Determinant of Pneumonia Among Children Aged 2-59 Months in Public Health Facilities in Worabe Town, Southern Ethiopia: Facility-Based Case Control Study

Childhood pneumonia remains a major health problem in developing countries, including Ethiopia with signicant morbidity and mortality. The determinants of pneumonia in children under –ve years of age children are numerous and vary widely vary across the regions of the world. Taking the signicance of the problem and variability of risk factors, a study is needed to identify the potential determinants of pneumonia in children under-ve children years of age. Methods A facility-based unmatched case-control study was conducted among 435 children (145 cases and 290 controls) aged 2-59 months at public health facilities in Worabe town from December 28, 2016 to January 30, 2017. Data were collected with a pretested interviewer-administered questionnaire, and entered into Epi info and transferred to SPSS version 22 for analysis. Univariate and multivariable logistic regression was employed with a 95% CI, and a p- value of < 0.05 was used as a determinant of pneumonia.


Introduction
Pneumonia is a respiratory tract infection that affects children. Streptococcus pneumoniae, Haemophilus in uenzae type b (Hib), and respiratory syncytial virus are among the common pathogens involved [1]. S. pneumoniae is the most common cause of bacterial pneumonia in children under ve years of age in the developing world. Microbes that are commonly found in a child's upper respiratory tract can cause lower respiratory tract infection. They may also spread via air-borne droplets from cough or sneeze or may spread through blood, especially during and shortly after birth [2].
Pneumonia is the major killer of children under the age of ve years than any other diseases known to affect children. Childhood pneumonia causes substantial mortality and morbidity among children under-ve, with developing nations carrying the highest pneumonia burden [3,4].
Every year, nearly 1 million children die of pneumonia worldwide and approximately about 15% of all deaths occur in children under age ve. This means a loss of over 2,500 children lives every day or 100 children every hour. It is most prevalent in sub-Saharan Africa and South Asia, Nigeria, Pakistan, the Democratic Republic of Congo and Ethiopia, accounting for 50% of total deaths [5][6][7]. In Ethiopia, pneumonia is the leading cause of death, accounting for 18% of all under-ve mortality burdens [8]. As a result, Ethiopia ranks the fth (62 deaths in 1000) among 15 countries in the world and has the highest death rate from clinical pneumonia in children under ve [9]. It also causes millions of morbidity burdens and costs the health services program, as health services are passed on to cure high pneumonia morbidity cases, with an estimated 3,370,000 children encountering pneumonia annually, which contributes to 20% of all causes of deaths killing over 40,000 under-ve children every year [10][11].
Ethiopia follows the same strategy and has adopted the World Health Organization (WHO) Integrated Management of Childhood Illness (IMNCI) guidelines since 2001. Moreover, with the objective of increasing access to life-saving interventions, Ethiopia made a policy breakthrough of introducing community-based treatment of pneumonia through health extension workers in 2010 [12]. Since then, 38,000 health extension workers from nearly 15,000 health posts have been equipped with the skills and supplies to treat pneumonia at the community level using the integrated community case management (ICCM) approach [13].
Previous studies indicated that some of most determinants for pneumonia include the educational status of parents, age of the mother, family child caring practice, family income, age and sex of the child, parental smoking or indoor air pollution from biomass fuel smoke, absence window in the kitchen, overcrowding, parental asthma, household history of pneumonia, malnutrition, lack exclusively breastfeeding, lack of zinc supplementation, comorbidity condition such as diarrhea, measles, acute upper respiratory infection (AURTI), previous history of asthma, and wide variation across the regions of the world [1,10,.
Contributing factors of pneumonia need to be studied to better inform health care providers and policy-makers to consider pneumonia prevention strategies. Although there are studies conducted in Ethiopia, the risk factors for pneumonia differ in different societies and study populations, and the ndings vary [37]. Taking the signi cance of the problem and variability of risk factors, research is needed to identify the potential determinants of pneumonia in children under ve children years of age. Above all, there was no previous study in this study area that could show the determinants of pneumonia. Therefore, the aim of this study was to identify determinants of pneumonia among children 2-59 aged months in public health facilities in Worabe town Sothern Ethiopia.

Study setting
The study was conducted in public health facilities in Worabe town, Silte zone, Southern Nation Nationalities and People's Region. Worabe town, the capital city of Silte zone is located 175km and 198km far from Addis Ababa and the regional capital, Hawassa, respectively. The town has a total population of 29,600, of which 4618 are children under ve years old, which is projected from the 2007 census report. There are two public health facilities in Worabe town and 6 private clinics. All of them were given IMNCI service according to the town health o ce report. The town implemented urban health extension programs [38].

