Nigerian Journal of Paediatrics

Prevalence of elevated blood Lead levels in children with chronic neurologic disorders in Benin City Nigeria

Niger J Paediatr 2019; 46 (3):133 – 139

ORIGINAL

Ibadin OM

CC – BY

Prevalence of elevated blood lead

Azunna C

Ofovwe EG

levels in children with chronic

neurologic disorders in Benin

City, Nigeria

DOI:http://dx.doi.org/10.4314/njp.v46i3.3

Accepted: 6th August 2019

Abstract : Background: Excess

with mixed forms, 23(16.5%) with

blood levels of lead in humans are

cerebral palsy, 8(5.8%) with atten-

Ibadin OM

(

)

injurious to tissues and organs

tion deficit and hyperactivity dis-

Ofovwe EG

chief among which is the central

order and 4 (2.9%) mental retarda-

Department of Child Health,

nervous system. Children with

tion. Mean BLL in subjects with

University of Benin/University of

chronic

neurologic

disorders

CNDs

of 25.05±16.65

µg/dl

Benin Teaching Hospital, Benin

(CNDs) with already compro-

(range: 8-72 µg/dl) was signifi-

City, Edo State.

mised brain function are unduly

cantly higher than the value in

Email: mikobadin@yahoo.com

predisposed to lead poisoning

controls

(19.24±10.17

µg/dl;

Micheal.ibadin@uniben.edu

because of some aberrant con-

range:8-53 µg/dl )(t=3.51, p=0.00).

ducts and behaviors inherent in

One hundred and one (72.7%) sub-

Azunna C

CNDs. Such children are there-

jects compared to 111 (79.9%)

Department of Paediatric,

fore at greater risk of further dete-

controls had elevated blood lead

Federal Medical Centre, Yenagoa,

rioration of brain functions should

levels eBLLs.

Prevalence

Bayelsa State.

they have elevated blood lead.

eBLLs was independent of gender,

Objectives: To determine blood

age, family SES and nutritional

lead levels in children with CNDs

status. Between subjects and

as well as in apparently healthy

Control

show

ever,

gender

controls

(24.92±15.97µg/dl vs 19.35±10.63

Methods: The case control, pro-

µ g / d l ; t = 2 . 7 4 =

spective and cross sectional study

p=0.01/25.28±17.96µ g/dl

involving 139 children (89 or

19.50±09.55µ g/dl;

t=2.01;

64% males and 50 or 36.0% fe-

p=0.04), age (11-15 years only)

males) aged 1-15 years (mean ±

(36.36±18.56µg/dlvs

19.45

SD: 6.54±4.04 years) and re-

10.76 µg/dl; t= 4.01; p=0.00) and

cruited from the Neurology Clinic

family SES (24.67±17.12 µg/dl vs

(COPD) of the University of Be-

18.12±09.17 µg/dl; t=3.42;p=0.00)

nin Teaching Hospital (UBTH)

significantly influenced the mean

Benin City was carried out be-

blood lead level (mBLL). mBLL

tween January and March of

was significantly higher in chil-

2013. Same number of apparently

dren with epilepsy and lowest in

children matched for age and gen-

those with mental retardation

der served as controls. A semi

(F=2.75; p=0.03). The only risk

structured, pre tested and re-

factor that predicted eBLLs was

searcher administered question-

finger sucking (OR=2.56; p=0.04

naire was used in obtaining rele-

95% CI=1.03-6.40).

vant information from the parents

Conclusion/Recommendations:

or guardians of study subjects.

eBLLs is rampant in the study lo-

Atomic absorption spectropho-

cale in both subjects and controls

tometer was used in determining

with the latter at heightened risk.

the blood lead levels while the

Hand sucking is a proven risk fac-

Vineland Social Maturity Scale

tor for eBLLs. Such children and

was used to assess personal and

others predisposed to eBLLs

social sufficiency among subjects

should be protected through im-

while socioeconomic classifica-

proved supervision, routine screen-

tion of the subjects was in accor-

ing and intervention where neces-

dance with the recommendations

sary.

of Ayodeji.

