ORIGINAL

Niger J Paed 2013; 40 (4): 379 –383

Atimati AO

Abiodun PO

Ofovwe GE

Relationship between vitamin A

status and anaemia among school

age children in Benin

DOI:http://dx.doi.org/10.4314/njp.v40i4,6

Accepted: 15th April 2013

Abstract Background: Anaemia

and vitamin A deficiency are two

major public health problems af-

fecting many developing coun-

tries world-wide. Vitamin A defi-

ciency, in addition to other health

problems, can contribute to anae-

mia. Therefore, the objective of

this study is to determine the rela-

tionship between vitamin A status

and anaemia among school age

children in Benin City.

prevalence of vitamin A deficiency

(plasma retinol <20µg/dl) was

29.6%. There was no subject with

(

)

Atimati AO

Abiodun PO, Ofovwe GE

severe vitamin

A

deficiency

Department of Child Health,

University of Benin Teaching Hospital,

PMB 1111, Benin City.

E-mail: tonyatimati@yahoo.com

Tel: +2348023417855

(plasma retinol <10µg/dl. The

mean haemoglobin concentration

was 10.5 ± 1.1g/dl., with a range

of 7.3 – 13.4g/dl. The prevalence

of anaemia (haemoglobin concen-

tration <11g/dl) was 58.6%. There

was no statistically significant cor-

relation between vitamin A defi-

ciency and anaemia, although the

haemoglobin levels tended to in-

crease with increased vitamin A

status.

Conclusion: This study shows high

prevalence rates of vitamin A defi-

ciency and anaemia in this part of

Nigeria. There was a trend of in-

creasing haemoglobin levels with

higher vitamin A status which

however, was not statistically cor-

related.

Methods: This is a cross-sectional

study carried out between June

2

005 and February 2006 on one

hundred and fifty-two children

within the age range of 6 and 12

years, randomly selected from

primary schools in a Local Gov-

ernment Area of Edo State.

Plasma vitamin A was assessed

by Bessey’s Spectrophotometric

method, while the Haemoglobin

concentration was assessed using

the photometric principle of

analysis.

Key Words: vitamin A

deficiency, Anaemia, school age

children.

Results: The mean plasma vitamin

A level was 27.7± 12.4µg/dl.,

with a range of 10 - 64µg/dl. The

Introduction

Vitamin A deficiency results from inadequate dietary

intake, increased utilization during rapid growth, in-

creased losses and inefficient utilization during infec-

tions such as diarrhoea, malaria, urinary tract infection,

Vitamin A deficiency and anaemia are major health

problems affecting young children in many developing

countries world-wide. Vitamin A deficiency is the single

most important cause of childhood blindness in develop-

6

measles and helminthic infestations. The consequences

of vitamin A deficiency are enormous, ranging from

reduced body immunity, anaemia, growth impairment,

reduced fertility to xerophthalmia which may lead to

1

ing countries . It also contributes significantly, even at

sub-clinical levels, to morbidity and mortality from

common childhood infections . An estimated 78 – 253

1

7

blindness. The prevalence of anaemia (which is defined

million preschool age children are suffering from vita-

min A deficiency globally. The prevalence of subclini-

cal vitamin A deficiency (serum retinol value below

as a reduction in the haemoglobin concentration below

1

8

11g/dl) in developing countries is about 42% among

9

pre-school and 53% in school aged children. In Nigeria

0

-

.7µmol/L or 20µg/dl) among pre-school children world

the overall prevalence of anaemia was 29.4% as reported

in the 1993 FMOH/UNICEF study with the highest

prevalence occurring in the South-east (49.₈6%) and the

lowest in the North-east region (11.1%). Causes of

anaemia in developing countries include iron deficiency,

malaria, hookworm infestation, and other nutritional

deficiencies that influence haemoglobin metabolism

2

wide ranges from 9.8%–35.6%. Higher prevalence rate

3

of 63% has been reported in pre-school age children in

Western Nigeria. In school age children a prevalence

rate of 20%, and 46._,3₅% was reported in Bangladesh and

4

North West Mexico respectively.

