Abstract

Background

The increasing global and national prevalence of childhood obesity particularly among schoolchildren has warranted a more viable school-based obesity intervention. Apart from physical activity, nutrition is important in any obesity intervention package. This study examined the effects of the MyBFF@school program with nutrition education intervention (NEI) on nutrition knowledge and attitude of overweight and obese secondary schoolchildren.

Methods

This is a cluster randomized controlled trial which involved schoolchildren aged 13, 14 and 16听years old from 15 out of 415 government secondary schools in central Peninsular Malaysia which were randomly assigned into six intervention (N鈥�=鈥�579 schoolchildren) and nine control (N鈥�=鈥�462 schoolchildren). The intervention group was given NEI consisting of a nutrition education module carried out by trained personnel for 24听weeks on top of the existing curriculum while the control group only followed the existing school curriculum by the Ministry of Education. The primary outcomes were the nutrition knowledge and attitude score. The mixed effect model taking into consideration the cluster effect was used to assess the changes of nutrition knowledge and attitude scores from baseline until 6听months.

Results

Overall, there was no significant increase in the adjusted mean difference (AMD) of nutrition knowledge score (AMD鈥�=鈥�0.33%, Confident Interval (95 CI): -4.35% to 5.01) between the intervention and control group after 6听months of intervention after controlling for nutrition knowledge score at baseline, gender, location and ethnicity. Similarly, after controlling for the nutrition attitude score at baseline, ethnicity, location and gender as well as taking into account the cluster effects, there was no significant increase on the AMD of nutrition attitude score in the overall (AMD鈥�=鈥�0.194, (95 CI): -1.17 to 1.56) and also among girls, location (urban vs rural) and Malays. There was also no significant reduction of AMD in the nutrition attitude score among boys and non-Malays.

Conclusion

MyBFF@school with NEI resulted with no significant improvement for nutrition knowledge and attitude among older schoolchildren. Therefore, to effectively impart the nutrition knowledge and change their nutrition attitude requires an in-depth study and multi-pronged and customized approach.

Trial registration

Clinical trial number: NCT04155255, November 7, 2019 (Retrospective registered). National Medical Research Register: NMRR-13鈥�439-16563. Registered July 23, 2013. The intervention program was approved by the Medical Research and Ethics Committee (MREC), Ministry of Health Malaysia and Educational Planning and Research Division (EPRD), Ministry of Education Malaysia. It was funded by the Ministry of Health Malaysia.

Background

Childhood obesity is a global public health concern. Among children and adolescents aged 5鈥�19听years, global trends reported in World Health Statistics 2018 have observed a significant increase in obesity from 0.8% in 1975 to 6.8% in 2016 [1]. In 2022, more than 390 million children and adolescents aged 5鈥�19 years were overweight including obesity with increasing prevalence from 8% in 1990 to 20% in 2022 [2]. In Malaysia, the obesity prevalence among adolescents has notably increased. Findings from the National Health and Morbidity Survey showed that the prevalence of overweight Malaysian adolescents aged 10鈥�17听years was 14.6% in 2012, but had increased to 15.6% in 2017. The prevalence of obesity increased from 12.3% to 14.8% over the same time period [3, 4]. Overweight and obese adolescents frequently suffer from body image and self-esteem problems [5]. They are also more likely to become obese as adults and suffer from non-communicable diseases such as cardiovascular diseases, type 2 diabetes mellitus, hypertension, and dyslipidemia [6].

School-based nutrition intervention is among the most effective and efficient ways to instill positive dietary changes and to influence or change the nutrition attitude of adolescents [7]. The type of school-based nutrition intervention that can be undertaken to instill positive dietary changes and to influence or change the nutrition attitude of adolescents are interventions that involve the commitment not only from the children themselves but also continuous support from the school administrators. Various studies have shown that nutrition education executed together with other obesity intervention programs effectively prevents and controls the escalation of obesity among schoolchildren [7,8,9]. Since these schoolchildren spent about 30% of their times in school, the control school environment would facilitate in increasing the nutrition knowledge and instilling the positive attitude. Previous school-based interventions in Asia have shown that obesity intervention is feasible and effective in a school setting. Intervention helps in changing the health behavior of children through a combination of nutrition education and physical activity, as well as by addressing psychological aspects related to the causes of childhood obesity [10,11,12].