Results: Subjects consisted of 80

Key words: Blood Lead, Chronic

(57.5%) with epilepsy, 24(17.3%)

Neurologic Disorders, Children,

Benin.

134

Introduction

sizable number of whom have epilepsy as co morbidity.

About 100 cases have mental retardation while about a

Lead is ubiquitous and poisonous heavy metal that is

third of this have ADHD.

widely distributed in the environment. In 1991, CDC in

A semi- structured, pre-tested and researcher adminis-

Atlanta defined elevated blood levels in children as

tered questionnaire was used to obtain relevant informa-

whole blood lead levels (BLLs) ≥10µg/dl. There is how-

tion. (biodata, parent’s occupation and level of educa-

ever, no known safe blood lead level. Sources of lead

tion, associated risk factors and possible sources of lead

poisoning include lead-based paint, lead-contaminated

exposure. Family socio-economic classification was

carried out using the method described by Oyedeji

water, food, motor batteries with its waste and inhalation

of dust from aerosolized leaded gasoline. Human activi-

Permission for the study was obtained from the Ethics

ties fostering enhanced lead exposure include: use of

and Research Committee of UBTH. Included as subjects

herbal remedies, ceramic glazes and toys and indiscrimi-

were children aged 1-15 years seen in neurology clinic

nate disposal of leaded materials.

with CND while controls were age and sex matched

apparently healthy children with non-neurological con-

Malnourished children and those of workers in lead

ditions seen for minor ailments. Children with suspected

smelting factories are particularly predisposed. Other

epilepsy mimics were however excluded. Only study

persons unduly predisposed to heightened lead levels/

participants whose parents/guardians gave written in-

poisoning are children with chronic neurologic disorders

formed consent took part in the study. Older children

(CNDs), on account of increased “hand to mouth” activ-

( > 10 years) whose mental state permitted (in cases of

ity (mouthing and chewing of objects), associated be-

subjects) also assented to participating in the study.

havioral disorders, attendant malnutrition, poor supervi-

Vineland Social Maturity Scale (VSMS) was used to

sion and neglect.

assess personal and social sufficiency of the subjects and

Unsafe blood lead levels particularly if sustained cause

controls in the areas of communication, daily living

toxicity to organs and tissues as it interferes with exten-

skills, socialization, motor skills and maladaptive behav-

ior.

sive body processes and functions. The nervous system

in the growing child is worse hit because of its potential

to disrupt development of the system.

Weight and length measurements and BMI calculation

were carried using standard methods to determine their

With already compromised brain functions children with

nutritional status. Length of children < 2 years was

CNDs are at increased risk of further brain damage as

measured with a length board. The height of children >2

elevated BLLs have been reported to disrupt brain func-

years was determined using the stadiometer. Average of

tion causing disorders of cognition, intelligence, non-

3 readings to the nearest 0.1cm was recorded in each

verbal reasoning, short term memory and learning.

5,6

case. Heights of those with CP were estimated as rec-

Worldwide, the magnitude and burden of mental, neuro-

ommended by Stevenson.

The BMI of subjects were

logical, and behavioral disorders are already huge with

plotted on appropriate BMI percentile charts which en-

CNDs being major contributors.

1,8

Determining the

abled their nutritional status to be determined.

BLLs in children with CNDs would be initial steps in

Four milliliters of venous blood was obtained from a

identifying those at risk with a view to taking measures

suitable superficial vein of each child using aseptic tech-

aimed at forestalling further deterioration of the already

niques and transferred into a metal free, pre- labeled

precarious health status of the child with CNDs which

EDTA plastic bottle. The whole blood samples from the

equates to preventing a second lifelong tragedy. It is

participants were stored within 6 hours of collection at -

20 C. They were transferred fortnightly in ice packs

therefore worthwhile evaluating the BLLs in such chil-

dren.

from Department of Child Health laboratory to the Nige-

rian Institute for Oil Palm Research (NIFOR), which is a

15minutes drive from UBTH. Determination of blood

lead was done using Atomic Absorption Spectropho-

Subjects and methods

tometer (AAS, Varian Spectra AA10 model). Average

of three readings of the absorbance were taken for each

The descriptive cross-sectional study was carried out at

specimen and concentration recorded in parts per million

the Child Neurology Clinic (CNC) and the General Out-

(ppm) and converted to µg/dl by multiplying by a factor

of 100.

