Association of biomass fuel use with acute respiratory infections among under- five children in a slum urban of Addis Ababa, Ethiopia
BMC Public Health
Association of biomass fuel use with acute respiratory infections among under- five children in a slum urban of Addis Ababa, Ethiopia
Habtamu Sanbata 0
Araya Asfaw 2
Abera Kumie 1
0 Department of Public and Environmental Health, College of Medicine and Health Science, Hawassa University , Hawassa , Ethiopia
1 School of Public Health, College of Health Sciences, Addis Ababa University , Addis Ababa , Ethiopia
2 Department of Physics and Center for Environmental Sciences, College of Natural Sciences, Addis Ababa University , Addis Ababa , Ethiopia
Background: Indoor air pollution from biomass fuel is responsible for 50,320 annual deaths of children under-five year, accounting for 4.9% of the national burden of disease in Ethiopia. Acute respiratory infections are the leading cause of mortality among children in Ethiopia. There is limited research that has examined the association between the use of biomass fuel and acute respiratory infections among children. Methods: A community based cross-sectional study was conducted during January to February 2012 among 422 households in the slum of Addis Ababa. Data were collected by using structured and pretested questionnaire. Odds ratio was done to determine association between independent variables and acute respiratory infections by using logistic regression analysis. Multivariate logistic regression was used to determine the presence of an association between biomass fuel use and acute respiratory infections after controlling for other confounding variables. Results: Nearly 253 (60%) of children live in households that predominately used biomass fuel. The two weeks prevalence of acute respiratory infection was 23.9%. The odds ratios of acute respiratory infection were 2.97 (95% CI: 1.38-3.87) and 1.96 (95% CI: 0.78-4.89) in households using biomass fuel and kerosene, respectively, relative to cleaner fuels. Conclusion: There is an association between biomass fuel usage and acute respiratory infection in children. The relationship needs investigation which measure indoor air pollution and clinical measures of acute respiratory infection.
Biomass fuel; Acute respiratory infection; Children; Slum; Addis Ababa; Ethiopia
Household energy affects health of the poor through a
variety of physical, social and economic aspects. The
most important direct health effect results from indoor
air pollution (IAP) produced by burning biomass fuels
and coal in simple stoves with inadequate ventilation .
Worldwide, more than three billion people depend on
solid fuels, including biomass (wood, dung, crop residues,
coal) for cooking and heating . IAP is responsible for
more than 1.6 million deaths annually and 2.7% of the
global burden of disease. Acute respiratory infections
(ARI) are the biggest killer of young children .
Biomass fuels are at the low end of the energy ladder in
terms of combustion efficiency and cleanliness. Biomass
combustion produces a large number of health-damaging
air pollutants including respirable particulate matter,
carbon monoxide (CO), nitrogen oxides, formaldehyde,
benzene, 1,3 butadiene, polycyclic aromatic hydrocarbons
(PAHs)and many other toxic organic compounds .
Over 70 percent of energy needs in most of the
subSaharan African countries are met by biomass fuels,
mainly for the household. The efficiency of fuel wood
used for cooking in developing countries is quite low,
leading to energy requirements that are several times
higher than in developed countries . Developing
countries are significantly affected by the problem due
to their increased use of polluting energy sources for
their energy demands. World Health Organization (WHO)
estimates on burden of diseases for the year 2002, IAP from
biomass use accounted for 3.7% of the burden of disease
in developing countries .
In Ethiopia, about 95% of the countrys energy supply
comes from biomass sources . IAP from biomass fuel
is responsible for 50,320 annual ARI deaths of children
under-five year, accounting 4.9% of national burden of
disease in Ethiopia . The estimated energy consumption
per household in Addis Ababa is approximately 7 GJ,
slightly less than half the per capita consumption.
