A CAJM  journal article.Objectives: Although prevalence of disease in sub-Saharan Africa is often quite high and attracts much research, relatively little is known about less critical maladies. We examined Helicobacter pylori infected students in rural Zambia. We attempted to determine if any socio-economic or co-occurring diseases were correlated to H. pylori infection. Understanding the context in which H. pylori infections occur may increase our understanding of this organism.
Design: We conducted a screening survey with diagnostic tests of primary and secondary school students to determine rates of H: pylori infection. We then correlated these rates to socio-economic factors such as income and tobacco use. We also explored the correlation of H. pylori to HIV and malaria.
Setting: Zimba, Zambia.
Subjects: Eighty seven primary and secondary school students.
Main Outcome Measure: Correlation of H. pylori to socio-economic factors.
Results: H. pylori infection was common (60.9%) and was consistent with rates found in other African countries. We found no significant correlation between//. Pylori and disease and socio-economic variables. Conclusion: In the studied population//, pylori infection does not appear to be correlated with the measured socio-economic or disease variables

Lefcort, H.

McLaughlin, D.I.

McLaughlin, N.J.D.

Central African Journal of Medicine

English

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The influence of socio-economic factors on Helicobacter pylori 
infection rates of students in rural Zambia
*NJD MCLAUGHLIN, **DI MCLAUGHLIN, *H LEFCORT
Abstract
Objectives: Although prevalence of disease in sub-Saharan Africa is often quite high and attracts much 
research, relatively little is known about less critical maladies. We examined Helicobacter pylori infected 
students in rural Zambia. We attempted to determine if any socio-economic or co-occurring diseases were 
correlated to H. pylori infection. Understanding the context in which H. pylori infections occur may increase 
our understanding of this organism.
Design: We conducted a screening survey with diagnostic tests of primary and secondary school students to 
determine rates of H: pylori infection. We then correlated these rates to socio-economic factors such as income 
and tobacco use. We also explored the correlation of H. pylori to HIV and malaria.
Setting: Zimba, Zambia.
Subjects: Eighty seven primary and secondary school students.
Main Outcome Measure: Correlation of H. pylori to socio-economic factors.
Results: H. pylori infection was common (60.9%) and was consistent with rates found in other African 
countries. We found no significant correlation between//. Pylori and disease and socio-economic variables. 
Conclusion: In the studied population//, pylori infection does not appear to be correlated with the measured 
socio-economic or disease variables.
Introduction
People in rural sub-Saharan Africa face the interrelated 
problems of high disease rates, high poverty, and poor 
access tohealthcare. Diseases such asmalariaand Acquired 
Immunodeficiency Syndrome (AIDS) are widespread, and 
in many areas are increasing.1 Furthermore, lack of access 
to medical resources precludes care for all except in the 
final stages of disease.
Compounding these problems is a second tier of less 
severe maladies such as chronic anaemia and colonization 
with the gastric bacterium Helicobacter pylori which is 
associated with gastric and duodenal ulcers. Although less 
pressing, these other maladies may interact and affect the 
morbidity and mortality of diseases such as AIDS and 
malaria.
Other factors contributing to poor health are socio­
economic variables such as income, education, the number 
of sexual partners, and tobacco use. For example, some
CentAfrJ Med 2003;49(3/4):38-41
studies indicate a positive correlation between H. pylori 
and tobacco smoking2,3 although other studies either do not 
support this4 or have even found a'negative correlation.5,6 
Similarly, income and education have been shown to be 
negatively correlated with H. pylori rates in Scotland3 and 
Ethiopia,7 although other studies in South Africa8 and 
Senegal9have not found this. Furthermore, due to cultural 
practices, H. pylori is correlated to religious affiliation and 
urban habitation when other socio-economic factors are; 
controlled.7
H. pylori is widespread in Africa. Infection rates for 
adults are 85% in Nigeria,10 82.8% in Senegal,9 and 77.5% 
in Zaire.11 In a review of published studies Kidd et aln 
found/ that throughout Africa about 61% of all adults test 
positive for H. pylori but most are asymptomatic.
H. pylori also appears to be contracted at a young age. In 
