Interventions to prevent obesity in the first 1000 days: scoping review

Intervenciones para prevenir la obesidad en los primeros 1000 días: revisión de alcance

Intervenções para prevenir a obesidade nos primeiros 1.000 dias: análise de escopo

Paola Alexandra Zepeda-Ríos paola.zepedar@uanl.edu.mx

Universidad Autónoma de Nuevo León, Mexico

Velia Margarita Cárdenas-Villarreal velia.cardenasvl@uanl.edu.mx

Universidad Autónoma de Nuevo León, Mexico

Danilo Castro-Sifuentes danilo.castros@uanl.edu.mx

Universidad Autónoma de Nuevo León, Mexico

Milton Carlos Guevara-Valtier milton.guevaravlt@uanl.edu.mx

Universidad Autónoma de Nuevo León, Mexico

Over the past four decades, the global prevalence of childhood obesity has increased exponentially¹, with 37 million children under the age of five being overweight or obese². Being overweight or obese in the early years of life has been shown to increase the risk of developing a number of early diseases such as asthma, coronary heart disease, type 2 diabetes mellitus, osteoarthritis, some cancers and others^{3), (4}, and is responsible for 2.6 million deaths each year⁵. Preventing childhood obesity is therefore a priority⁶.

Early life is a critical period for the development of obesity. International child health organizations have developed guidelines and recommendations to prevent, control and reduce obesity during the first 1000 days⁷ - a crucial period of human development from conception to 2 years of age⁸. These recommendations aim to implement evidence-based interventions that comprehensively address key modifiable risk factors during the prenatal and postnatal stages to prevent childhood obesity^{9), (10}. It is, therefore, important to identify the types of interventions that have been implemented to prevent childhood obesity in the first 1000 days and whether they have evidence of effectiveness.

Previous systematic reviews have assessed interventions in these stages and found promising results; however, the prenatal or postnatal stages have been considered indistinctly^{11), (12}, so this review sought to assess only those interventions that considered both stages of development, as the evidence mentions the importance of considering the first 1000 days in a comprehensive way⁹. Therefore, the aim of this scoping review was to identify and characterize the interventions implemented in the first 1000 days (considering the prenatal and postnatal period together) for the prevention of overweight and obesity. The information gathered can serve as a guide for health care providers and researchers looking for opportunities to implement interventions aimed at preventing childhood obesity.

This a registered scoping review^{13), (14}, which used the 5 stages of Arksey and O'Malley's methodological framework¹⁵.

For interventions reported in systematic reviews, a total of 387 references were identified after removing duplicates; 378 were excluded based on title and abstract, leaving a total of 9 articles to be assessed in full text. The search was supplemented with a strategy to identify randomized clinical trials of individual interventions, of which 5 were excluded because they did not meet the criteria, and the remaining 9 trials were considered eligible. The total number of articles included in both searches was 14, comprising 10 interventions^{17), (30}. See Figure 1.

Figure 1
PRISMA-ScR flow diagram for identifying studies from databases and registries

In order to answer the research questions, the corresponding articles were reviewed, and the results were categorized along three main dimensions: characteristics ofthe study population, characteristics of the intervention design, general characteristics and outcomes of effective interventions.

Study population characteristics

All interventions were carried out in high-income countries, none in middle- or low-income countries. Participants were women aged over 18 years from low socioeconomic backgrounds. Four of them belonged to the Latino subcultural group, one to the African American group, and the rest were not specified (n=5). Half of the interventions (n=5) started when the mother was in the third quarter of pregnancy, and the rest in the second and third quarters (n=5). See Table 1.

Table 1
General characteristics of the study population, 2012-2022

Design characteristics of the interventions

Seven interventions used behavior change theory in their design, with social cognitive theory being the most commonly used. All interventions were face-to-face and delivered mainly by nurses and dietitians. The duration of the interventions ranged from 2 to 3 years.

Although all the interventions started in the prenatal period, only two of them addressed maternal factors, such as gestational weight gain. The others developed educational programs that focused on postnatal factors, such as infant nutrition.

Integration of physical activity and sleep was less common. Finally, the Starting Early Program (StEP) ⁽²⁰, Minding the Baby²¹, and Healthy Beginnings^{29), (30} interventions were found to have statistically significant outcomes related to infant weight. See Table 2.

