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Fetal blood lead values in a rural area
112
Brief clinical and laboratory observations
Fetal blood lead values in a rural area
The Journal of Pediatrics January 1974
Table I. Comparison of cord blood lead values in various studies
II ,am-I
No. o~
Juan J. Gershanik, M.D.,* G. Gary Brooks, M.D.,
Site
and Joseph A. Little, M.D., Shreveport, La.
R esiden ce background
Blood lead level (tzg/lO0 ml.)
By groups
IN RECENT YEARS, a dangerous trend toward contamination of the environment has been developing and a genuine concern for the potential hazards posed by the increasing amounts of lead in the air has been expressed. 1,2 Lead has been shown to cross the placenta, 3 thus the vulnerable unborn infant may be at risk from this environmental hazard. Several investigators have found measurable amounts of lead in cord blood specimens. 4-6 The present report describes the results of blood lead values in a group of newborn infants in a selected geographic area. MATERIALS
Over-all
Urban Suburban
13 15
22.1(_+9.0)* 2011(_+7.0)* 18.3(_-2-4.2)*
New Haven, Urban Conn. 5 Suburban
13 11
11.9(_+3.3)* 12.3(_+3.3) 12.7(-+3.4)*
Boston, Mass, 4
Shreveport, La.
Urban Rural
170 48
9.7(+_ 3.9) 8.3(_+2.4)
9.4(+ 3.7)
*Values calculated from the corresponding publications.4,5 pies was 9.7 _+ 3.9/zg per 100ml., compared with a level for rural cord samples of 8.3 + 2.4/zg per 100 ml. This difference was statistically significant (P (0.05).
AND METHODS
Between March 1 and September 30, 1972, specimens of umbilical cord blood were collected from infants delivered at Confederate Memorial Medical Center, the only hospital rendering inpatient service to the indigent population of this area. None of the mothers of the infants included had a history of lead exposure or clinical symptoms of lead toxicity. Cord blood samples were collected in B-D No. 4610 10 ml. Vacutainer tubes containing 143 U.S.P. units of heparin.t The lead content of these tubes was 0.5/xg or less. All samples were then refrigerated prior to use and analyzed within one week. Lead values were analyzed by atomic absorption spectrophotometry. 7 In accordance with the maternal place of residence, the neonatal samples were categorized as urban or rural. RESULTS Satisfactory blood specimens were collected from 218 newborn infants (cord blood). The over-all mean lead value of cord blood samples was 9.4/xg per 100 ml. --3.7 S.D. The mean blood lead level for urban cord samFrom the Departments of Pediatrics and Obstetrics and Gynecology, Louisiana State University Medical Center, and The Confederate Memorial Medical Center. *Reprint address: Department of Pediatrics, L.S.U. Medical Center, School of "Medicine in Shreveport, P.O. Box 3932, Shreveport, La. 71130.
tBecton, Dickinsonand Company,Ruthelrford,N. J.
DISCUSSION A significant difference is discernible in a comparison of the lead levels of the urban vs. rural groups of the newborn population when analyzed by their maternal residence backgrounds. The increased value of blood lead in urban over rural population has been previously recognized. 8 Although this difference is probably multifactorial, it correlates with atmospheric lead concentrations. Previous cord blood surveys failed to demonstrate significant differences by place of residence. Scanlon 4 could not demonstrate a significant difference between urban and suburban segments of the Boston population. Others have also failed to show any significant difference between suburban a n d ' " u r b a n g h e t t o " patients. 6 The small size of the s a m p l e s m a y have prevented the detection of significant changes. It is important to state that, despite the statistical differences of the samples by place of residence found in our study, there are no available data to determine a possible biologic value of this finding. It is noteworthy that this study found a lower mean blood lead value than other apparently similar surveys4,5 (Table I). One study, on umbilical cord blood lead levels had reported values up to 39/zg of lead per 100 ml. of whole blood. 4 The average blood lead level in urban infants in Boston was placed at 22.1 /xg per 100 ml. The explanation of the lower blood lead levels in our study compared to other surveys is unknown to us. It is possi-
Volume84 Number 1
Brief clinical and laboratory observations
ble that methodology played a role. T h e newborn infant derives his lead burden from his mother, w h o ingests lead with her diet and also absorbs lead from the air. 9 In 1969, the annual average of atmospheric lead concentrations in Boston was 1.19/zg per cubic meter, while our area reported 1.05/~g per cubic meter. 10 T h e s e low environmental lead concentrations m a y have little effect on blood lead levels. 8
SUMMARY Lead levels were determined from neonatal samples of blood collected at a general-care hospital. The cord blood lead values of babies f r o m urban maternal residences were significantly higher than those f r o m rural e n v i r o n m e n t s . T h e over-all cord blood lead value was (mean _ S.D.) 9.4 _+ 3.7/xg of lead per 100 ml. o f whole blood. This level represented a considerably l o w e r value than others previously reported and suggests a lower " n o r m a l " value for our population. The statistical analyses were performed by Dr. Rufus Walker and Mr. David Carp of Computer Science Department.