The aim of this study is to assess the effects of My Body is Fit and Fabulous at School (MyBFF@school) with nutrition education intervention (NEI) on nutrition knowledge and attitude among overweight and obese secondary schoolchildren compared to schoolchildren following existing school nutrition programs.

Methods

The collected data were part of the MyBFF@school obesity intervention study. This study was a school-based cluster randomized controlled trial (C-RCT) (Fig.听1). The clusters were government secondary schools with schoolchildren aged 13, 14, and 16听years in three states in central Peninsular Malaysia, namely Kuala Lumpur, Selangor and Negeri Sembilan. Schoolchildren aged 15 years old (Form 3) were excluded from this program as they were involved in major national examinations. A total of 15 out of 416 eligible government secondary schools were randomly assigned into six intervention (n鈥�=鈥�579 children) and nine control schools (n鈥�=鈥�462 children) taking into consideration the school type and location. The location of the schools as either in urban or rural areas was based on the current classification used by the Ministry of Education Malaysia which was adopted from the National Census by the Department of Statistics Malaysia (DOSM) 2010 [13]. Blinding of the intervention was not possible as the schools involved in the intervention or control needed to be disclosed for approval from the Ministry of Education, Malaysia apart from the staff in charge of the intervention schools needed to be trained. Recruitment of the participants within the selected clusters was based on the inclusion and exclusion criteria. The detailed methodology including the inclusion and exclusion was published by Mokhtar et al. (Mokhtar AH, Wan Mohd Zin RM, Yahya A, Md. Zain F, Selamat R, Ishak Z, Jalaludin MY: Rationale, design and methodology of My Body is Fit and Fabulous at School (MyBFF@school) Study: A multi-pronged intervention program to combat obesity among Malaysian school children). Written informed consent was obtained from parents or guardians prior to the study. Schools selected for intervention underwent the MyBFF@school with NEI, whereas control schools followed only the regular school health education syllabus. Schools involved in other obesity intervention programs were excluded from the study (Mokhtar AH, Wan Mohd Zin RM, Yahya A, Md. Zain F, Selamat R, Ishak Z, Jalaludin MY: Rationale, design and methodology of My Body is Fit and Fabulous at School (MyBFF@school) Study: A multi-pronged intervention program to combat obesity among Malaysian school children).

Fig. 1

CONSORT Diagram for nutrition component in MyBFF@school

Anthropometric measurements

Body impedance analyzer (InBody 720, Korea) was used to measure body weight, body fat mass, skeletal muscle mass, and percentage body fat. Body height was measured to the nearest 0.1听cm using a calibrated stadiometer (Seca 217, Germany), with the participants not wearing shoes and socks (Mokhtar AH, Wan Mohd Zin RM, Yahya A, Md. Zain F, Selamat R, Ishak Z, Jalaludin MY: Rationale, design and methodology of My Body is Fit and Fabulous at School (MyBFF@school) Study: A multi-pronged intervention program to combat obesity among Malaysian school children).

Nutrition Education Intervention (NEI)

NEI was specifically designed to address childhood obesity and consisted of a nutrition education module (NEM). The NEM consisted of five topics, each of which was divided into several sub-topics (refer to Table听1). The topics covered included challenges in body weight loss and management, knowledge of body weight and risk factors, eating well-balanced meals, fruit and vegetable intake, increased plain water consumption, reduction in the consumption of snacks, the importance of eating breakfast, preparing a healthy meal, smart shopping, and advice for eating out. The NEI using the NEM was carried out by trained personnel who were employed under the MyBFF@school research project during co-curriculum activities after school hours for a duration of 24听weeks. Each nutrition session was conducted once every two weeks for 40鈥�60听min per session. NEIs were adapted from the Malaysian Childhood Obesity Treatment Trial [14] and were delivered using interactive methods during practical sessions (Mokhtar AH, Wan Mohd Zin RM, Yahya A, Md. Zain F, Selamat R, Ishak Z, Jalaludin MY: Rationale, design and methodology of My Body is Fit and Fabulous at School (MyBFF@school) Study: A multi-pronged intervention program to combat obesity among Malaysian school children). These interactive NEI strategies had emphasised on hands-on competencies of nutrition education although with limited use of digital resources as shown in Table听1.