Patient Clinic (GOPC) of the University of Benin

Teaching Hospital (UBTH), Benin City. The Hospital is

an 860 bed tertiary health care facility providing all lev-

The test results were made available to the study partici-

els of care for inhabitants of Edo, Delta and neighboring

pants and the managing physician alerted where values

states.

were elevated.

The CNC holds on Wednesdays and an average of 20

SPSS version 20.0 Statistical software was used to ana-

patients are seen during each clinic day. Of the 20 cases

lyze the cleaned data. Mean (+SD) were calculated for

eight new ones are seen per week. The clinic is covered

continuous data while categorical data were presented as

by 2 child neurologists, 3 residents and 2 nurses. The

proportions. Test of significance was done using Pear-

GPOC holds daily and an average of 20 children are

son’s Chi - square and Fisher’s Exact test where applica-

seen daily in the clinic. In the clinic register are over 500

ble were used to test strength of association between

cases with epilepsy, 105 cases with cerebral palsy, a

proportions. Comparison of mean values was done using

135

independent t-test while the multiple logistic regression

subjects and same numbers of matched controls. The

models were used to test for predictors of elevated BLLs

mean ± SD age of subjects of 6.54 + 4.04 years was

while level of significance was set at p < 0.05 at 95%

comparable to that of controls (6.45 + 3.95 years).

confident interval.

Among the 139 subjects, 96 (69.1%) were drawn from

upper social class while 43 (30.9%) were from lower

social class. The proportions of children with CNDs

were: epilepsy, 80(57.5%); mixed (children with more

Results

than one form of CNDs), 24(17.3%); cerebral palsy, 23

(16.5%); attention deficit hyperactivity disorder, 8

One hundred and thirty nine children were recruited for

(5.8%) and mental retardation (MR) 4(2.9%). More chil-

the study. The 139 subjects with complete data were

dren in the age bracket 1-10 years compared to older

children had the various forms of CNDs (c =19.12,

matched for age group and gender.

There were 89 (64.0%) male and 50 (36.0%) female

p=0.01) (table 1).

Table 1: Socio-demographic characteristics of subjects according to the different forms of CNDs

Socio-demographic

Epilepsy

Mixed

ADHD

p- value

Features

n=80(%)

n=24(%)

n=23(%)

n=8 (%)

n=4(%)

Age group (years)

1-5

30(37.5)

11(45.8)

18(78.3)

5 (62.5)

1(25.0)

6-10

28(35.0)

9(37.5)

5(21.7)

3 (37.5)

1(25.0)

19.12*

0.01

11-15

22(27.5)

4(16.7)

0(0.0)

0(0)

2(50.0)

Gender

Male

58(72.5)

12(50.0)

11(47.8)

6(75.0)

2(50.0)

8.0*

0.08

Female

22(27.5)

12(50.0)

12(52.2)

2(25.0)

2(50.0)

SE status

Upper

55(68.5)

16(66.7)

16(69.6)

6(75.0)

3(75.0)

0.37*

1.0

Lower

25(31.2)

8(33.3)

7(30.4)

2(25.0)

1(25.0)

*Fisher’s exact test; CP: Cerebral Palsy; ADHD: Attention Deficit Hyperactivity Disorder; MR: Mental Retardation; Mixed:

More than one form of the disorders

Influence of gender age and family socioeconomic status

Mean blood lead levels in subjects according to age,

on elevated blood lead levels

gender and family socio-economic status.

