Interventions to prevent obesity in Latinx children globally: protocol for a systematic review and meta-analysis

Rates of childhood obesity have accelerated rapidly over the past decade in low- and middle-income countries and in Latin America in particular [1, 2]. Approximately 42.5 million children (about 20%) in Latin America had overweight or obesity in 2008–2013, and current rates may be higher [3]. Even more concerning, children in Latin America have experienced one of the fastest increases in age-standardized body mass index (BMI) globally [2]. Children in Latin America and the Caribbean now rank among the highest globally in terms of mean BMI, on par with those of high-income countries [2]. Given the precipitous rise in Latinx children with obesity, prevention in this population remains a critical public health priority.

In addition to the rising trends in children with obesity in Latin America and the Caribbean, Latinx children are disproportionately affected by obesity in high-income countries such as the United States (US). According to data from 2011 to 2012, nearly 40% of Latinx children in the US had overweight or obesity, representing the highest rates across all ethnic and racial groups [4]. Latinxs are one of the fastest growing populations in the US, reaching nearly 60 million in 2018 [5]. Although studies have demonstrated that recent Latinx immigrants to the US experienced lower rates of chronic disease compared to their non-Latinx white peers, more time spent in the US has been associated with having obesity [6].

The major drivers of obesity among Latinx children are diverse. Researchers have documented a shift in dietary intake and energy expenditure, referred to as the global nutrition transition, that has resulted in rapid increases in non-communicable diseases in less developed regions such as Latin America [7]. The consequences of this transition include rapid dietary changes, particularly increases in sugar-sweetened beverages [8, 9], animal product and processed food consumption [9, 10], and a concomitant decrease in vegetable and legume intake [8‐10]. The nutrition transition has also resulted in changes in the local food environment, such as greater proximity to supermarkets and fast food outlets [11], and increased exposure to food advertising [12, 13], which play an important role in increasing rates of obesity among Latinx children. In addition, Latinx children have decreased physical activity and increased sedentary behaviors due to factors such as changes in transportation networks [14].

The local context within individual countries is diverse and complex, resulting in variable environmental and demographic influences on obesity outcomes among Latinx children [15]. Overweight and obesity varies by ethnicity (e.g., indigenous versus non-indigenous) [15], geographic location (e.g., urban versus rural residence) [16], socioeconomic status [17], and maternal education [15]. For example, there is evidence that Honduras and Peru experienced a higher prevalence of overweight and obesity in urban compared to rural areas, while the opposite was true in Bolivia and Nicaragua [15]. Despite these differences, the shared economic ties, common health threats, and increasing immigration between regions such as Latin and North America have prompted researchers to call for global responses to help prevent obesity among Latinx populations [18]. In particular, public health officials have endorsed policy, systems, and environmental strategies for obesity prevention to influence individual behaviors within broader social and environmental contexts [19, 20].

To date, two systematic reviews have summarized interventions to prevent obesity among Latinx children in the US [21, 22], and only one systematic review has summarized interventions in the US and Latin America through 2010 [23]. Importantly, these reviews identified few studies that targeted policy, systems, and environmental intervention strategies for obesity prevention [23]. In recent years, several obesity prevention interventions aimed at Latinx children have been published, with mixed results [24‐30]. Given the continuing rise in the number of children with obesity, there is a need to update the literature to identify and highlight successful interventions. To our knowledge, no study has systematically investigated interventions to prevent obesity among Latinx child populations globally over the past decade. As such, we will conduct a systematic review and possible meta-analysis of interventions for obesity prevention among Latinx children. The objectives of this systematic review are to answer the following research questions:

In this paper, we aim to outline the protocol for a future systematic review of obesity prevention interventions in Latinx children.

In this paper, we outline a protocol for conducting a systematic review and possible meta-analysis of obesity prevention interventions among Latinx children, including the rationale for selection and use of appropriate tools and strategies to manage and conduct the review. This systematic review and potential meta-analysis will be the first to examine the efficacy and effectiveness of obesity prevention interventions among Latinx children globally over the past decade. We may conduct secondary analyses to examine differences in obesity outcomes according to study and participant characteristics, such as geographic location, child age, child gender, study setting, and quality of studies. By evaluating the impact of interventions on obesity-related outcomes, we hope to identify the most effective interventions and their policy, systems, and environmental strategies for obesity prevention in Latinx children. We will also identify potential gaps in the literature to inform future intervention efforts.