Traditional fuels (fuel wood, charcoal and dung) meet about
75% of household energy needs. Kerosene, Liquefied
Petroleum Gas (LPG) and electricity provide the remaining
25%. In the last decade, kerosene use in Addis Ababa has
declined considerably as a result of a doubling in the cost
of kerosene, largely because of the removal of subsidies. At
the same time, the price of electricity has declined by more
than 50% and it is currently sold at approximately 75%
less than the price of kerosene . A large proportion of
kerosene users have shifted to fuel wood .
Recent study conducted in Addis Ababa indicated the
average fine particulate matter (PM2.5) concentration
measured in homes using biomass fuel far exceeded
WHO guidelines . The city highest 24-hour geometric
mean of PM2.5 concentrations observed in households
using predominantly biomass fuel , kerosene, and clean
fuel are 1,134 g/m3 (SD = 3.36), 637 g/m3 (SD = 4.44),
and 335 g/m3 (SD = 2.51) respectively . Thus, the
IAP in the city is high. Biomass fuel will continue to be
used by a large number of households for the foreseeable
future. The burden of disease due to IAP is exceedingly
affecting children in poor slum urban households in
Addis Ababa. There is limited evidence that link biomass
fuel use with ARI among under-five children in Ethiopia.
The aim of this study was to assess the association of
biomass fuel and ARI among children under-five in the
urban slum of Addis Ababa.
Study design and setting
A community based quantitative cross- sectional study
was conducted to answer the research objectives. Data
were collected using structured questionnaire by
administering face to face interviewing of mothers. The study
was conducted in Addis Ababa, the capital city of
Ethiopia. The city is situated at the center of the country
at an altitude varying between 2,200 and 2,800 meters
above sea level (masl), between latitude 9.0300 N and
longitude 38.7400 E. Average annual temperatures
range from 8.2C to 25.1C. The administrative structure
of the city Addis Ababa has 10 sub-cities and 116
districts (woredas). The city has a projected population
of approximately 3.4 million people and over 500,000
households with an average family size of six. With an
estimated area of 530.14 square kilometers, this chartered
city has an estimated density of 5,165.1 inhabitants per
square kilometer . An estimated 80% of the population
in Addis Ababa lives in poor and overcrowded districts
. The study unit embraced all households with
underfive children. Sampling units were households with
children under five years in Addis Ababa.
Sample size and sampling procedure
The sample size was calculated using a single population
proportion formula using the following parameters: 95%
confidence level (1.96), margin of error (0.05), expected
prevalence of children with acute respiratory infection
50%. With this assumption a total of 422 household with
children under- five were included in this study. The
sampling procedure involved a three-staged sampling
scheme aimed at obtaining 106 households in each
selected sub-city using a probability to population size.
A sub-city is the largest administrative structure in the
city. In the first stage, total ten sub-cities were stratified
into four based on similarity of crowdedness, housing
situation and sanitation coverage of the city. From each
strata one sub-city was selected by lottery method and
thus four total sub-cities were selected from ten of the
city. In the second stage, each Districts (Woredas) was
clustered and three districts (woredas) from each of the
four cities (total 12 districts) were selected targeting 34
to 37 households per district (woreda). In the third stage
selection of houses having under-five children was
conducted by using systematic random sampling method.
This process have been then followed by a complete
household listing operation, which was carried out in all
the selected district (woreda) to provide a sampling
frame for the third -stage selection of households with
children under- five years.
Data collection method
Data were collected during January to February 2012
through structured questionnaire through interviewing
mothers of under- five children. The questionnaire was
developed after critical discussions with public health
experts. The questionnaire was adapted from WHO
guidelines for survey of household fuel use  and for
ARI module .