Among subjects eBLLs was independent of gender, age

The mean (±SD) BLL was significantly higher in male

and family socio- economic status (Table II). Similarly

subjects (24.92 ± 15.97 µg/dl) compared to male con-

age, gender and family socio- economic status did not

trols (19.35 + 10.63 µg/dl)(t= 2.74, p= 0.01). Similar

influence the occurrence of elevated BLLs in controls.

trend was observed with female subjects compared to

Mean blood lead levels in subjects and controls.

controls [(25.28+17.96 µg/dl vs 19.50+9.55 µg/dl,

The mean ± SD BLL in the subjects with CNDs of 25.05

(t=2.01, p=0.04)]. Mean BLL in children aged 11-15

± 16.65 mg/dl (range; 8 – 72mg/dl) was significantly

years was significantly higher than the mean value in

higher than the value in controls (19.24 ± 10.17 mg/dl,

controls of comparable ages. Among the subjects higher

range 8 – 53mg/dl) (t = 3.51, p = 0.00).

mean BLL was recorded in older children compared to

younger ones (C vs E, t=3.669, p=0.004 (95% CI: 6.801

Table 2: Influence of gender, age group and socio economic

-21.179; D vs E, t=3.879, p=0.0002 (95% CI: 7.171-

status on elevated blood lead levels in subjects and controls

22.329) . Mean BLL in subjects drawn from upper SEC

Socio demo-

Elevated BLLs

was significantly higher than the value in controls

graphic fea-

Subjects

Controls

(24.67 + 17.12 µg/dl vs 18.12 + 9.17 µg/dl, t = 3.42, p =

tures

n=101(%)

n=111(%)

p- value

0.00) (Table 3).

Gender

Male (n=89)

63(70.8)

71(79.8)

1.93

0.17

Female (n=50)

38(76.0)

40(80.0)

0.23

0.63

Prevalence of elevated blood lead levels in children with

Age (years)

chronic neurologic disorders

1-5 (n=65)

45(69.2)

51(78.5)

1.43

0.23

6-10 (n=46)

32(69.6)

38(82.6)

2.15

0.14

11-15 (n=28)

24(85.7)

22(78.6)

0.49

The prevalence of elevated blood lead levels (eBLLs)

SE status

( >10 µg/dl) according to the different forms of CNDs is

Upper (n=96)

66/96(68.8)

*83(79.0)

2.26

0.13

as shown in Table III. Though fewer (101/139 or 72.0%)

Lower (n=43)

35/43(81.4)

*28(82.4)

0.01

0.91

subjects compared to controls (111/139 or 80.0%) had

eBLLs there were however, more subjects with very

* For controls total number of children in upper and lower SE statuses

high values (> 20 µg/dl) (71/101 or 70.3%) compared to

respectively were 105 and 34.

Significant: Nil Not Significant

controls (61/111 or 55.0%). Prevalence of eBLLs was

A vs B, c =0.215, p=0.643; C vs D, c = 0.001,p=0.970 ; C vs E, c =

highest in children with epilepsy compared with other

forms of CNDs (c =8.32, p= 0.06). Furthermore, more

0.190, p=0.124 ; D vs E, c = 0.214, p=0.164; F vs G, c =0.029,

p=0.864.

136

children with eBLLs had values in the third category of

of low, moderately low, adequate, moderately high and

elevated BLLs (20-44 µg/dl).

high) subjects with “adequate’’ and “moderately high”

Mean BLL was significantly associated with the form of

adaptive levels had mean BLLs of 26.05±15.51µg/dl

CNDs (F =2.75 p = 0.03) as children with mixed disor-

and 29.60 ±20.23 µg/dl respectively. Though these were

ders (more than one form of CNDs) and epilepsy had

higher than values in subjects with “moderately low”

significantly higher mean BLLs compared to other

adaptive level (20.00±12.66 µg/dl) there was however

forms of CNDs. (Table 4). Some intra group differences

no correlation between adaptive level and BLLs (r=0.04;

also existed in the mean BLLs (table 4).

p=0.59).