This review will build on the findings of previous systematic reviews and also provide an important update and global perspective on interventions for obesity prevention in Latinx children. Of the previously published systematic reviews on this topic, two focused on interventions conducted in the US [21, 22], and one investigated interventions in the US and Latin America [23]. These reviews identified several effective school-based obesity prevention interventions in the US and Latin America, and demonstrated the effectiveness of including parent components in school-based interventions [21‐23]. Several successful primary care-based interventions were highlighted in Latin America; however, effect sizes were small [23]. Importantly, these reviews examined studies published prior to 2010 [21, 23] and 2012 [22], and included only those published in English. In addition, no systematic review has included interventions conducted in Latinx populations in regions outside of the US and Latin America, such as the Caribbean, where childhood obesity rates are similar to that of Latin-American countries [41]. This systematic review will address these gaps by providing an update of the literature published since 2010. We will include non-English language studies if available, as well as interventions conducted in Latinx child populations in any country or setting. These steps will allow us to provide a more complete synthesis of current evidence on this topic.

This review will include interventions that use policy, systems, and environmental strategies for obesity prevention. These approaches have emerged as effective strategies to address complex public health issues, such as obesity prevention in children [19, 42]. Rather than focus on individual determinants of obesity, policy, systems, and environmental strategies attempt to influence the broader social and environmental context to support diet and physical activity changes [19]. These approaches are particularly important for low-income and racial and ethnic minority populations that are at greater risk for obesity, such as Latinx children, since they address underlying determinants of health and social inequity [20, 43]. The World Health Organization has endorsed integrated and multi-sector interventions to prevent obesity in children, particularly in low- and middle-income countries, that recognize related issues such as food security and undernutrition [44]. Policy, systems, and environmental strategies may be implemented in a variety of sectors and settings. For example, dietary behaviors may be influenced through nutrition education in early care and education and school settings, food distribution in community environments, or taxation at the national level. Understanding the nature and efficacy of strategies that have been implemented for obesity prevention among Latinx children is critical to advancing successful approaches on a broader scale [19, 44].

We acknowledge there may be several limitations to this review. First, by including only studies with a measure of obesity as an outcome, we may be overlooking promising intervention strategies that measure secondary outcomes, such as changes in diet, physical activity, or sleep — behaviors related to obesity. However, interventions that address specific behaviors, such as sugar-sweetened beverage intake [45] and physical activity [46, 47], have been reviewed and summarized elsewhere. Second, we anticipate that the intervention strategies, settings, and outcome measures used may vary across studies. To address this, we will attempt to group studies according to relevant characteristics, such as intervention strategy, setting, or child age. We may then provide a narrative review of the included studies by relevant characteristics. Third, it is possible that in conducting meta-analyses, we may introduce meta-bias into our review [48]. We will take steps to address this issue, including examination of funnel plots, and completing a quality of evidence synthesis using the GRADE approach. Finally, our review may be restricted by the number of interventions for obesity prevention with comparable exposure and outcomes variables, thus limiting our ability to conduct meta-analyses. Regardless, we will present a tabular synthesis of included studies and their outcomes.

This protocol paper details the methodology for conducting a future review of obesity prevention interventions in Latinx children. The protocol described will also serve as guidance for researchers that aim to implement future systematic reviews on similar topics. Ultimately, the systematic review resulting from this protocol will provide an important update to the literature regarding interventions to address obesity in Latinx child populations globally over the past decade. Given that rates of obesity are increasing rapidly among this population of children in both high-income and developing countries, preventing obesity among Latinx children is an issue of critical global public health importance. Results from this review will help to highlight effective obesity prevention strategies in a vulnerable population of children. This review may also shed light on gaps in the literature to inform directions for future intervention research. Results will be relevant to stakeholders across multiple sectors engaged in childhood obesity prevention in Latinx children.