Abstract
Background:
Delayed trophic feeding initiation is a significant risk for physical and neurological complications in neonates; however, data on feeding initiation in the current study setting are limited.
Objective:
This study aimed to determine the time to initiation of trophic feeding and to identify reasons for delayed initiation among preterm neonates.
Methods:
A prospective cohort study was conducted among 153 neonates admitted to Neonatal Intensive Care Units from February to April 20, 2023. Data were collected via Kobo and analyzed with STATA. Kaplan–Meier survival curves and Cox proportional hazards models were used for analysis.
Primary and secondary outcomes:
Median time and rate of trophic feeding initiation were estimated using Kaplan–Meier and simple frequency statistics, respectively, and adjusted hazard ratio with 95% confidence interval was used to identify factors for delayed initiation.
Results:
Among 153 neonates followed for 6853 person-hours, 85% initiated trophic feeding. The incidence rate of trophic feeding initiating was 1.9/100 person-hours with a median time of 41 h (95% confidence interval: 31–45). Delayed initiation was significantly associated with gestational age <34 weeks (adjusted hazard ratio: 0.54, 95% confidence interval: 0.37–0.79), first min APGAR score <7 (adjusted hazard ratio: 0.4, 95% confidence interval: 0.25–0.65), fifth min APGAR score <7 (adjusted hazard ratio: 0.51, 95% confidence interval: 0.34–0.79), small for gestational age (adjusted hazard ratio: 0.54, 95% confidence interval: 0.33–0.88), cesarean delivery (adjusted hazard ratio: 0.47, 95% confidence interval: 0.31–0.71), being out-born (adjusted hazard ratio: 0.50, 95% confidence interval: 0.30–0.83), respiratory distress syndrome (adjusted hazard ratio: 0.63, 95% confidence interval: 0.43–0.94), and hemodynamic instability (adjusted hazard ratio: 0.46, 95% confidence interval: 0.31–0.68).
Conclusion:
The study found a significant delay in trophic feeding initiation, despite guidelines recommending within 24 h. Gestational age <34 weeks, low APGAR scores, small for gestational age, cesarean delivery, being out-born, respiratory distress syndrome, and hemodynamic instability were associated factors. The authors emphasize the need for healthcare workers to begin trophic feeding within 24 h, regardless of these factors. They also recommend conducting larger studies nationwide to strengthen the evidence on this issue.
Introduction
Preterm neonates are neonates born before 37 full weeks of gestation, with around 15 million such births occurring annually. These neonates are at high risk for serious health issues and long-term disabilities if not provided with proper care, particularly during the neonatal period.1–3
Early postnatal nutritional management is essential for their brain development and can significantly improve their long-term neurodevelopmental and metabolic outcomes. This management is critical during a phase of rapid growth and nutrient accumulation, helping to prevent deficiencies and promoting gut development, infection resistance, feeding tolerance, and overall health.4–10
Trophic feeding (TF), which involves providing minimal enteral nutrition shortly after birth, is vital for stimulating intestinal function and preventing gastrointestinal issues. Evidence suggests that early TF can lead to quicker achievement of full feeding and earlier hospital discharge. Factors such as maternal health and delivery methods can influence the initiation of breastfeeding, which is closely related to TF practices.2,4,10,11 Moreover, current evidences support early TF to achieve early full feed and discharge.2,12 Early breastfeeding initiation has been reported to be influenced by factors such as maternal illness during pregnancy, cesarean section, and preterm birth, all of which are directly linked to TF. 13 Furthermore, studies indicate that gestational age (GA), respiratory distress syndrome (RDS), and delivery method have an impact on early initiation of TF.9,14–16 To tackle delays in starting TF, the federal ministry of health and the regional health bureau in the current study setting adopted a feeding protocol for preterm neonates in 2020 from WHO and UNICEF. According to this protocol, breast milk is the primary nutritional source and TF should be started as the baby is stabilized within 24 h of life, and should be given with amount of 10 ml/kg/day, can be increased up to 24 ml/kg/day. However, physicians may opt for formula feeding if breast milk is unavailable due to circumstances like maternal illness or death. 17
Despite this guidelines, studies indicate that 80%–90% of preterm neonates do not receive TF within 48 h, leading to high mortality rates and growth restrictions. On these studies, about 29% dying before discharge, and 86.2% experienced extra uterine growth restriction due to lack of early enteral TF.6–9,18 Healthcare providers often hesitate to start TF due to concerns about aspiration, abdominal issues, and the risk of necrotizing enterocolitis (NEC), which stems from inadequate knowledge and resources, including a shortage of breast milk.14,19,20
Evidence on the exact status of starting time of TF among preterm neonate admitted to Neonatal Intensive Care Unit (NICU) in Ethiopia is not adequately studied and has limited data. Therefore, the objective of this study was to determine the initiation time of TF and identify the possible reasons for delayed initiation among preterm neonates. So this study achieved its objectives by determining median TF initiation time and identifying significant factors of delay such as GA of <34 weeks, APGAR score of <7, being small for GA (SGA), born with cesarean section, being out-born, having RDS, and hemodynamic instability.
