Abstract: Background: Overweight/obesity has shown an increasing trend in many countries. Unhealthy eating behaviors have frequently been related to overweight/obesity. Objective: This study aimed to determine the association of overweight/obesity and eating behaviors with behavioral problems in school-age children. Methodology: A cross-sectional study of school-age children aged 7-12 years was conducted. Body mass index for age z-score was measured and participants were classified into 3 groups including normal weight, overweight and obesity. Caregivers provided information regarding eating behaviors and completed the child behavior checklist. Results: There were 430 participants included for analysis. The mean age of the study sample was 10.56 (1.44) years of which 51.39% were male. Children with overweight and obesity were 21.40 and 20.47%, respectively. Unhealthy eating behaviors, including skipping breakfast and media use during meals were more common in the obesity group than the normal weight group without statistical significance. Although, there was minimal correlation between sweetened beverage intake and the total behavioral scores, the mean total behavioral problems scores were not different among the three groups. However, some eating behaviors including sweetened beverage intake, dessert intake and frequent eating outside were found to be associated with the total behavioral problem scores from the multiple linear regression analysis (p = 0.001, 0.02 and 0.008, respectively). Conclusion: Although the association between overweight/obesity and behavioral problems was not found in this study, some unhealthy eating behaviors were found to be related to behavioral problems. Promoting healthy eating behaviors may be a primary step to prevent behavioral problems and obesity.
INTRODUCTION
Childhood overweight and obesity have shown an increasing trend in most developing countries. There are changes in urban areas of Thailand toward Westernized lifestyle patterns and dietary habits including increased fast food consumption and sugar-sweetened beverage intake and a decreased intake of fruit and vegetables1,2. Moreover, there has been a decrease in physical activity level and an increased in sedentary behaviors. The prevalence of obesity in 2-19 years old children and adolescents in the 2011-2012 nationally representative National Health and Nutrition Examination Survey in the US3 was approximately 17%, whereas in Thailand, the Thai National Health Examination Survey between 2008 and 2009 reported that 8.7% of 6-11 years old and 11.9% of 12-14 years old were overweight and obese4. Children living in urban and sub-urban areas were 1.6-1.8 times more likely to be overweight than those in rural area4.
Currently obesity in children has been of greater concern because it increases the risk of obesity in adults. Risk of adult obesity is likely to be 41% if a child5 is obese at 7. Various measures using to define obesity include weight for height and Body Mass Index (BMI). Weight for height z-score (WHZ) is often used in pre-school children while BMI z-score and weight for height are used in school-age children and adolescents.
Obesity is a multifactorial disorder affecting all organ systems. Becoming obese earlier in life increases health risks including hypertension, diabetes, dyslipidemia, obstructive sleep apnea and metabolic syndrome6,7, paralleling an increasing prevalence in younger children5. In addition, obesity is also interrelated with a lower quality of life, negative self-perceptions, learning problems and increased behavioral problems as well as bullying problems8-10. Unhealthy eating behaviors including the number of meals served outside the home, fast food meals, the type of snacks served at school or at home, skipping breakfast and eating when watching television have frequently been reported as being related to obesity from previous studies in children11 and adults12,13.
Behavioral or psychological problems have been viewed as both causes and effects of overweight. Overweight/obesity can be a possible result of psychological symptoms and psychological symptoms may be a result of being overweight14,15. Further review studies have found associations of behavioral and emotional problems with overweight in adolescents16,17. Some evidence has suggested that overweight/obesity was related to emotional and behavioral problems in pre-school, school-age children and adolescents18-20. Higher BMI was reported to be associated with increased likelihood of developing internalizing problems in middle childhood21. However, an association between behavioral problems and BMI in children has not been observed in other studies14,22-24. These inconsistent findings may be a result of different settings, different measurements, or various samples. Findings regarding correlations between eating behaviors and emotional problems directly have been limited. A study has found that eating behaviors were related to depressive symptoms in children25. Therefore, this study aimed to determine the association of overweight/obesity and eating behaviors with behavioral problems in school-age children.
