A CAJM article on plasma cholesterol distribution in rural Nigeria.Several reports indicate the close relationship between high plasma cholesterol levels with the occurrence of atherosclerosis.1,2 The prevalence of atherosclerosis has been reported to be much higher in Caucasians than in Black Africans.3 Large differences in total plasma cholesterol levels between these populations have been reported and have been attributed to differing dietary patterns between them.4-7 Thus data on the distribution of cholesterol in groups of subjects randomly selected from communities are important since they provide opportunities for intra and international comparisons which may thus lead to identification of habits or traits which influence plasma cholesterol levels

Erasmus, R.T.

Pakeye, T.

Uyot, C.

Central African Journal of Medicine

English

IDS OpenDocs

Vol. 40, No. 11 
ORIGINAL ARTICLES
Condom use and the risk of IIIV infection: who is 
being protected?...................................................
Plasma cholesterol distribution in a rural Nigerian 
population -  relationship to age, sex and body mass
Cross sectional sero-epidemiological prevalence 
of poliovirus antibodies post immunization with 
three doses of TOPV............................................
Do traditional mosquito repellent plants work as 
mosquito larvicides?.............................................
( A preliminary investigation into psychological disorders in Mozambican refugees: prevalence and clinical features..............................................
Acute poisoning in a paediatric intensive care unit 
in Harare................................................................
Umbilical hernia in Bulawayo: some observations 
from a hospital based study..................................
CASE REPORTS
Traveller’s loiasis in Zimbabwe: a case report.....
Symptomatic polycystic liver disease: a case......
November, 1994 
M T Mbizvo, S Ray, M Bassett, W McFarland,
R Machekano, D Katzenstein.............................. 294
R T Erasmus, C Uyot, T Pakeye......................... 299
S A Tswana, C Berejena, SR Moyo,
0  Mudyarabikwa................................................. 303
NLukwa...............................................................306
A P Reeler............................................................309
1 Chitsike.............................................................315
G Mawera, GI Muguti......................................... 319
LM Bordon, M Maurice...................................... 323
LM Bordon, L Chivete........................................ 327
CO NTENTS
SU P P O K T F n r v  riM AS M F n t r  ai a to snrTFTV
III"1 International conference on AIDS, Wash­
ington DC, USA . June 1— 5,1987 .
11. Latif AS, Katzenstein DA, Bassett MT, Hous­
ton S, et al. Genital ulcers and transmission o f  
HIV among couples in Zimbabwe. AIDS 1989; 
2(8); 519— 23.
12. M bizvo MT, Adamchak DJ. Condom use and 
acceptance: a survey o f  male Zimbabweans. 
Cent AfrJM ed  1989; 35(11): 519— 23.
13. Piotrow PT, Kincaid DL, Hindin MJ, et al. 
Changing men’s attitudes and behaviour: the 
Zimbabwe m ale motivation project. Stud in 
Fam Plann 1992; 23(6):365— 75.
14. LagaM , Alary M ,N zilaN ,M an oka AT, Tuliza 
M, Bebets F, et al. Condom promotion sexually 
transmitted diseases treatment, and declining 
incidence o f  HIV-1 infection in female Zairean 
sex workers. Lancet 1994;344:246— 48.
15. HanenbergRS,RojanapithayakomW ,Kunasol 
P, Sokal DC. Impact o f  Thailand’s HIV-control 
programme as indicated by the decline o f  sexu­
ally transmitted diseases. Lancet 1994;344: 
243— 45.
Plasma cholesterol 
distribution in a rural 
Nigerian population — 
relationship to age, sex and 
body mass
*RT ERASM US, *C UYOT, **T PAKEYE  
SUM M ARY
Plasma cholesterol was measured in 417 healthy rural 
Nigerians consisting of 230 males (mean age 36,60 ±  1,29
