Document zo63G3D6LKGebbExrRgpo4ZZa

/Q7? 10 8 8 The Journal of 3? E DIA T RIG S I I 'oUime Ntctnbei Table <.antro Does asymptomatic lead have latent sequelae? in children Seventy children who had had exposure to lead but had not had symptoms related to it were evaluated at four years of age using a.series of psychological tests. Results were compared to those, of similar evaluations of 72 children with comparable socioeconomic backgrounds but presumably without unusual exposure to lead. Sixty-five per cent of the control children but only thirty-five per cent of the lead-exposed ones performed normally in all areas tested (I.Q., fine motor development, gross motor development, concept formation, behavior). Deficits occurred most frequently in fine motor function and behavior. The majority of children in each group had an average l.Q. Brigitte de la Burde, M.D.,* and McLin S. Choate, Jr., M.S., Richmond, Va, A l a r g e percentage of children who sur vive acute lead encephalopathy have brain damage manifest by gross neurologic and sensory abnormalities; these include mental retardation, convulsions, hemiparesis, blind ness, and severely deviant behavior.1'3 .Many children with lead poisoning with out clinical encephalopathy show subtle signs of brain injury on later evaluation. These deficits occur most frequently in the area of visual motor perception or behavior while in many instances the global intelligence re mains nonnaf4' 5 It lias been suspected that lead acquired in quantities insufficient to cause acute clini cal symptoms may result iij neurologic dam age.1,' 3> 0 Controlled prospective .studies have From, the Department of pediatrics. Medical College of Virginia, Health Sciences Division of the Virginia Commonwealth University, Supported by Public Health Service Contract No. PH43-68-11 from the National Institutes of Health. fAddress: Child Development Study, Box 24, iCY.S**t ation, Richmond, Vrra. 23223. totf Sl, No. 6, jbp. 1088-1091 not been" done to prove or refute these mi/-'quences.6 This research was undertaken tdetermine if children with asyniptnnms lead exposure do show latent sequelae. MATERIALS AND METHODS The development of 4-year-old childm. with proved lead exposure was coinpnnTv,. that of 4-year-old children with simibi family background who presumably had r.c: had undue exposure to lead. All children were members of the Uni--' Development Study at the Medical (lullir^ of Virginia in Richmond, a participant iiu:. tution of the Collaborative Study of On-br... Palsy, Mental Retardation, and Other V: sory Disorders of Infancy and Childhc*! The total population consisted of IDmothers who were followed during pmpiaro and delivery and whose children were )-: natally evaluated by regular pediatric licimlogic. examinations, psychological testing, an.', medical interviews. Beginning in 1963 trained interviewTM s Bl l. Asymptomatic lead exposure and latent sequelae 10 89 en Mile I. {Iharaeteris.tics of children with lead exposure and of those in the ! :>tful "roup Characteristics Children with lead exposure N 70 R.iit iVv ,>tir^ronomic index 5 SRA nonverbal J.Q.* Il'rinim,' density V-i rf children below 6 yr. Black Male Mean Mean Mean Mean 64 32 3.2 77 1.5 . 2.1 White 6 Female 38 S.D. 1,3 S.D. 16.7 people/room `fVilMietl fjy Science Kescaiclt Associates, Inc., Chicago, Hi., VM7. Children without lead exposure N -- 72 Black 64 Male 34Mean 3.2 Meari 81 Mean, 1.5 Mean 2.2 White 8 Female 38 S.D. 1.3 S.D. 16.4 people/rooni ,>i>s[ioncd all mothers at each clinic visit i rrynrding their children's pica habits, the drAmre ingested, and the duration of the ; r.rui. During home visits the family compo- ; .-umi and the living conditions, including l and state of repair of the dwelling, were : v.iluairtl. This approach developed more ; -lialile information than that usually gar- : rrrfi in the regular clinic.7 t. From all children with a definite history i -i paint and plaster intake between one and | -am* years of age, 70 individuals were j j jrcted who lived in old dilapidated houses | mi had positive tests for urinary copropor- o x im:- j .i;yriiis.s TJ'he urine samples were examined V ,cn In ' r the presence or absence of fluorescence ptoinatic ami reported as positive or negative. In addi- he, - - :;,,n, ail 70 youngsters had a blood lead level ; f DM mg. per cent or above (mean 0.058 per cent; jratige 0,04 to 0.1 mg. per cent) children . -r a lead level of at least 0.03 mg. per cent pared to dth positive radiographic findings consisting similar f lead lines in the long bones, metallic den- had nor .lies in-the intestines, or both. Blood lead vi'l determinations were performed with .c Child tl.tr United States Public Health Service College biiliizone procedure in the toxicology labora- nt insli- f--rv of die Commonwealth of Virginia's medi- 3erebni ,tl examiner. All radiographs were taken at :er Sen- 4* department of radiology of the Medical Idhotxi. f ullcgc of Virginia