Data source and study sites
This analysis used data derived from the BADUTA study conducted in 2015-2016 in Sidoarjo and Malang District of East Java, Indonesia.The Ministry of Health, Republic of Indonesia identified Malang and Sidoarjo Districts as the study sites for evaluating the BADUTA program since they represented peri-urban and rural areas of East Java Province.In both districts, we selected six sub-districts to conduct the trial. The sub-districts in Sidoarjo District were Tulangan, Wonoayu, Sidoarjo, Prambon, Taman, and Krian; and in Malang District were Dampit, Turen, Tumpang, Poncokusumo, Gondanglegi, and Jabang.
We have presented detailed information about the BADUTA study protocol elsewhere [21]. We used data for this analysis from two independent cross-sectional surveys conducted in 2015 at the beginning and 2017 at the end of the project. To assess breastfeeding self-efficacy amongst mothers, we only used information collected from mothers of children less than six months of age.
Background information on study sites
East Java Province is one of the provinces in Indonesia located on Java Island, and the capital is Surabaya City, the second-largest city in Indonesia. East Java's total population is approximately 37 million people, the second-most populous province in the country [22]. Malang District, located in the center-south region of East Java Province, has an estimated total population in 2017 of 2,576,596 people[23]. Most of the people were working as laborers or private employees (37.63%) [23]. Sidoarjo District, located north of Surabaya City, has an estimated total population in 2017 of 2,207,600 people [24].
Study design and samples of the study
We conducted an observational epidemiological study to examine factors associated with low breastfeeding self-efficacy. We combined the data from the baseline and endline cross-sectional surveys for both the intervention and comparison groups in the BADUTA study for our analysis.
The sampling design in this trial used a three-stage cluster sampling procedure. In each of the twelve subdistricts selected at the initial stage, we selected tenvillages using the probability proportionate to size sampling method. Next, we selected two sub-villages from each chosen village using simple random sampling method. Finally, we conducted a mini census to list all children aged <2 years, in each of the selected sub-villages. Using the listing as a sampling frame, we selected 12 children aged <2 years and their mothers using simple random sampling.
In the baseline survey of the BADUTA study, the sample size for children under two years old was 2435 children,while in the endline survey, the sample for children under two years old was2740[21]. We only used information from 1210 women with children under six months (575 from the baseline and 635 from the endline survey) for this analysis.
Survey instruments and field personnel
The field team carried out house-to-house interviews using pre-tested and structured questionnaires. The information collected in this study included socio-economic and demographic characteristics; infant feeding practices as well as the intention of the mother to breastfeed and self-efficacy for breastfeeding of the mothers; child morbidity, reported by mother/caregiver; as well as contact with the health system and exposure to the interventions. Information about the mothers’self-efficacy for breastfeeding was collected using the Breastfeeding Self-Efficacy Scale-Short Form questionnaire developed by Dennis [16], a 14-item instrument to measure breastfeeding confidence.
At the baseline, we established eight fieldwork teams in each district. However, in the endline study, we established ten fieldwork teams to shorten data collection duration. Each team consisted of one field coordinator, one assistant field coordinator, and ten enumerators for interviews. There were 10 field coordinators, 130 interviewers, and 20 nurses or midwives recruited [21]. The nurses and midwives collected theblood samples and took anthropometric measurements.
Before data collection, all field workers attended a one-week training program to standardize the enumerators, and their coordinators, with the questionnaire, sampling methodology, andinterview techniques. The training covered different aspects of the study, i.e., an overview of the BADUTA study, the use of CommCare application,household listing and data collection procedures, explanations of study instruments (listing forms and questionnaires), quality controls for data collection, as well as a field plan. The training program included a two-day tryout to allow all training participants to practice the household listing and interviews using the CommCare application. A pre and post-test werealso carried out before and after the training sessions, respectively. Enumerators with low post-test results were monitored closely by field coordinators and supervisors, particularly at the beginning of data collection, to ensure their ability and quality to conduct all fieldwork activities.
Data were collected electronically on hand-held devices using the CommCare system developed by Dimagi [25]. Information was recorded on structured, error detecting forms on tablets and then dispatched directly to a server to clean and merge. Field supervisors and a data manager monitored the data quality regularly.
Outcome variable
This analysis's outcome variable was mothers’self-efficacy for breastfeeding as a binary variable (low or high self-efficacy on breastfeeding). We defined breastfeeding self-efficacy as the mothers’beliefs and confidence in their ability to breastfeed their infants successfully. Information about the mothers’self-efficacy for breastfeeding was collected using the Breastfeeding Self-Efficacy Scale-Short Form[16].For each of the 14 statements, we asked the mothers to give a score from 1 to 5 that offered a range of answer options from “stronglydisagree”to “strongly agree,”respectively. We added all the scores to calculate the total score. As in other studies, we based the breastfeeding self-efficacy classification on the median of the total score [26, 27]. Previous studies supported using either the mean or the median as the cut-off point to categorize low and high breastfeeding self-efficacy [27-29]. We classified mothers scoring less than the median as having a low self-efficacy on breastfeeding. Thosescoring equal to or above the median we classified as having a high self-efficacy.
Potential predictors
The potential predictors were selected using the analytical framework shown in Figure 1. In total, there were 17 potential predictors of breastfeeding self-efficacy included in the analyses, categorized into six sub-groups: (1) context/demographic variables; (2) household characteristics; (3) maternal characteristics; (4) child characteristics; (5) breastfeeding characteristics; and (6) antenatal and delivery care characteristics.