*Department o f Chemical Pathology 
University ofllorin 
Ilorin, Nigeria
**Department o f Epidemiology and Community Health 
University o f Ilorin 
Ilorin, Nigeria 
Present address:
RT Erasumus
Department o f Pathology, Faculty of Medicine 
P.O. Box 5623, Boroko, Papua New Guinea
CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 40, No. 11,1994
years) and 187 (mean age 34,60 ±  1,38 years). Mean 
plasma cholesterol concentrations were found to be 
2,91 ±  0,22 mmol/1 and 3 ,2 6 ±  0,25 mmol/1 in males and 
females respectively. These differences were highly 
significant (p<0,025). The lowest plasma cholesterol 
levels were observed in the 11 to 20  year age group and 
the highest in the >61 years age group. A  strong 
correlation, which was higher in m ales than females 
was observed between plasma cholesterol and age (r == 
0,48; p<0,01). N o  significant correlation was observed 
between body m ass index (BMI) and plasma choles­
terol in both male female subjects.
These results suggest that plasma cholesterol con­
centrations observed in rural Nigerians may be related 
to their physical activity and the consumption o f  a low  
fat diet.
INTRODUCTION
Several reports indicate the close relationship between 
high plasma cholesterol levels with the occurrence of 
atherosclerosis.1,2 The prevalence o f  atherosclerosis 
has been reported to be much higher in Caucasians than 
in Black Africans.3 Large differences in total plasma 
cholesterol levels between these populations have been 
reported and have been attributed to differing dietary 
patterns between them.4-7 Thus data on the distribution 
o f cholesterol in groups o f  subjects randomly selected 
from communities are important since they provide 
opportunities for intra and international comparisons 
which may thus lead to identification o f  habits or traits 
which influence plasma cholesterol levels.
There have been several reports on the pattern of 
plasma cholesterol in urban Nigerians.4,5,7'8 These re­
ports suggest that differences exist in the plasma cho­
lesterol levels o f  Nigerians in the low and high socio­
econom ic income groups.4,9 Indeed som e studies from 
Nigeria reported that although the mean plasma choles­
terol levels are much lower in Nigerians than in Cauca­
sians, Nigerians in the high incom e group tend to have 
similar plasmacholesterol levels to their Western coun­
terparts .9,1° However, the distribution o f  plasma choles­
terol amongst Nigerians residing in rural areas where 
the majority o f  Nigerians reside, has not been exten­
sively studied. Ib is  paper reports on the distribution of 
plasma cholesterol concentrations in a healthy N ige­
rian rural population and in addition, examines the rela­
tion-ship o f plasma cholesterol to age, sex and body mass.
299
CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 40, No. 11,1994
MATERIALS AND METHODS
Subjects: 500 subjects aged 11 to 95 years were 
recruited from one o f  the rural villages near Ilorin, 
Nigeria. Admission into the study was voluntary and 
consent was obtained from each subject. The subjects 
represented the major age groups in the village (except 
for subjects under the age o f  10 years). Each subject 
underwent a thorough medical examination and was 
screened with biochemical tests to eliminate subjects 
with various diseases such as Diabetes mellitus, liver 
iisease and uraemia. Subjects were also screened for 
tiypertension (blood pressure S  140/90 mmg Hg) to 
exclude hypertensives from the study. Each volunteer 
was questioned intensively about their socio-econom ic 
status, dietary and exercise schedule. The screening 
left us with 417 subjects.
Physical exercise and diet: The majority o f  the 
subjects were farmers who engaged in daily exercise by 
virtue o f  their daily subsistence activities and trekked 
