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OAR Box 1128 

Prepped by Ollie Stewart 

Document Number: 

100)11-1-429 

Docket Number: 

A-83-22 

Printed 4/21/2008 11:07:15 AM Sheet 100 of 198 
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ElOOD LEUD COJ'CiJ^TLATICKS EJ SCrOOL AGI CKILDRZK, I"TELLIGZ?:C2, 

ATT.s.II^m A!!D EEHAVIOUR 

Background information to a paper presented st the 

Annual Conference of the British Psychological Society 

st the University of lork, April 1953 

Villism Yule 

Richard Lansdown 

Janet Hunter 

V^rie Anne Urbanovic? 

Barbara Clayton . 

i.'evor Delves 

ORIGINAL FILE COPY 

DO NOT REMOVE 

ECAO/TIC 

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Jej5**:5,W*Bft'—<uj 

The measurement of lead in blood 

In the studies reported tocsy body lead concentrations were assessed by 

measuring lead in blood sainples taken from e?ch child. Ihe unit of measurer.er.t 

most cormonly used is micrograms per 100 millilitres: /tg/cl. 

A recently published national estimate of blood le»d levels in the United 

States, based on an n of 9933, showed median levels ffiling during childhood: 

Teble one: Median blood leed levels by ag. (U.S.A.) From yfehaffey et al (1?££) 

Age group 

in years 

0.5-2.0 

3 - 5 

6 - 6 

9-1 1 

12 - 14 

15 - 17 

«ng/dl 

15 

15 

13 

12 

11 

11 

Age group 

in years 

16 - 24 

25-3 4 

35-4 4 

45-5 4 

55 - 64 

65 - 74 

/~_/d l 

•12 

13 

13 

14 

14 

13 

Detailed analyses were carried out on the group 0.5 to 5 years since it was 

here that associations betveen blood lead level, income of family and urbanisation 

were strongest. 

lhe prevalence of elevated lead levels (i.e.>30/«g/dl) was 12.2V in black 

children and ?.0°' in white children. Children from both black and white families 

whose incomes vere under I 6,000 had a significantly higher prevalence of 

elevated leads-than those from richer households. 

Children living in inner cities had higher median levels than those living in 

rural areas, with the same blackA'hite difference holding up irrespective of 

geographical location. 

Table two: Blood lead levels by farcily income ar.d urbanisation (U&Q Mahaffey et sl. 

Annual income 

of family 

< $ 6,000 

Z6 - 14,999 

> $ 15,000 

Urbanisation 

i '• m. pop. 

Central citie s 

Uon " " 

Urban < 1 m. 

Rursl 

•-S 

23 

21 

17 

22 

23 

19 

20 

18 

Else* 

¥.elevated 

18.5 

12.1 

2.8 

15.2 

18.6 

3.3 

10.2 

10.5 

_TKite 

x .^-elevated 

18 

15 

14 

17 

?7 

16 

15 

13 

5.9 

2.2 

0.7 

4.0 

4.5 

5.8 

1.6 

1.2 

z 

20 

16 

14 

16 

20 

16 

16 

14 

races 

h elevated 

1C.9 

4.2 

1.2 

7.Z 

1V6 

«.7 

3.5 

2 . i 
?*~er.t rritish ?tMci€* of School -re Children 

P.4 

~rse studies of the «ssocistion tetween cisoc lees levels, intelligence, 

etteinner.t m d beh»viour have been carried out cy the foliovir.g team: 

Tr v'illi»s Yule 

Tr ?-ieh»rd lansdown 

•>r.et Vur.ter 

;>rie Anne Urbanowicz 

Institute of Psychiatry, London 

The Hospitals for Siek Children, Lor.don 

Institute of -syer.istry, Lor.cor. 

Institute of Psychiatry, London 

T-ofessor 3*rb»ra Cleyton 

Ir Trevor Selves The University of Southampton 

All three studies were funded by the Medical Research Council 

TT.e first London Study (Yule et el 1961, Lansdown et al 1963) 

r.: 166 (£5>' of the possible sample) 

Tsile three: £oc3 

: i. e 

i : 6.6 

: :: »:M 10.2 

= i class ccr.sosition of sar.rle 

III M 4o.4 

IV 11.4 

V 1.2 

T'zle four: Blood le»d levels by social class 

ri 

I * II 14 

: :: v. 17 

III M 77 

IV 4 v 21 

s.? . 12 

£ 141 

Table five : Blooc 

lead group 

1. 7-10 *>g 

2. 11-12 /- g 

3. 15-16/^g 

4. 17-32 /»g 

7«fcle six : '*'n< 

C.A. in months 

i SE F p 

12.07 3.17 3.19 0.C153 

11.94 2.62 

15.47 4.24 

16.10 4.83 

13.17 3.97 

13.51 

lead levels by age in months 

5 SD 

110 21 

109 24 

97 20 

Si- 15 

0 0 • 

single parent 

unernpioyed 

not taowr. 

