Nutritional status among primary school students and its association on academic performance in north-central Ethiopia: Cross-sectional study design

Background: Under-nutrition is a fundamental factor which resulted in delayed cognitive development and underachievement of academic performance later in children’s life at school. The extent of under-nutrition in Ethiopia has been established well but there are insufficient evidences about its relationship with the educational achievement of school-age children. Objective: To assess the correlation of nutritional status with academic performance among public primary school children Method: - An institution-based cross-sectional study was conducted over 399 primary school children in Debre-Tabor Town, Amhara Regional State North-Central Ethiopia, 2018 after selecting them with simple random sampling. The nutritional status was assessed using the anthropometric measurement of WHO 2007 reference as Height for Age Z-score (HAZ), Weight for Age Z-score (WAZ) and Body Mass Index for Age Z-score (BAZ). Academic performance was assessed by calculating two semesters of overall subjects’ average score. Descriptive statistics, Pearson’s correlation test, and linear regression were used for statistical analysis. Data were analyzed using SPSS version 24 and nutritional status was analyzed using WHO AnthroPlus version 1.0.4 (5-19 years). Result: - Almost half of study participants were male 209(52%), 291(73%) from married family, and 177(44%) were comes from family having more than five members. The mean age of the study participants were 11.85. The prevalence of stunting, wasting, underweight and overweight was 22%, 32.4%, 24.3%, and 1.3% respectively. The prevalence of any form of malnutrition was 56.14% and the mean academic performance for study participants was 71.65(±12.63 SD). There was a statistically significant positive relationship between academic achievement and HAZ. Age of child and absenteeism were associated negatively while attending preschool, the type of head of the house, and


Introduction
Globally the death of 45% under-five children and 38% of early school leaving are attributed to malnutrition. Moreover, there is an estimation of over 450million children will be affected by stunting which is the impact of chronic undernutrition by 2025 [1]; [2,3].
Only Africa shares 38% stunted, 27% wasted and 24% overweight children in under-five children. More specifically from 59 million continental prevalence East African region constitutes 24% and aggressively suffering from stunting compared to the West Africa region which was 19.2% (19.2%) [4].
Primary education is an instrument to meet United Nation Education, scientific and Cultural Organization (UNESCO) goal "quality education and lifelong learning for all by 2030" and "end poverty by 2030" [5]. Besides, it is one of the most potent approachs to realize Ethiopia's current Gross Transformation Program (GTP) development vision to become a middle-income economy by 2025 [6]. Progress had achieved over Millennium Development Goals (MDG) and Education for All (EFA) goals. But, still, 58 million primary school-age children are out of school worldwide due to various reason including nutritional challenges [7].
Ethiopian elementary or primary education is free with the target of having less than 1% for dropout and repetition rate [8]. Previously it was indicated that the factors of poor academic performance in primary school children need to be investigated with more powerful design [9]. And also, despite greater demand to improve students' academic performance in developing countries various hampering factors were identified like undernutrition and childrens health status, which adversely affects the ability to learn and poor performance [10,11]; [12].
Various researches have been consistently describing the impact of well nourishment for its positive effect over intelligence, academic achievements, learning and cognitive performance, maintaining education thereby preserving the nation for the grave effect of malnutrition [13] ; [14]; [15]; [16]. So nutritional intervention is important for children attending primary school since it enhances efforts to reduce levels of malnutrition and supplement better academic achievement in the preschool years.
Malnutrition remains a key crisis in adolescents' school performance due to inappropriate eating practices [11]. Moreover, primary school children who are suffering from malnutrition exhibit underachievement of academic performance with a potential decline in future mental excellence. [17].
Stunting and under-nutrition have immediate and long term effects that range from immediate school dropout to the worse deprivation of growth and development, and subsequent cognition which negatively affects educational achievements [18]; [19].
Various factors of malnutrition like food insecurity, skipping breakfast, overweight, and underweight were shown a strong association with decreased school performance in UK, Brazil, and the USA [16]; [20]; [21]. More specifically, Educational underachievement was seen in 31.5% of obese, 30.0% of underweight and 22.9% of overweight children respectively [22].
Consistently, the USA school breakfast program was proven the increment of academic achievement over program utilizers [21]. Another study also showed Children having frequent breakfast had performed well in IQ test scores while those who occasionally have breakfast perform low [23]. In Zimbabwe, also having frequent meals and taking a regular breakfast, lunch and dinner have show positive effects on children's learning achievement [19].
In addition to underlying nutritional problems, various studies found that boys suffer more from poor educational achievement (23%) than girls (18.6%) [22]; [17]. Another study in Morocco also showed a more profound effect of malnutrition over the boy's school grade average than girls. This study reveals 30.1% of girls and 38.7% of boys rated as poor for mathematics and 17.1% of girls and 37.3% of boys rated as poor to average [11].
Socio-demographic factors including sex, absenteeism, and distance from school, grade attended, parental socio-economic status and parental involvement in their children's schooling were found to be significantly associated with primary school children's academic performance [24-26].
African malnourished school-age children are at risk of repeating grades and dropping out of school with an achievement of 0.2 to 1.2 years less in school education [27]. Moreover, more than a quarter of children in sub-Saharan Africa are too thin which is resulted in impaired mental development and low educational achievement [25]. By 2025 an additional 11.7 million children will be stunted in sub-Saharan Africa when compared to the 2010 data [1].
Ethiopian Demographic and Health Survey (2016 EDHS) report shows that the prevalence of under-five severe malnutrition was 18% for stunting, 3% for wasting and 7% for underweight respectively [28]. The Cost of Hunger in Africa (COHA) summary report revealed that more than 2 out of every 5 children in Ethiopia are stunted with 16% repetitions in primary school children and achievement of 1.1 years less in schooling [29].
Even though researches done in South Gondar and Goba Town conclude that nutritional status did not show an association with the academic performance [12,26]. Other pocket studies done in various areas of Ethiopia consistently reporting association and effect of undernutrition over mathematics score [12]; and overall academic performance [25]; [24].
. Like as it was investigated in various developed and developing countries, the effect of nutritional status on the school performance needs to be consistently identified in our context for a convincing planner and diverting potential for intervention since factors differ across various socio-demographic factors. With a diverse role of nurses even as school nurses, the output of this study probably shifts the attention of school nurses for specific nutritional intervention at school level parallel to other routine services and nurses working in policy design for resource and effort mobilization. By far this study benefits the regional education and health office policymakers and zonal planners to intend appropriate nutritional interventions through SFP and NEP at school to deal with the impact of malnutrition on academic performance among primary school children.