Table 3: Mean blood lead levels in subjects and controls

Table 5: Risk factors predicting elevated blood lead levels in

according to gender, age group and socio economic status

subjects

Socio-

Subject

Control

n (%)

95% C.I.for

demographic

µg/dl

valu

Features

Habit

Gender

Finger sucking

10(9.9)

0.04

2.56

1.03 – 6.40

Male

24.92 ± 15.97

19.35 ± 10.63

2.74

0.01

Pica

10(9.9)

0.25

0.41

0.09 – 1.89

Female

25.28 ± 17.96

19.50 ± 9.55

2.01

0.04

Environmental

Age Group (years)

Water storage

100(99.1)

0.90

0.97

0.57 – 1.64

1-5

22.62 ± 15.64

19.57 ± 10.05

1.32

0.19

House type

101(72.7)

0.51

1.27

0.62 – 2.57

6-10

21.61 ± 13.98

18.80 ± 10.25

1.10

0.28

Painted house

11(10)

0.56

1.63

0.32 – 8.36

11-15

36.36 ± 18.56

19.45 ± 10.76

4.01

0.00

Flaking paint

36(35.5)

0.50

0.75

0.33 – 1.72

SE status

Use of generator

76(75.5)

0.13

2.64

0.76 – 9.19

Upper

24.67±17.12

18.12 ± 9.17

3.42

0.00

Flat level

20(19.9)

0.87

1.07

0.46 – 2.48

Lower

25.91±15.71

23.35±12.35

0.78

0.44

House location

40(40.0)

0.74

0.97

0.79 – 1.18

Others

Significant:

Use of eye cos-

6(5.9)

0.83

0.78

0.08 – 7.92

C vs E, t=3.669, p=0.004 (95% CI: 6.801-21.179)

metics

D vs E, t=3.879, p=0.0002 (95% CI: 7.171-22.329)

Wash toys

30(27.0)

0.21

1.35

0.84 – 2.16

Not Significant: A vs B, t=0.122, p=0.903; C vs D, t = 0.350,

Adaptive levels

101(72.7)

0.17

0.75

0.49 – 1.14

p=0.727; F vs G, t=0.405, p=0.686.

Table 4: Mean Blood lead level in subjects according to form

Nutritional status of study participants and mean blood

of CNDs

lead levels.

Chronic neu-

n (%)

Mean blood

p value

rologic disor-

Lead Level

The mean BLL of subjects with adequate nutrition was

der (CND)

(µg/dl)

significantly higher than mean BLL of controls with

Epilepsy

80(57.5)

27.21 ± 17.00

similar nutritional status ( t=3.12, p = 0.00). No signifi-

Mixed

24(17.3)

28.54 ± 17.61

cant intra group differences in mean BLLs existed

Cerebral palsy

23(16.5)

17.91 ± 13.81

2.75

0.03

among the subjects (table 6). Mean BLL was therefore

ADHD

8(5.8)

21.13 ± 13.09

independent of nutritional status of subjects. (table 6)

Mental retarda-

4(2.9)

9.75 ± 2.87

tion

Table 6: Mean blood lead level of subjects and controls ac-

Mixed group consist of more than one category of CND

cording to nutritional status

Significant:

Nutritional

Subjects

Controls

Subjects

Control

A vs C, t=2.403, p=0.018, 95%CI: -16.998 -1.622

Status

n (%)

Mean

value

A vs E, t=2.041, p=0.044, 95%CI:-34.476-0.442

BLL

(µg/dl)

B vs C, t=2.296, p=0.026, 95%CI:-19.95-1.310

B vs E, t=2.097,p=0.040, 95%CI: -37.21-0.32

Under-

17 (12.23)

Not Significant:

weight

22.76±1

A vs B, t=0.334, p=0.740; A vs D, t=0.981, p=0.330; B vs D,

5.91

t=1.089, p=0.385; C vs D, t=0.575, p=0.570; C vs E, t=1.159,

Normal

105

123

25.17±1 19.50±

3.12

0.00

p=0.257; D vs E, t=1.680, p=0.124.