Data collectors were community health extension
workers with similar professional experience. The data
collectors were extensively trained by the principal
investigator and a pediatrician for two days on interviewing
techniques, observational, data recording, approaches to
promote health education, and advocacy of child health
screening. One professional expert was assigned in
each sub-city for monitoring and supervision of data
Information on types of fuel used for cooking was
gathered. To elicit this information the question What
type of fuel does your household mainly use for cooking?
was asked. The question was then followed by a list of
different fuel names to choose from. The choice
include fuel wood, crop residues, dung cakes, charcoal,
kerosene, Liquefied Petroleum Gas (LPG) and
electricity. Exposure assessment questions also collected on
socio demographic like sex of household head, family
size, education level, cigarettes smoking habit, housing
characteristics, type of stove used and ventilation
efficiency, behavioral measures, most commonly whether
child is carried by the mother while she is cooking also
time spent near fire, and child stays in smoke,
questions on location of the child relative to cooking place,
cooking done in same room as where children sleeping
were included. Use of biomass fuels kerosene, LPG and
electricity is the main independent variable of the
Child health screening
Questionnaire respondents were residents who voluntarily
agreed to participate upon having the purpose of the
research explained. Mothers were asked to describe the
health status of children under five year within the
household with respect to ARI. First, mothers were
asked whether there were any children who were
coughing. If the answer was yes, mothers were asked to
describe the breathing (i.e.: short and/or rapid breathing).
Children who suffered from coughs, accompanied by
chest in drawing, shortness of breath, and rapid
breathing were diagnosed with an acute respiratory infection,
according to the WHO clinical case definition .
Suffering from ARI was the dependent variable used in this
Acute respiratory infection (ARI)
This study uses the WHO definition, which defines ARI
to include any combination of the following symptoms:
cough with or without fever, blocked or runny nose, sore
throat, and/or ear discharge with infection of the lungs.
Serious forms of ARI result in pneumonia or
bronchopneumonia . Therefore, acute respiratory infections
refer to upper respiratory and lower respiratory infections.
Acute lower respiratory infection
Serious form of ARI, resulting in pneumonia or
Acute upper respiratory infection
Infection of the upper respiratory tract involving larynx,
pharynx, tonsillar glands, Eustachian tube, nasal cavities
Fuel type refers to the source of energy used for cooking
and was classified into three categories: biomass fuels
(wood, dung cakes, charcoal, urban residues), kerosene,
and clean fuel (LPG and electricity).
Improved cook stove
There is no international definition for the exact fuel
savings that are necessary for a stove to be considered as
an improved stove. However, an improved cook stove is
a device that is designed to consume less fuel, save time,
reduce the volume of smoke produced compared to the
Traditional cook stove
There is no universally accepted definition for traditional
cook stoves that is linked to performance or technical
standards. Thus, throughout this paper, the term refers to
cook stoves constructed by household members that are
not energy efficient and have poor combustion features
using for cooking purpose.
Indoor air pollution
Indoor air pollution refers to the toxic emissions from
cooking, especially from the use of wood, dung, charcoal,
kerosene and other cooking fuels.
Refers to any member of the household that smokes
more than one cigarette a day at home.
Refers to the process of supplying or removing air from
any enclosed space by natural or mechanical means. In
this study, ventilation is measured by households that
have properly built doors, windows (fanlight, hopper, or
sliding sash windows), or mechanical apparatuses (fans
and air conditioner).
Data quality assurance
The questionnaire was written in English and administered
in Amharic, the local language, by linguistic professionals.
It was validated by independent repeat administration on
consecutive days in approximately 10% of the households.
The pre-test was conducted among 5% of the
respondents to test the efficacy of the research instruments
and to discover possible weaknesses, inadequacies, and
ambiguities so that they was able to corrected before
actual data collection started. Data collection was
overseen by a field supervisor who cross-check all field
forms after each day of data collection to ensure that
the forms were completely filled and data were
consistent. Any mistake or omission was corrected as on the
same day of data collection. Double data entry was
used to check any inconsistency in responses from
Data management and analysis
Coded data entry was done in EPI INFO version 6.04
for data clearance and skip pattern prior to analysis
using the SPSS (Statistical Package of Social Science)
Version 20.0 package. Cleaning was made to avoid
missing values, outliers and other inconsistencies.