Aim, Design, and setting
The study aims, to assess the association of nutritional status with academic performance.
An institution-based cross-sectional study was conducted from March 30 to April 30, 2018, at Debre Tabor Town, North-Central Ethiopia which is located 665kms north of Addis Ababa . The 2017 population projection the total population of the town showed 96,973 [30]. As information obtained from the town education sector, the town has two preparatory schools, fourteen elementary schools of which seven governmental, and nine Kindergarten schools. The total population of public primary school children was 6,935 of which 49.14% were males.

Participants and Sampling
The study was conducted over primary school attending students. Single population proportion formula was used to estimate sample size by considering a 95% confidence level, 0.05 margin of error and average academic performance of 62.25% in the study area [26]. The required sample after adding 10% of the non-response rate was 399. First simple random sampling was used to select three schools from seven schools, and then the proportional allocation of sample to the population size of selected school were employed, and then final systematic random sampling of every nine students were taken as techniques to obtain final study participants after getting complete list of students from each school.

Study instrument
The first part of the data collection tool was a structured socio-demographic questionary prepared to collect information about parental socio-demographic and economic status was used. This section consists of twenty questions originally prepared in English and translated to local language Amharic and it was adapted from previous studies [12,26]. The third part of the data collection tool was height scale, which was measured in meter by data collector while the student stands side to meter posted over the wall. Again this also taken two times by independent data collectors for having average measurements.
The fourth part of the data collection tool was the WHO standard Reference guideline, 2007. It was used to interpret and judge taken weight and height during data collection.
Accordingly, as HAZ score < -2SD (stunted), WAZ score < -2SD (wasted) and BAZ score < -2SD (underweight) or thin), BAZ > +1SD (overweight) and BAZ > +2SD (obese). The fifth part of the data collection tool was a sheet for measurements of academic performance. It was prepared for recording two consecutive semester student scores from the school roster.

Data collection
Six trained Health extension workers as a data collectors and two trained BSc nurses as supervisors were recruited for the process. Consent was obtained from their parents and informed assent was obtained from children for their authorization to get their anthropometric measurements. The data collection was done in each section of grade by arranging a convenient time and mobilization of measuring equipment. The previous grade also obtained from schools record officers for having statistical tests with anthropometric measurements.

Data quality control
The Random selection of students who participated in the study was used as quality assurance. Moreover, training of data collectors, conducting pretest over 5% of the population and day to day discussion about the progress with supervisors and data collector were activities to maintain the quality of the study. Other measures were using standard tool to measure and interpret the measurement.