(75.53)

(88.49)

6.43

10.43

Overweight

10 (7.19 ) 12(8.63)

29.10±2 17.00 ±

1.87

0.08

Risk factors for elevated blood lead levels in children

0.77

7.83

with CNDs

Obese

07 (5.03) 04(2.88)

23.00±

23.75±

-0.07 0.94

18.08

11.44

Of the factors evaluated, only finger sucking was predic-

Not Significant:

tive of eBLLs. A child engaged in finger sucking was

A vs B, t=0.563, p=0.574; A vs C, t=0.893, p=0.380; A vs D,

two and half times more likely to have eBLLs compared

t=0.032, p=0.975; B vs C,t=0.706, p= 0.484; B vs D, t=0.336,

to those who do not. (OR = 2.56, p = 0.04, C.I 1.03 –

p=0.737; C vs D, t=0.627, p=0.540

6.40) (table 5).

Subjects’ adaptive levels and blood lead levels.

Utilizing the Vineland Adaptive Behavior Scale (range

137

Discussion

Children with CND suffer from poor care and supervi-

sion from care givers. They are also more likely to have

In the study, high prevalence of eBLLs was observed in

behavioural aberrations that can predispose them to in-

subjects and in controls suggesting high environmental

creased lead exposure. These may explain the higher

lead contamination in the study locale. This may be re-

mean blood lead levels in the study subjects compared

lated to increased exposure to lead by the general popu-

to controls. A similar observation had been made by

lation as found with the increasing use of lead based

Kumar et al in 1998 among children with neurological

disorders in Varanasi India.

paints in homes, indiscriminate importation and disposal

of lead containing gadgets (car batteries and electronic

About 75% of children with ADHD had eBLLs with a

waste).

mean value of 21.13µg/dl. Wang et al in 2008 in a study

involving Chinese children aged 4-12 years with ADHD

Nigeria has a history of environmental lead contamina-

noted a lower prevalence of 24.0% and mean BLL of

tion from past use of leaded petrol and use of lead based

8.77µg/dl. They had suggested that lead exposure early

paint in homes. The high prevalence of eBLL of 72.2%

in childhood may have contributed to the occurrence of

ADHD in their children. More plausible is the fact that

noted in the study is higher than the 60.0% reported by

Kumar et al in children with CNDs in India. Lewendon

ADHD may be associated with habits that unduly pre-

et al in 2001 in South West England carried out a simi-

dispose to lead poisoning. The higher mean BLLs and

lar study among children with developmental and be-

prevalence of eBLLs in individuals with ADHD in the

havioral problems and reported a low prevalence of

current study may have to do with the higher level of

12%. The differences in prevalence between the studies

lead pollution in the study locale.

may be a reflection of the levels of environmental lead

pollution, characteristics of the study subjects and effec-

Children with epilepsy and mixed forms of CNDs had

tiveness or otherwise of policies instituted by the con-

higher mean BLLs compared to others suggesting that

cerned nations to regulate lead levels in the environ-

perhaps there are peculiar social conditions inherent in

ment.

epilepsy that unduly predispose sufferers to lead poison-

ing. In between seizures some of such children are

Mean BLL in subjects with CNDs was significantly

known to be hyperactive physically, interacting more

higher than values in age and sex matched controls per-

with the environment. Later in life some children with

haps affirming the proposition that children with CNDs

epilepsy do also develop psychiatric complications with

have higher incidences of social and behavioral prob-

attendant deviant behaviors that could lead to undue

lems that predispose them to lead ingestion/inhalation,

ingestions of materials containing lead.

hence elevated levels of blood lead compared to their

apparently healthy counterparts. More male subjects

Children with mental retardation had low mean BLL. In

compared to male controls and more female subjects

contradistinction Okoronkwo and Dadin Kowa in Jos in

compared to female controls had higher means of BLLs.

2003 recorded a much higher value of 25.3µg/dl among

100 mentally retarded children aged 6 to 14 years. The

A less important role for gender as a modifier of BLL is

thus suggested though males compared to females,

lower mean BLL found in Benin compared to what ob-

across most age brackets, are more physically active and

tained in Jos may have to do with the fact that unlike Jos

more likely to interact with an environment that is al-

mining activities in Benin is virtually non-existent. Men-

ready polluted with lead.

tally retarded children compared to other forms of CNDs

also tend to get a lot of attention that tend to be protec-

As earlier noted by Okoronkwo and Dadin Kowa in

tive from care givers and such may reduce their contact

2003 in Jos, BLLs were higher in adolescents compared

with potential sources of lead. Children with mixed dis-

to other age groups.

