Changing trends in the epidemiology of pediatric lead exposure: interrelationship of blood lead and ZPP concentrations and a comparison to the US population

OBJECTIVES

To determine blood lead and zinc protoporphyrin (ZPP) concentrations in a pediatric population, confirm their interrelationship at low blood lead concentrations, and assess changing trends through comparison of these data with those found in a similar population 10 years earlier and to US national values.

STUDY DESIGN AND METHODS

The study was conducted in a large pediatric hospital in the Washington DC area (CNMC) on patient whole blood specimens (n = 4908) (0-17 years) accrued from January 2001 to June 2002. Pediatric blood lead concentrations were determined by atomic absorption spectrophotometry, and ZPP by hematofluorometry. The data were analyzed using a computer adaptation of the Hoffmann approach.

RESULTS AND CONCLUSIONS

Blood lead level (BLL) means ranged between 2.2 and 3.3 micro g/dL, and the median BLL was 3 micro g/dL throughout. Mean ZPP concentrations ranged between 21.1 and 26.6 micro g/dL and the median concentrations between 21 and 27 micro g/dL. In comparison to data obtained from a similar pediatric population at CNMC between 1991 and 1992, pediatric BLLs have significantly declined in the Washington DC area. The current data are also compared with data obtained from the National Health and Nutrition Examination Survey (NHANES III) of the US population. The interrelationship between ZPP and BLLs is examined.

Intravenous iron replacement with sodium ferric gluconate complex in sucrose for iron deficiency anemia in adults

BACKGROUND

When oral iron replacement therapy is ineffective, IV or IM iron dextran products have been used successfully in many patients. However, adverse events, including urticaria, anaphylaxis, and death, sometimes are associated with the use of these products.

OBJECTIVE

The aim of this study was to assess the efficacy and tolerability of sodium ferric gluconate complex (SFGC) in sucrose in the treatment of adults with iron deficiency anemia.

METHODS

This was a single-center, open-label, uncontrolled study. Consecutive adults in need of IV iron replacement who experienced severe reactions to generic IV iron dextran and who had previously failed to respond to oral iron products were treated with a single dose of IV SFGC (312, 375, or 500 mg) infused over 2 hours. A second dose of SFGC could be administered 6 to 8 weeks later, if needed.

RESULTS

Six patients (3 men, 3 women; mean [SD] age, 77.0 [10.4] years) were enrolled. All patients received a single-dose infusion of SFGC, and 2 patients received a second dose. No adverse events were observed at the lower doses (312 and 375 mg); however, both patients given the 500-mg dose reported transient nausea, and 1 had pruritus and the other had transient hypertension.

CONCLUSION

The results of this study show that SFGC is a satisfactory alternative when IV iron replacement is needed by adults with iron deficiency anemia.

Pediatric reference ranges for zinc protoporphyrin

OBJECTIVE

To determine pediatric reference ranges for zinc protoporphyrin (ZPP).

DESIGN AND METHODS

The study was conducted in a large pediatric hospital on patient blood specimens (n = 6,478) (0-17 y) accrued from January 2001 to June 2002. The data was analyzed employing the Hoffman approach, which was computer adapted.

RESULTS AND CONCLUSIONS

The 2.5(th) and 97.5(th) percentiles for children age 0 to 12 months were 9 to 40 microg/dL (16.6-73.6 micromol/mol heme) for female subjects and 8.5 to 34.5 microg/dL (15.6-63.5 micromol/mol heme) for males. The 97.5(th) percentiles decreased for the 13 to 24 months age group for females (32 microg/dL) (58.9 micromol/mol heme). There was a significant decrease in the 97.5(th) percentile for zinc protoporphyrin (ZPP) concentrations for the 5 to 9 yr age group, the 97.5(th) percentile being 30 microg/dL (55.2 micromol/mol heme) in both genders, which increased to 33.5 microg/dL (61.6 micromol/mol heme) in the 10 to 17 yr female age group but not for the males (31.5 microg/dL) (58.0 micromol/mol heme). The highest medians were 25.5 microg/dL (46.9 micromol/mol heme) for females, and 21.5 microg/dL (39.6 micromol/mol heme) for males in the 0 to 12 months age group.

The response of normal and iron anemic calves to nasal infection with an attenuated strain of parainfluenza-3 virus

Calves with experimentally induced iron deficiency anemia and normal calves, both groups deprived of colostrum, were exposed to intranasal instillation of an attenuated parainfluenza-3 virus strain.

The calves became infected, but there was no difference in the clinical picture between the 2 groups of calves. Neither was there a difference in the humoral or local immune response to parainfluenza-3 virus.

Ferrokinetic studies in normal and iron deficiency anemic calves

Ferrokinetic studies were performed on control calves and on calves with experimentally induced iron deficiency anemia, all 15 weeks old.

The plasma iron clearance half time was about 4 times shorter in the experimental than in the control group. The low plasma iron concentration in the anemic calves was partially compensated by a more rapid plasma iron disappearance. Therefore the difference in the plasma iron turnover rate was reduced.

The mean value of plasma iron daily renewal rate was about 3 times higher in the experimental than in the control group.

The maximum uptake of injected ⁵⁹Fe into blood cells was reached 14 to 16 days after injection. The uptake of ⁵⁹Fe was about 10% higher in the control than in the experimental group.

Using the values from the ferrokinetic study, the iron need for calves could be estimated. The requirement of iron to maintain a normal and constant Hb in a calf weighing 100 kg at a growth rate of 1 kg/daily was estimated as being 17.5 mg/day. Based on information in the literature and assuming a retention of dietary Fe of 25%, the total daily iron need for such a calf gaining 1 kg/day would be 160–180 mg.