Variables and Measurements
The study uses stunting, underweight and wasting as an indicator of nutritional status among study participants. The children's body weight was measured to the nearest 0.1kg with light closing and bare foot using a digital weighing scale by trained data collectors.
At first and always before the next child the weight measure scale checked against zero reading. Then the child stood with both feet in the center of the scale. This means that the scale reads zero when no weight is placed on it. Their height was measured using a meter to the nearest 0.1cm without shoes in a standing position. A Child stood on a flat surface with feet flat, together and against the wall. Legs, arms, and shoulders were straight, at sides and level respectively.
Academic performance was the dependent variable for the study and operationally measured by taking two semester's average score result of the total subjects obtained from the individual child's semester grade report and considered as good if it is more than the mean academic performance and poor if less than the mean academic performance.
Students' grade report cards were taken as a measure of academic performances (Zaini MZ et al., 2005).
Nutritional status: is the child's state of the body which is determined by anthropometric measurement indices as stunted, wasted, underweight or overweight based on the WHO standard reference 2007 [31].
Anthropometric measurements: is the nutritional status measurement method of primary school children to identify whether they are stunted, wasted underweight or overweight.
Malnutrition: is a poor nutritional status of primary school children which is expressed in anthropometric indices when the Z-scores for the WHO standards of 2007 are less than or equal to minus two (Z-scores < -2SD) or more than plus one for BAZ (z-score > +1 SD).
Stunting: indicates the nutritional status of the study participants when their height for age z-score is less than or equal to minus two (HAZ < -2SD) for the WHO standard reference 2007.
Well nourished: indicate children's nutritional status which is measured as HAZ greater than minus two standard deviations (HAZ> -2 SD) to the WHO reference 2007. Underweight: indicates the child's nutritional status among the study participants which is measured as body mass index for age z-score less than or equal to minus two (BAZ<-2SD) of the WHO standard reference 2007.
Wasting: is the nutritional status of primary school children aged 7-10 years and expressed in weight for age z-score less than or equal to minus two (WAZ < -2SD) of the WHO standard reference 2007.
Overweight: is the school-age childrens nutritional status which is measured in terms of body mass index for age z-score greater than or equal to plus one (BAZ ≥ +1 SD) of the WHO standard reference 2007.
Primary school children: -Children who attend primary school(one to eight grade) and are in the age group of 7-14 years as set by ESDP IV [9].

Results
Socio-demographic and economic characteristics of the study participants A total of 399 public primary school children were enrolled with a 100% response rate. Out of these participants, (52%) were males and (48%) were females with a mean age of 12 (±1.9 SD) and 11.8 (±1.8 SD) respectively. The Overall mean of the study participants was Mean 11.85 year. Nearly three fourth of the study participants (73%) were in the age group 11-14. The large proportion of the participants (62%) came from the second cycle (5-8 grades). Almost all of the children were Orthodox Christian (96%) in religion, from urban (99%) and married families (73%). The majority of the participants, (42%) were headed by both father and mother. More than half of the participants, 56% were from a family size of less than five.
The majority of the study participants were born from no formal education mothers (45%), government employee fathers (37%), monthly income of >2000 ETB (62%) and house wife mothers (55.4%). Only half of the study participants, 55% have attended preschool.
Regarding breakfast, almost all of the participants (97%) ate breakfast and more than half, 55% of them ate breakfast always. Most of the participants, 97% travels for less than 30 minutes to go to school with an average time of 14.4minute (± 8.4 SD) for males and 15.3minute (±8.8 SD) for females respectively. Most of the participants, (71%) were absent from school and 86% of them absent from the school for less than 5 days. ( Table 1) Nutritional status of primary school children The anthropometric assessment of the study participants revealed that the overall prevalence of any form of malnutrition was 56.14%. Out of this, 88 (22%) were stunted, 34 (32.4%) wasted, 97 (24.3%) underweight and 5 (1.3%) overweight. (See Table 2 Table 3) Relationship between nutritional status and academic performance There was a statistically significant positive relationship between academic achievement and the HAZ of the study participants. This positive relationship indicates that as children become well-nourished their height for age z-score increases positively to the appropriate growth and development stage. This, in turn, resulted with enhanced educational achievement(See Table 4)

Socio-demographic predicting factors of academic performance
In the bivariate linear regression model, variables including head of the house, occupation of father, age of a child, grade attended by by child, child attending preschool, breakfast habit, absenteeism, and monthly income were significantly associated with the academic performance of school-age children. After controlling confounding factors in the multiple linear regression model, age of the child, head of the house, attending preschool, breakfast habit and absenteeism were only variables that significantly associated with the educational achievement of the school-age children. Age of the child and absenteeism were variables that have a statistically significant negative association. Variables including head of the house, attending preschool and breakfast habits have a statistically significant positive association with educational achievement. An increase of child age by a unit of year decreases mean academic score by 5.07 (B= -5.07, 95.0% CI: -7.86, -2.28).