3

80

9

including vitamin A. Nutritional iron deficiency and

deficiency. Their weights and heights were taken to as-

sess their nutritional status.

vitamin A deficiency are the two most pr₁e₀valent nutri-

tional deficiencies in developing countries. Anaemia is

a major contributor to infant and under-five mortality in

Nigeria, and may lead to irreversibly impaired mental

development and cogn₁itive function during the critical

Seven milliliters (7mls) of blood was withdrawn from a

peripheral vein. The blood was emptied into two EDTA

bottles – five millilitres (5mls) into the container for

plasma vitamin A estimation which was wrapped with

aluminium foil, and two millilitres (2mls) into the con-

tainer for haemoglobin estimation. The sample bottle for

vitamin A estimation was placed in ice pack for onward

transfer to the laboratory where the plasma was sepa-

rated by centrifuging. The analysis of plasma vitamin A

was by Bessey’s method of ultraviolet destruction of

retinol, and was carried out in the Edo State Waste Man-

agement Laboratory in Benin City. The haemoglobin

concentration was estimated by the photometric princi-

ple of analysis using the Swelab’s AutoCounter.

1

years of development. Vitamin A deficiency is postu-

9

lated to cause anaemia through three mechanisms:

modulation of erythropoesis, reduction of the body’s

immunity to infectious diseases thus leading to anaemia

of infection and modulation of iron metabolism.

Various studies worldwide have reported a close asso-

ciation between vitamin A status and anaemia. A high

correlation between haemoglobin concentration and

plasma/serum retinol concentration was found among

4

school aged children in Bangladesh. Various studies

have been carried out on vitamin A in Nigeria, some of

which have_,₈r_,eported on the prevalence rate of vitamin A

Inclusion Criteria: Primary school children between

the ages of 6 and 12years in the selected schools.

3

deficiency and vitamin A levels in children under the

1

2

age of five years. These studies however, did not in-

clude school age children in which vitamin A de_,₅ficiency

Exclusion Criteria:

4

have been reported in studies outside Nigeria. An un-

1. Children with a history of fever or diarrhoea in the

preceding four weeks to the time of recruitment.

2. Children with measles or history of measles in the

preceding six weeks.

published study carried out in Benin-city by Otobo

showed a high correlation between vitamin A deficiency

and anaemia. The study was however a hospital-based

study among pre-school age children with malaria. This

study is therefore aimed at examining the relationship, if

any, between vitamin A status and anaemia at the com-

munity level in public primary school children in Egor

Local Government Area of Edo State.

3

Children with sickle cell anaemia and those with

overt malnutrition

Results

A total of one hundred and fifty-two subjects, compris-

ing eighty females (52.6%) and seventy-two males

(47.4%), ultimately participated in the study. The ages

of the subjects ranged from 6 – 12 years with a mean

age (±SD) of 9.36 ± 1.78 years. The mean age of the

male subjects was 9.23 (± 1.92) years while that of the

females was 9.44 (± 1.65) years. There was no statisti-

cally significant difference in the mean age between

both sexes (t = 0.7251, p =0.4695). The plasma vitamin

A level of all the subjects ranged from 10 - 64µg/dl with

a mean level of 27.7 (± 12.4) µg/dl. The mean plasma

vitamin A level of the female subjects (28.7 ± 13.6µg/dl)

was higher than that of the male subjects (26.6 ± 11.0µg/

dl) as shown in Table 1, although the difference was not

statistically significant (t = 1.526, p = 0.8597).

Materials and methods

This study was undertaken in public primary schools in

Egor Local Government Area of Edo State. The public

schools were chosen for this study because of their lar-

ger population size. Ten schools, which amounted to

thirty percent of the total of 33 public schools in the

Local Government Area, were randomly selected for the

study. A total of 152 subjects were selected by multi-

stage sampling from the ten public primary schools.