and interpreted by a : 3,400 iialificd radiologist, None of these children tgnnney M obviotis signs of lead intoxication by re po\t - - -umination or from the mother's report, ncuro- Fnurteett children were treated with cal- ng,-ruid hiu yersnnate. All children were observed all repeated blood lead level determina- viewer* : imiis and had normal values (0.03 mg. per cent or below) on- discharge from the pedi atric clinic. The control subjects were drawn from a group of children who had no history' of paint or plaster ingestion on any of our six specific interviews Up to four years of age. Children eating foreign materials other than paint or plaster were included in this group, Unfortunately blood lead levels or radiographic studies were not done on this sample. . Thus the control subjects were selected by choosing children from an environment which provided very little Opportunity for the ingestion of lead-containing substances and who had no measurable coproporphyrins in their urine. Seventy-two children, living in recently built homes in good repair, were matched for age, race, sex, and several sdcioeconomic variables (Table I). The socio economic index used takes into account education and occupation of the head of the household and family income.0 The majority ' (87 per cent) of control children lived in city housing projects. Those cared for by babysitters in old neighborhoods were ex cluded. Families in both experimental and control groups lived in the same general area of Richmond and came from the same basic population. From the group of children with. lead exposure as well as the control group all individuals were excluded who showed signs of neurologic abnormality or developmental lag on pediatric and neurologic examinations during the newborn period and at four months or at the eight-months developmen tal test .(Bayley .scale). Also excluded were children who had confirmed or suspected ; : 1 :j j. J * j ' ' i .; 1 ( ' '? r v. i: 5 ( 1090 cle la Bunle and Choate The Journal of Pediatrics December 1972 Table XL Performance of 4-year-old children with lead exposure and of the control children on selected psychological tests Item I.Q. (Billet)* Borderline Mentally defective Fine motor areaf Performance suspect Performance abnormal Gross motor area+ Performance suspect Performance abnormal Concept fonnation Performance suspect Performance abnormal Behavior profiled Performance suspect Performance abnormat = 5.38, P < 0.05 fx2 = 5.02, P < 0.05, tx" as 2.74, N;S. {* as 0.88, N.S. Ilx* ~ 9.50, P.< 0.01. Children Children with lead without lead exposure exposure #o. ! 69 11 16.0 6 8:7 No. 7i 7 .0 % 9.8 0.0 69 70 29 42.0 18 25.7 2 2.9 .0 0.0 69 .10 14.5 1 1.4 71 5 0 7.0 0.0 67 10 14.7 0 0.0 71 6 .I 8.4 1.4 69 18 26.1 3 4.3 72 7 0 9.7 .0.0 disease or injury of the central nervous sys tem before four years of age. A series of psychological tests was admin istered to all children between the ages of 31 j-jo and 4%a years (majority at ) This evaluation was done by experienced examin ers, following uniform rules for test adminis tration and coding without knowledge of any prior history of the patient.10 The test series included the Stanford-Binet Short Jfirm L-M. Fine motor development was assessed with the Wallin peg board, copy forms, stringing beads, and Porteus mazes III and IV, It was coded normal if the child grassed three items, suspect if only one or two items were passed, and abnormal if none of the four items was passed. Gross motor de velopment was assessed with line walk, hop ping, and ball catch. It was coded normal when two subtests were passed, suspect when one was passed, and abnormal when none of Table III. Results of the psychological evaluation of 4-year-old children with lead exposure and of those in the control group* Psychological evaluation Normal I.Q. All other areas of the test batteryf normal Children yVhildten with lead without lead exposure exposure No. j <7, No. 7, 24 34.8 46 .64.9 Normal I.Q. 28 40.7 Failure in one or more of the other areas of the test batteryf" 18 25.3. Low I,Q4 All other areas of the test batteryf normal 3' 4.2 1 1.4 Low 1.Q4 Failure in one or more of the other areas of the test batteryf 14 . 20.3 6 8.4 *X=: = 13.23, P < 0.01. f:See Table II. *Low I.Q. combined for a .2 x 3 contingency table dec in low cell frequency of low I.Q. only. the three items was passed. Some aspects of concept formation were examined with a modification of the Grahain-Ernhart block sort test. Included was * behavior profile consisting of ten 5-point rating scales for die child's behavior during the psychological test situation. Interinstitutional quality control trials of the Collaborative Project have shown tester-observer ratings for these scales to be in complete agreement in 91 per cent of 1 IB .cases. RESULTS Findings for the major areas of the psychological evaluations of children with lead ex posure and those without are shown in Table II. Testing