This may reflect the increased

orders/epilepsy are more likely to be disadvantaged neu-

levels of socioeconomic and physical activities in such

rologically and therefore more prone to neglect, poor

older children. It may also imply the tendency for lead to

supervision and more aberrant behaviors. This may ex-

accumulate over time following consistent exposure.

plain why children with mixed disorders and epilepsy

Subjects from upper SEC had significantly higher mean

had significantly higher mean BLLs compared to chil-

BLL than controls. In contradistinction, Khan et al in

dren with other forms of CNDs.

1995 in Pacific North West Washington and Lewendon

et al

in 2001 in South West England found no signifi-

A probable implication of high mean BLLs found in

cant association between socio -economic status and

children with CND in this study is that it could cause

mean blood lead levels in children with CND. Our ob-

further deterioration of their existing precarious neuro-

servation may have to do with the nature of pollutants

logical disorders such as worsening cognitive impair-

the subjects are exposed to. Lead contamination from

ment, reduced intelligence, seizure disorders, loss of fine

motor skills and more behavioral abnormalities.

car batteries, electronics and other lead laden gadgets are

more likely to be experienced by children with CND

Subjects engaged in finger sucking were two and half

drawn from the upper SEC. The regional differences

times more likely to have elevated BLLs. This is an ac-

knowledged risk factor in lead exposure. Children en-

may also be explained by the extent and robustness of

the control measures instituted by the various countries.

gaged in the act usually have their fingers soiled with

14,16

materials laden with contaminants including lead prior

to sucking. “Hand to mouth” activities such as

138

mouthing” of objects and finger sucking do coexist.

The significantly higher mean BLLs in children with

Children with CND are noted to carry out more of these

CND who had normal nutritional status compared to

behaviors alongside other aberrant conducts such as pica

their control counterpart also goes to embellish even

which do predispose to increased lead levels in such

further perhaps the unique predisposition of the former

children. This is corroborated by findings in the study.

to lead poisoning.

Though not significant the risk of having eBLL was two

This study revealed high prevalence of eBLLs in chil-

and half times higher in children with CND who lived in

dren with CNDs which perhaps may be indicative of

homes that used generators. There is paucity of studies

high environmental lead pollution in the study locale.

that evaluated the use of generators as a risk factor for

Epileptic children and those with mixed CNDs are un-

eBLLs. It may be inferred from this that the use of gen-

duly predisposed to higher levels of BLLs. Patients with

erators in homes expose children to lead contaminated

CNDs that engage in hand sucking are at accentuated

fumes. The use of generators in homes in Nigeria to

risk of having high BLLs. Children at risk of excessive

provide power supply is rampant. Suspicion is rife that

levels of lead should be protected. Measures to reduce

the state may not have fully implemented the policy to

environmental lead pollution as may be instituted by the

remove lead content in gasoline as leaded gasoline still

government may also be helpful.

tops the list of sources of environmental lead exposure

via the inhalational route in Nigeria. Adulterated gaso-

line frequently sold by marketers in Nigeria could be a

veritable source of pollution.

Acknowledgement

Against expectations lead levels in children with CNDs

Resident doctors in the Department of Child Health Uni-

had no correlation with their degree of adaptation. Theo-

versity of Benin Teaching Hospital (UBTH) Benin City

retically, persons with low adaptive level should have

assisted with data and sample collection. We are in-

high BLLs and reverse could also be true. However

debted to them. The immense roles played by staff of

CNDs are complex morbidities with diverse manage-

the Nigerian Institute of Oil Palm Resrearch (NIFOR)

ment options. The environment including quality of care

regarding sample analyses are greatly appreciated while

plays key roles in determining outcome. This may ex-

the services of Dr D Nwaneri in data handling were in-

plain why the adaptation at the individual level would

valuable.

not play decisive role(s) in the level of blood lead in

such children.