REFERENCES 1. Hernberg, S., and Nikkanen, J.: Enzyme inhibition by lead under normal urban conditions, Lancet 1: 63, 1970.
Ophthalmoplegia in maple syrup urine disease David S. Zee, M.D.,* John M. Freeman, M.D.,
113
2. Chow, T., and Earl, J. L.: Lead aerosols in the atmosphere: Increasing concentrations, Science 169: 577, 1970. 3. Cantarow, A., and Trumper, M.: Lead poisoning, Baltimore, 1944, The Williams & Wilkins Company, p. 143. 4. Scanlon, J.: Umbilical cord blood lead concentrations, Am. J. Dis. Child. 121: 325, 1971. 5. Harris, P., and Holley, M. R.: Lead levels in cord blood, Pediatrics 49: 606, 1972. 6. Rajegowda, B. K., Leonard, G., and Evans, H. E.: Lead concentrations in the newborn infant, J. PEDIATR.80:116, 1972. 7. Hessel, D. W.: A simple and rapid quantitative determination of lead in blood, Atomic Absorp. Newsletter 7: 55, 1968. 8. U. S. Department of Health, Education and Welfare, Public Health Service, Division of Air Pollution: Survey of lead in the atmosphere of three urban communities, Public Health Service Publication 999-AP-12. Cincinnati, 1965, Public Health Service, p. 94. 9. Committee on Biologic Effects of Atmospheric Pollutants: Lead--airborne lead in prospective, Washington, D. C., National Academy of Science, 1972, chap. 3, p. 47, 70. 10. 1969 National Aerometric Data Bank Report: Environmental Protection Agency, Research Triangle Park, N.C.
fluctuating levels o f consciousness and muscle tone, and convulsions. ~ Ophthalmologic abnormalities have usually been minor features in previously reported cases o f M S U D . This report describes an infant whose presenting s y m p t o m and m o s t p r o m i n e n t neurologic abnormality was ophthalmoplegia.
and Neil A. Holtzman, M.D., Baltimore, Md. CASE REPORT
E A R L Y DIAGNOSIS of maple syrup urine disease (MSUD) is imperative since appropriate dietary restrictions can p r e v e n t s e v e r e m e n t a l r e t a r d a t i o n a n d neurologic disability. Affected infants usually b e c o m e ill in the neonatal period with vomiting, feeding difficulty, From the Departments of Neurology and Pediatrics, Johns Hopkins Hospital. Supported by the John A. HartJbrd Foundation, Inc., and National Institutes of Health Neurology Training Grants Nos. 5-TOI-NS 05300-13 and 5-TOI-NS 05663-02 and by Grant RR-52 from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health. *Reprint address: Department of Neurology, Johns Hopkins Hospital, Baltimore, Md 21205.
A three-week-old white female infant was admitted to Johns Hopkins Hospital because of irritability, poor feeding, and inability to move her eyes. The infant weighed five pounds, eight ounces at birth and was the product of an uncomplicated term pregnancy, labor, and breech delivery. She was vigorous, fed well, and was discharged at four days of age. During her first week at home, she became irritable and fed poorly. At ten days of age, her parents noticed increasing lethargy which lasted for a period of 48 hours. Subsequently, she became more alert, but continued to feed poorly. Her family observed that she blinked infrequently and her eyes appeared to be fixed in one position. Her symptoms persisted and she was referred to Johns Hopkins Hospital for evaluation of ophthalmoplegia and feeding difficulty. On admission, examination revealed a pale, irritable infant ~vith normal vital signs, although her respirations were occasionally irregular. She would not follow a light or bright object.
