The purpose of this literature review is to determine the variables and provide the rationale for selecting the variables involve in the study.
The commonness of obesity has reached worrying stages, influencing almost both developed and developing nations of all socio-economic groups, regardless of age, gender or race. Globally, approximately more than 22 million children below the age of 5 are extremely overweight and it has been founded that one in 10 children are overweight (Kosti & Panagiotakos, 2006). Technically, Malaysia is also one of the developing Asian countries that suffer from a fast widespread presence of adolescent obesity which is accordant with the global trends (Yang et al., 2017). Therefore, obesity does not happen overnight because it evolves slowly from poor eating habit and bad choices of lifestyle among individual. The result from Journal of Tropical Pediatrics research in 2016 shows that the occurrence of obesity and overweight increase continuously both in rural and urban secondary school (Zhang et al., 2016). However, the occurrence of obesity in urban secondary school are significantly higher compared with rural secondary school (Zhang, Wang, Zhao & Chu, 2016). The respondent of the particular research consist of students aged between 7 years old and 18 years old (Zhang et al., 2016).
National Health Service (NHS) in the United Kingdom also claim that childhood obesity is said can be a powerful sign of weight-related health issues that will affect their adulthood if they keep practicing the unhealthy lifestyle (National Health Service, 2016). Moreover, research in 2018 found that there is an association between obesity and the frequency of exercise among participant (Elsangedy et al., 2018). Moreover, in a recent article, the authors have stated that poor sleep and physical activity which is exercise can be included in a list of risk factor of obesity among adolescent (Ji et al., 2018). Furthermore, the Journal of Social Science & Medicine in
2017 declare that family income has a relationship with weight-related health issues which obesity among adolescent (Cook, Tseng, Tam, John & Lui, 2017). The previous authors in 2017 also claim that eating behavior affect the occurrence of obesity among adolescent (Demir & Bektas, 2017).
Thus, all these variables will be explained in detail in another part of the literature review of the previous journal and article as below.
2.2 PARENTS INCOME
In 2016, there is a research that has been done to determine the factor that affects weight-related health problems among Asian adolescent with special attention towards Asian ethnicity, socioeconomic status (SES), and their interaction (Cook, Tseng, Bautista & John, 2016). The finding of the study indicates that there is an association between low family income and overweight that affect the Asian American adolescents unfavorably (Cook et al., 2016). At the same time, Alvarado’s journal in 2016 also mentioned that one of the time-varying factors which are income could affect the individuals’ weight status (Alvarado, 2016). However, the results of the research are not enough to support the statement. It is because the households’ income alone is not sufficient to be one of the risk factors of obesity among adolescent (Alvarado, 2016). Besides that, one of the International Association for the Study of Obesity articles stated that the socio-economic status (SES) indicator showed that the wealthy family was more likely suffer from obesity for both men and women (Dinsa, Goryakin, Fumagalli ; Suhrcke, 2012). Adolescent whose parents’ income was either low or average were more likely to be obese compared with adolescent whose family have a high income (Strauss & Knight, 1999).
2.3 EATING BEHAVIOR
The definition of eating behavior can be understood as a complex interplay of physiologic, psychological, social, and genetic factors that influence meal timing, quantity of food intake, and food preference (Grimm & Steinle, 2011). Next, eating behaviors can be one of the reason of the occurrence of obesity as well as metabolic syndrome and other complications that increased by a variety of common genetic
variants (Grimm & Steinle, 2011). Adolescent with unpredictable characteristics might be associated with their obesity or overweight issues (Yavuz & Selcuk, 2018). Hence, the children with negative affectivity in infancy were suggested to have higher risk for weight-related health issues which is obesity (Yavuz & Selcuk, 2018). In fact, the behavior might affect their adulthood if they do not change it. In return, the parents who have children with negative temperamental affectivity were suggested to feed their children with the purpose of soothing rather than to please the satiety cues of the children which increases the likelihood of developing emotional eating (Yavuz & Selcuk, 2018). Furthermore, in another Journal of Eating Behaviors the factors that influence the adolescent obesity were found to be enjoyment of food, emotional overeating, food responsiveness, satiety responsiveness and also food fussiness (Demir & Bektas, 2017). However, satiety responsiveness is not used in this research. In addition, the previous research in 2017 found that one of the eating behaviors which is emotional feeding is the third most significant factor of adolescent weight-related problem which is obesity (Altan & Bektas, 2017).
Exercise can be understand as activity requiring physical effort, carried out to sustain or improve health and fitness (Oxford Dictionary, n.d.). Next, exercise can decrease the fat stores in the body which has metabolic effects on the obesity as well as increasing caloric expenditure and improving glucose tolerance together with the lipid profile. As a result, exercise can reduces the damage of weight-related problems which is obesity (Paes, Marins & Andreazzi, 2015). The statement can be supported by referring the article in Korea that declared Trans-theoretical model based exercise (TTM) intervention combined with exercise classes were effective to control weight among obese adolescent (Ham et al., 2016). Furthermore, the increase of exercise tolerance might also enable the adolescent to continued participate in any physical activity including school sports (Gow et al., 2016). This kind of physical activity can help to lose weight and enhanced the cardiometabolic outcomes (Gow et al., 2016). According to American Heart Association, cardiometabolic outcomes refer to obesity, hypertension, Type Two Diabetes Mellitus and also cardiovascular disease (Webb, S. R., & P., 2018). In addition, the result from the previous research done on medical student also showed that there are 54% of the students who do not exercise compared
with students who do exercise with 46% respectively (Katuka et al., 2016). This show that the lack of exercise can cause obesity problems (Katuka et al., 2016).
Sleep restriction or short sleep can be describe as sleep time less than the average basal level of about 9 hour per night for adolescents (Carskadon, Acebo & Jenni, 2004). Available evidence suggests that disturbed sleep and restricted sleep are associated with de?cits in functioning across a wide range of indicators of psychological, interpersonal and somatic well-being (Roberts & Duong, 2014). Yet, the results in Journal of Psychosomatic Research revealed that there was no association between sleep restriction and obesity (Roberts & Duong, 2015). The authors of the journal also stated that sleep restriction did not increase future risk of obesity, nor did obesity increase risk of future sleep restriction (Roberts & Duong, 2015). When children were preschool-aged, approximately 25% had a bedtime of 8:00 p.m. or earlier, 50% had bedtimes after 8:00 p.m. but by 9:00 p.m. and 25% had a bedtime after 9:00 p.m (Anderson, Andridge & Whitaker, 2016). Earlier bedtimes at preschool age were associated with lower risk for adolescent obesity (Anderson, Andridge & Whitaker, 2016). The authors also mentioned that the earlier bedtime will results to lower mean of BMI and lower likelihood to have overweight issues (Anderson, Andridge & Whitaker, 2016). Sleep restriction has been regularly shown to increase hunger, appetite and food intake, with the increase in caloric intake in excess of the energy requirements of extended wakefulness (Reutrakul & Cauter, 2018). Meanwhile, additional sleep cause 14% reduction in overall appetite and 62% reduction in desire for sweet and salty foods (Reutrakul & Cauter, 2018). In another case, late bedtime was significantly associated with obesity whereas early wake-up was not (Sasaki et al., 2018).