Patients and methods
Study design, settings, and period
An institution-based, observational, prospective cohort study was conducted among 153 preterm neonates admitted to the NICUs of four randomly selected public hospitals in Addis Ababa. These hospitals were chosen from a total of 10 public hospitals with NICU facilities in the city. In addition to the outpatient and inpatient services given, hospital data indicate that over 8300 newborns are admitted to the NICU each year across all four hospitals, with roughly 36% of them being preterm. The data were collected between February 20, 2023 and April 20, 2023.
Populations
All preterm neonates (GA <37 weeks) admitted to the NICUs of all public hospitals during the study period comprised the source population, and those admitted to the NICUs of the selected public hospitals during the same period constituted the study population.
Inclusion and exclusion criteria
Preterm neonates with a GA of <37 weeks admitted to the NICU of the selected public hospitals during the study period and whose parents provided informed consent for participation were included in the study.
However, neonates with pre-diagnosed or suspected Stage II or III NEC were excluded, as they should be accurately diagnosed and managed before starting enteral feeding. In addition, neonates with Stage III asphyxia prior to enrollment in the cohort were excluded. Furthermore, neonates with major gastro-intestinal malformations, like esophageal atresia and imperforated anus, duodenal and jejunal atresia, intestinal obstruction/perforation, or paralytic ileus were excluded. Neonates with incomplete medical records that hindered assessing the time to TF initiation were also excluded. Finally, neonates who started direct breastfeeding or another type of feeding before admission, and had unknown APGAR score, birth weight, and GA were also excluded.
Sample size determination
Dupont and Plummer’s software for calculating sample size and power was used to estimate the sample size. 21 Two populations were taken into consideration for the 168-h follow-up period in order to determine the ideal sample size. The following assumptions were used in the calculations: a power of 80%, a two-sided significance level of 5%, and a 1:2 ratio of exposed (<34 weeks) to nonexposed (⩾34 weeks). The estimated median survival time for the exposed and the nonexposed groups was taken from a prior study. 14 The highest sample size, 157 for GA (52 for <34 weeks and 105 for ⩾34 weeks), was utilized after comparing the sample sizes of each variable (Supplemental File 1).
Sampling method/procedure
Four hospitals were selected by a simple random sampling method (lottery method), and the total sample, 157, was proportionally allocated to the 2-month average preterm NICU admission of each study hospital. Then, each study participant was recruited in each study hospital using systematic random sampling (Supplemental File 2).
Operational definitions
TF: The first minimal enteral feeding to prime the gut regardless of method or volume. TF is a minimal volume of enteral nutrition (mainly expressed breast milk), should be given with amount of 10 ml/kg/day, can be increased up to 24 ml/kg/day either with cup or nasogastric tube feeding method. 11
Early initiation of TF: Preterm neonates start TF within 24 h of birth.
Delayed initiation of TF: Preterm neonates start TF after 24 h of birth.
Survival time: Is the duration in hours starting from birth, when the neonate is waiting without starting any type of feeding.
Event: Refers to the occurrence of a specific outcome of interest that the analysis aims to study. In this study when the preterm neonates started first TF within the follow-up period, it was considered as event.
Censoring: Refers to failure to fully observe a specific outcome of interest. In this study, preterm neonate who died, left against medical advice, transferred or referred before starting TF, or not started TF at end follow-up were considered as censored.
