Study area
The study was conducted in Meket Woreda. Meket Woreda is one of the thirteen Woredas in North Wallo Zone of Amhara Region, Ethiopia. According to 2007 Central Statistics Agency (CSA) report, the Woreda has a total population of 226, 644. From which, 112,246 are females. The Woreda was identified as one of the most drought-affected and food insecure Woreda in the Region.
According to the Woreda education bureau report, in the Woreda, there are 50 full cycle primary schools with the total of 51,869 (25,719 males and 26,150 females) students. The SFP was implemented in 5 schools with the total of 5,079 (2,560 male and 2519 female) students.
Study design and population
A school-based comparative cross-sectional study was conducted among primary school students, from April 1-27/2015. All full cycle primary school students in the Woreda were the source population and students in selected schools were the study population. In the study area, school meal was given to the students starting from grade one. Students from grade four and above (students who took school meal for three or more years) were included in this study. Similarly, students from grade four and above were also included in schools had no school feeding program.
Sample size, sampling procedure, and data collection
The required sample size of the study was calculated using two population proportion formulas by considering the following assumptions: a 95% confidence level, 50% proportion of under-nutrition among students who did not take meal at school and 40% proportion of under-nutrition among students who took meal at school, since there was no previous study, 80% power to detect 10% difference, the population allocation ratio is 1:2, Design effect 2 and 10% non response rate. The final sample size was 1176. Of these, 392 students were from schools had no SFP and 784 students were from schools had SFP.
The study participants were selected using multi-stage stratified sampling method. Using list of Kebeles as a sampling frame, 12 Kebeles were selected from 45 Kebeles in the Woreda by simple random sampling (SRS) technique (lottery method). Next, schools in selected Kebeles were stratified as school had SFP and had no SFP.
In selected Kebeles, there were 12 schools (8 schools without SFP and 4 schools with SFP). Two schools with SFP and four schools without SFP were selected by SRS technique using the list of schools in selected Kebeles as a sampling frame. The calculated sample size was allocated to the selected schools based on proportion to the size of the students from each school. Finally, using school registration log book as a sampling frame, students were selected by SRS technique. The interview with students’ mothers was conducted in the school compound considering privacy.
Data were collected by Amharic version structured interviewer-administered questionnaire. The questionnaire was taken from similar literature (17) and it used to assess socio-demographic characteristics, environmental hygiene and feeding practice of the students. Eight diploma and two BSC nurses were recruited as a data collector and supervisor, respectively.
The anthropometric measurement was taken from students. During anthropometric measurement, the equipments which were used to measure weight were calibrated each day prior to the actual data collection by using a known weight material. Weight was measured to the nearest 0.1kg using a digital scale. The scale was adjusted before weighing every student by setting it to zero. The students were lightly dressed during having the weight taken.
Height was measured to the nearest 0.1 cm using a vertical measuring stadiometer taking all assumptions of height measurement in to consideration. During taking height, the student stood keeping normal anatomical position without shoes and heels, buttock, shoulder, and back of the head touched measuring board. Then, headpiece of the measuring board touched top of the head. For both weight and height two readings were recorded and the computed averages were used in the analysis.
The z-score values for BMI-for-age and height for age were calculated using WHO Anthro-Plus software. Calculated z-scores of BMI-for-age and height for age were used to classify thinness and stunting using the new WHO 2007 reference value, respectively.
Operational definition
School feeding program (SFP) participants- are students who took meal at school.
School feeding program (SFP) non- participants- are students who did not take meal at the school.
Stunted- is defined as low height-for-age at < -2 SD of the median value of the WHO international growth reference.
Severely stunted- is defined as very low height-for-age at < -3 SD of the median value of the WHO international growth reference.
Not stunted- is defined as normal height-for-age at > -2 SD of the median value of the WHO international growth reference.
Thinness–is defined as low BMI-for-age at < -2 SD of the median value of the WHO international growth reference
Severely thin-defined as very low BMI-for-height at < -3 SD of the median value of the WHO international growth reference
Normal–is defined as BMI-for-age between +2 SD and > -2 SD of the median value of the WHO international growth reference
Overweight-is defined as high BMI-for-age at >+2 SD of the median value of the WHO international growth reference
Data Quality Control
Using trained data collector and supervisor, pre-testing the questionnaire and checking weighing scale for functionality were measures taken to assure the quality of data. Moreover, the collected data were reviewed and errors were returned to the data collectors for correction in a daily base. Supervisors and investigators closely supervised the data collection procedure.
Data processing and analysis
Data were entered and analyzed using SPSS version 20 software. Nutritional status of the students was compared. Bivariate and multivariable logistic regressions were done to identify factors associated with stunting and thinness. The crude Odds ratio was done and p-value < 0.2 was taken as a cut-off point to select variables for the final model. Age was controlled during the multivariable logistic regression analysis. The adjusted Odds ratio was computed to determine the strength of association and control confounders. The p-value less than 0.05 was considered statistically significant.
Ethical consideration
The study was approved by Ethical review Board of College of Medicine and Health Sciences, Bahir Dar University. Letter of permission was taken from zonal and Woreda health bureaus as well as the school administrators. Since it causes less than minimum risk, verbal consent was taken from parents and assent was taken from students. Privacy and confidentiality were maintained throughout the study period by excluding personal identifiers from the data collection tools.