Position guidelines and evidence base concerning determinants of childhood obesity with a European perspective

Childhood obesity is one of the most pressing global public health issues, with rates increasing fastest in countries at low levels of income. Obesity occurring during childhood is likely to persist throughout the life course, and it is a cause of increased disease risk from the early years of life. This supplement is the result of collaborations involving a large and multidisciplinary group of researchers that were established in the context of the ongoing European Horizon 2020 project Science and Technology in childhood Obesity Policy (STOP). The aim, as in the entire STOP project, is to generate evidence that can support better policies to tackle the problem of childhood obesity in Europe and elsewhere. Quality of life and health well-being concerning children needs to consider personalized, population, and planetary facets to tackle childhood obesity at early stages of life, for in-deep phenotyping, integrating personalized medicine and precision public health interventions at global levels. This supplement contributes to this aim.

Fecal microbiota relationships with childhood obesity: A scoping comprehensive review

Childhood obesity is a costly burden in most regions with relevant and adverse long-term health consequences in adult life. Several studies have associated excessive body weight with a specific profile of gut microbiota. Different factors related to fecal microorganism abundance seem to contribute to childhood obesity, such as gestational weight gain, perinatal diet, antibiotic administration to the mother and/or child, birth delivery, and feeding patterns, among others. This review reports and discusses diverse factors that affect the infant intestinal microbiota with putative or possible implications on the increase of the obesity childhood rates as well as microbiota shifts associated with excessive body weight in children.

Mediterranean diet and adiposity in children and adolescents: A systematic review

Our aim was to summarize, through a systematic review, the current evidence from dietary intervention and observational studies on the impact of adherence to the Mediterranean diet on adiposity markers and obesity in children and adolescents. We searched Medline up to June 1, 2021 for the identification of intervention and observational studies meeting the inclusion criteria, following the PRISMA statement. We included 55 articles: 8 intervention studies and 47 observational studies. Three trials report a beneficial effect of the dietary intervention, whereas two did not, and three did not compare with a control. All observational studies were cross-sectional, and only five studies also included a longitudinal analysis. More than half of the cross-sectional studies found no significant association between adherence to Mediterranean diet and adiposity. Three out of the five longitudinal studies found a negative association. The majority of both observational and intervention studies was of low quality. Despite a large number of published studies, overall, there is only limited evidence of a beneficial effect of following a traditional Mediterranean diet to maintain a healthy body weight in childhood. More high-quality intervention and longitudinal data are needed to form the base of large-scale health programs to prevent childhood obesity.

The built environment as determinant of childhood obesity: A systematic literature review

We evaluated the epidemiological evidence on the built environment and its link to childhood obesity, focusing on environmental factors such as traffic noise and air pollution, as well as physical factors potentially driving obesity-related behaviors, such as neighborhood walkability and availability and accessibility of parks and playgrounds. Eligible studies were (i) conducted on human children below the age of 18 years, (ii) focused on body size measurements in childhood, (iii) examined at least one built environment characteristic, (iv) reported effect sizes and associated confidence intervals, and (v) were published in English language. A z test, as alternative to the meta-analysis, was used to quantify associations due to heterogeneity in exposure and outcome definition. We found strong evidence for an association of traffic-related air pollution (nitrogen dioxide and nitrogen oxides exposure, p < 0.001) and built environment characteristics supportive of walking (street intersection density, p < 0.01 and access to parks, p < 0.001) with childhood obesity. We identified a lack of studies that account for interactions between different built environment exposures or verify the role and mechanism of important effect modifiers such as age.

A systematic review of metabolomic studies of childhood obesity: State of the evidence for metabolic determinants and consequences

Childhood obesity has become a global epidemic and carries significant long-term consequences to physical and mental health. Metabolomics, the global profiling of small molecules or metabolites, may reveal the mechanisms of development of childhood obesity and clarify links between obesity and metabolic disease. A systematic review of metabolomic studies of childhood obesity was conducted, following Preferred Reporting Items for Systematic Reviews (PRISMA) guidelines, searching across Scopus, Ovid, Web of Science and PubMed databases for articles published from January 1, 2005 to July 8, 2020, retrieving 1271 different records and retaining 41 articles for qualitative synthesis. Study quality was assessed using a modified Newcastle-Ottawa Scale. Thirty-three studies were conducted on blood, six on urine, three on umbilical cord blood, and one on saliva. Thirty studies were primarily cross-sectional, five studies were primarily longitudinal, and seven studies examined effects of weight-loss following a life-style intervention. A consistent metabolic profile of childhood obesity was observed including amino acids (particularly branched chain and aromatic), carnitines, lipids, and steroids. Although the use of metabolomics in childhood obesity research is still developing, the identified metabolites have provided additional insight into the pathogenesis of many obesity-related diseases. Further longitudinal research is needed into the role of metabolic profiles and child obesity risk.

