Study area and period
The study was conducted from March 15 to April 15, 2020, in Legambo District, South Wollo zone, Northern Ethiopia. The district is found in the South Wollo zone Amhara region. it is situated on the beautiful highlands of south Wollo at an altitude of about 3000 m above sea level and is located 100 km to Dessie (the capital city of South Wollo zone), 430 km from Bahir Dar (the Capital city of the Amhara region) and 501 km far from Addis Ababa (the Capital city of Ethiopia). The district has 33 health Posts, 9 health centers, 1 hospital, 78 Health extension workers. The total population of the district was 281,974 with 147,160 males and 134,748 females while the total number of children with the age of o month to 23 months was 10,172 in the year 2017 which was projected from the Woreda Administration office .
A community-based unmatched case-control study design was employed.
All mother-child pairs with 0–23 months residing in the Legambo district during the study period were included in the study. Whereas, children with the age of 0 to 23 months suffering from chronic illnesses and those on treatment such as TB, HIV were excluded from the study.
Sample size determination
The sample size was calculated using Epi Info version 220.127.116.11 by considering the following assumptions: proportion of reach wealth status who utilized GMP service was 19.5% among controls and 5% among cases from the study conducted in Southern Ethiopia, 5% type I error, 80% power, 1:3 cases to controls ratio, design effect of 1.5 and 10% non-response . The final sample size was 363(91 cases and 272 controls).
A multi-stage sampling technique was used to select the study participants. Out of 34 kebeles in the district, 7 kebeles were selected using the lottery method. The list of mother-child pairs aged 0–23 months and their house numbers from each kebele were obtained from the health extension workers. House to house censuses was made to identify cases and controls and children aged 0–23 months were identified and registered sequentially and had got identification number as case and control. And then, the total sample size was allocated proportionally to each kebele. Finally, both cases and controls were selected by a simple random sampling technique.
Case: Participation of a child for GMP services at least once for 0 months, at least two times for 1–3 months, at least five times for 4–11 months, and at least four times per year for 12–23 months.
Control: a child who had not participated in GMP services at least once for 0 months, at least two times for 1–3 months, at least five times for 4–11 months, and at least four times per year for 12–23 months.
Good knowledge: is defined as scored above 7 from the total ten knowledge questions .
Poor knowledge: is defined as scored below 7 were considered as having poor knowledge .
Unfavorable attitude: is defined as a score of < 75%.
A favorable attitude: is defined as a score of ≥75% .
Data collection tools and procedures
The data were collected using an interviewer-administered structured questionnaire. The questionnaire includes socio-demographic, economic, health care, behavioral factors, and maternal/caregiver’s related characteristics and adapted from previous studies [12, 13, 16, 21, 22] and collected by well trained and experienced two clinical nurses and three diploma midwives and three health officer supervisors.
ANC visit was assessed based on the minimum recommended visits (yes; for having four or more visits and no; for less than four visits). And, PNC was also assessed based on the minimum recommended visits (yes; for having at least one visit in the post-partum period and no; for not visits at all). The vaccination status of children was checked by observing the immunization card and if not available mothers /caregivers/ were asked to recall it. BCG vaccination was checked by observing a scar on right (also left) arm. The wealth index of households was determined using the Principal Component Analysis (PCA) by considering latrine, water source, household assets, livestock, and agricultural land adopted from EDHS 2016 . The responses of all variables were classified into two scores. The highest score was coded as 1 and the lower score was given code 0. Assumptions of PCA were checked to carry out the wealth index score. In PCA to determine the number of components that would retain, eigenvalue-one criterion was used and those variables having a commonality value of greater than 0.5 were used to produce factor scores. Lastly, the score for each household on the first principal component was retained to create the wealth score. Finally, tertials of the wealth score were created to categorize households as poor, medium, and rich.
Distance to health facility determined by the distance (time taken to reach the health facility from mothers’ home to the nearest health facility). Distance to health facility was classified as less than 1 h and more than 1 h to reach the nearest health facility . Knowledge of mothers towards GMP service utilization was assessed using ten knowledge questions. Each questions has two response (yes = 1 or 0 = no). The total score ranges from 0 to 10. A score above 7 was categorized as good knowledge and below 7 was categorized as poor knowledge . The attitude of the mother to GMP service was assessed by 12 attitude questions using Likert scale measures (1 = strongly disagree, 2 = disagree, 3 = neutral, 4 = agree and 5 = strongly agree). The total score ranges from 12 to 60. A score of ≥75% was categorized as favorable attitude and a score of < 75% was categorized as unfavorable attitude .
Data quality assurance
The questionnaire was translated to the Amharic language and translated back to English to ensure consistency. The questionnaire was pre-tested in 5% of the sampled population in non-selected kebeles before the actual data collection. Data collectors and supervisors were trained for 2 days. Test-retest reliability of the research instrument was established during pretesting. Test re-test reliability was established by examining the consistency of pre-test responses. On spot-checking and corrections were made for incomplete questionnaires by the supervisor. The overall data collection process was controlled by the principal investigator.
Data processing and analysis
The data were coded and entered and into Epi info version 7 and exported to SPSS version 23 for analysis. Descriptive statistics were computed and presented using tables, figures, and charts. Model goodness of fitness was assessed by using Hosmer and Lemeshow test. Multi-colinearity between independent variables was checked. Bi-variable logistic regression was executed and variables with p < 0.25 were fitted to the final multivariable logistic regression to adjust for potential confounders. In the final model, variables with a P-value < 0.05 and AOR of 95% CI were considered to declare the statistical significance and the strength of association.