Brief clinical and laboratory observations
Fetal blood lead values in a rural area
The Journal of Pediatrics January 1974
Table I. Comparison of cord blood lead values in various studies
II ,am-I
No. o~
Juan J. Gershanik, M.D.,* G. Gary Brooks, M.D.,
Site
and Joseph A. Little, M.D., Shreveport, La.
R esiden ce background
Blood lead level (tzg/lO0 ml.)
By groups
IN RECENT YEARS, a dangerous trend toward contamination of the environment has been developing and a genuine concern for the potential hazards posed by the increasing amounts of lead in the air has been expressed. 1,2 Lead has been shown to cross the placenta, 3 thus the vulnerable unborn infant may be at risk from this environmental hazard. Several investigators have found measurable amounts of lead in cord blood specimens. 4-6 The present report describes the results of blood lead values in a group of newborn infants in a selected geographic area. MATERIALS
Over-all
Urban Suburban
13 15
22.1(_+9.0)* 2011(_+7.0)* 18.3(_-2-4.2)*
New Haven, Urban Conn. 5 Suburban
13 11
11.9(_+3.3)* 12.3(_+3.3) 12.7(-+3.4)*
Boston, Mass, 4
Shreveport, La.
Urban Rural
170 48
9.7(+_ 3.9) 8.3(_+2.4)
9.4(+ 3.7)
*Values calculated from the corresponding publications.4,5 pies was 9.7 _+ 3.9/zg per 100ml., compared with a level for rural cord samples of 8.3 + 2.4/zg per 100 ml. This difference was statistically significant (P (0.05).
AND METHODS
Between March 1 and September 30, 1972, specimens of umbilical cord blood were collected from infants delivered at Confederate Memorial Medical Center, the only hospital rendering inpatient service to the indigent population of this area. None of the mothers of the infants included had a history of lead exposure or clinical symptoms of lead toxicity. Cord blood samples were collected in B-D No. 4610 10 ml. Vacutainer tubes containing 143 U.S.P. units of heparin.t The lead content of these tubes was 0.5/xg or less. All samples were then refrigerated prior to use and analyzed within one week. Lead values were analyzed by atomic absorption spectrophotometry. 7 In accordance with the maternal place of residence, the neonatal samples were categorized as urban or rural. RESULTS Satisfactory blood specimens were collected from 218 newborn infants (cord blood). The over-all mean lead value of cord blood samples was 9.4/xg per 100 ml. --3.7 S.D. The mean blood lead level for urban cord samFrom the Departments of Pediatrics and Obstetrics and Gynecology, Louisiana State University Medical Center, and The Confederate Memorial Medical Center. *Reprint address: Department of Pediatrics, L.S.U. Medical Center, School of "Medicine in Shreveport, P.O. Box 3932, Shreveport, La. 71130.
tBecton, Dickinsonand Company,Ruthelrford,N. J.
DISCUSSION A significant difference is discernible in a comparison of the lead levels of the urban vs. rural groups of the newborn population when analyzed by their maternal residence backgrounds. The increased value of blood lead in urban over rural population has been previously recognized. 8 Although this difference is probably multifactorial, it correlates with atmospheric lead concentrations. Previous cord blood surveys failed to demonstrate significant differences by place of residence. Scanlon 4 could not demonstrate a significant difference between urban and suburban segments of the Boston population. Others have also failed to show any significant difference between suburban a n d ' " u r b a n g h e t t o " patients. 6 The small size of the s a m p l e s m a y have prevented the detection of significant changes. It is important to state that, despite the statistical differences of the samples by place of residence found in our study, there are no available data to determine a possible biologic value of this finding. It is noteworthy that this study found a lower mean blood lead value than other apparently similar surveys4,5 (Table I). One study, on umbilical cord blood lead levels had reported values up to 39/zg of lead per 100 ml. of whole blood. 4 The average blood lead level in urban infants in Boston was placed at 22.1 /xg per 100 ml. The explanation of the lower blood lead levels in our study compared to other surveys is unknown to us. It is possi-
Volume84 Number 1
Brief clinical and laboratory observations
ble that methodology played a role. T h e newborn infant derives his lead burden from his mother, w h o ingests lead with her diet and also absorbs lead from the air. 9 In 1969, the annual average of atmospheric lead concentrations in Boston was 1.19/zg per cubic meter, while our area reported 1.05/~g per cubic meter. 10 T h e s e low environmental lead concentrations m a y have little effect on blood lead levels. 8
SUMMARY Lead levels were determined from neonatal samples of blood collected at a general-care hospital. The cord blood lead values of babies f r o m urban maternal residences were significantly higher than those f r o m rural e n v i r o n m e n t s . T h e over-all cord blood lead value was (mean _ S.D.) 9.4 _+ 3.7/xg of lead per 100 ml. o f whole blood. This level represented a considerably l o w e r value than others previously reported and suggests a lower " n o r m a l " value for our population. The statistical analyses were performed by Dr. Rufus Walker and Mr. David Carp of Computer Science Department.