Study design and period
An unmatched case-control study was conducted from December 28, 2016, to January 30, 2017.

Source population
All children were aged two months to ve years in public health facilities of Worabe town.

Study population
Children who were 2-59 months old visited the selected health facilities during the study period. Cases were children aged 2-59 months who visited pediatric units, registered and classi ed for pneumonia as de ned by the Federal Democratic Republic of Ethiopian Ministry of Health IMNCI guideline adopted from WHO [39]. A control group was de ned as children aged 2-59 months who attended the public health system in Worabe town with a diagnosis of nonpneumonia.

Sample size determination
A sample size of 435 (145 cases and 290 controls) was determined using Epi-Info version 3.5.4 statistical software with assuming two side con dence level (Cl) 95%, power=80%, ratio control to case 2:1 and taking a history of AURTI as a predictors of pneumonia with percent of control exposed 22.4%, 1.80 Odds ratio from a case control study [21] and an estimated nonresponse rate of 10%.

Sampling technique
All public health facilities in the town were purposively included based on patient load and the presence of accessible trained staff on IMNCI. The sample size was distributed to each health facility based on the average number of daily case loads.
According to the zonal health bureau Health Management Information System report preceding ve months prior to the study, the average number of daily pneumonia patients was seven under-ve pneumonia cases per day in Worabe comprehensive specialized hospital and two per day in Worabe Health Center [40]. Based on this, the sample size allocated for the Worabe health center was one case and two controls on a daily basis with a total of 21 cases and 42 controls, and the sample size allocated for Worabe Comprehensive Specialized Hospital (WCSH) was six cases and twelve controls on a daily basis with a total of 124 cases and 248 controls.
Selection of cases: All cases (diagnosed and recorded as pneumonia/severe pneumonia) were considered in the study until the required sample size was reached/ful lled.
Selection of controls: As the control-to-case ratio was 2:1, two children who did not have pneumonia and visited selected health facilities for different services at the time of data collection were randomly selected by systematic random sampling after the cases were identi ed.

Inclusion criteria
The study included all children who were between 2 and 59 months of age, those who were residents of Worabe town for a minimum of six months, and visited the pediatric unit of WCSH and Worabe Health Center during the study period.

Exclusion criteria
Children with the following conditions were excluded from the study: cardiac disease, cough that lasted >15 days (suspected of pulmonary tuberculosis), cough because of the recent history of aspiration of a liquid or a foreign body and caregiver who did not have any information about the child at the time of data collection.

Study variables
The variables included in this questionnaire were both independent and dependent variables for which an association was going to be assessed.

Independent variables
Sociodemographic factors, Parental factors such as educational and occupational status, parental smoking, age of the mother, family size, and family-caring practice (parental/home maid, place of child during cooking and family income).
Child factors included age and sex, immunization status, a pre-existing illness such as a history of diarrhea, AURTI, and acute lower respiratory tract infection/pneumonia in the last 2 weeks and asthma.
Environmental factors: type of fuel used for cooking, crowding status, place of cooking, parental asthma, and household history of tuberculosis and pneumonia Nutritional factors in the child: undernutrition, breastfeeding status of the child for the rst 6 months and duration of breastfeeding, age of complementary feeding started and zinc supplementation.

Dependent variables
Pneumonia among children 2-59 months of age.

Operational de nitions
Pneumonia: A child aged 2-59 months with cough and/or di cult breathing less than two weeks of duration plus fast breathing and/or chest in drawing.
Fast breathing is de ned as: For children in the age interval of 2 months to 11 months, 50 breaths per minute or more For children in the age interval of 12 months to 5 years, 40 breaths per minute or more History of acute upper respiratory tract infection (AURTI): a child who had a history of ear infection, common cold, tonsillitis, or pharyngitis in the last fteen days prior to data collection.