about five kms daily. The average annual income o f  the 
subjects was less than N l,5 0 0 . Using 24 hour dietary 
recall data, the diet o f the majority o f  subjects (99 pc) 
was found to consist o f  yam, cassava, m aize with 
legumes, vegetables and fruits (high carbohydrate, low  
fat, low  protein). M ilk and eggs were hardly consumed 
while meat was eaten only on special occasions.
Procedures: The height o f  each subject was mea­
sured with the subject standing direct and looking 
straight ahead (without shoes). Body weight was mea­
sures using a portable weighing scale (Hanson, Sw e­
den). Each subject was weighed with the minimum o f  
clothing. Blood pressure o f each subject was measured 
in the semi-supine (sitting) position after 10 minutes o f  
rest using an Accouson sphygmomanometer.
Blood was collected between 0800 and 1000 hours 
from fasting subjects into (a) plain tubes for cholesterol 
and (b) tubes containing fluoride oxalate for glucose 
analysis. The serum was separated within two hours o f  
collection. Samples were stored at -20°C  until analy­
sis. Cholesterol was measured by the method o f  Abell 
using Lieberman B urchard reagent11 and glucose by the 
method o f  Trinder.12 Quality control was assessed by 
including control sera (Precinon L, Boehringer, W, 
Germany) in the assays. Body Mass Index (BMI) was 
calculated by dividing the body weight (kg) by the 
square o f  the height (M2).
Statistical analysis: Student’s test was used for 
statistical comparison o f  the means o f  various param­
eters. Correlation coefficients (r) were determined to 
examine the linear relationship between plasma cho­
lesterol and age and body mass index.
RESULTS
H ie  distribution o f  age, sex and body mass index (BMI) 
arc shown in Table I. There was a total o f  417 subjects 
consisting o f  230 (55,2 pc) males and 187 (44,8 pc) 
females. Subjects under the age o f  20  years formed the 
largest group (32,6 pc). Female subjects were generally 
heavier than males though this was not statistically 
significant.
Table I: Age, sex and body mass distribution of 
subjects.
Age group pc Sex No. Age BMI
11-20 32,6 M 77 17,14 ±0,30 18,50±0,24
(136) F 59 16,1 ± 0,26 19,58 ±0,35
21-30 M 37 25,2 ± 0,37 19,90 ±0,26
(62) 14,9 F 25 25,3 ± 0,46 21,60±0,5
31-40 M 28 33,9 ± 0,64 20,30 ±0,42
(56) 13,4 F 28 34,6 ±  0,60 21,00±0,45
41-50 M 30 46,8 ±  0,53 19,60 ±0,39
(55) 13,2 F 25 41,1 ± 0,62 20,60 ±0,58
51-60 M 26 54,1 ± 0,61 20,0 ± 0,43
(51) 12,2 F 25 56,4 ± 0,56 20,70 ±0,62
261 M 32 71,0 ± 1,70 19,30 ±0,38
(57) 13,2 F 25 70,6 ±  1,70 20,70 ±0,42
Total M 230 36,60 ±1,29 19,15 ±0,36
(417) 100 F 187 34,60 ±1,38 20,24 ±0,49
Table II summarises the results o f  the total plasma 
cholesterol in male and fem ale subjects o f  each age. 
Plasma cholesterol concentrations increased with age 
in both sexes, the lowest level being observed in the 11 
to 20 age group and the highest in the >61 years age 
group. Plasma cholesterol concentrations were higher 
in female than male subj ects in each age group but were 
o f significance only in the 11 to 20, 21 to 30, 31 to 40  
and 41 to 50 age groups (p<0,025).
CENTRAL AFRICAN
JOURNAL OF MEDICINE
Vol. 40, N o.ll, 1994
Table 11: Distribution o f plasma cholesterol (±sem).
Age group Sex Choi Sem Range P
11-20 M 2,56 0,12 1,5-5,4
F 2,88 0,15 1,5-5,2 <0,025
21-30 M 2,74 0,18 1,5-5,7
F 3,21 0,26 2,1-6,8 <0,025
31-40 M 2,73 0,14 1,5-4,5
F 3,32 0,21 1,6-5,7 <0,01
41-50 M 2,84 0,26 1,7-6,5
F 3,35 0,34 1,6-6,5 <0,025
51-60 M 3,2 0,25 1,6-6,3
F 3,39 0,31 1,6-6,3 NS
-60 M 3,36 0,32 1,5-6,5
F 3,38 0,21 1,7-5,4 NS
Total M 2,91 0,22 1,5-6,5
F 3,26 0,25 1,5-6,8 <0,028
p values represent differences between males and females of 
each age group.
A strong correlation between age and plasma choles­
terol was observed (r =  0,48; p<0,01). This correlation 
was higher in male (r = 0,7; p<0,01) than female 