Prenatal exposure to antibiotics and risk of childhood overweight or obesity: A systematic review and meta-analysis

Infant antibiotic use has been modestly associated with childhood overweight, while evidence on prenatal exposures remains less clear. A systematic review and meta-analysis were conducted to examine associations between maternal antibiotic exposure and subsequent risk of childhood overweight/obesity. Publications were retrieved from PubMed and Web of Science databases up to December 2019. A random effects model was used to summarize risk estimates, overall, and by period and frequency of exposure. Ten observational studies were included in the narrative synthesis. We did not observe a clear pattern of association between prenatal antibiotic use and childhood overweight/obesity. There were suggestive associations for repeated exposures (≥3 courses) and those taking place during the second trimester of gestation, which were also pointed out in our meta-analysis (relative risk, RR_2T  = 1.15 (95% CI 1.04; 1.28, I²  = 18%), and RR_3courses  = 1.31 (95% CI 1.03; 1.67, I²  = 65%), respectively). In most studies, however, confounding by underlying infections cannot be ruled out. Overall, current data do not conclusively support the hypothesis that prenatal exposure to antibiotics is a risk factor for childhood obesity/overweight. Further studies, controlling for underlying infections and exploring the association according to frequency, period (both prenatal and intrapartum) and type of antibiotic, are needed to clarify this association.

Guide and advances on childhood obesity determinants: Setting the research agenda

Childhood obesity demands global solutions. Low birth weight and small for gestational age were associated with childhood obesity. Available data do not support prenatal exposure to antibiotics as risk factor for childhood obesity, and posology must be assessed. Prenatal exposure to persistent organic pollutants shows associations with childhood obesity. Gut microbiota composition influences obesity onset in childhood. Despite the unquestionable role of Mediterranean diet on healthy weight, there are only incomplete indications of metabolic benefits in childhood weight after following Mediterranean diet. Negative association between total dairy consumption and childhood obesity has been found, but inverse causality could not be discarded. Ultra-processed food intake is an adverse determinant of childhood obesity. Physical inactivity and sedentarism are critical risk factors of children adiposity; hence, built environment and environmental features will be determinants of childhood obesity. A consistent metabolic pattern of childhood obesity was observed; metabolomics research is needed to assess the role of specific molecules concerning childhood obesity. Epigenetic experiences support association with childhood obesity for DNA methylation of specific genes and miRNAs. Therefore, recent childhood obesity rates cannot only be explained by genetic predisposition and changes in lifestyle habits. It implies gene-environment interactions. It will be the next research.

Perspectives and challenges of epigenetic determinants of childhood obesity: A systematic review

The tremendous increase in childhood obesity prevalence over the last few decades cannot merely be explained by genetics and evolutionary changes in the genome, implying that gene-environment interactions, such as epigenetic modifications, likely play a major role. This systematic review aims to summarize the evidence of the association between epigenetics and childhood obesity. A literature search was performed via PubMed and Scopus engines using a combination of terms related to epigenetics and pediatric obesity. Articles studying the association between epigenetic mechanisms (including DNA methylation and hydroxymethylation, non-coding RNAs, and chromatin and histones modification) and obesity and/or overweight (or any related anthropometric parameters) in children (0-18 years) were included. The risk of bias was assessed with a modified Newcastle-Ottawa scale for non-randomized studies. One hundred twenty-one studies explored epigenetic changes related to childhood obesity. DNA methylation was the most widely investigated mechanism (N = 101 studies), followed by non-coding RNAs (N = 19 studies) with evidence suggestive of an association with childhood obesity for DNA methylation of specific genes and microRNAs (miRNAs). One study, focusing on histones modification, was identified. Heterogeneity of findings may have hindered more insights into the epigenetic changes related to childhood obesity. Gaps and challenges that future research should face are herein described.