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In the group of contextual and intervention variables, we constructed a composite variable indicating the total number of interventions from 13 variables representing breastfeeding-related interventions in the BADUTA study. Those 13 interventions were: (1) discussing breastfeeding with cadres on a home visit during pregnancy; (2) discussing exclusive breastfeeding in pregnant women’s class during pregnancy; (3) did not receive any free formula milk after delivery (part of the Baby Friendly Hospital Initiative); (4) discussing breastfeeding with a village facilitator during pregnancy; (5) watching a breastfeeding-related video shown by the village facilitator during pregnancy; (6) discussing the topic of breastfeeding in emo-demo sessions; (7) receiving mobile phone messages on early initiation of breastfeeding; (8) receiving mobile phone messages on the benefits of colostrum; (9) receiving mobile phone messages on exclusive breastfeeding; (10) receiving mobile phone messages on exclusive breastfeeding problems and how to handle them; (11) receive breastfeeding counseling by midwives during pregnancy; (12) receive breastfeeding counseling by cadres during pregnancy; and (13) watching TV commercials about breastfeeding. For each question, we scored the answers oneif the mothers answered “yes,”and scored zeroif answered otherwise. We then summed all the scores to obtain a total intervention score. We then categorized the total intervention score for each individual into “no intervention”(total score = 0); “one intervention”(total score = 1); “two interventions”(total score = 2), and “three or more intervention”(total score is ³3). Finally, we calculated the total intervention score for all women from both the intervention and comparison groups included in this analysis. Our purpose was to assess any breastfeeding intervention's impact, whether from the study interventions or routine programs, on breastfeeding self-efficacy. We have documented a detailed explanation of the interventions in the BADUTA study elsewhere [21].
In household characteristics, we constructed the household wealth index variable using Principal Component Analysis (PCA) [30]froman inventory of the household’s facilities and assets. These items included ownership of electricity, drinking water, toilet facility, type of toilet facility, fecal final disposal, and ownership of bicycle, television, water heater, 12kg of LPG, fridge, and car. We ranked households by this index and classified them into five quintiles, i.e., poorest, poor, middle, rich, and richest categories of households.
In the breastfeeding knowledge and experience group, we developed one composite variable to represent mothers’knowledge about breastfeeding. We constructed this variable from five questions: (1) the best food or liquid to be provided to children aged < 6 months; (2) the duration for exclusively breastfeeding a child; (3) the duration a child should receive breast milk; (4) the benefits of giving breast milk to children; and (5) the time a child should receive complementary feeding. A score of one was assigned to all correct answers and zero for all incorrect answers for each question. We summed all the scores to get the total knowledge score, and we calculated the median value. We developed two categories of knowledge: (1) a high level of knowledge for those whose total knowledge score was greater or equal to the median, and (2) a low level of knowledge for those whose total knowledge score was less than the median. To test if previous experience with feeding infants influenced breastfeeding self-efficacy, we also used an indicator for previous live births as we did not specifically ask the mothers about their earlier breastfeeding experiences.For the variable of problems with breastfeeding, we categorized mothers into four groups: (1) Mothers who did not experience any problems with breastfeeding; (2) Mothers who had breastfeeding problems not related to illness; (3) Mothers who had breastfeeding problems related to illness or anatomical conditions; and (4) Mothers who had both types of problems. We categorized mothers as having as “breastfeeding problems not related to illness,who mentioned their breastmilk was insufficient, or they could not express it, or the infant refused breastfeeds. We categorized mothers with problems due to swollen breasts/mastitis, sore nipples, or flat/embedded/large nipples as a “problem related to illness/anatomical conditions.”We categorized mothers reporting both types of breastfeeding problems as “mothers who had both types of problems.
Data analysis
To examine the characteristics of all variables (outcome variables and potential predictors) used in the analysis, we used contingency tables. We then applied logistic regression analyses to determine factors associated with all outcome variables using ORs (odds ratios) as the estimated measure of association. We used Stata survey commands (svyset) to adjust for the clustering from the cluster randomization. All estimates presented in this analysis considered the complex sample design.
In the first step of logistic regression, we usedbivariate analyses to independently assess the relationship between outcome variables and their potential predictors. In the second step, we performed multivariate analyses using a backward elimination method to remove all variables not significantly related to the study outcome, with a significance level of 0.05. Two variables selected a priori and retained in the final model regardless of the significance level were: (1) Period of the survey (baseline or endline) and (2) the fulfillment of the minimum requirement of four antenatal care visits by trimester (met or did not met). We obtained the adjusted ORs (aOR) and 95% confidence intervals (95% CIs) for all the final model variables.
In multivariate analysis, we used problems of breastfeeding and the number of breastfeeding interventions as composite variables. After obtaining the final model (Model #1), we developed the second model by replacing breastfeeding problems with each type of breastfeeding problem (Model #2). We also developed the third model by replacing the breastfeeding intervention variable with all the individual exposure to intervention indicators (Model #3). We then retained the other variables in the final model of Model #1 in Model #2 and Model #3. We used Stata/MP software (version 13.1; StataCorp) for all analyses.
Collaborating institutions
This study was conducted by an International Research Consortium that comprised of experienced researchers from the University of Sydney (Australia), the London School of Hygiene and Tropical Medicine (LSHTM) (United Kingdom), the Center for Health Research Universitas Indonesia (CHR-UI), the Indonesia Nutrition Foundation for Food Fortification (KFI), and the Southeast Asian Ministers of Education Organization (SEAMEO), Regional Center for Food and Nutrition (RECFON).