Discussion
This study attempted to assess the association of nutritional status with academic performance and to determine the socio-demographic and economic predictors of academic performance among public primary school children in Debre-Tabor Town, Amhara regional state North-Central Ethiopia.
The overall prevalence of any form of malnutrition for the current study was 56% which is higher than the finding of Hawa Gelan in 2017 in Oromia, Ethiopia (34.6% ) [25]. However, this finding is less than the finding in Sri Lanka in 2015 (60.2%) [17]. This variation could be due to a difference in the two countries' socio-economic differences.
The finding of this study revealed that the prevalence of stunting was 22% which is higher than a finding from Oromia, Ethiopia (20.6%), Harar, Ethiopia (8.9%), Adama, Ethiopia (15.6%), India (18.5%) and Brazil (1.7%) [20,25,[32][33][34]. On contrary, this finding was less than the findings of Fogera, Ethiopia (37.2%), Kenya (24.5%), Egypt (53.2%) and Lambani, India (37%) [15,[35][36][37]. The higher prevalence of stunting could be early life malnutrition in the young infant period which is a sensitive period for nutrient deficiencies. This disparity could be due to a difference in the composition of diets with essential nutrients like proteins, carbohydrates, fats, vitamins and minerals. These macro and micronutrients are vital for body makeup, immunity and cognitive development of children.
The prevalence of wasting in this study was 32.4% which was almost similar to a finding in India (33.3%) [38]. However, this finding was higher than a finding in Fogera, Ethiopia (30.7%), Hawa Gelan in Oromia, Ethiopia (12.7%), Sidama, Ethiopia (28.2%) and that of Kenya (9.7%) [25, 35,36,39]. The finding of wasting in this study was lesser when compared with a finding in Sri Lanka (50.4%) [17]. The discrepancy in acute malnutrition might be due to a difference in children's health status, nutrient composition (balanced diet), diet size and frequencies of the meal. Acute conditions like diarrhea and upper respiratory problems are also key factors for children's acute malnutrition since it reduces their appetite and impede their immunity.
Again in this study, the prevalence of underweight was 24.3% which was almost similar to a finding in Bahir Dar, Ethiopia (24.8%) and the regional state of the study area (24%) [28,40]. This finding was higher than the findings in Adama, Ethiopia (21.3%), Oromia, Ethiopia (14.2%), Kenya (14.9%) and that of Lambani, India (14.66 %) [15,25,33,35]. On contrary, this finding was lesser than findings in Fogera, Ethiopia (59.7%) and Sri Lanka (33.7%) [17,36]. The inconsistency might be due to differences in socio-economic status and cultural beliefs about foods. Children from rural areas are more at risk for malnutrition than urban children. Additionally meal frequencies affect children's nutritional status in which children having regular meals at morning, lunch and night will have better status than those having any of the three meals.
The prevalence of overweight in this study was 1.3%. This result is less than a finding in  [20,33,41,42]. This disparity might be due to variations in individual nutrient intake and food preferences. Also, differences in socio-economic status could be the reason as Ethiopia is a lower-income country. Lower income countries are at risk of food insecurity which affects children's diet composition, diet size, and frequency of meal.
For the current study, the mean academic performance for study participants were (71.65±12.63 SD) which is a higher achievement when compared with a study done in Hawa Gelan in Oromia, Ethiopia (67.2% ±15.4% SD), Tach-Gaynt, South Gondar, Ethiopia (62.25%), Hawassa, Ethiopia (35.1 ± 4.1SD), Sri Lanka in 2015 (<40%) and Nigeria (66.19 ± 17.00 SD) [17,25,26,43,44]. The variation could be the difference in the assessment of academic performance, learning methods, learning resources accessibility, tutors given and grading or scoring systems. In this study males perform better (72.02±11.57 SD) academically when compared with female students (71.24±13.73 SD). This finding is consistent with a research finding in North-Central and South Central Ethiopian that males have performed 2.39 times better than females in academic performances [24,26]. In contrary findings in Nigeria, Morocco, India and Asia, revealed that girls have better educational performance than boys [11,17,22,43]. It may be related to the social status of females in the community and recognition of their learning. Moreover, the lack of role model and a high percent of students were not passing through preschool training may contribute to the disparities.
In this study, primary school children from high monthly income parents performed better (72.91±1234 SD) than those from low (69.53±14.46 SD) income parents. Educational achievement was poor for those who absent for more than five days (69.42±12.61SD) when compared to those absent for five days (7.343±12.21 SD). Children who were The result of this finding shows that there was a statistically significant positive relationship between HAZ and academic achievement (p-value=0.009) which is in line with the finding done in Goba town and Hawa Gelan in Oromia, Ethiopia and Sri Lanka [12,17,25]. It is also consistent with a finding in Morocco in 2016 [11]. This indicates that as children become well-nourished their height for age z-score increases to the appropriate growth and development stage which in turn resulted in positive educational achievement.
In the current analysis, WAZ and BAZ did not show a statistically significant relationship with the academic performance of the study participants which is consistent with a finding in various areas of Ethiopian: Tach-Gynt, South Gondar; Gurage Zone; and Goba town [12,24,26]. However, this is not consistent with the finding in Oromia, Ethiopia and Sri Lanka in which both WAZ and BAZ had significant positive associations with learning achievement [17,25]. Even though, it is beyond the scope of this study the discrepancy could be variation in nutrients taken by children which may have either synergistic or antagonistic effects with each other. At this point, this finding sought a more powerful study design that can indicate a causal relationship among factors.
In this study age of child and absenteeism have a statistically significant negative association with educational achievement. Predictors including head of the house, attending preschool and breakfast habit associated positively with the educational achievement of the school-age children. In this study monthly income did not show significant association with the academic performance which is opposing to Hawa Gelan finding that study participant from high monthly income households perform 2.85 times better than those from low monthly income households [25]. In this study breakfast habits and attending preschool were significantly positively associated with academic performance. This finding is conflicting to the finding in Goba town, Oromia that breakfast habits and attending preschool did not show significant association [12]. Variables including sex of the child, residence, maternal education, paternal education, parental occupation,and family size were not significantly associated with an academic performance which is parallel to the finding of Goba town in Oromia, Ethiopia [12].
Absenteeism was significantly associated with school-age children's academic performance which is parallel to the finding of Tach