Nigeria 82% of those infected acquire the bacterium by age 
10;10 in South Africa 67.3%13 and 80%8 by age 10; and in 
Zaire 66% by age nine.11
*Biology Department 
Gonzaga University 
Spokane, WA 
99258 
USA
■‘'■'■ The Bozeman Clinic
931 Highland Blvd Suite 3360
Bozeman, MT
59715
USA
Correspondence to:
Dr Hugh Lefcort 
e-mail: lefcort@gonzaga.edu 
TEL: 509-323-6706 
FAX: 509-323-5804
Cent Afr J Med 2003 ;49(3/4) 38
Although prevalence of disease in sub-Saharan Africa is 
often quite high, relatively little is known about associated 
health and social demographics. We examined students 
and determined rates of H. pylori and then we explored if 
correlations exist between H. pylori and rates of infection 
with diseases and to socio-economic factors. Understanding 
the context in which//, pylori infections occur may increase 
our understanding of this organism.
Materials and Methods
Background.
The study was conducted between 19 January 2000 and 
19 February 2000 in Zimba, Zambia. Zimba has a population 
of 4 000 people and is located in rural southwestern 
Zambia about 70 km north of Livingstone. Most of the 
people are employed in subsistence agriculture (maize, 
ground nuts, and cabbage) but a small percentage work as 
teachers, nurses, and low level government officials. Water 
is drawn from bore holes and a nearby lake. Health care is 
limited and is mainly provided by state clinics and a 
missionary hospital. Maladies of protein deficiency such 
as Kwashiorkor are as widespread as is HIV. Tuberculosis 
rates have also experienced a recent increase.
Selection of Subjects.
We surveyed 87 students (40 females and 47 males, aged 
14 to 23) at three local schools. One school was a primary 
day school made up of poor students, one was a technical 
school of slightly higher income students, and one was a. 
secondary boarding school of more affluent pupils.
An announcement of free screening was made once to all 
classes that were meeting on one given day. Students 
readily volunteered and every student in each of the classes 
we chose went to the clinic. The students were not 
compensated. Donors were anonymous (given a number 
and not asked their names) and individual test results were 
provided if requested.
Parental permission was obtained and ethical approval 
was given by the Gonzaga University Animal Care and 
Ethics Committee (12/10/99), the Zimba Mission Hospital 
Director, and each school Headmaster.
We conducted individual oral interviews and asked the 
students about age, gender, town of origin, tobacco use 
number of lifetime sexual partners, past treatment for 
malaria and present abdominal pain.
We also determined degree of poverty/wealth by asking 
the students about the occupation of their parents. uPoor 
was defined as both parents engaged in subsistence 
agriculture. Moderate as one parent or member in the 
household working as anurse, teacher, government official, 
and/or attending the technical school and affluent as able to 
attend the secondary boarding school. These categories 
and rankings were confirmed by the class teachers in all 
cases except one and that student was excluded from the 
analysis. An attempt was made during data analysis to 
control for family and extended family size but the different 
income categories did not differ for this variable.
Parameters such as “past treatment of m alaria, and 
“present abdominal pain” are subjective since fever and/or 
headache is sometimes referred to as malaria in this 
geographic region. Additionally “reported abdominal pain” 
is similarly broad since it may include gynaecological 
symptoms in adolescent females. However, since we were 
dealing with children our choice of terms was intended to 
be subjective. The questions were asked only to establish 
a general state of health. The actual diagnosis of H. Pylori, 
HIV, or malaria was done using the fluid samples we 
collected.
Laboratory Tests.
At the Zimba Mission Hospital we drew two millilitres 
of blood from each student which we tested within 12 
hours for HIV, malaria, H. pylori, and haematocrit. Blood 
was drawn by syringe from the median cubital vein and 
then injected into both a citrated capillary tube and a 
noncitrated capillary tube. Malaria infection was determined 
using Field A and B stains and rated by severity as 1+, 2+, 
and 3+, with 1+ being considered mild and 2+ and 3+ being 
severe. H. pylori was determined using Quickview tests 
(Quidel Corporation) which is a lateral-flow immunoassay 
that detects IgG antibodies specific toH. pylori. Haematocrit 
was determined by spinning the capillary tubes and then 
using a haematocrit reader (Clay Adams Co.). HIV was 