MATERIALS AND METHODS
Participants: A descriptive cross-sectional study of school-age children was performed in a primary school in a city of Northern Thailand. School children aged from 7-12 years from 1st to 6th grade were enrolled. Caregivers were approached through school teachers and questionnaires were sent from January, 2016 to March, 2016. Twenty children from each classroom were randomly selected. Children whose BMI was lower than 5th percentile, who had chronic illness or were on any medication which may have an effect on weight (such as corticosteroids) were excluded. Informed consent was obtained from all participant’s caregivers. The study was approved by the Ethics Committee of the Faculty of Medicine, Chiang Mai University.
Measurement: Participants were classified into 3 groups depending on their nutritional status: Obese, overweight and normal weight using the Body Mass Index (BMI) for age z-score. The "WHO AnthroPlus" software (version 2009) was used for the assessment of the nutritional status according to World Health Organization (WHO) Child Growth Standards. The BMI z-score of +1 to +1.99 was classified as overweight, +2 to +2.99 was obesity and +3 and higher was classified as morbid obesity26.
The child behavior checklist (CBCL) for age 6-18 was used to evaluate behavioral problems in this study27,28. The CBCL, developed by Achenbach TM is a widely-used tool to facilitate the identification of problem behavior in children, consisting of 113 behavioral items 27. The total behavioral problem scores from the CBCL comprises internalizing behavior problems (anxiety/depression, with drawal and somatic complaints) and externalizing behavior problems (aggressive behavior and delinquent behavior) as well as other problems such as social problems, thoughts and attention problems. Higher scores indicate a greater number of emotional and behavioral problems. Caregivers were also asked to provide information regarding eating behaviors and completed the child behavior checklist.
Data analysis: The SPSS software version 22.0 (IBM, Inc., Chicago, IL) for windows was used for data analysis in this study. Descriptive data were presented as a percentage, mean, range and standard deviation. An ANOVA and chi-square test were used to compare mean and proportion among the three groups. The Pearson correlation was used to identify correlations between eating behaviors and behavioral problems. Multiple linear regression analysis was used to determine factors influencing behavioral problems. The dependent variable was the total problem scores and independent variables were age, gender and unhealthy eating behaviors.
Since the prevalence of obesity could not be estimated before the study, the sample size cannot be determined. However, after the enrollment of participants, there were 88 cases of obesity, 92 cases were overweight and 250 cases within normal weight ranges. From a prospective study, high externalizing behavior was associated with a higher BMI with an odds29 ratio of 2.9. With α of 0.05 and only obesity and normal weight groups, this provided a power of 0.7.
RESULTS
There were 449 participants returned the questionnaires. Since there were 11 cases with incomplete information regarding demographic characteristics and 8 cases did not fulfill the inclusion criteria, therefore, 430 cases were included in the analysis. The mean age of the study sample was 10.56 (1.44) years of which 51.39% were male. Children with overweight and obesity were 21.40 and 20.47%, respectively. Characteristics of all participants are shown in Table 1.Regarding unhealthy eating behaviors, approximately 20% of participants reported daily consumption of sweetened beverage and 25% reported a daily intake of dessert. There were 17% of participants reported skipping meals which was usually breakfast and 60% reported using media during meals.
Almost 30% of children reported daily exercise or physical activities. When classified into 3 groups, children from the overweight and obesity groups were younger and there were a higher percentage of males than in the normal weight group. Unhealthy eating behaviors including skipping breakfast and media use during meals were more common in the obesity group than the normal weight group without statistical significance. Frequent and daily physical activities were significantly more common in the normal weight group than the obesity group (Table 2).
Although there was minimal correlation between sweetened beverage intake and the total behavioral scores as shown in Table 3, there was no statistically significant difference in the mean total behavioral problem scores among the three groups. However, some eating behaviors including sweetened beverage intake, dessert intake and frequent eating outside (both eating out in a restaurant and take away) was found to be associated with the higher total behavioral scores from the multiple linear regression analysis (p = 0.001, 0.02 and 0.008, respectively) as shown in Table 4.
