drinking and smoking habits as independent variables, indicated that only drinking habit and age were significantly contributed to the dependent variable.

Blood Lead and ZPP Concentrations of Underground Parking Lot Workers / 영남의대학술지

A study was conducted to investigate the blood lead and zinc protoporphyrin(ZPP) concentrations of the underground parking lot workers who exposed to vehicular exhaust aerosols which contained lead. The blood samples were collected from 25 study subjects of underground parking lot and from 33 controls in Taegu, from July to October, 1997. And also the related factors to the blood lead and ZPP concentrations were investigated. Blood lead concentration and ZPP concentration were measured by flameless furnace atomic absorption spectrophotometer (IL.551) and hemetofluorometer, respectively. The mean blood lead concentrations of study subjects and controls were 23.10+/-20.77microgram/dl and 12.99+/-12.71microgram/dl, respectively(p<0.05), and the mean blood ZPP concentrations of study subjects and controls were 40.72+/-9.46microgram/dl and 38.21+/-10.97microgram/dl, respectively. No significant correlations were observed between the blood lead concentration of the study subjects and their job duration and between blood ZPP concentration of the study subjects and their job duration. There were no statistically significant differences in the blood lead concentration and the blood ZPP concentration of smokers and nonsmokers. In multiple regression analysis on blood lead concentration of the study subjects and controls, occupation was a only significant dependent variable. In case of bood ZPP concentration, age was a only significant dependent variable in the study subjects and controls.

The effect of smoking and drinking habit on the health status of lead workers / 예방의학회지

To investigate the effect of smoking and drinking habit on the health status in lead using industries, 2,785 male workers in lead using industries (7 storage battery industries, 7 secondary smelting and related industries, and 4 primary metal and other manufacturing industries) were selected for this study. This study was carried out as a part of periodic health examination. Selected study variables were zinc protoporphyrin in whole blood (ZPP), SGOT and SGPT for laboratory test. Questionnaire for lead related symptoms and smoking and drinking habit was provided to all the workers and filled up by themselves and reconfirmed by physician. The results obtained were as follows; 1. The overall smoking and drinking rate of study population were 69.8% and 73.6%, respectively. While the smoking and drinking rate of storage battery workers were 68.8% and 72.3%, those of secondary smelting industries and other industries were 66.0% and 66.4% and 74.6 and 80.3% respectively. 2. While the mean values of blood ZPP of lead exposed workers were significantly higher than other group, those of SGOT of storage battery workers were significant higher than other worker. But there were no differences of mean values of other variables. 3. Smoking habit did not affect on the mean value of blood ZPP of workers in special health examination group, but there were significant differences of blood ZPP and SGOT between drinker and non-drinker. 4. Symptom prevalence of lead exposure were higher in drinking and smoking group than non-drinking and non-smoking group. 5. In multiple regression analysis of the total lead related symptoms, blood ZPP, SGOT, and SGPT as dependent variable, respectively, and age, work duration, blood ZPP, pack year and amount of alcohol drinking as independent variables, work duration, pack year, amount of alcohol drinking, age contributed to total symptoms; and age, work duration, pack year contributed to blood ZPP; and age, amount of alcohol drinking, work duration contributed to SGOT; and pack year contributed to SGPT.

The change of validity of blood zinc protoporphyrin test by different cut-off level in level workers / 예방의학회지