Consistency and completeness of data were checked
using frequency and a 2 by 2 tables. Descriptive
statistics such as frequency distributions and measure of
central tendencies were calculated for dependent and
independent variables. Bivariate and multivariate
analysis using binary logistic regressions were done to
determine the presence of a statistically significant
association between explanatory variables and the
outcome variables. Crude Odds Ratio (OR) with 95%
Confidence Intervals (CI) was done to determined
association between independent variables and ARI. The
multivariate logistic regression analysis was done using
enter method hierarchically to assess the relative effect
of the explanatory factors on acute respiratory
infection. Multivariate logistic regressions analyses were
used to determine the presence of an association
between explanatory variables and acute respiratory
infections by controlling the effect of other variables. To
limit many variables and unstable estimates in the
subsequent models, only variables that reached a p-value
less than 0.30 at the bivariate analysis level were kept
in the model. Data were presented using figures and
The study had ethical approval from Addis Ababa
University and Health office of Addis Ababa. The study
was in words communicated to each respondent and
verbal consent was secured once agreement on the
interview was obtained. Inconveniences for refusals
were respected. Children whom found in their
households with severe pneumonia were referred for treatment
to near health institution. Results of the study will be
planned to be communicated to the local authorities and
A total of 422 samples in Addis Ababa households were
involved in this study. The overall average family size
was 5 persons per household. There were 285 (67.5%)
male head of households and 137 (32.5%) were
femaleheaded. The marital status distribution of house hold head
were344 (81.5%) married, 31 (7.3%) single, 26 (6.2%)
divorced, and 21 (5.0%) were widowed. The religion of the
households head were predominantly Orthodox Christian
and Muslim, 264 (62.6%) and 106 (25.1%) respectively, the
remaining 52 (12.3%) were Protestant.
In terms of smoking habit, 62 (14.7%) had at least one
member within the household who smokes more than
one cigarette a day at home compared with 360 (85.3%)
non-smokers (see Table 1).
Regarding the housing units, 224 (53.0%) of the kitchens
were attached to the house and 198 (47.0%) were detached
from the house. About 203 (48.0%) households cook in a
Table 1 Socio-demographic characteristic of sampled
households in Addis Ababa, February 2012
Main means of income Merchant
Educational level of
Five and above 5
Read and write
Diploma and above
room that is also used for living/sleeping while 97 (23.0%)
households had separate rooms for cooking and sleeping
and 25 (6.0%) households cook outside of the house. The
means of ventilation used 125 (52.0%) households are
windows and open doors. However, 115 (48.0%) households
were found to have no proper ventilation.
Association between the prevalence of acute respiratory
infections and biomass fuel
About 145 households (34.4%) used charcoal, 89
households (21.1%) used wood fuel, 82 households (19.4%)
used electricity, 76 households (18.0%) used kerosene, 18
households (4.3%) used urban residues and leaves, 10
households (2.4%) used LPG.
The prevalence of ARI observed during the two week
period included 76 cases of ARI (29.9%) in households
using biomass fuels (fuel wood, dung cakes, residues
and/or charcoal), 16 cases (21.1%) in households using
kerosene, and 9 cases (9.8%) in households using clean
fuels. The overall prevalence of ARI in the sample was
found to be 23.9%.
Bivariate logistic regressions were used to estimate the
relative association of household energy use and other
exposure variables on ARI. Children of female headed
homes were 44% less likely to have ARI than males
(COR 0.56; 95% CI: 0.35-0.89). Cigarette smoking was
associated with ARI. Children living in a smoking family
were 2 times more likely to have ARI than that of
nonsmokers (COR 1.96; 95% CI: 1.10-3.49) (Table 2). Mothers
behavior towards cooking places in relation to the childs
location was also analyzed. Children who were held by
their mothers were nearly two times more likely to suffer
from an ARI than children who were not held by their
mothers while cooking (COR 1.88; 95% CI: 1.19- 2.95)
(see Table 2).