Table 1 Module for Nutrition Educational Intervention (NEI) for secondary schoolchildren

Pre- and post-nutrition knowledge and attitude assessment

A similar pre-tested questionnaire was used for both pre-intervention (baseline) and post-intervention (after 6听months) assessments. Questionnaires were administered to all participants in both the intervention and control groups to assess their nutrition knowledge and attitude (KA). This nutrition knowledge questionnaire was developed for MyBFF@school by its nutrition intervention component team in the form of a 10-question true/false/don鈥檛 know nutrition knowledge questionnaire. Correct answers were given a score of 1, whereas wrong and I don鈥檛 know answers were given a score of 0. The total score for every respondent was calculated from the correct responses with a maximum of 10 points, which were then converted to a percentage. The Cronbach's alpha coefficient for the 10-item nutrition knowledge scale was 0.537. The nutrition attitude assessment consisted of 15 questions assessed on a five-point Likert scale ranging from strongly disagree (1 point) to strongly agree (5 points). An intermediate (neutral) option was allocated 3 points. The total nutrition attitude scores were also converted into percentage. The Cronbach's alpha coefficient for the 15-item nutrition attitude scale was 0.657. The total scores for the KA items were then ranked and classified into three levels: poor (<鈥�50%), fair (between 50 and 75%), and good (more than 75%) [15].

Statistical analysis

All data were managed using REDCap electronic data capture tools. A web-based application was designed to support data capture for research studies [16]. All analyses were performed based on the intention-to-treat for each outcome measure. Descriptive statistics were used to describe the baseline data. The chi-square test was applied to analyse the categorical data. KA assessment scores were computed as mean and standard deviation. Comparison of nutrition KA scores after 6听months and at baseline for both intervention and control groups was made using a Repeated Measure ANOVA with Greenhouse鈥揋eisser Test. The mixed effect model taking into account the cluster effects was used to assess the changes of nutrition knowledge and attitude scores from follow up until end of 6 months. All data analyses were conducted using SPSS Statistics (Version 24; IBM Corp., Armonk, NY, USA) except for the intraclass correlation coefficient (ICC) and mixed effect model which were analysed using STATA Version 14. Results were considered statistically significant at p鈥�&濒迟;鈥�0.05.

Results

Demographic characteristics of the respondents at baseline

A total of 1041 secondary schoolchildren, with a mean age of 14.41听years, participated in this study. As shown in Table听2, the majority were Malays (79.1%), followed by Indians (14.7%), Chinese (6.0%), and others (0.3%), forming the intervention group (n鈥�=鈥�579) and the control group (n鈥�=鈥�462). A slight majority of the respondents were girls (58.7%) living in urban areas (64.1%). There were significant differences in the distribution of the children by location (蠂²鈥�=鈥�28.39, p鈥�<鈥�0.001), age groups (蠂²鈥�=鈥�16.23, p鈥�<鈥�0.001), and ethnicity (蠂²鈥�=鈥�26.17, p鈥�<鈥�0.001). There were no significant differences between the intervention and control groups in any anthropometric measures (body weight, body height, BMI-for-age z-score, skeletal muscle mass, body fat mass, and body fat percentage).

Table 2 Characteristics of the respondents at baseline among secondary schoolchildren

Grading of nutrition KA at baseline and after 6听months of MyBFF@school with NEI

Our study indicated that the majority of schoolchildren in both the intervention and control groups had fair nutrition knowledge at baseline, albeit slightly higher in the intervention group (Table听3). At baseline, there was a significant difference in nutrition knowledge between the girls and the overall intervention group. However, after six months, there was no significant difference either in the overall group or by gender. The majority of the participants in both the intervention and control groups also had a fair nutrition attitude at baseline and after 6听months. There was also no significant difference on the grading of nutrition attitude at baseline and after 6听months between the intervention and control group. Participants from both groups, however, showed a reduction in the grading of nutrition attitude score after 6听months of NEI (Table听3).

Table 3 Grading nutrition KA scores in the intervention and control groups

The effects of NEI on nutrition KA scores

Table 4 shows that without controlling the nutrition knowledge score at the baseline, ethnicity, gender and location, nutrition knowledge significantly increased among girls from mean鈥壜扁�塖D: 66.14%鈥壜扁��14.13 at baseline to 68.43%鈥壜扁��14.85 after 6听months in the intervention group. Among boys, nutrition knowledge scores dropped in the intervention group whereas the nutrition knowledge score slightly increased in the control group from baseline to 6听months but this change was not significant in either group. Table 4 also shows significant decreases in nutrition knowledge from baseline to 6听months for boys and rural schoolchildren in the intervention group. As noted in Table听5, although there was an increase on the adjusted mean difference (AMD) of nutrition knowledge score in the overall group, girls, urban, rural and Malays, these increases were however not significant after controlling for the nutrition knowledge score at baseline, ethnicity, location and gender while for boys and non-Malays, there was no significant reduction of AMD of nutrition knowledge score.