Measurement of blood lead (PbB) and blood zinc protoporphyrin (ZPP) are most common biological indices to identify the individual at risk for excess or the health sequences by lead exposure. Because PbB is known most important and reliable index of lead exposure, PbB is often regarded as a gold standard to detect lead exposure. But in Korea PbB is a secondary test item of detailed health check-up with positive finding of screening test in most occasion. Our lead standard requires all lead workers to take annual heath-check twice a year for investigation of their health effect due to lead exposure. Blood ZPP is one of most important index to detect high lead absorption in lead workers as a screening test. Measurement of blood ZPP is known well to correlate with PbB in steady state of exposure in most lead workers and is often used as a primary screening test to detect high lead absorption of lead workers with the advantage of simplicity, easiness, portability and low cost. The current cut-off criteria of blood ZPP for further detailed health check-up is 100 ng/dl which is supposed to match the level of 40 ng/dl of PbB according to our standard. Authors tried to investigate the validity of current criteria of cut-off level(100 ng/dl) of blood ZPP and possible another better cut-off level of it to detect the lead workers whose PbB level over 40 ng/dl. The subjects in our study were 212 male workers in three small scale storage battery industries. Blood ZPP, PbB and hemoglobin(Hb) were selected as the indices of lead exposure. The results were as follows. 1. The mean of blood ZPP, PbB and Hb in lead workers were 79.5+/-46.7 ng/dl, 38.7+/-15.1 ng/dl, and 14.8+/-1.2 g/dl, respectively. There were significant differences in blood ZPP, PbB and Hb by industry(P<0.01). 2. The percents of lead workers whose blood ZPP were above 100 ng/dl in the group of work duration below 1, 1-4, 5-9 and above 10 years were 8.6%, 17.2%, 47.6%, and 50.0%, respectively. The percents of lead workers whose PbB were above 40 ng/dl in those were 31.4%, 40.4%, 71.4%, and 86.4%, respectively. 3. The percents of lead workers whose PbB were below 40 ng/dl, 40-59 ng/dl and above 60 ng/dl were 54.7%, 34.9% and 10.4%, respectively. Those of lead workers whose blood ZPP were below 100 ng/dl, 100-149 ng/dl and above 150 ng/dl were 79.2%, 13.7% and 7.1%, respectively. 4. Simple linear regression of PbB on blood ZPP was statistically significant(P<0.05) and as PbB was 40 ng/dl, blood ZPP was 82.1 ng/dl. 5. While the highest sensitivity and specificity of blood ZPP test to detect lead workers with PbB over 40 ng/dl were observed in the cut-off level of 50 ng/dl and 100 ng/dl of blood ZPP, respectively, the highest validity(sensitivity+specificity) of blood ZPP to detect lead workers with PbB over 40 ng/dl was observed in the cut-off level of around 70 ng/dl of blood ZPP. But even with optimal cut-off level of around 70 ng/dl of blood ZPP, still 25.0% of false negative and 20.7% false positive lead workers were found. As the result of this study, it was suggested that reconsideration of current blood ZPP cut-off of our lead standard from 100 ng/dl to somewhat lower level such as around 70 ng/dl and the inclusion of PbB measurement as a primary screening test for lead workers was highly recommended for the effective prevention of lead workers.

A study on lead exposure indices of male workers exposed to lead less than 1 year in storage battery industries / 예방의학회지

This study intended to obtain an useful information for health management of lead exposed measuring the lead exposure indices and workers and determine biological monitoring interval in early period of exposure by work duration in all male workers (n=433 persons) exposed less than 1 year in 6 storage battery industries and in 49 males who are not exposed to lead as control. The examined variables were blood lead concentration(PBB), Zinc-protoporphyrin concentration(ZPP), Hemoglobin(HB) and personal history; also measured lead concentration in air(PBA) in the workplace. According to the geometric mean of lead concentration in the air, the factories were grouped into three categories: A; When it is below 0.05mg/m3, B; When it is between 0.05 and 0.10mg/m3, and C; When it is above 0.10mg/m3. The results obtained were as follows: 1. The means of blood lead concentration(PBB), ZPP concentration and hemoglobin(HB) in all male workers exposed to lead less than 1 year in storage battery industries were 29.5+/-12.4 microgram/100ml, 52.9+/-30.0 microgram/100ml and 15.2+/-1.1 gm/100ml. 2. The means of blood lead concentration(PBB), ZPP concentration and hemoglobin(HB) in control group were 5.8+/-1.6 microgram/100ml, 30.8+/-12.7 microgram/100ml and 15.7+/-1.6 microgram/100ml, being much lower than that of study group exposed to lead. 3. The means of blood lead concentration and Zpp concentration among group A were 21.9+/-7.6 microgram/100ml, 41.4+/-12.6 microgram/100ml; those of group B were 29.8+/-11.6 microgram/100ml, 52.6+/-27.9 microgram/100ml; those of group C were 37.2+/-13.5 microgram/100ml, 66.3+/-40.7 microgram/100ml. Significant differences were found among three factory group(P<0.01) that was classified by the geometric mean of lead concentration in the air, group A being the lowest. 4. The mean of blood lead concentration of workers who have different work duration(month) was as follows; when the work duration was 1-2 month, it was 24.1+/-12.4 microgram/100ml,; When the work duration was 3-4 month, it was 29.2+/-13.4 microgram/100ml; and it was 28.9+/-34.5 microgram/100ml for the workers who had longer work duration than other. Significant differences were found among work duration group(P<0.05). 5. The mean of ZPP concentration of workers who have different work duration(month) was as follows; When the work duration was 1 2 month, it was 40.6 18.0 g/100ml, When the work duration was 3-4 month, it was 53.4+/-38.4 microgram/100ml; and it was 51.5+/-60.4 microgram/100ml for the workers who had longer work duration than other. Significant differences were found among work duration group(P<0.05). 6. Among total workers(433 person), 18.2% had PBB concentration higher than 40 microgram/100ml and 7.1% had ZPP concentration higher than 100 microgram/100ml; In workers of factory group A, those were 0.9% and 0.0%; In workers of factory group B, those were 17.1% and 6.9%; In workers of factory group C, those were 39.4% and 15.4%. 7. The proportions of total workers(433 person) with blood lead concentration lower than 25 microgram/100ml and ZPP concentration lower than 50 microgram/100ml were 39.7% and 61.9%, respectively; In workers of factory group A, those were 65.5% and 82.3%; In workers of factory group B, those were 36.1% and 60.2%; In workers of factory group C, those were 19.2% and 43.3%. 8. Blood lead concentration (r=0.177, P<0.01), ZPP concentration (r=0.135, P<0.01), log ZPP (r=0.170, P<0.01) and hemoglobin (r=0.096, P<0.05) showed statistically significant correlation with work duration (month). ZPP concentration (r=0.612, P<0.01) and log ZPP(r=0.614, P<0.01) showed statistically significant correlation with blood lead concentration. 9. The slopes of simple linear regression between work duration(month, independent variable) and blood lead concentration(dependent variable) in workplace with low air concentration of lead was less steeper than that of poor working condition with high geometric mean air concentration of lead. The study result indicates that new employees should be provided with biological monitoring including blood lead concentration test and education about personal hygiene and work place management within 3~4 month.