REFERENCES 1. Hernberg, S., and Nikkanen, J.: Enzyme inhibition by lead under normal urban conditions, Lancet 1: 63, 1970.
Ophthalmoplegia in maple syrup urine disease David S. Zee, M.D.,* John M. Freeman, M.D.,
113
2. Chow, T., and Earl, J. L.: Lead aerosols in the atmosphere: Increasing concentrations, Science 169: 577, 1970. 3. Cantarow, A., and Trumper, M.: Lead poisoning, Baltimore, 1944, The Williams & Wilkins Company, p. 143. 4. Scanlon, J.: Umbilical cord blood lead concentrations, Am. J. Dis. Child. 121: 325, 1971. 5. Harris, P., and Holley, M. R.: Lead levels in cord blood, Pediatrics 49: 606, 1972. 6. Rajegowda, B. K., Leonard, G., and Evans, H. E.: Lead concentrations in the newborn infant, J. PEDIATR.80:116, 1972. 7. Hessel, D. W.: A simple and rapid quantitative determination of lead in blood, Atomic Absorp. Newsletter 7: 55, 1968. 8. U. S. Department of Health, Education and Welfare, Public Health Service, Division of Air Pollution: Survey of lead in the atmosphere of three urban communities, Public Health Service Publication 999-AP-12. Cincinnati, 1965, Public Health Service, p. 94. 9. Committee on Biologic Effects of Atmospheric Pollutants: Lead--airborne lead in prospective, Washington, D. C., National Academy of Science, 1972, chap. 3, p. 47, 70. 10. 1969 National Aerometric Data Bank Report: Environmental Protection Agency, Research Triangle Park, N.C.
fluctuating levels o f consciousness and muscle tone, and convulsions. ~ Ophthalmologic abnormalities have usually been minor features in previously reported cases o f M S U D . This report describes an infant whose presenting s y m p t o m and m o s t p r o m i n e n t neurologic abnormality was ophthalmoplegia.
and Neil A. Holtzman, M.D., Baltimore, Md. CASE REPORT
E A R L Y DIAGNOSIS of maple syrup urine disease (MSUD) is imperative since appropriate dietary restrictions can p r e v e n t s e v e r e m e n t a l r e t a r d a t i o n a n d neurologic disability. Affected infants usually b e c o m e ill in the neonatal period with vomiting, feeding difficulty, From the Departments of Neurology and Pediatrics, Johns Hopkins Hospital. Supported by the John A. HartJbrd Foundation, Inc., and National Institutes of Health Neurology Training Grants Nos. 5-TOI-NS 05300-13 and 5-TOI-NS 05663-02 and by Grant RR-52 from the General Clinical Research Centers Program of the Division of Research Resources, National Institutes of Health. *Reprint address: Department of Neurology, Johns Hopkins Hospital, Baltimore, Md 21205.
A three-week-old white female infant was admitted to Johns Hopkins Hospital because of irritability, poor feeding, and inability to move her eyes. The infant weighed five pounds, eight ounces at birth and was the product of an uncomplicated term pregnancy, labor, and breech delivery. She was vigorous, fed well, and was discharged at four days of age. During her first week at home, she became irritable and fed poorly. At ten days of age, her parents noticed increasing lethargy which lasted for a period of 48 hours. Subsequently, she became more alert, but continued to feed poorly. Her family observed that she blinked infrequently and her eyes appeared to be fixed in one position. Her symptoms persisted and she was referred to Johns Hopkins Hospital for evaluation of ophthalmoplegia and feeding difficulty. On admission, examination revealed a pale, irritable infant ~vith normal vital signs, although her respirations were occasionally irregular. She would not follow a light or bright object.