Role of ethnicity in framing childhood obesity as a public health problem

Abstract

The prevalence of overweight and obesity in children and adults has risen to alarming levels across the world and is also markedly increasing in developing countries. In Colombia, a multi-ethnic country, the prevalence of overweight and obesity among low-income populations is growing. Childhood obesity is a complex systemic issue that needs to be addressed across a range of areas in order to offer appropriate support to policy development. Arriving at a better understanding regarding the influence of other exposure variables in Colombia, such as ethnicity and race, as a part of that complexity, may provide additional insight. This thesis accordingly seeks to understand better the role of race and ethnicity in framing childhood obesity as a public health problem in Colombia, taking an international comparison approach.

This thesis involved the review of the use of ethnicity as a variable in childhood obesity research in five countries: Colombia, Brazil, Mexico, Canada and the United Kingdom. A systematic review was also performed to synthetise state-of-the-art research throughout the same countries. The lack of detailed research analysing ethnicity in Colombia in this context made it necessary to conduct a secondary analysis.

Results revealed that the majority of studies are not using robust conceptualisations and clear definitions of ethnicity, which might negatively impact possible interpretations of data in light of ethnic differences in childhood obesity. The systematic review indicated that most authors have focused on physiology when analysing ethnic variations in childhood obesity risk factors; consequently, policy and interventions targeting these populations are not based on robust evidence of prevalence and causality. A secondary analysis was performed to understand the relationship between ethnicity and childhood obesity in Colombia. To explain all potential ways in which ethnicity could be associated with childhood obesity, directed acyclic graphs were employed. These included paths through socioeconomic variables, food security, obesity-related behaviours or a combination of the above.

The association analysis revealed differences by ethnic group: wealth index was positively associated with childhood overweight and obesity, especially among Indigenous children. Severe levels of food insecurity were inversely associated with obesity in this same ethnic group, while in both Indigenous and Afro-descendant children, it was associated with maternal obesity. When mediation models were tested, socioeconomic factors and food insecurity proved to be mediators only for Indigenous children.

Findings of this thesis are a contribution to orientate actions to tackle childhood obesity as a public health problem, not only in Colombia but in ethnically diverse countries. Recommendations for public policy are based on actions for promoting taxation of unhealthy food and food labelling, as well as ensuring food security for ethnic minority groups, target programmes to prevent obesity in adolescent and infants, and promoting the health of mothers. Regarding practice, the development of more completed registers and health-related surveys in Colombia to enable data linking is a highly relevant recommendation. Future research in the fields of ethnicity, childhood obesity and the combination of these may benefit from insights of this thesis.