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 five 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 office report. The town implemented urban health extension programs .
Study design and period
An unmatched case-control study was conducted from December 28, 2016, to January 30, 2017.
All children were aged two months to five years in public health facilities of Worabe town.
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 classified for pneumonia as defined by the Federal Democratic Republic of Ethiopian Ministry of Health IMNCI guideline adopted from WHO . A control group was defined 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 confidence 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  and an estimated nonresponse rate of 10%.
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 five months prior to the study, the average number of daily pneumonia patients was seven under-five pneumonia cases per day in Worabe comprehensive specialized hospital and two per day in Worabe Health Center . 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/fulfilled.
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 identified.
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.
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.
The variables included in this questionnaire were both independent and dependent variables for which an association was going to be assessed.
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 first 6 months and duration of breastfeeding, age of complementary feeding started and zinc supplementation.
Pneumonia among children 2-59 months of age.
Pneumonia: A child aged 2-59 months with cough and/or difficult breathing less than two weeks of duration plus fast breathing and/or chest in drawing.
Fast breathing is defined 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 fifteen 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 modifications [17-28]. 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-five clinics who received two days of training regarding the research. After the study participants were identified 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 difficult 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 significant 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% confidence intervals.