References

1. Markowitz M. Lead Poisoning.

6. Agency for Toxic Substances

10. Sparrow SS, Cicchetti DV,

In: Kliegman RM, Stanton BF,

and Disease Registry

Balla DA. Vineland-II: Survey

St Geme III JW, Schor NF,

(ATSDR). Toxicological pro-

Forms Manual ; Vineland

Behrman RE (eds) Nelson

file for lead. [cited accessed

Adaptive Behavior Scales ;

Textbook of Pediatrics. 20

24th september 2010]. Avail-

Survey Interview Form and

edn. Elsevier Pliladel-

able from: http://

Parent/caregiver Rating

phia.2016:3431-342.

www.atsdr.cdc.gov/toxprofiles/

Form ; a Revision of the Vine-

2. American Academy of Paediat-

tp13.pdf.

land Social Maturity Scale by

rics. Lead exposure in children:

7. Institute of Medicine Commit-

Edgar A. Doll. 2nd edn: Pear-

Prevention, detection and man-

tee on Nervous System Disor-

son Assessments. MInneapo-

agement. Comm Environ Hlth

ders in Developing Countries.

lis. 2005.

Paediatr. 2005;116:1036-46.

Neurological, Psychiatric, and

11. Stevenson RD. Use of seg-

3. Schmidt CW. Unfair trade, e-

Developmental Disorders:

mental measures to estimate

waste in Africa. Environ Hlth

Meeting the Challenges in the

stature in children with cere-

Perspect. 2006;144:232-5.

Developing World; : National

bral palsy. Arch Paediatr Ado-

4. Kumar A, Dey PK, Singla PN,

Academies Press. Washington

lesc Med. 1995;149:658-62.

Ambasht RS, Upadhyay SK.

DC.2001.

12. Dogan P, Dogan M, Klock-

Blood lead levels in children

8. Izuora GI. A pilot study on

enkamper R. Determination of

with neurological disorders. J

disability in children around

trace elements in blood serum

Trop Pediatr. 1998;44:320-2.

Enugu. W Afr J Med.

of patients with Behcet dis-

Cecil M, Brubaker J, Adler M,

1988;7:117-23.

ease by total reflection x-ray

Dietrich N, Altaye M, Egelhoff

Oyedeji GA. Socio-economic

florescence analysis. Colin

C, et al . Decreased brain vol-

and cultural background of

Chem. 1993;39:1037-41

ume in adults with childhood

hospitalized children in Ilesha.

13. Nduka JK, Orisakwe OE,

lead exposure. PloS Med.

Nig J Paediatr. 1985;12:111-7.

Maduagwuna CA. Lead levels

2008;5:112.

in paint flakes from buildings

in Nigeria: a preliminary

study. Toxicol Ind Hlth.

2008;24:539-42.

139

14. Lewendon G, Kinra S, Nelder

16. Khan CA, Kelly CP, Walker

18. Mathee A, Von Schirnding

R, Cronin T. Should children

WO. Lead screening in chil-

YER, Levin J, Ismail A, Hunt-

with developmentaland behav-

dren with attention deficit

ley R, Cantrell A. A survey of

ioural problems be routinely

hyperactivity disorder and de-

blood lead levels among

screened for lead? Arch Dis

velopmental delay . Clin Pedi-

young Johannesburg school

Child. 2001;85:286-8.

atr. 1995;34:498-501.

children. Environ Res.

15. Okoronkwo MO, Dadin Kowa

17. Wang H, Chen X, Yang B, Ma

2002;90:181-4.

SJ. Serum lead levels of men-

F, Wang S, Tang M, et al . Case

19. Orisakwe OE. Environmetal

tally handicapped children in

control study of blood lead

pollution and blood lead levels

Jos, Plateau State of Nigeria. J

levels and attention deficit hy-

in Nigeria: who is unexposed.

Med Trop. 2003;5:36-44.

peractivity disorder in Chinese

Int J Occup Med Environ Hlth

children. Environ Hlth Per-

2009;15:315 - 7.

spect. 2008;116:1401-6.