After obtaining ethical clearance from the Ethical com-

mittee of the University of Benin Teaching Hospital,

Benin, a consent form and self administered question-

naire were given to each subject to be completed by

their Parent/Guardian. Mebendazole tablet, an anti-

helminthic , was administered orally, three weeks before

sample collection to each subject at a dose of 100mg

twice daily for three days. This was aimed at deworming

the children, thereby eliminating any possible transient

drop in serum retinol lev₁el that is known to occur with

Table 1: Gender distribution of vitamin A status

Sex

Vitamin A Status

Total

Deficient Normal Mean (µg/dl ± SD)

M

F

Total

22

23

45

50

57

107

26.6 ± 11

28.7 ± 13.6

27.7 ± 12.4

72

80

152

1

helminthic infestations. The subjects were examined

for presence of palor, jaundice, bossing of the skull,

splenomegaly and hepatomegaly which might be indica-

tive of sickle cell anaemia. Their eyes were examined

for features of xerophthalmia such as bitot spots and

corneal ulceration which are signs of vitamin A

t = 1.526, p = 0.8597

Of the 152 subjects, 45 (29.6%) consisting of 22 males

and 23 females had vitamin A deficiency with plasma

vitamin A level below 20µg/dl. All the vitamin A

3

81

deficient subjects had mild/moderate deficiency with

plasma vitamin A levels between 10µg/dl and 19µg/dl.

None of the subjects had severe vitamin A deficiency

Discussion

Vitamin A deficiency and anaemia often co-exist in

some communities and are associated with high mort₁a₄l-

ity rates especially in children under five years of age.

Vitamin A deficiency and anae₄_,m₅ ia have however been

reported in school age children.

(

<10µg/dl). 45 subjects (29.6%) had plasma vitamin A

level between 20µg/dl and 29µg/dl while 62 subjects had

levels of ≥30µg/dl.

The range of the haemoglobin concentration was 7.3 to

The mean (± SD) plasma vitamin A level of 27.7 (±

12.4) µg/dl in this study₅ is similar to 31.8 (± 18.6) µg/dl

1

3.4g/dl with a mean (±SD) concentration of 10.5 (±

.1g/dl). There was no statistically significant difference

1

reported by Ajaiyeoba in pre-school age children in a

in the haemoglobin concentration between males and

females (t = 1.571, p = 0.1198). The prevalence of anae-

mia was 58.6% with 89 subjects having haemoglobin

concentration less than 11g/dl. Forty-six (30.3%) had

mild anaemia (Hb level between 10 – 10.9g/dl) while

forty-three (28.3%) had moderate anaemia (Hb between

nation-wide study in Nigeria, and 26.8 (±7.0) reported

by Persson et al in school age children in Bangladesh.

4

This finding however differs from the report of Valencia

5

et al with lower mean of 21.6 (± 5.2) µg/dl. This differ-

ence in the mean plasma vitamin A level is also re-

flected in the prevalence of vitamin A deficiency which

5

7

– 9.9g/dl). T₃here was no subject with severe anaemia

was higher in the report of Valencia et al (46.3%) com-

1

(

Hb < 7g/dl). Fifty-five percent (55%) of the female

pared with 29.6% in this study. The difference between

the mean plasma vitamin A level in this study and that

subjects were anaemic as compared to 62.5% of the

male subjects, showing no significant statistical differ-

ence.

5

of Valencia et al may be due to differences in the popu-

lation studied. While this study was carried out in an

5

urban setting Valencia et al studied a rural population.

Table 2: Relationship between vitamin A status and anaemia

Other authors have reported lower vitamin A levels in

1

6

rural compared with urban populations. The preva-

lence of vitamin A deficiency of 29.₁6₇% in this study,

which is of public health significance, i₅s similar to the

Haemoglobin Status

Vitamin A Status

Total

Normal (%) Deficient (%)

1

Anaemic

Non – Anaemic

59 (66.3)

48 (76.2)

30 (33.7)

15 (23.8)

89 (100)

63 (100)

28.1% reported by Ajaiyeoba in Nigeria.

The mean (±SD) haemoglobin concentration of 10.5

Table 2 shows the relationship between vitamin status

and anaemia. Of the anaemic subjects, 33.7% were

deficient in vitamin A in contrast to 23.8% in the non-

anaemic subjects. There was however no statistically

significant difference in the vitamin A₂status of the anae-

mic and non- anaemic subjects (χ = 0.1879, p =

(

dl reported by Cornet et al in Southern Cameroon. This

is however, lower than 11.9 (±2.3) g/dl reported by Ade-

±1.1) g/dl found in this stu₁₈dy is similar to 10.7 (±2.1) g/

1

9

wuyi in the middle belt of Nigeria. This difference

might be as a res₁u₉lt of the difference in the population

studied. Adewuyi studied a mixture of urban and rural

children comprising both pre-school and school age

children in contrast to urban school age children in this

study. The anaemia prevalence rate of 58.6% in this

0

.2105).