Low birth weight and small for gestational age are associated with complications of childhood and adolescence obesity: Systematic review and meta-analysis

In recent decades, the incidence of type 2 diabetes (T2D) has increased dramatically in children and adolescents, posing a real public health problem. Beyond unhealthy diets and sedentary lifestyles, growing evidence suggests that some perinatal factors, such as low birth weight (LBW), are associated with higher risk of T2D in adulthood. In this regard, it remains unclear whether the increased risk is already present in childhood and adolescence. We conducted a systematic review and meta-analysis to clarify the association of LBW or being small for gestational age (SGA) with insulin resistance in childhood and adolescence. The systematic review resulted in 28 individual studies, and those with the same outcome were included within two random-effects meta-analyses. Compared with children or adolescents born with adequate size for gestational age, those SGA had 2.33-fold higher risk of T2D (95% confidence interval [CI]: 1.05-5.17). Furthermore, LBW and being SGA were associated with 0.20 higher mean homeostasis model assessment of insulin resistance (HOMA-IR) values (95% CI: 0.02-0.38). Given the high prevalence of preterm babies, from a population perspective, these results may be of great importance as they point to the existence of a potentially vulnerable subgroup of children and adolescents that could benefit from screening tests and early preventive strategies.

Making Childhood Obesity a Priority: A Qualitative Study of Healthcare Professionals' Perspectives on Facilitating Communication and Improving Treatment

In Romania, one in four children has excess weight. Because childhood obesity is a sensitive topic, many healthcare professionals find it difficult to discuss children's excess weight with parents. This study aims to identify barriers and facilitators in childhood obesity-related communication, as perceived by healthcare professionals in Romania. As part of the STOP project, healthcare professionals (family physicians, pediatricians, and dieticians) who treat children with excess weight were invited to a telephone interview. The semi-structured questions were translated from a questionnaire previously used at the Swedish study site of the STOP project. Interviews were transcribed and then used for thematic analysis. Fifteen doctors and three dieticians (16 females and 2 males), with average 18.2 ± 10.1 years of experience, were interviewed. Four main themes were identified. Professionals reported that when children began experiencing obesity-related stigma or comorbidities, this became the tipping point of weight excess, where parents felt motivated to begin treatment. Barriers in communication were part of several layers of distrust, recognized as tension between professionals and caregivers due to conflicting beliefs about excess weight, as well as lack of trust in medical studies. Most respondents felt confident using models of good practice, consisting of a gentle approach and patient-centered care. Nonetheless, professionals noted systemic barriers due to a referral system and allocation of clinical time that hinder obesity treatment. They suggested that lack of specialized centers and inadequate education of healthcare professional conveys the system does not prioritize obesity treatment and prevention. The interviewed Romanian doctors and dieticians identified patient-centered care as key to treating children with obesity and building trust with their caregivers. However

their efforts are hindered by healthcare system barriers, including the lack of specialized centers, training, and a referral system. The findings therefore suggest that, to improve childhood obesity prevention and treatment, systemic barriers should be addressed.

Trial Registration:ClinicalTrials.gov, NCT03800823; 11 Jan 2019.

Planting a seed - child health care nurses' perceptions of speaking to parents about overweight and obesity: a qualitative study within the STOP project

BACKGROUND

Nurses in child health care (CHC) centers in Sweden play a key role in the early detection and management of childhood overweight/obesity, through meeting families early, regularly and over many years. However, research focusing on CHC nurses' perceptions of their role in childhood overweight/obesity management is scarce. As part of the EU-funded project "Science and Technology in childhood Obesity Policy" (STOP), this study examines CHC nurses' perceptions of speaking to parents about children's overweight/obesity and of their role in referring children to treatment for overweight/obesity.

METHODS

All registered CHC nurses in Stockholm County (n = 442) received an email invitation letter explaining the study. Individual face-to-face visits (n = 15) in selected centers, and phone calls (n = 24) to nurses working in these centres were also conducted. In total, 17 CHC nurses (all female, average work experience 6.7 years (SD ± 4.9 years)) from 10 municipalities (including four of the top five municipalities with the highest prevalence of overweight and obesity) in Stockholm County were interviewed. The interviews were conducted by phone, transcribed and analyzed using thematic analysis.

RESULTS

Two main themes were developed through the analysis: 1) The relationship between the nurse and the parent and 2) Glitch in the system. Under the first theme, nurses reported that weight-related discussions were facilitated by building and maintaining trust with parents. However, nurses also said they were reluctant to address children's weights if this could compromise parents' trust. Under the second theme, nurses highlighted several organizational barriers to addressing a child's weight with parents, including insufficient cooperation with other healthcare providers and limited time for visits. Nurses also identified lack of sufficient knowledge about what to offer the family and lack of confidence in their communication skills as additional barriers.

CONCLUSIONS

We found that pediatric nurses perceive relational and organizational factors as barriers to address childhood obesity with parents. To improve care, it is necessary to provide nurses with continuing education about obesity and communication skills and organizational support to improve communication within the healthcare system.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03800823; 11 Jan 2019, prospectively registered.