Children live in home without proper ventilation was
two times more likely suffering from ARI than in
ventilated home (OR 2.41; 95% CI: 1.34-4.32) (Table 3).
The distribution of children ARI prevalence with respect
to fuel and stove type characteristics is summarized in
(Table 4). Overall, biomass, kerosene, and all stoves except
improved biomass stoves are strongly associated with
increased probability of ARI among children.
Multivariate logistics regression analysis of household
energy use and other exposure variables on ARI
Variables that have a p-value less than 0.30 with ARI in a
bivariate analysis were subjected to a multivariate logistics
regression analysis. fuel use, sex of head of households,
cigarette smoking, ventilation, and holding a child on the
mothers back while cooking were Included in model (see
The odds of ARI was 2.96 (95% CI: 1.38-3.87) in
households using biomass fuel relative to households
Sex of household head
Five and above
Read and write
Diploma and above*
Made from mud
Brick, stone and block
Table 2 Bivariate analysis of household characteristics on
ARI prevalence in children in Addis Ababa, February 2012
Table 3 Bivariate analysis of housing& kitchen
characteristics effects on ARI prevalence in children
in Addis Ababa, February 2012
Table 4 Bivariate analysis of effects of household fuels
use and stove type on ARI prevalence in children in
Addis Ababa, February 2012
ARI (n = 422)
Traditional biomass stove
Improved biomass stove
Child holding during cooking
for cooking in Addis Ababa. Fewer households use
electricity and LPG as cooking fuel, approximately one-fifth of
the households sampled.
The result of this study indicated two weeks prevalence
of ARI among children under-five years was 23.9%.
Nearly, one-fourth of children that are highly vulnerable
population groups living in slum area of Addis Ababa
were suffering from both upper and lower respiratory
infection. This Study was comparable with study
conducted in shebadeno southern Ethiopia 21%  and
some studies in conducted in Africa , particularly well
comparable with ARI prevalence of Ethiopia (24%) in
2000 , Study conducted in Tanzania ARI in the
sample was found to be 29.76% prevalence for children
under age 5 in Tanzania . But slightly lower than a
study in Zimbabawe shows 16% children suffered from
ARI  and Ethiopia national figure prevalence of
(13%) in 2005 . This might be because children in
the inner slum city stay in homes being exposed to indoor
air pollution from biomass fuel due to space scarcity to
stay outside. Underlying risk factors such as malnutrition
among children may also aggravate the problems.
The sex of the head of household was significantly
associated with ARI prevalence in children. This shows
that children who live in male- headed homes less
exposed to ARI than female- headed. This result is
contrary to existing literature and expected results. A
previous study conducted in Ethiopia indicated no
significant association of ARI prevalence with sex of household
using cleaner fuels after adjusting for sex, smoking,
ventilation, child handling behavior. Overall, type of
fuel, sex of the household, ventilation, and child
handling behavior were important predictors of ARI among
under- five children.
Of the study households, biomass fuel (charcoal, fuel
wood, residues and dung) was the most widely used fuel
Table 5 Multivariate analysis effects of fuels used for cooking on ARI prevalence in children in Addis Ababa,
No. of children with ARI (n = 422)
head . A study in urban household in Nigeria also
indicated that the sex of household heads did not show
any relationship between with the use of biomass fuel use
. This inconsistency may be due to socio-economic
Cigarette smoking is also associated with ARI
prevalence. Children live in a smoking household are two times
more likely to suffer from ARI than that of non-smoking
households. This may increase the concentration of
indoor air pollution concentration which aggravate ARI in
children. This was consistent with the studies conducted
in Africa, in Kenya smoking increased the risk of ARI with
an odds ratio of 1.48 (95% CI 1 072.04) in the logistics
model . Another study also showed that cigarettes
smoking increased the risk of ARI from airborne
pollutants in young children . Similarly, a Study conducted
in an urban slum of India indicated that smoking habits
strongly influences the incidence of ARI .