The mean haemoglobin concentration of the subjects in

relation to their vitamin A status is shown in Table 3.

The mean haemoglobin concentration was highest for

the subjects with plasma vitamin A ≥30µg/dl.

9

study is similar to the global prevalence rate of 53% in

school age children in developing countries, reported by

the United Nations.

A lower prevalence rate of anaemia 31% and 1.4% was

Table 3: Mean Haemoglobin concentration in relation to

vitamin A status

4

5

reported by Persson et al and Valencia et al in school

age children in Bangladesh and North west Mexico re-

spectively. This difference may be attributed to the pos-

sible different aetiologic factors responsible for anaemia

in the population studied. The low prevalence of anae-

Vitamin A Status µg/dl

n

Mean Hb conc ± SD (g/dl)

<

2

≥

20

0 - 29

30

45

62

10.32 ± 1.20

10.47 ± 1.02

10.70 ± 1.05

5

mia reported by Valencia et al was associated with a

low prevalence of iron deficiency (4.4%) which was

attributed to the Yaqui Indian diet (corn tortillas, pinto

beans, wheat flour tortillas), which is rich in energy,

protein and iron. Although the diet of the population

ANOVA

p = 0.209

Similarly, the mean haemoglobin concentration of the

subjects with vitamin A level between 20 and 29µg/dl

was higher than those with vitamin A level below 20µg/

dl. This difference was however, not statistically signifi-

cant (p = 0.209). There was no statistically significant

correlation between vitamin A levels and haemoglobin

concentration of subjects in this study (Pearson’s

r = 0.0523, p = 0.5220, 95% Cl = – 0.1078 - 0.2098),

despite increased haemoglobin levels with improved

vitamin A status.

4

studied by Persson et al was not evaluated in relation to

anaemia, there was a comparative prevalence rate of

anaemia (31%) and iron deficiency (30%). In this study

the prevalence of iron deficiency was not evaluated to

ascertain its possible contribution to anaemia. Other

possible contributors to the high prevalence of anaemia

may include helminthiasis, which₁₉was reported by Pers-

4

son et al in their study. Adewuyi reported malaria and

nutritional iron deficiency as the main contributors to

3

82

2

1

anaemia in Central Nigeria.

Nabakwe et al did not find any statistically significant

association between vitamin A status and haemoglobin

concentration in pre- school children in Western Kenya.

The use of Spectrophotometry instead of High Perform-

ance Liquid Chromatography (HPLC) is a limitation in

this study, since HPLC is more sensitive and specific

that Spectrophotometry.

The trend of an increasing mean haemoglobin concen-

tration with increasing plasma vitamin A level (when

stratified into <20µg/dl, 20 - 29µg/dl and ≥30µg/dl)

found in this study is similar to that reported by Persson

4

et al in Bangladesh. This association was however, not

statistically significant in this study, in contrast to the

4

finding of Persson et al where the association between

the mean haemoglobin concentration and vitamin A

status was statistically significant. This difference might

be due to the different method of analysis of plasma

vitamin A level; spectrophotometry in this study versus

High Performance Liquid Chromatography in Persson et

Conclusion

This study shows that there is a high prevalence of vita-

min A deficiency and anaemia amongst school age chil-

dren in Egor Local Government Area of Nigeria, which

is of public health significance. It therefore indicates that

vitamin A deficiency and anaemia are not limited to

under-fives and that programmes directed at reducing

the prevalence of vitamin A deficiency and anaemia

might need to also focus on this age group. There was a

trend of increasing haemoglobin levels with higher vita-

min A status. This was however not statistically corre-

lated.

4

al’s study. It could also have resulted from the popula-

tion studied; urban in this study versus rural in Persson

4

et al’s study. This difference could also have resulted

from intrinsic factors within the popu₀lation in this study

2

as similarly reported by Mejia et al in Central Amer-

2

0

ica. Mejia et al reported a significant association be-

tween haemoglobin concentration and plasma vitamin A

level in children between the ages of 5 and 8 years, but

not in the age group of 1 – 4 and 9 – 12 years. Similarly,

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