Left censored: Some members of the cohort might be transferred, died, lost, or left the facility before the end of the follow-up period without having the event of interest and we call them as “left censored.”
Right censored: TF was not be started for some members of the cohort at the end of the follow-up period, and we considered them as right censored.
Follow-up time: Time from birth to the first 7 days of life.
Prediagnosed NEC: Refers to neonates who had either suspected, Stage II or Stage III NEC based on modified Bell’s Staging, but not confirmed NEC. 22
Hemodynamic instability: If the patient has at least one of the physiologic parameters, including systemic hypertension, hypotension, tachycardia, or bradycardia alone or in combination, then the patient has experienced hemodynamic instability. 23
Perinatal asphyxia: Is decreased oxygenation state by persistently scoring an APGAR score of <7 for more 5 min. 17
Study variables
The dependent variable was time to initiate TF, and the independent variables were neonatal and maternal sociodemographic variables, neonatal-related factors, obstetric and gynecologic-related factors, and health service-related factors.
Data collection instrument and procedure
Data were collected through a semistructured, pretested interviewer-administered questionnaire 14 and a chart extraction checklist (Supplemental File 3). The purpose of the questioner was to collect data related to maternal sociodemographic characteristic (age, residence, marital status, educational status, and occupation); maternal obstetric characteristics (gravidity, parity, antenatal care visit, and place and mode of delivery); and given for mothers who delivered preterm newborns. While, the purpose of the data abstraction form is to collect necessary data such as GA, birth date and time, birth weight, APGAR score, enteral feeding initiation status and starting time, volume and mode of feeding, the presence of other medical condition, and the reason for delay if not TF started timely. Eight nurses (two from each hospital) were involved in the data collection and supervised by the principal investigator.
Data quality management
In order to maintain consistency, the data collection tools were first produced in English, then translated into Amharic, the local language, and then back to English. All the data collectors received 2 days of theoretical and practical training on the study objectives, data collection procedures, study participants’ approach, and ethical issues. A pretest was done on a 5% sample size in a hospital, that is, not included in the study. Every day, the primary investigator verified that each questionnaire was complete and consistent.
Data processing and analysis
Data were entered and analyzed using STATA software 14.0. Descriptive statistics were used to describe the frequency and percentage. The cumulative survival time was calculated from the observed survival times using the Kaplan–Meier curve, and the log-rank test was performed to compare the two survival curves. The study employed bivariate Cox regression analysis to evaluate the impact of individual independent variables on the outcome variable. To find the independent determinants of beginning TF, variables with a p < 0.25 in the bivariate Cox regression analysis were fitted in the multivariable Cox regression analysis. In multivariate analysis, all statistical tests were considered significant at a p < 0.05.
Ethical clearance
Ethical clearance letter was obtained from the School of Nursing and Midwifery’s Research Ethics Committee, Addis Ababa University (protocol no. REC-23-SON). Permission was obtained from each study hospital before the actual data collection began. Written informed consent was obtained from the parents or legally authorized representatives for each neonate. For parents with no formal education, written informed consent was signed after the data collector read all information with understandable language. Data were collected from all participants anonymously and kept confidential. The privacy of participants and their right to withdraw from the study were upheld without any bias.
Results
Sociodemographic characteristics of the neonates and mothers
Out of 157 participants, about 153 parents or caregivers of preterm neonates were agreed for their newborn’s participation in this study, which makes a response rate of the study 97.5%. Among 153 preterm neonates, 130 (85%) neonates started TF within 11–147 h, and 9 (5.9%) died. The mean GA of the preterm neonates was 34 (SD ± 2) with a range of 28–36 weeks. All the preterm neonates were low birth weight with a mean weight of 1703.6 (SD ± 451.9) g, ranging from 800 to 2490 g.
The age of the mothers ranged from 18 to 39 years, with a mean age of 27.88 years. The preterm neonates had a mean APGAR score of 6.5 (± 1.2 SD) in the first min and 7.0 (± 1.3 SD) in the fifth min. The majority, 110 (72%) of neonates had RDS, 82 (74.5%) had a weight appropriate for GA, 66 (43%) had hemodynamic instability, and 32 (48.5%) of them were diagnosed with perinatal asphyxia (Table 1).