subjects (r =  0,2; p<0,05). N o significant correlation 
was observed between body mass index (BMI) and 
plasma cholesterol levels in both male and female 
subjects respectively (Table III).
Table III: Correlation between plasma cholesterol, 
age and body mass.
Age Body Mass
Males Females Males Females
Cholesterol (r)* 0,7 0,2 0,08 0,01
P <0,01 <0,05 NS NS
r represents the correlation coefficient
DISCUSSION
The result o f  the present study indicate that plasma 
cholesterol concentrations in rural Nigerians are much 
lower than values reported for urban Nigerians.4 71013 
Taylor and Agbadana9 also reported lower concentra­
tions o f  plasma cholesterol in rural than urban Nigeri­
ans o f  similar age and sex. Our results, though lower, 
are also similar to those reported in rural South Afri­
cans14 The lower plasma cholesterol levels observed in
rural Nigerians may be due to differing dietary patterns 
between rural and urban Nigerians. It has been reported 
that many urban Nigerians have abandoned the tradi­
tional diets and have adopted ‘western’ style diets.15 In 
addition, the degree o f physical activity may also play 
an important role.14 In our study, more than 90  pc o f  our 
survey sample consumed a diet which consisted exclu­
sively o f  carbohydrates and vegetables with virtually 
no animal fats. In addition, they engaged in daily 
physical exercise (farming) and trekked an average o f  
five km daily.
The results o f  this study suggest that age and sex may 
be the two most important factors influencing plasma 
cholesterol in the rural Nigerian. Though this has also 
been observed in urban Nigerians, a firm relationship 
has not been established.5,7’8 Body m ass did not appear 
to influence plasma cholesterol levels. Our observa­
tions are similar to those reported in northern Nigerians 
and Black South A fricans5,16 Body mass as w ell as age 
and sex have been reported as influencing plasma 
cholesterol concentrations in other races.17,18
W hen comparing our results to healthy Caucasians 
o f  similar age and sex, plasma cholesterol concentra­
tions were observed to be almost half in values to those 
reported in Caucasians.17,19 It is now w ell recognised  
that hypercholesterolinaemia is one o f  the m ost signifi­
cant biochemical risk factors associated with coronary 
heart disease.7 Coronary heart disease is now one o f  the 
major causes o f  mortality and morbidity in Caucasian 
populations.1,3,19Genetic as w ell as dietary factors have 
been implicated in the pathogenesis o f  coronary heart 
disease.1,7 It is probable that the low  incidence o f  
coronary heart disease reported in Nigerians and other 
Black Africans3 may be related to their low  plasma 
cholesterol levels. In recent times an increased inci­
dence o f  ischaemic heart disease has been reported in 
the middle class populations o f  Kenya and has been 
attributed to the adoption o f  a ‘western’ style diet and 
inadequate physical activity.70 In Nigeria, where rapid 
urbanisation has recently taken place71 it may be appro­
priate to initiate programmes which w ill advise the 
public on diet and the beneficial effect o f  exercise. This 
may be instrumental in preventing the introduction o f  a 
pathological state, which hitherto has virtually been 
unknown in Nigeria.
ACKNOWLEDGEMENTS
W e wish to thank Mrs M adeline Oakiva for typing the 
manuscript. This work was supported by the University 
o f  florin Senate Research Grant 1986/1987.
301
ENTRAL AFRICAN
XJRNAL OF MEDICINE
Vol. 40, No. 11,1994
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Plasma cholesterol distribution in a rural Nigerian population - relationship to age, sex and body mass

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Plasma cholesterol distribution in a rural Nigerian population - relationship to age, sex and body mass

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