Study area and period
The study area is Mecha district which is located at 530 kms in Northwest direction of Addis Ababa, the capital city of Ethiopia, and 35 kms in the Southwest direction of Bahir Dar, capital city of Amhrara National Region State. It is one of the thirteen districts found in West Gojjam Administrative Zone. The district comprises three climatic zone; high land “Dega”, mid-altitude “Wena Dega” and lowlands “Kola”. The mean annual rainfall ranges from 1,000mm to 2,000mm. The district has 156,027 hectares area, of which 72,178 hectares are used for cultivation and about 1,386 hectares covered by water bodies. The district has 40 Kebeles (Kebele is the lowest administrative unit in Ethiopia) (10 irrigation users and others are non-irrigated). Irrigation users are all households in a Kebele have access to the irrigation system from Koga dam (16). Based on the 2007 national census, the estimated population of the district in 2019, is about 303,208, of which 150,088 are males and 153,120 are females. The district has 10 health center and 38 health posts and 1 government hospital during the time of the study (17). The district is one of the food surplus areas and the commonest staple foods are maize, millet, teff and barley (16). The study was conducted from October to December in 2019,
Study design and population
A community-based comparative cross-sectional study design was employed to assess the prevalence and its associated factors of childhood stunting. All mothers/care-takers with children age 6-59 months in both irrigation users and non-irrigation were source of population in the district. All mothers/care takers with children age 6-59 months in the randomly selected Kebele were study populations.
Sample size determination
The adequate sample size for this study was determined using two-population proportion formula [n (in each group) = f (α, β) (p1q1 + p2q2) / (p1 - p2)²] with the following assumptions: f (α, β) =7.84, when the power = 80%, the level of significance = 5% and the prevalence of stunting among irrigating (P1) was 10% and non-irrigated (P2) was17% from previous study in Kenya (18), design effect of 1.5 and 5 % of non-responses rate. Based on the above assumptions, a sample size of 1164 HHs (582 irrigation users and 582 non-irrigation users) was calculated for the study.
Sampling technique and sampling procedure
First, Kebeles in the district were stratified based on irrigation status (irrigation users and non-irrigation users). Six Kebeles from each stratum were selected randomly and proportion to size allocation was made to determine the required households from each randomly selected Kebeles. Households from randomly selected Kebeles were selected using systematic sampling technique. Sampling interval was determined by dividing the total number of households in each Kebele with the allocated sample size. The schematic sampling procedures was attached as supplementary file (Supplement file 1)
Data collection tools
Socio-demographic and other data were collecting by using structured questionnaire adapted from different standard questionnaires and literatures. The anthropometric data was collected by using WHO Recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old (19). A vertical or horizontal measuring board reading a maximum of 175cm and capable of measuring to 0.1cm was used to take the height of a child. The child stands on the measuring board barefoot; have hands hanging loosely with feet parallel to the body, and heels, buttocks, shoulders and back of the head touching the board. The head was held comfortably erect with the lower border of the orbit of the eye being in the same horizontal plane as the external canal of the ear. The headpiece of the measuring board is then pushed gently, crushing the hair and making contact with the top of the head. Height is then read to the nearest 0.1cm. For those with written evidence, date of birth was obtained from clinic cards, child health cards and immunization status certificates of the children, unless by asking mother/care takers age was determined.
Operational Definitions
Irrigation users are all households in a Kebele have access to the irrigation system whereas non-irrigation users refer household which did not have irrigation system. Improved water includes piped water on premises such as piped household water connection located inside the user’s dwelling, plot or yard, public taps or standpipes, tube wells or boreholes, protected dug wells, protected springs and rainwater collection. Unimproved drinking water sources include unprotected dug wells, unprotected springs, carts with small tank/drum, tanker trucks, surface water (river, dam, lake, pond, stream, canal, irrigation channels) and bottled water. Improved sanitation facilities are used by only one family and can include toilets connected to sewers or septic systems, water-based toilets that flush into pits, simple pit latrines with slabs, and ventilated improved pit latrines. Unimproved sanitation facilities include those shared by more than one household, flush/pour flush to elsewhere in the environment without proper waste water treatment, the use of buckets, hanging latrines, or pit latrines without slab coverings and open defecation
Data quality assurance
Pretest of the questionnaire, training and calipering of the weigh scale were done to assure data quality. The questionnaire was developed from previous literature and field pre-tested on five percent of sample size was done. Before the actual data collection, training was given for data collectors and supervisors. During the training, the trainers give instructions on the questions to be asked, their meaning, how to ask them, and how to record the answers. Data collectors and supervisors were also trained using role play practices. The equipment that was used to measure the anthropometric variables was calibrated between five respondents for actual data collection by using a known weight material. At the end of every data collection day, each questionnaire was examined for its completeness and consistency by the principal investigator and pertinent feedback was given to the data collectors and supervisors. All completed Epi (survey solution software) collected data entered questionnaire was conducted daily and Examined by principal investigator.
Data processing and analysis
Data were collected using Epi collect survey solution software and directly downloaded to Excel, exported to SPSS version 23. Data was cleaned before data analysis. The anthropometric data was exported to WHO Anthro plus software to computed individual level of nutritional status. Frequencies, proportions and chi-square were computed for description of the study population in relation to socio-demographic and other variables. Bivariate and multivariable analysis logistic regressions were done to determine the association between stunting and explanatory variables. Those independent variables whose p-value less than 0.2 at the bivariable regression were included in a multivariable logistic regression model. Adjusted odds ratio with 95% CI was calculated to measure the degree of association between stunting and explanatory variables. A-p-value <0.05 was used as cutoff point to declared statistically significant variables with the outcome variable.
Ethical consideration
The study was approved by the Ethics Review Board of College of Medicine and Health Sciences Board (CMHS/IRB 03-008), Bahir Dar University. A support letter from the University was written to the Amhara Regional Health Bureau. Permission and a letter of support for the study were then obtained from the Amhara Region Health Bureau and the Regional Health Bureau letter (ሽ/ዳ/03/455) was given to the district health office to commence the study. Information related ethical issue was given for mothers/caretakers (since most of them are farmers and could not able to read and write) by reading its content attached together in the first part of the questionnaire. Each study participant was briefed on the objective of the study, and informed about the right to refuse to participate in the study or to discontinue at any time. Participants were also informed that all data was confidential and personal identifiers were not registered. Interview was conducted after the parents and/or legal guardians of the child participants on their behalf provided verbal consent to participate in the study.