Sociodemographic and clinical characteristics of mothers and neonates admitted to public hospitals from February 20 to April 20, 2023 (n = 153).
GA: gestational age; TF: trophic feeding.
Survival status of neonates on time to initiate TF
A total of 6853 person-hours of risk time were followed for 153 pairs of newborns and mothers. The follow-up period ranged from 11 to 147 h. Out of 153 preterm newborns, 130 (85%) started TF, and the remaining 23 (15%) were censored.
The overall incidence of initiating TF was 1.9/100-person hours of observation. The cumulative probabilities of initiating TF by the end of 24, 48, and 72 h were 24.3%, 63.9%, and 77.8%, respectively (Figure 1).
The Kaplan–Meier survival estimates of time to initiate TF among neonates admitted to selected hospitals; from February 20 to April 20, 2023 (n = 153).
The median time to initiate TF for the entire cohort was 41 (95% confidence interval (CI): 31–45) h. The log-rank test analysis indicated that there were substantial differences in median time to initiate TF among preterm neonates across categories of several variables. Accordingly, there was a significant difference in median time to initiate TF for GA <34 weeks neonates, 52 h, and for those GAs ⩾34 weeks, 33 h. Concerning clinical-related factors of preterm neonates, the median time to initiate TF for neonates who had RDS was 46 h (95% CI: 41–47) and without RDS was 29 h (95% CI: 23–41). Similarly, the median time to initiate TF was significantly different for neonates with hemodynamic instability 46 h (95% CI: 36–69) and without hemodynamic instability 39 h (95% CI: 29–45; Table 2 and Figure 2).
Survival time and log-rank analysis for the study population according to different characteristics of neonates admitted to public hospitals from February 20 to April 20, 2023 (n = 153).
AGA: appropriate for gestational age; CI: confidence interval; C/S: cesarean section; GA: gestational age; SGA: small for gestational age; VD: vaginal delivery.
Kaplan–Meier survival estimates of time to initiate TF by gestational age (a), first min APGAR score (b), fifth min APGAR score (c), hemodynamic instability (d), weight for age (e), respiratory distress syndrome (f), mode of delivery (g), and place of delivery (h) among preterm neonates admitted to public hospitals (n = 153).
Survival functions of time to initiate TF among different groups of preterm neonates
Predictors of time to initiate TF in preterm neonates
Findings from the bi-variate analysis showed that GA, first-min APGAR score, fifth-min APGAR score, hemodynamic instability, RDS, weight for GA, sustained suckling, mode of delivery, and place of delivery were associated with time to initiate TF in preterm neonates admitted to NICU at p < 0.25 (Table 3 and Figure 2(a)–(h)). Similarly in multivariate analysis, all variables except sustained suckling remained as significant predictors of time to initiate TF among the preterm neonates admitted to the NICU at p < 0.05 (Table 3).
Results of the bivariate and multivariate Cox regression analysis of time to initiate TF among preterm neonates admitted to public hospitals from February 20 to April 20, 2023 (n = 153).
AGA: appropriate for gestational age; AHR: adjusted hazard ratio; AOR: adjusted odd ratio; CHR: crude hazard ratio; CI: confidence interval; COR: crude odd ratio; C/S: cesarean section; SGA: small for gestational age; TF: trophic feeding; VD: vaginal delivery.
Indicates statistically significant variables in the multivariable analysis.
In this study, the multivariate analysis revealed that the hazard of initiating TF among preterm neonates born with <34 weeks of gestation was 46% less likely compared to those preterm neonates born with ⩾34 weeks of gestation (adjusted hazard ratio (AHR): 0.54, 95% CI: 0.37–0.79). The hazard of initiating TF among preterm neonates of a first-min APGAR score below seven was 60% less likely in comparison to neonates with an APGAR score of seven and above (AHR: 0.4, 95% CI: 0.25–0.65). Similarly, the hazard of initiating TF among preterm neonates who scored below seven APGAR at the fifth min was 49% less likely as compared to preterm neonates with seven or above (AHR: 0.51, 95% CI: 0.34–0.79). Also, the hazard of initiating TF was 46% less likely among preterm neonates who were SGA compared to their counterparts (AHR: 0.54, 95% CI: 0.33–0.88).