Data collection tools and procedures
A structured questionnaire was developed based on a review of previously published studies and adapted to the local situation with certain modi cations [17][18][19][20][21][22][23][24][25][26][27][28]. The questionnaires included information on the possible risk factors for pneumonia, including sociodemographic factors, environmental/home-based factors, nutritional factors, immunization status, pre-existing illness and child care practices. Data were collected by IMNCI-trained nurses working in under-ve clinics who received two days of training regarding the research. After the study participants were identi ed as cases and controls, mothers/primary care takers were interviewed based on the interviewer-administered pretested structured questionnaire, but the data collectors were blinded to the status of the respondent.
Anthropometric measurements: Weight and height of the child were taken at the beginning of the interview by data collectors.
A suspended scale of 25 kg capacity graduated at 0.1 kg was used for weighing infants and children. After taking the weight of every child, the scale was checked for its accuracy. The scale reading was taken to the nearest 0.1 kg. Length measurements in the lying position were taken for children less than two years of age, and height measurements were taken for children 2-5 years of age. The anthropometric data were analysed in terms of weight for age, length for age, and weight for length using WHO Anthrosoftware to prepare for SPSS. The WHO (2006) growth standard was used to report anthropometric measurements result by Z-score, and the global acute malnutrition standard was used to classify the child's nutritional status as normal, stunted, wasted or underweight.

Data quality management
Before conducting the study, data collectors were trained for two days. The questionnaire was pretested on a 5% sample size at Kbit Primary Hospital to ensure the validity and reliability of the survey tools. After collecting the pretest data, it was checked for potential problems related to the tool, such as any di cult question that was understandable or unclear to reply and corrective measures were taken.

Data processing and analysis
The collected data were checked for completeness, coded and entered into Epi Info version 7 and exported to the statistical package for social sciences (SPSS) version 22 for analysis. The entered data were cleaned and checked for consistency and extent of outliers. Different statistical assumptions and appropriate corrections were made prior to analysis. Descriptive analyses were carried out for each of the independent variables. Binary logistic regression analysis was used to test the association between the independent and dependent variables. Bivariate analysis was performed for each of the independent variables with the outcome variable. Variables that had a p-value < 0.2 on bivariate analysis were taken as candidates for multivariable logistic regression model analysis to identify their independent effects. Finally, variables with p-values less than 0.05 on multivariable logistic regression analysis were considered statically signi cant factors for the outcome variable. The strength of the association between the dependent variable and independent variables was expressed by odds ratios (ORs) with 95% con dence intervals.

Socio-demographic characteristics
A total of 435 (145 cases and 290 controls) children aged 2 to 59 months participated in the study, making the respondent rate 100% for both groups. The highest proportion of cases (57.2%) and controls (62.4%) were in the age group of 2-11 months, with mean ages of 14.6 (SD± 12.8) and 12.6 months (SD± 12.7) for cases and controls, respectively. Approximately 52% of cases and 51% of controls were male. In the bivariable logistic regression analysis, none of the sociodemographic variables except family size illustrated an association with the occurrence of pneumonia in children (p=0.1) at a p-value <0.2 signi cance level (Table 1).   (Table 3). Factors associated with pneumonia among children aged 2-59 months Logistic regression analysis showed that stunting, previous history of asthma diagnosis in the child, place of the child during cooking, absence of chimney in the cooking room and history of AURTI in the last 2 weeks prior to data collection were determinants of pneumonia. The ndings revealed that the odds of stunting were 3.6 times higher among children with pneumonia than controls (AOR=3.6, 95% CI: 1.8, 7; P<0.001). On the other hand, the odds of carrying the child on the back while cooking/besides the cooking mother were twice as high as those of compared to children outside of cooking the room among cases than controls (AOR= 2, 95% CI: 1.2, 3.3; P=0.006).
Similarly, the odds of children living in households with no chimney in the cooking room were 2.2 times higher among cases than controls (AOR= 2, 95% CI: 1.3, 3.7; P=0.003).
The odds of having a previous history of asthma were vefold higher among cases than controls (AOR= 5, 95% CI: 2, 12; P<0.001). Likewise, the odds of having a history of AURIT in the last 2 weeks prior to data collection were 3.7 times higher among children with pneumonia than among children without pneumonia (AOR= 3.7, 95% CI: 2.3, 6.1; P<0.001) ( Table 4).