tested using a Western Blot test (Astra Pharmaceuticals) of 
blood plasma 
Statistical Tests.
We used param etric Pearson Product Moment 
Correlations (PPMC) for continuous variables or variables 
with more than three categories and nonparametric Kruskal 
Wallis One Way ANOVA on Ranks for data with only two 
categories. Alpha was set to 0.05.
Results
H. pylori was present in 60.9% of the students and it was 
correlated with lower haematocrit levels (PPMC = -0.250, 
n = 87, p=0.019, Figure I). Haematocrit was also lower in 
females (Kruskal Wallis One Way ANOVA, H = 4.45, d.f. 
= 1, p=0.035) although it was consistent with the normal 
drop due to menses seen in females when compared to 
males. H. pylori was lower in students who smoked 
cigarettes but this did not reach statistical significance 
(Kruskal Wallis One Way ANOVA, H = 3.42, d.f. = 1, 
p=0.064, Figure II).
Students who smoked reported greater abdominal pain 
(PPMC = 0.281, n = 87, p = 0.011) and more sexual 
partners (PPMC = 0.396, n = 87, p=0.0003). Smoking rates 
were also higher in older age groups with 19 to 23 year olds 
smoking more than 14 tol8 year olds (Kruskal Wallis One 
Way ANOVA, H = 3.93, d.f. = 1, p=0.047).
The HIV positive rate among students was 9.2%. Infection 
with HIV was positively correlated \^ith age (PPMC = 
0303, n = 87, p=0.004, Figure III) while H. pylori infection 
was slightly, but not significantly, correlated with age 
(PPMC = 0.166, n = 87, p=0.125, Figure IV). Only one
Cent A frJ  Med 2003;49(3/4) 39
Figure I: Pecentage haematocrit levels of those with and 
without H. pylori infections.
Figure II: H. pylori rates of smokers and nonsmokers of 
tobacco cigarettes.
Figure III: HIV infection rates of younger and older 
students. '
Figure IV: H. pylori infection rates of younger and older 
students.
student had an active case of malaria. The lack of other 
active malaria infections was due to the schools’.policies 
of sending ill students home. However, 77.8% of the 
students reported past treatment for malaria.
All other possible combinations of variables were not. 
significantly correlated.
Discussion
H. pylori infection was common (60.9%) although it was 
consistent with rates found in other African countries. H. 
pylori was not statistically correlated with any socio­
economic or disease variable that we measured.
We found that H. pylori was not correlated to self- 
reported gastro-intestinal upset. H. pylori is often associated 
with gastro-intestinal upset and ulceration,12,15 In Zairians 
with gastroduodenal disorders, H. pylori has been found in 
87.5%. of patients,11 while another study found rates of 
91.7%.16 However, it is not correlated with self-reported 
dyspepsia in the United Kingdom17 or Australia.18 Studies 
in more affluent countries like Taiwan2, and Australia18 
seem to suggest that the debilitating effects of H.pylori are 
higher in men, but studies in Africa have not found this.8:9,19 
We found equal rates of H. pylori in both males and 
females and both reported equal rates of gastro-intestinal 
upset (39.6%).
CentAfr J Med 2003;49(3/4)
H. pylori was correlated with lower haematocrit levels 
but it is unclear from our correlational data whether H. 
pylori is the cause of lower haematocrit or whether people 
who are partially anaemic are more susceptible to H. 
pylori.
There has been much debate on the association between.
H. pylori and smoking tobacco. Some studies have found 
a positive correlation2’3 while others find no correlation,4 
or a negative correlation.5’6 We found a nearly significant 
(p = 0.064) negative correlation between smoking and H. 
pylori. Ogihara et al6 argue that since smoking increases 
gastric acidity it may defend against//, pylori. Yet increased 
gastric acidity could also cause increased peptic ulcers. 
Indeed, smokers in our study reported significantly greater 
rates of abdominal pain than non smokers.
In conclusion, in the studied population//.pylori infection 
does not appear to be correlated with the measured socio­
economic or disease variables.
Acknowledgements
We wish to thank World Medical Missions for arranging 
our visit and D Mwafe for laboratory services. We would 
also like to thank D Boose, D Lefcort, and S Palpant for 
reading earlier drafts of this manuscript. Funding was 
provided in part by Astra Pharmaceuticals.
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The influence of socio-economic factors on Helicobacter pylori infection rates of students in rural Zambia

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The influence of socio-economic factors on Helicobacter pylori infection rates of students in rural Zambia

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