STRENGTHS AND LIMITATIONS OF THE STUDY
Using a wider range of student class grades from two to eight and a large sample size can be taken as strength of this study. But, this study was confined to public schools, as a result, it may decrease confidence about all students in the study area a since significant number of students were attending education in private schools. This study also fails to provide evidence about the causal relationship and only limited to thedescription of a possible association. Moreover, it would have been better and more powerful if the study was incorporated measurements of biochemical parameters in addition to anthropometric measurements that may help to describe and rationalize some of the discrepancies with other studies. A limited number of variables under study may not show the whole factor of school performance and the absence of follow-up and control group also decrease the power of analysis. Furthermore, other factors of poor academic performance like peer influence, teaching style, and teacher factors were not also considered in this study which can also be taken as a limitation.

Conclusions
The present study revealed that the prevalence of under-nutrition among school-age children is high in the study area with a large overall prevalence of malnutrition. The prevalence for each nutritional indicator was 22% for stunting, 32.4% for wasting, 24.3% for underweight and 1.3% for overweight. The mean academic performance of the study participants was 71.65±12.63 SD. A significant positive relationship was seen between HAZ and the academic achievement of the study participants. In this study age of the child, head of the house, attending preschool, breakfast habit and absenteeism were variables that significantly associated with the educational achievement of the study participants. As result, The zonal health and education bureau should work in collaboration with other organizations (NGOs) to combat malnutrition and to strengthen the positive effect of nutrition on the educational achievement of primary school children. The school teachers should encourage students to have breakfast, attend class attentively, motivate female students and create the opportunity to discuss with family about student status.
We also recommend researchers to conduct a further study with a strong study design to investigate the true relationship between nutritional status and academic achievement of school-age children.

Ethical clearance and consent for participation
Ethical clearance was obtained from Addis Ababa University school of Nursing and midwifery Ethical committee with Rf No aau/chs/chsg14/2018 on February 07/2018. A formal written letter was given to Debre-Tabor Town Education Sector, Health bureau and to the respective primary schools and health centers. Then a written consent was obtained from the parents of the participant children and informed assent was obtained from children for their authorization to get their anthropometric measurements. Codes were given to the study participants in order to keep their confidentiality.

Consent for publication
Not applicable collection and research reports. DG: had revised the proposal, participate in data collection and research reports. AA: had revised the design, the proposal, and research report and prepare the manuscript. DT: had revised the proposal and research report. All authors read and approved the final manuscript.  T a b l e 3:-Descriptive result for academic achievement of study participants in Debre-Tabor Town, Amhara Regional State, North-Central Ethiopia, 2018, (N= 399).