with the Stanford-Binet revealed a mean I.Q. of 89 (S.D, 13.1) for patients with lead exposure and a mean I.Q. of 94 (S.D, 10.5) for the control subjects. Both samples had large numbers of children with average intelligence (lead-exposed children 75.3 per cent, control subjects 88.8 per cent). Fine motor tests were most frequently failed in both groups, but failure occurred almost DUP040009112 T diatnri n -W..' .i''i Ffii' in 'fnhrr U Asymptomatic lead exposure and latent sequelae 1091 It. .. Qtip*' ' \ itdun out lead poturr 64 ') M M '}' !wir as often in lead-exposed children. Fail* i-iiv in tire gross motor category was apparent a lysser degree. There was no significant .irfrri'iirc'on ihi; Grahain-Ernhart block sort A 'nt, 9 .Deviations in our over-all behavior ratings &k mined almost three times as often in chil frrti wilii lend exposure' compared to the .iitrcil subjects. The most frequent combitia ."!i of behavior characteristics was extreme oMtiyism, distractibiiity, and constant need 'r attention. This triad occurred in 18 chil->n H'iJi lead exposure (25.7 per cent) --nijiared to four control subjects (5.5 per -si., (v2 11.17, P < 0.01). T.tliln III, representing the outcome of the mile test series, shows that children with -ill exposure compared to the control sub * H had a significantly greater chance to a deficit in one or more of the areas '-iiol. bl !'** M DISCUSSION AND SUMMARY peels ill a i itl. prf.it) I** for Oir ical ' text control e shown a to 1s t t of 111* psy< holead rxin Table rcvi-aln! patient" I. of '>) ts. ren with cliihlrrb ;f rent. Iy failed. f aim**' Psychological evaluation at four years Twd the performance of lead-exposed ' lifircn to be inferior tp that of youngsters aim in all likelihood were not exposed to in cused .quantities of lead, A large number 4 inid-cXposed children had normal intelliuiit'c but failed in one or more of the other ij'-as tested. The most significant difference '.iiweeii both groups was found in the fine fur and behavior areas. Since the group 4 lead-exposed children contained more . vut.illy subnormal children, low I.Q, might ' -.' biased these results. When only children litii nonhal I Q. were evaluated, the differ:.-ac in the behavior area remained signifi.Uit. I he presented results are considered pre Binary. Load levels in the control group aetf not done. The selection of control chilV ii was based on their presumably Iead- environments and was further supported i negative coproporphyrin urine tests, fiurofony definite statements regarding cup.-irntive differences in lead burden in the > .groups cannot be made. .Admittedly, the jh-iwires found may be due to environ "iiial factors other than lead. More rigidly controlled prospective studies should be done to clarify whether subclinical amounts of lead do have measurable sequelae. The deficits found may be reflected m the child's later development or they may im prove or disappear if, for example, they had resulted from an increased lead burden at the lime of testing.11 We hope to shed some further light on this issue by re-examining the same groups of children at seven years of .age. The authors are indebted to' the Child De velopment Study staff psychologists, to Miss Gail Halsey, Department of Biometry, and to Mrs. Phyllis McDonald and Mrs. Jill Miller for nevertiring assistance. REFERENCES 1. Chisolm, J, J>, Jr.: Chronic lead intoxication in children, Dev. .Med, Child Neurol. 7: 529, 1965. 2. Perlstcin, M. A., and Attala, R.: Neurologic sequelae of plumbism, Clin. Pediatr. 5: 29-, 1966. ; 3. Lin-Fu, J, S.: Childhood lead poisoning, an eradicable disease, Children 17: 2, 1970. 4. Byers, R. R., and Lord, E. E.: Late effects of lead poisoning on mental development,' Am. J. Dis. Child. 66: 471, 1943. 5. Thurston, D. L., Middlekainp, J. N,, and Mason, E.: The late effects of lead poisoning, J. Ped iat r . 47: 413, 1955, 6. Wiener, O.: Varying psychological sequelae of lead ingestion in children. Public Heal ill Rep. 85: 19, .1970. 7. de la Burde, B., and Reames, B.: Prevention of pica, the major cause of lead poisoning ip children. In press. B. Benson, P. E,, and Chisolm, J. J., Jr,: A reliable qualitative urine coproporphyrin test for lead intoxication in young children, J. Pe d ia t r . 5.6: 759, 19.60. 9. Myriantliopoulos, N. C,, and French, K. S.: An application of the U. S. Bureau of The Census Socio-economic Index to a large di versified patient population. ,Soe. Sci. Med. 2: 28;3, 1966. It). Four-year psychological examination manuals for Form PS 20-25, Colloborative Study of Cerebral Palsy, Mental Retardation and Other Neurological and Sensory Disorders of Infancy and Childhood, August, 1963, and December, .19.64, 11, S.mith, M. D., Baehner, R. L., Carney, T., an,d Majors, W. J.: The sequelae of pica with and without lead poisoning: A comparison of the sequelae five or more years later. I. Clini cal and laboratory observations, Am. J. Dis. Child. 105: 609, 1963.