In addition to these predictors, the hazard of initiating TF was 53% less likely among preterm neonates who were born with cesarean section compared to that of vaginal delivery (AHR: 0.47, 95% CI: 0.31–0.71). Neonates, who were not born within the study hospitals, were 50% less likely to initiate TF than those born within the study hospitals (AHR: 0.50, 95% CI: 0.30–0.83).
Moreover, the hazard of initiating TF was 37% less likely among neonates who had RDS compared to their counterparts (AHR: 0.63, 95% CI: 0.43–0.94). The hazard of initiating TF among neonates who have hemodynamic instability was 54% less likely compared to neonates without these problems (AHR: 0.46, 95% CI: 0.31–0.68; Table 3).
Discussion
This study investigated the timing of TF initiation and its influencing factors among 153 preterm neonates in NICUs. According to the 2020 WHO and UNICEF feeding protocol, TF should commence within 24 h after stabilization, starting with 10 ml/kg/day and potentially increasing to 24 ml/kg/day. 17 Unfortunately, only 37 out of 153 newborns (24.3%) started TF within this recommended timeframe, and just over 88% were fed breast milk.
This initiation rate is similar to a previous study in Ethiopia, which reported 25%, but it’s higher than a related study in China, where only 15% started within 24 h. Conversely, studies from Nigeria and Kenya showed better results, with 45% and 48% of preterm babies starting TF, respectively.10,24,25
Overall, about 130 (85%) did eventually begin TF. This is in line with a Nigerian study that found an initiation rate of 86.4%, but it falls short of findings from Iran (88.6%) and Northwest Ethiopia (91%).4,14,24 The observed discrepancy in 24-h TF initiation may be linked to differences in healthcare providers’ expertise and the methods used in these studies.
In this prospective study, the median time to initiate TF was 41 h (95% CI: 35–46) which unfortunately does not meet the guidelines. 17 The finding is supported with a study conducted in Ethiopia (42 h), 14 but shorter than what was reported in China (67 h) 10 and Nigeria (93.6 h). 24
The research also identified eight key factors that can predict whether a baby will start TF early. For instance, preterm babies born before 34 weeks are 46% less likely to begin TF early compared to those born at or after this GA. This finding aligns with other studies from Northwest Ethiopia 14 and Australia. 26 Similarly, neonates who were small for their GA are also 46% less likely to start TF early, likely due to their lower weight and underdeveloped intestines, which can lead to feeding complications. 27
One important factor was the first-min APGAR score; those with scores below seven are 60% less likely to start early TF compared to those who scored seven or higher. This observation is backed by research from Northwest Ethiopia. 14 Additionally, babies with a 5-min APGAR score below seven are 49% less likely to initiate TF compared to those with better scores. Lower APGAR scores can signal issues like reduced oxygen levels during birth, which may affect blood flow to the gastrointestinal tract, leading to serious conditions like NEC and feeding intolerance.28,29
Regarding mode of delivery, Preterm neonates born via cesarean section are 53% less likely to start TF compared to those delivered vaginally. This may be due to mothers who have cesarean sections being less likely to provide expressed breast milk. This finding is consistent with a study in Northwest Ethiopia. 14 TF is also significantly influenced by place of delivery. Preterm neonates born outside the study hospitals are 49% less likely to initiate TF than those born within the hospitals, likely due to delays in transportation.
Furthermore, preterm neonates with RDS are 37% less likely to start TF, as RDS increases the risk of aspiration and feeding intolerance,30,31 and this finding is also supported by an other study in Ethiopia. 14 Additionally, those preterm neonates experiencing hemodynamic instability have a 54% lower likelihood of initiating TF, possibly due to concerns about the risk of NEC. This finding is consistent with studies conducted in Ethiopia, Tanzania, and Spain.14,32,33
Generally, the study shows that TF often started much later than the recommended 24 h, pointing to the need for NICUs to review and strengthen their early feeding routines. An extra attention is especially important for preterm neonates who are very small, born before 34 weeks, or has low APGAR scores. These infants need quick evaluation and careful planning to know when they’re ready to feed. Better teamwork between delivery staff and the NICU, especially making breast milk available early and helping mothers express milk promptly, can help reduce delays. Strengthening referral and transport systems, along with clear communication between facilities, also plays an important role in ensuring that transferred babies can begin feeding sooner.