DISCUSSION
The findings from this study have revealed that overweight and obesity in school age children between 7 and 12 were 21.40 and 20.47%, respectively. This might not reflect the precise prevalence of overweight/obesity because there was a low response rate (44.9%) was found in this study and those caregivers of children with overweight/obesity might be more interested in participating in the study. However, this study was conducted in a primary school in a city where participants were from middle and middle to high income socioeconomic, so that overnutrition can be found more often than a previous report of the prevalence across the whole province. According to the Department of Health, the prevalence of overweight/obesity in 5-14 years old children in Chiang Mai was 10.4%30. Overweight/obesity was found in all ages from the full range of 7-12 years old children and more common in males.
| Table 1: | Characteristics of participants included in analytic sample |
| BMI: Body mass index, SD: Standard deviation | |
| Table 2: | Behavioral problem scores and eating behaviors in children classified as normal weight, overweight and obesity |
| ANOVA for continuous variables and χ2 for categorical variables, SD: Standard deviation, a Normal weight vs obesity groups, bNormal weight vs overweight groups | |
| Table 3: | Correlation between unhealthy eating behaviors and behavioral problem scores |
| **p = 0.01 (2-tailed), *p = 0.05 (2-tailed) | |
| Table 4: | Factors associated with the total behavioral scores from the multiple linear regression analysis |
| SE: Standard error, BMI: Body mass index | |
These findings were similar to the report from the Centers for Disease Control and Prevention in a survey31 carried out between 1988-94 and 2013-4 and a national sample of 10-17 years old children and adolescents20 which found more males than females and younger age with overweight/obesity. Adiposity rebound occurs between 4-7 years of age, hence obesity was frequently found in 7 and 8 years old children in this study as a result of weight gain.
Unhealthy eating behaviors were related to overweight/obesity in previous studies32-34. In this study, these eating behaviors were not statistically significantly different among overweight, obesity and normal weight groups. This may be explained by the various etiologies relating to obesity such as genetics, low physical activities, or multifactorial causes. Another possible reason may be the subjectivity and heightened awareness of the participant’s caregivers who have been educated regarding eating behaviors and obesity. However, the caregivers of the obesity group reported more behaviors of skipping breakfast and media use during meals in their child than those of the normal weight group without statistical significance. The exercise and physical activities reported by caregivers were significantly lower in the obesity group than the normal weight group. In another study of school children aged from 6-18 years, 95% of the participants reported at least one unhealthy eating behavior but no significant relationship was found with overweight or obesity32. The explanations of their finding were the increased calories in homemade food or by responder’s bias resulting in a trend toward denying.
Emotional and behavioral factors reported by caregivers among the three groups were not significantly different. The findings were inconsistent with previous studies which have reported a correlation between emotional/behavioral problems and obesity in preschool children and school age girls18,19. There were other studies, however, which found no relation between obesity and behavioral problems22,35. Possible explanations are that overweight and obese children have low physical activities so that their caregivers view them as having fewer externalizing behavioral problems than those of normal weight children.
There was limited information regarding a correlation between eating behaviors and behavioral problems. One study has found a relationship between unhealthy eating behaviors and internalizing behavioral problems25. This study has revealed a minimal correlation between sweetened beverage intake behavior and behavioral problems. However, after adjusting confounding variables, besides the age, some unhealthy eating behaviors including sweetened beverage intake, dessert intake and frequent eating outside were among factors associated with the total behavioral scores from the multiple linear regression analysis.
While, this study provided information regarding eating behaviors and the assessment of behavioral problems using the appropriate tool, CBCL, some limitations need to be addressed. Firstly, the low response rate of the participants may result in the statistical significance of the differences. Secondly, characteristics of the participants may be different from other studies so the findings in this study could not be generalized. Also, as the participants were voluntarily taking part in the study; full randomization was not possible. Lastly, information regarding eating behavior and emotional/behavioral problems were obtained from only caregivers, it is possible school teachers or the children themselves could provide more accurate information.
CONCLUSION
Childhood obesity is a major health problem as its prevalence is increasing. Although the association between overweight/obesity and behavioral problems was not found in this study, some unhealthy eating behaviors were found to be related to behavioral problems. Promoting healthy eating behaviors may be a primary step in the prevention of behavioral problems and obesity.
ACKNOWLEDGMENT
The authors would like to thank the school teachers, caregivers and children for their participation in this study.