Table 4 Mean nutrition KA score in the intervention and control groups

Table 5 Unadjusted and adjusted nutrition knowledge and attitude score

The result of our study also showed that there was only a significant reduction of nutrition attitude score for boys from mean鈥壜扁�塖D: 65.08%鈥壜扁��8.8 at baseline to 63.85%鈥壜扁��7.35, p鈥�=鈥�0.02 after 6听months without controlling for the nutrition attitude score at the baseline, ethnicity, gender and location (Table听4). However, after controlling for the nutrition attitude score at baseline, ethnicity, gender and location as well as taking into account the cluster effects, there was no significant reduction of nutrition attitude among boys while there was no significant increase on the AMD of nutrition attitude score in the overall, girls, location (urban vs rural) and Malays (Table听5). The non-significant reduction of AMD in the nutrition attitude score was also noted among boys and non-Malays.

Nutrition KA by item

After 6听months of participation in the MyBFF@school with NEI, correct responses for each item in the nutrition knowledge domain indicated that the highest correct scores were on the following items: 1) intake of vegetable can help in controlling body weight, 2) between six and eight glasses of water should be consumed each day, and 3) carbonated drinks (e.g., canned drinks) are not recommended because they contain a lot of sugar. On the other hand, the lowest correct scores (<鈥�50% correct) for nutrition knowledge were for the calculation of the BMI formula and knowing that the portion size for vegetables should be at least two servings per day. In both the intervention and control groups, the highest percentage of correct scores for the nutrition knowledge was for the point that between six and eight glasses of water should be consumed each day.

For nutrition attitude, the highest mean [4.20 (1.10)] was for 鈥淚 do not like drinking plain water,鈥� with a maximum score of 5, which indicated strong agreement. The lowest mean [1.69 (0.87)] for nutrition attitude was noted for 鈥淚 am worried when I am overweight,鈥� with a minimum score of 1.

Discussions

Our findings showed that nutrition knowledge score was only significantly increased among girls (mean鈥壜扁�塖D: 66.14%鈥壜扁��14.13) at baseline to 68.43%鈥壜扁��14.85 after 6听months in the intervention group while there was no significant different for the overall, gender, ethnicity and location without controlling the nutrition knowledge score at the baseline, ethnicity, gender and location. This finding which showed girls had significantly higher nutrition knowledge scores than boys, consistent with other studies [17, 18]. In the Malaysian context and culture, this could be due to girls being more concerned about nutrition and food selection. The findings of our study are also consistent with the findings of other studies which suggested that nutrition education programs were effective in improving adolescents鈥� nutrition knowledge [19,20,21,22]. However, after controlling for the nutrition knowledge score at baseline, ethnicity, location and gender as well as taking into consideration the cluster effects, the findings of our study showed that among these older schoolchildren, the NEI incorporated into the MyBFF@school intervention had no significant increase on the AMD of nutrition knowledge score in the overall, girls, urban, rural and Malays. In addition, there was no significant reduction of AMD of nutrition knowledge score for boys and non-Malays.

Similarly, after controlling for the nutrition attitude score at baseline, ethnicity, location and gender taking into account the cluster effects, there was no significant difference on the increase of AMD between the intervention and control group of nutrition attitude score in the overall, girls, location (urban vs rural) and Malays. There was also no significant reduction of AMD in the nutrition attitude score among boys and non-Malays although there was a significant reduction of AMD for nutrition attitude score among boys prior to controlling for the nutrition attitude score at baseline, gender, ethnicity and location. Although our NEI was undertaken for 24听weeks with relatively short contact hours, with a total of 12 contact hours of NEI, its positive effects on the nutrition attitude of the respondents may have been limited. This was noted in our findings, whereby we observed no significant increase in the AMD in the overall nutrition attitude of the children in the intervention group as compared to the control group. This might be attributed to the lack of extensive and continuous intervention, since intervention was conducted only once every two weeks for 45鈥�60听min per session on alternate weeks for 24听weeks. Our findings are also consistent with those of a school-based nutrition education program among junior high school students in China, which suggested that no significant change of attitude in the students was due to the fact that continuous intervention was lacking [21].