— 

and ?t.->nd=rd deviations of criterion r.essures 

T'eale Analysis of Rending Ability Accuracy 

Vernor. Spelling"} 

M*ths J 

'••'ISC - S Verfci 

Comprehension 

»tinc:rd score 

1 quotient 

Performance " 

Pull Scale VJ. 

X 

102.44 

1C2.66 

101.67 

?4.?4 

=4.36 

56.75 

10C.25 

96.21 

7.2 

1.2 

13.9 

s_ 

2*.7: 

25.6c 

24.' ° 

14.s" 

i?.29 

14.2-

15.-4 

. 15.44 

* 

* 

r* 

g 
P.5 

.1- • _ - i ••' — • 

*.*. 

•^mMm&t^y 

_. C^- 7 * Sir; £*j r, * , v- . 

•l*t 

_r'r5i ^ 

1670^ ; r ly * j • p** ccv^ri^r.ce — social clafj "*r"i?llct 

lead group 

• 7-"C^g 

? "-'-A S 

- '5-16/^g 

4 n-32 A . 

sc 

Pb 

<\ccur« 

i 2 i 

1*0 

5£ 

69 

ns 

0.001 

xy Com?. 

1-7 

no 

55 

66 

0.095 

0.001 

adjusted 

Spelling 

i?4 

9c 

52 

e9 

0.60 

0.001 

r.eans 

X.ths 

57 

97 

95 

54 

0.C13 

ns 

Verbs1 * 

"MI.48 

1?1.45 

O* s i 

0..09 

0.043 

"erf. ' 

105.:9 

'. "-. 

37. ?0 

9e.6C 

ns 

0.1C2 

?s i:. 

'".' 2 

•?2. = : 

55.75 

95.70 

0.C29 

0.027 

ITE The analyses noted above vere repeated with each dependent variable 

regresses against blood lead, with age also regressed in the reading scores 

and results sirdiar to those of the .nalyses of covariance were obtained. 

The Second London Study 

n: 194 (68V of the possible sanple) 

T=ble ei.ht 

I 

II 

III KM 

Table nine: 

I & II 

111 rm 

III M 

IV & V 

s.?. & u. 

: Soci' 

2.1 

35.5 

ie.6 

Elood 

n 

66 

56 

65 

10 

14 

1 class composition of 

III M 35.0 

IV *.6 

v 1.5 

lead levels by social 

x SE 

12.77 2.99 

11.92 5.52 

15.19 2.67 

15.50 4.e2 

12.29 2.50 • 

the sa.T3le (#) 

single parent 

unemployed . 

not known 

6.2 

1.0 

C.5 

_____ 

class (5 cases missing) 

F p 

1.319 0.34 

. -

The mean blodd lend level of the whole spnple was 12.75 >»>.g/dl SE 5.07 

¥ 

Sfc 

__ 

B£ 

'ss: 

te 
P.6 

£2 

RU 

Tnbig ten; lle^ns anr* strnrprri deviations of criterion ne=sures 

C.A. in months 

Neale Analysis of Re-ding Ability .Accuracy 

Comprehension 

Vernon Spelling! st«.nd_.rd score 

' " "aths J 

109.10 ? *c, tf * 

S « r I 

VISC - R Verbal quotient 

Performance " 

Pull Scale IQ 

112. 

110. 

99. 

99. 

103. 

,17 

,10 

.36 

,10 

.36 

106.40 

105.24 

23. 

24. 

Ii. 

16. 

14, 

13, 

14, 

,:6 

-35 

.25 

.16 

.91 

.51 

.20 

T'tle eleven: inslysis of covariance - social cl^ss Tssrtialled out 

ft 

le-d group 

1 7-12 ^ g 

ii 13-24/^g 

cr 

KS*S 

Pb 

n 

O CVI CO 00 

.ACC. 

114 

111 

ns 

ns 

Comp. 

113 

109 

0.02 

ns 

adjusted m 

Spelling 

101 

99 

ns 

ns 

eans 

Maths 

100 

99 

ns 

ns 

Verbal Q 

,104.46 

' 103.43 

0.001 

ns 

'erf. Q 

106.20 

106.32 

0.04 

ns 

FS IQ 

1C6.£6 

105.16 

0.C01 

ns 

Mi Regression analyses vere also carried out and in no case did lead account.for 

a significant amount of residual variance. 

• ••» 

V J: 

3 
P.7 

Istle t-wglve;;.n?lyses of variance with sample divided into manual and non manual 

social cl°-55 groups 

fi 

'.-1 

4 

M 

M 

M 

Dependent lead group 

variabl e 

Age 1 

in months 2 

Verbal 

Quotient 

-.-..ent 

Full Sea] 

1. 