Discussion
In this study, preexisting respiratory illnesses, such as a history of asthma in the child and a previous history of AURTI, undernutrition (stunting), absence of chimney in the cooking room and carrying the child on back during cooking, were found to be signi cant risk factors associated with pneumonia among children aged 2-59 months.
The odds of carrying the child on the back while cooking/besides the cooking mother was 2 times greater than that of children outside of the cooking room among cases than controls. This might be due to indoor air pollution from biomass fuel smoke, as the majority of the households use wood and charcoal for cooking with no chimneys in the cooking area. This result is consistent with a cross-sectional study conducted in north west Ethiopia that found that a child who carries back during cooking was ve times more likely to develop pneumonia than their counterparts [17]. Similar ndings were obtained in different countries that reported indoor air pollution as risk factor for pneumonia [15,25,28,29,30]. However, two studies conducted in Ethiopia contradicted the current study results (those reported an absence of a signi cant association between the place of the child during cooking and the occurrence of pneumonia in children) [18,23]. The variation of the results could be due to differences in study setting and methodology.
Stunting was also another factor identi ed to be signi cantly associated with pneumonia, indicating that the odds of stunting were 3.6 times higher among children with pneumonia than controls, which this is in line with a study conducted in Northwest Ethiopia and Bangladesh [17,19]. The possible reason might be that stunting shows long-term malnutrition, which weakens the child's immunity and makes the child vulnerable to pneumonia. From different prospects of different studies, malnutrition (undernutrition) weakens the respiratory muscles needed to clear secretions in the respiratory tract, which intern predisposes to pneumonia [1,24,41].
In this study, there was the strongest association between pneumonia and a history of asthma, indicating that children who had a previous history of asthma had approximately vefold increased odds of developing pneumonia compared to their counterparts. According to the WHO 2008 bulletin report, concomitant diseases such as asthma were likely risk factors for the occurrence of childhood pneumonia [15]. Other studies conducted in different parts of the world also reported that a history of asthma is associated with the occurrence of pneumonia episodes [21,36]. In a study conducted in the Philippines, 55.4% of children who developed consolidated pneumonia had asthma as an underlying illness [27]. However, in the present study, it was unable to conclude whether uncontrolled asthma or an underlying asthmatic condition was a risk factor for pneumonia or whether pneumonia was a trigger of asthma attack. Further study is need to de ne a causal relationship between asthma and pneumonia.
Finally, a history of AURTI in a child in the last two weeks preceding the current pneumonia was identi ed to put a child 3.7 times at risk of pneumonia compared to their counterpart. This is in line with the study conducted in southwest Ethiopia, which indicates that the risk of pneumonia is more than 5 times for children who had previous AURTIs [23], and a similar nding in the Netherlands showed a strong relation between the occurrence of community-acquired pneumonia and an increasing number of previous AURTIs (the risk of pneumonia was 2.46 times & 1.8 times more likely if the child had three and two episodes of AURTIs respectively, in the past) [21]. However, a study conducted in Ethiopia reported no signi cant association between occurrences of pneumonia and preceding infection of AURTI in children [22]. A possible explanation might be that AURTI increases susceptibility to infections that intern predispose patients to pneumonia or that there might be descending infection from the upper to lower respiratory tract.

Limitations of the study
The diagnosis of pneumonia was based on the clinical WHO IMNCI classi cation guidelines, which introduced misclassi cation recall bias; the study did not considered privates health facilities and did not consider the complete population.

Conclusions
This study suggests that children stunting, a previous history of asthma and upper respiratory tract infection, the absence of chimney in the cooking room and carrying the child on back during cooking; are strongly associated with an increased risk of childhood pneumonia. Therefore, the zonal health bureau, in collaboration with the agricultural o ce needs to improve the nutritional status of children, and the town administrative health o ce, in collaboration with the health facilities should provide health education to the community about the health risk of child exposure to biomass fuel smoke and to have chimneys in the cooking room.

Declarations Competing interests
The authors declare that they have no competing interests

Funding
No funding was received for this study.
Availability of data and materials All necessary data are available within the paper.
Ethical approval and consent to participant The study was ethically approved by the Institutional Review Board of Saint Paul's Millennium Medical College Department of Public Health. An o cial permission letter was obtained from the study site. The objectives, expected outcomes, bene ts, and risks of the study were explained to mothers/guardians/caregivers of the study participants. Data were collected after written informed consent was obtained. The study was conducted in accordance with the Declaration of Helsinki.

Consent for publication
Not applicable Authors' contributions RKS Designed the study, was involved in data collection, data analysis and interpretation, wrote the paper and prepared the manuscript for publication. YAW&MMA Data analysis; and interpretation and prepared the initial draft of the manuscript for publication. SMA Had oversight of all the stages of the research, critically reviewed the nal draft of the paper and the prepared manuscript for publication. The nal manuscript was read and approved by all authors.