Relationship of between blood lead level and lead related symptoms in low level lead exposure / 예방의학회지

This study intended to obtain an useful information on the prevalence of subjective symptoms, and to clarify the interrelationships between blood lead and lead related symptoms in low level lead exposure. The 93 male workers exposed to lead and 56 male nonexposed workers were examined for their blood lead (PBB), Zinc-protoporphy (ZPP), hemoglobin (HB) and personal history, and completed 15 questionnaires related to symptoms of lead absorption; also measured lead concentration in air (PBA) in the workplace. The results obtained were as follow; 1. The means of blood lead (PBB), blood ZPP and hemoglobin (HB) among workers exposed to lead were 26.1+/-8.8 microgram/dl, 28.3+/-26.0 microgram/dl and 16.2+/-1.2g/dl; whereas those of nonexposed workers were 18.7+/-5.1 microgram/dl, 20.6+/-8.7 microgram/dl and 17.3+/-1.1g/dl. The means of above three indicies between two groups showed significant difference statistically (p0.05). 3. The most frequently by complained symptom was "Generalized weakness and fatigue", and fewest symptom was "Intermittent pains in abdomen". 4. Only two symptoms out of fifteen symptoms checked by themselves revealed significant difference between exposed and nonexposed groups. These were "Intermittent pains of abdomen" and "Joint pain or arthralgia" (p<0.05). No positive correlation was found between the levels of blood lead and symptom groups categorized as gastrointestinal, neuromuscular and constitutional symptoms. 5. Blood lead (r=0.3995) and ZPP (r=0.2837) showed statistically significant correlation with mean lead concentration in air, whereas correlations were not demonstrated between blood lead and lead related symptoms or blood ZPP and lead related symptoms. 6. Blood lead (PBB) and ZPP showed association (r=0.2466) and the equation PBB=23.75+0.0842 ZPP was derived. 7. On stepwise multiple regression, using blood lead level as a dependent variable and ZPP, hemoglobin (HB), age, work duration (WD) and symptom prevalence as a independent variables, only ZPP significantly contributed a lot to blood lead level. 8. While the ZPP measurement was found to be a good indicator in evaluating health effect of lead absorption in low level lead exposure, lead related symptoms were not sensitive enough to evaluate of lead absorption in low level exposure.

The Effect of Maintenance Free Respirator on the Prevention of Lead Absorption in Lead Using Workers of Korea / 대한산업의학회지

One year field study of 400 lead workers on the effect of maintenance free respirator(MFR) to alleviate the lead burden revealed that MFR protection program with biological monitoring with simple measurement of zinc protoporphyrin in whole blood could be applied as an interim method to prevent lead workers from lead burden even in fairly bad working condition until fundamental environmental control will be taken in korea.