3 

4 

1 

2 

3 

4 

1 

2 

5 

* 

.e 

1 

2 

3 

4 

- .. c roups 

_

-

4

0 

• _ 1 n 

7

 " 7 -1 / . 

• 

/ " g 

/ - g 

/ ~ g 

Ae 

Eon 

X 

113 

103 

115 

99 

102.3 

109.9 

103.7 

110.5 

104.0 

110.6 

106.3 

112.3 

103.4 

m.4 

105.3 

112.5 

n 

23 

26 

21 

21 

Manual 

SD SD 

22 22 

2S 26 

25 25 

28 28 

17 

• 14 

14 

15 

13 

16 

15 

10 

13 

15 

15 

. 13 

F 

2.37 

1.93 

• • 

1.85 

2.52 

P 

0.07 

0.13 

0.14 

0.06 

Manual 

X 

124 

112 

117 

96 

102.3 

96.3 

98.9 

99-4 

110.2 

103.6 

103.5 

1C3.4 

106.9 

100.7 

101.1 

101.3 

n 

16 

25 

21 

25 

SD 

24 

22 

28 

19 

12 

9 

14 

16 

14 

15 

11 

15 

13 

11 

13 

16 

• 

F 

5.71 

O.31 

1.04 

0.6 3 

p 

0.0013 

0.82 

0.38 

0.48 

» 
'it 

P.8 

Ihe Leeds Study 

Bats collection snd ?n=lysis not yet complete. Ihe figures given belov 

these available on 1 ___rch. 1963. 

Bats collected so fsr on 302 children 

Tpble thirteen; Social cl^ss composition of sample (*) 

I 1.3 

II 7.6 

III KM 4.6 

III M 41.1 

IV 7.0 

V 1.3 

single perent 7.6 

unemployed 9.9 

not known 19-5 

T.ble fourteen; Flood le*d levels by social class group 

n SD 

I -i II 

I II >! 

IV & V 

«*. . . 

Unemployed 

27 

14 

124 

25. 

23 

30 

11.15 

5.71 

12.17 

11.64 

12.78 

12.77 

3.38 

2.27 

3.96 

3.38 

5.43 

3.32 

Mean blood lead level on 300 children ( 2 missing) 11.65 /»• g/dl SB 3.87 

•_ 

Table fifteen: Me?ns end standard deviptions on criterion me=sures 

C.A. in months 

Teale Anrlysis of Reading Ability Accuracy 

Comprehension 

Vernon Spelling 1 stendar d scor e 

11 Maths J 

VflSC - R Verbal quotient 

rerformance " 

Full Scale IQ 

X 

118.76 

114.40 

113.19 

26.64 

100.03 

97.96 

102.51 

100.12 

SD 

26.06 

22.65 

24.33 

15.26 

14.as 

1

s

 Q 

13.6 

13.4 
Tablffi sixteen; VI5C scores by socigl class group 

P.9 

ler.d 

group 

Verbal 1 

ruotient 

CVJ 

I 

Performance 

cuotient 1 

2 

Full Scale 

I Q • - 1 CVJ 

le=d groups 

1 5-H /~g/dl 

2 12-26 /^g/d l 

ron 

X 

107.03 

110.09 

111.57 

112.63 

110.03 

112.45 

n 

41 

»nua l 

SD 

12.73 

H.39 

13.11 

13.33 

12.05 

11.25 

Manual 

x SD 

98.56 13.41 

97.16 13.17 

103.50 12.22 

103.23 13.66 

100.79

 1 2.03 

99.75 12.91 

n 

148 
P.10 

References 

R.L-nsdovn, /J.Yule, M.A.Urbanowicz 4 I.B.Millar (1963) Elood lead, 

intelligence, attainment, and behaviour in school children: overvie'.-: 

of a pilot study In M.Rutter &. fi .Russell Jones (eds.) lead Versus ?. 

John VJiley tr Sons 

ealth 

.a 

' :*_ 

h 

_ 

%r 

1 

K.R.Mahaffey, J.L.Annest, J.Roberts t. R.S.Murphy (1962) ?Cationai 

Estimates of Elood Lead Levels: United States 1976-1980 Kew Fngland 

Journ?! of Medicine 307 573-616 

V.YuIe, R.lansdown, I.E.Millar & M.A.Urbanowicz (1961) Ihe Relationship 

Eetveen Elood Lead Concentrations, Intelligence and .Attainment in a School 

''osul.tion: ->. °ilot Study revelo cmer.t. 1 "edicir.e £• Child "eurclo^v 

?*' 567-576 : " 

%