Table 2
Design characteristics of the total number of interventions identified for the period 2012-2022

General characteristics and outcomes of effective interventions

Finally, as this is a scoping review, we did not carry out a comprehensive analysis of outcomes³¹; however, we found that effective interventions were delivered to pregnant women from the third quarter onwards. According to the components, these interventions were based on the major risk factors for childhood obesity, supported by cognitive-behavioral theories. Delivery was face-to-face, mainly by nurses, and the impact of the intervention was influential in maintaining or improving nutritional status. This is described in Table 3.

Table 3
General characteristics and outcomes of effective interventions to prevent overweight and obesity in the first 1000 days of life

The aim of this study was to identify and characterize interventions delivered during the first 1000 days of life for the prevention of childhood obesity. We identified 10 interventions reported in 14 articles between 2012 and 2022.

We found that the development and implementation of interventions are concentrated in high- income countries, in line with other systematic reviews^{11), (12), (32}, and that while in the past overweight was almost exclusively a problem of high-income countries, prevalence patterns have now changed, with low-and middle-income countries accounting for three-quarters of childhood overweight worldwide^{2), (33}. Policies focusing on the prevention of childhood obesity in the first 1000 days have recently been implemented in Latin America³⁴ and publications from this region with positive results are expected soon.

More than half of the interventions included racial/ethnic subgroups in their study populations, such as Latinos and African Americans, who are considered to be groups with a high prevalence of risk factors for childhood obesity^{35), (36}; however, they did not include cultural or environmental aspects beyond the vulnerability or ethnicity of the population, which is seen as an area of opportunity. This highlights the need for future interventions to consider the socioeconomic status, environment and culture in which children and families live, as these variables may influence weight-related behaviors, as do dietary practices and physical activity^{37), (38}.

Regarding the start of implementation, most interventions were initiated in the third quarter of pregnancy; however, evidence suggests that ideally they should be initiated before conception, but if this is not possible, they should be initiated from the first quarter of pregnancy and continued until the child is two years old³⁹. As previously mentioned, it was found that none of the interventions included preconception care, but they did include follow-up for two years or more, which aligns with the scientific evidence reported in previous systematic reviews^{11), (12), (40}. Preventive interventions delivered at these stages may prepare the mother-to-be to reduce risk factors for childhood obesity, and there is, therefore, a need to continue to research this period^{8), (9), (11), (38}.

This scoping review found three interventions with statistically significant results: StEP²⁰, Minding the Baby²¹ and Healthy Beginnings²⁹. Key features of these interventions were that they were multi component and targeted the main risk factors for obesity in early childhood; they also used theoretical models that focus on how perceptions, beliefs and thoughts influence behavior. This allows for a coherent, evidence-based structure that facilitates the understanding of health determinants, the prediction and evaluation of out comes,and the reproducibility and generalizability of interventions^{6), (9), (41}.

The delivery method for these three interventions was face-to-face home visits, with a minimum follow-up of 2 years. Evidence suggests that, beyond the provision of information, this individualized face-to-face support builds a relationship of trust between the facilitator and the mother, promoting favorable outcomes in terms of improvements in developmental indicators, infant feeding practices and parenting, all in disadvantaged families^{42), (43}.

Likewise, it was seen that the use of technology was incorporated into the interventions, the most common being telephone calls, text messages and computer use. The use of technological resources to promote health is an opportunity to bring educational strategies to the population⁴⁴. In recent years, the number of people using these tools on a daily basis has increased, providing an opportunity for educators and researchers to reduce the cost of implementing obesity prevention interventions, thus reducing the gap in access to health services^{45), (46}.

Cultural adaptations are considered necessary to improve identified outcomes⁴⁷, and the use of technology and interventions that take into account multifactorial aspects such as culture, dietary practices and physical activity has significant effects on participants' weight^{32), (48}.

Limitations include the fact that, by its nature, this scoping review did not include a quality assessment of the reviewed studies or an in-depth review of the statistical results, which may limit the generalizability of the findings. Strengths include that the design allowed for a systematic synthesis of research characteristics and findings, which could contribute to health professionals' decision making in preventing of childhood obesity.

It is encouraging that from the ten selected interventions, three were found to be effective in preventing childhood overweight and obesity in the first 1000 days of life. The characteristics summarized in terms of study population, intervention design and outcomes of effective interventions provide evidence that can be used to determine whether these interventions will work in other contexts, such as low- and middle-income countries and in groups vulnerable to developing childhood obesity.

In addition, the use of cultural adaptation processes could be a useful strategy to reduce development and implementation time and optimize resources. Ensuring that interventions cover all of the above aspects will result in better prevention of childhood obesity.