Strength and limitations of the study
As a strength, the study included data from more than 30% of public hospitals in Addis Ababa, which is scientifically representative of the study area. However, the study encountered some limitations. First, the discussion section regarding associated factors become shallow to compare due to scarcity of previous similar study in the area as well as abroad. Second, since the study period was short, it may mask seasonal variability. Third, some responses, particularly those related to birth interval, number of times the mother received antenatal care, and history of pregnancy-related complications, might be subject to recall bias, and it may affect the data quality.
Conclusion and recommendation
In this study, there was a significant delay to initiate TF among preterm neonates in spite of the recommendation to start TF within 24 h. After adjustment for confounding, GA of <34 weeks, APGAR score of <7, being SGA, born with cesarean section, being out-born, having RDS, and hemodynamic instability were found to be statistically significantly factors of delayed initiation of TF. Hence, hospitals are encouraged to follow clear, evidence-based feeding guidelines that support starting trophic feeds within 24 h once a preterm infant is stable. More support should be given to help mothers express milk early and regularly, particularly after cesarean births or when separated from their babies. Improving communication and stabilization during newborn transfers can also prevent feeding delays. Finally, early management of breathing and circulation problems is essential so feeding can begin safely and without unnecessary postponement.
Supplemental Material
sj-pdf-1-smo-10.1177_20503121251403900 – Supplemental material for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa
Supplemental material, sj-pdf-1-smo-10.1177_20503121251403900 for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa by Mehuba Hassen, Mekonen Adimasu Kebede and Erdaw Tachbele in SAGE Open Medicine
Supplemental Material
sj-pdf-2-smo-10.1177_20503121251403900 – Supplemental material for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa
Supplemental material, sj-pdf-2-smo-10.1177_20503121251403900 for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa by Mehuba Hassen, Mekonen Adimasu Kebede and Erdaw Tachbele in SAGE Open Medicine
Supplemental Material
sj-pdf-3-smo-10.1177_20503121251403900 – Supplemental material for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa
Supplemental material, sj-pdf-3-smo-10.1177_20503121251403900 for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa by Mehuba Hassen, Mekonen Adimasu Kebede and Erdaw Tachbele in SAGE Open Medicine
Supplemental Material
sj-pdf-4-smo-10.1177_20503121251403900 – Supplemental material for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa
Supplemental material, sj-pdf-4-smo-10.1177_20503121251403900 for Trophic feeding initiation and its predictors in preterm neonates admitted to Neonatal Intensive Care Units: Multicenter study, Addis Ababa by Mehuba Hassen, Mekonen Adimasu Kebede and Erdaw Tachbele in SAGE Open Medicine
Footnotes
Acknowledgements
We would like to express our sincere appreciation to Addis Ababa University for sponsoring the study, and to hospitals, study participants, health professionals, and data collectors for their invaluable contributions. Finally, we would like to extend our thanks for research square to disseminate our preprint for the scientific community.
Ethical considerations
Ethical clearance letter was obtained from the School of Nursing and Midwifery’s Research Ethics Committee, Addis Ababa University (protocol no. REC-23-SON).
Consent to participate
Permission was obtained from each study hospital before the actual data collection began. Written informed consent was obtained from the parents or legally authorized representatives for each neonate. For parents with no formal education, written informed consent was signed after the data collector read all information with understandable language. Data were collected from all participants anonymously and kept confidential. The privacy of participants and their right to withdraw from the study were upheld without any bias.
Author contributions
Mehuba Hassen conceptualized and designed the study, collected, analyzed, and interpreted the data. Mekonen Adimasu Kebede and Erdaw Tachbele involved in designing and analyzing data, writing of the article, and advising the entire research article. They were also involved in the interpretation of the data and contributed to article preparation. All authors have read and approved the final article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The source of funding was Addis Ababa University. The University has no specific role in the conceptualization, design, data collection, analysis, decision to publish, or preparation of the article.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data availability statement
The datasets used and analyzed during the study are available from the corresponding author on reasonable request.
Supplemental material
Supplemental material for this article is available online.
References
Supplementary Material
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