Nevertheless, other studies have shown that even short durations of nutrition intervention, if conducted often (e.g., once a week for six weeks), can have positive effects on the attitude of schoolchildren [22]. Another study by Sharif Ishak et al. among adolescents aged 13 and 14听years old showed that although there were significant improvements in the nutrition knowledge of the intervention group, improvements in the attitude were not significantly difference between the intervention and control group [23]. These two studies however did not control the nutrition knowledge and attitude score at the baseline. In this respect, it seems that the more frequent the reinforcement, the more likely that it will bring positive results in nutrition attitude. Another study by Jha et al. among school children aged between 12 and 16听years old in India also showed no statistically significant difference in the mean score of attitude for healthy diet practices in both intervention and control groups [24]. The reduction of positive nutrition attitudes could, however, result from stigmatization, since the obesity intervention in our study only involved overweight and obesity adolescents and not children of normal weight. As reported by previous study, stigmatization of obese individuals can generate health disparities and interfere with obesity intervention efforts [25].

The by-item assessment of nutrition knowledge of the adolescents showed that, despite being in the category of older adolescents attending secondary schools, a high percentage of individuals experienced difficulty in calculating their BMI. There was only a slight increase in those able to correctly answer the BMI calculation in the intervention group (from 10.5% at baseline to 13.6% after 6听months). Therefore, more practical approaches toward understanding and applying the BMI concept should be given greater emphasis, since this forms the basis of self-monitoring of body weight.

The findings of our study also showed that the majority of older school children or adolescents knew that regular intake of vegetables can help in controlling body weight, that plain water should be consumed daily, and that the intake of carbonated drinks should be reduced because of their sugar content. The findings concerning the overall attitude toward eating vegetables ranged from 3.5 to 3.7 out of a maximum of 5 points on the Likert scale. Slightly higher values in the control group indicated that they did not like to consume vegetables. A similar study conducted on middle school students in Michigan showed that students involved in a nutrition education program were more likely to report increased fruit and vegetable consumption relative to students in a control group [26]. Findings from Malaysia National and Health Morbidity Survey 2017 showed that only 9.1% of overweight adolescents and 6.0% of obese adolescents consumed an adequate amount of vegetables [5]. A similar trend was observed for those who dislike plain water, which noted a higher scale score of 4.12 to 4.20 on a 5 point Likert scale. Although the majority of the children knew the effects of consuming carbonated drink, they did not deny that they liked carbonated drinks. Various studies have shown that excessive intake of sugar from soft drinks increases energy intake, thus increasing the risk of becoming overweight or obese [27, 28]. The WHO guideline for sugar intake recommends the reduction of free sugars to less than 10% of total energy intake in both adults and children [29]. Therefore, concerted efforts have been made to reduce the intake of carbonated drinks, especially among adolescents, whereby the current Malaysian School Management Canteen Guidelines has banned the sale of carbonated drinks in school canteens.

One of the strengths of our study was this was designed as a Randomised Cluster Control Trial taking into consideration the cluster effects, location (urban vs rural) as well as the ethnicity. Therefore, the findings that could be generalized and adopted to the population. On the other hand, one of the limitations of the present study was the Cronbach鈥檚 alpha coefficients for nutrition knowledge and attitude were rather low which could possibly affect the overall consistency of the nutrition knowledge and attitude. Another limitation of the study was the MyBFF@school was lacking of direct parental involvement despite these schoolchildren had obtained the parental consent to participate in the study. Besides that, since the nutrition education intervention was conducted after school hours, full participation of these children was rather a challenge.

Conclusions

The present study shows that NEI has no significant positive effects on overall nutrition knowledge or attitude of secondary schoolchildren and older adolescents. Since our findings showed no significant increase or improvement of nutrition knowledge and attitude scores of these secondary school children in our study, an in depth and different NEI which specifically tailored to the older or secondary schoolchildren need to be executed. To ensure the implementation and maintenance of the measures taken to combat obesity, including inculcation of positive attitude among older adolescents, continuous multi-pronged strategies and involvement from various sectors are required. A need for NEI inclusion in schools has been acknowledged.