This study shows strong associations with increased
between biomass fuel and prevalence of ARI in children.
Children living in households that are reliant on biomass
fuels are about three times more likely to suffer from an
ARI compared to children living in homes reliant on
clean fuels. This implies that the children
exposureresponse for biomass fuel smoke is the most toxic
among all the fuel types. This was followed by kerosene
and electricity/natural gas. This result similar with most
studies conducted in Africa. Study in Zimbabwe showed
that children in households using wood, dung, or straw
for cooking were more than twice as likely to suffer from
an ARI compared to children from households using
LPG or electricity .
This study was consistent with study in South Africa
on children living in households that are reliant on solid
fuel are 2 to 4 times more likely to suffer from an Acute
Lower Respiratory Infection (ALRI) compared to children
living in homes reliant on electricity . But
inconsistence with study in Tanzania indicated that the effect of
biomass fuel on ARI is the same as the effect of kerosene
. A Nigerian study also showed that the use of unclean
energy among urban households is confounded with
health related problems of IAP .
Children who live in households without ventilation
were about two times more likely to suffer from an ARI
compared to children who live in than in ventilated
households. Study indicated child holding at back during
cooking is associated with children ARI prevalence.
Children in home mother hold child at back while
cooking is about two times suffer from ARI). Patterns of
time-activity, which place children near sources of pollution
such as cooking stoves, contribute to the increased risk of
ARI from airborne pollutants in young children .
This study provided quantitative snapshot of urban
homes using a variety of fuels. Households in this study
were grouped based on whether there were children living
in the homes and type of cooking fuel used (wood,
residues, charcoal, kerosene LPG or electricity). But it is
common in Addis Ababa to find one house using more than
one fuel. Such grouping home without more information
on children from homes using a combination of several
fuels may lead to different effect values on children ARI
prevalence. ARI was assessed by the use questionnaire
which required mothers to explain on the health of their
children with respect to ARI in the period two weeks
prior to the survey. Since this is not an objective way
of collecting health information, the method used to
collect health information may have caused
underestimation or overestimation of ARI frequency in children.
Biomass fuel is the dominant fuel used for cooking in
Addis Ababa, Ethiopia. This study shows strong
associations between biomass fuel and prevalence of ARI in
children under-five year. Apart from family size,
educational level and kitchen characteristics others factors
like sex of head of house hold, cigarette smoking habits,
fuel type, ventilation , holding child at back while cooking
a influence the prevalence of ARI in children under-five.
Therefore, an effective mitigation strategy should employ
multiple interventions such as improvements in fuels,
cooking technologies, ventilation conditions. Additional
behavior adjustments such as ensuring children are kept
away from smoke and not smoking in closed range of
children. The relationship needs to be further investigated
using more direct measures of IAP exposure and clinical
measures of acute respiratory infection needed to confirm
the association. Other cofounders like nutritional status,
immunization status, and behavior should also be studied.
The authors declare that they have no competing interests.
HS was the principal investigator of the study and took the leading role from
origin, design and supervising data collection process to the final analysis
and preparation of the manuscript. AA and AK participated in the supervise
study and reviewing the whole document and provided critical comments.
All authors read and approved the final manuscript.
We would like to thank the Addis Ababa Universitys Environmental Science
program and Environmental and Development Action of Ethiopia (ENDA
Ethiopia) for their financial support. Moreover, support from the EPA is highly
appreciated. Furthermore, we would also like to acknowledge Addis Ababa
Health Bureau and the woreda health office for their relevant support. Finally,
we thank Addis Ababa health extension workers, field workers, supervisors, the
mothers, and other caretakers of study children who participated in this study.
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