Lifestyle, self-esteem and obesity among children

Abstract

Background: Childhood obesity remains a major public health concern. While preventing childhood obesity is important, the effectiveness of existing prevention strategies is indefinite. Important obesity contributors are speculated to be overlooked while the role of well-studied obesity-related factors has been questioned.

Objectives: 1) Although the association between lifestyle and obesity is seemingly well-established, how an overlooked dietary factor, breakfast location, associates with obesity was investigated 2) At a time where inconsistencies in findings for the frequently studied association between TV viewing and obesity still exist, this thesis tested for the existence of the said association in the understudied Chinese population 3) The effect of mental health on childhood obesity is understudied. Using self-esteem as a mental health indicator, the effect of self-esteem on childhood obesity was investigated

To understand the role of lifestyle factors in the association between self-esteem and obesity, how 4) breakfast habit and 5) TV viewing habit associates with self-esteem was explored

Methods: A cohort of 83405 primary 4 (P4) Department of Health Student Health Service participants (49.7% male, mean age 9.9 years) in 1998-2000 were successfully tracked for 2 years into primary 6 (P6). A self-administered health questionnaire collected information on the breakfast and TV habits of participants alongside other lifestyle characteristics. Self-esteem was assessed using the four Culture Free Self-Esteem Inventories for Children (SEI) subscales. Body mass index (BMI) was derived using objectively measured weight and height. Weight status was classified in accordance to International Obesity Task Force standards. Logistic, multinomial logistic and linear regression were used to yield adjusted odds ratios (AOR) and β-coefficients for becoming overweight/obese in P6 (among P4 normal weight children), breakfast skipping/location, TV viewing habit and SEI subscale scores. Breakfast skipping behaviour was tested as a mediator in the association between self-esteem and obesity using standard mediation procedures. Breakfast and TV viewing habits were tested as effect modifiers in the same association by inclusion of interaction terms in models.

Results: Among normal weight P4 children, those who skipped breakfast (AOR: 1.24; 95% CI: 1.02 to 1.51) or ate away from home (1.39; 1.20 to 1.60) were more likely to become overweight/obese in P6. Poor self-esteem was also associated with higher AORs for becoming overweight/obese, particularly among girls.

While TV viewing in P4 did not predict overweight/obesity in P6, those who increased TV watching hours (≤2h/day to 2h/day) during the two follow-up years were 32% more likely to become overweight/obese in P6 than their counterparts who maintained watching ≤2h/day.

Breakfast habit and self-esteem was bi-directionally associated. Although a curvilinear inverted J-shaped relation between P4 TV viewing and P6 self-esteem was observed, self-esteem did not predict TV viewing habit.

While neither breakfast nor TV viewing habit significantly interacted with self-esteem to predict obesity, breakfast skipping was found to be a potential partial mediator in the association between self-esteem and obesity.

Conclusion: Breakfast location, self-esteem and TV viewing patterns over time are important to consider in relation to childhood obesity. Additionally, the association between self-esteem and obesity could be mediated by lifestyle factors.