Changes in objectively measured BMI in children aged 4-11 years: data from the National Child Measurement Programme

Assessing the impact of obesity interventions in the early years: a systematic review of UK-based studies

OBJECTIVES

Childhood obesity rates in the UK are high. The early years of childhood are critical for establishing healthy behaviours and offer interventional opportunities. We aimed to identify studies evaluating the impact of UK-based obesity interventions in early childhood.

DESIGN

Systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA SOURCES

Nine databases were searched in March 2023.

ELIGIBILITY CRITERIA

We included UK-based obesity intervention studies delivered to children aged 6 months to 5 years that had diet and/or physical activity components and reported anthropometric outcomes. The primary outcome of interest was z-score Body Mass Index (zBMI) change (within and between subjects). Studies evaluating the effects of breastfeeding interventions were not included as obesity prevention interventions, given that best-practice formula feeding is also likely to encourage healthy growth. The publication date for studies was limited to the previous 12 years (2011-23), as earlier reviews found few evaluations of interventions in the UK.

DATA EXTRACTION AND SYNTHESIS

The reviewers worked independently using standardised approach to search, screen and code the included studies. Risk of bias was assessed using Cochrane tools (ROB 2 or ROBINS-I).

RESULTS

Six trials (five studies) were identified, including two randomised controlled trials (RCT), one cluster randomised trial (CRT), two feasibility CRTs and one impact assessment. The total number of participants was 566. Three trials focused on disadvantaged families and two included high-risk children categorised as having overweight or obesity. Compared with baseline, five interventions reported reductions in zBMI, three of which were statistically significant (p<0.05). Compared with control, five interventions showed zBMI reductions, one of which was significant. Only two trials were followed up beyond 12 months. All studies were found to have a high risk of bias. Meta-analysis was not possible due to the heterogeneity of studies.

CONCLUSION

UK evidence was limited but some interventions showed promising results in promoting healthy growth. As part of a programme of policies, interventions in the early years may have an important role in reducing the risk of childhood obesity.

PROSPERO REGISTRATION NUMBER

CRD42021290676.

Prediction of childhood overweight and obesity at age 10-11: findings from the Studying Lifecourse Obesity PrEdictors and the Born in Bradford cohorts

BACKGROUND

In England, 41% of children aged 10-11 years live with overweight or obesity. Identifying children at risk of developing overweight or obesity may help target early prevention interventions. We aimed to develop and externally validate prediction models of childhood overweight and obesity at age 10-11 years using routinely collected weight and height measurements at age 4-5 years and maternal and early-life health data.

METHODS

We used an anonymised linked cohort of maternal pregnancy and birth health records in Hampshire, UK between 2003 and 2008 and child health records. Childhood body mass index (BMI), adjusted for age and sex, at 10-11 years was used to define the outcome of overweight and obesity (BMI ≥ 91st centile) in the models. Logistic regression models and multivariable fractional polynomials were used to select model predictors and to identify transformations of continuous predictors that best predict the outcome. Models were externally validated using data from the Born in Bradford birth cohort. Model performance was assessed using discrimination and calibration.

RESULTS

Childhood BMI was available for 6566 children at 4-5 (14.6% overweight) and 10-11 years (26.1% overweight) with 10.8% overweight at both timepoints. The area under the curve (AUC) was 0.82 at development and 0.83 on external validation for the model only incorporating two predictors: BMI at 4-5 years and child sex. AUC increased to 0.84 on development and 0.85 on external validation on additionally incorporating maternal predictors in early pregnancy (BMI, smoking, age, educational attainment, ethnicity, parity, employment status). Models were well calibrated.

CONCLUSIONS

This prediction modelling can be applied at 4-5 years to identify the risk for childhood overweight at 10-11 years, with slightly improved prediction with the inclusion of maternal data. These prediction models demonstrate that routinely collected data can be used to target early preventive interventions to reduce the prevalence of childhood obesity.

Reduced Consumption of Sugar-Sweetened Beverages Is Associated with Lower Body Mass Index Z-Score Gain among Chinese Schoolchildren

To examine whether reducing sugar-sweetened beverage (SSB) consumption is associated with reduced body mass index z-score gain among Chinese schoolchildren in Nanjing, China, a randomized controlled trial (RCT) was conducted in four selected primary schools from September 2019 to September 2020. Students in the third grade in the Intervention Group received school-based and home-based interventions for two consecutive semesters to reduce SSB consumption, while two schools in the Control Group did not receive any interventions. Weight changes were expressed as body mass index (BMI) z-scores as standard deviations of the BMI distribution per age and sex group. Changes in SSB consumption before and after the interventions were categorized into Level-Up if it increased, Level-Same if it was maintained and Level-Down if it decreased. Multivariable linear regression models were used to explore the association of different levels of changes in SSB consumption pre- and post-intervention with the BMI z-score. Among 1633 participants who completed the trial, the mean age at baseline was 9.36 years (±0.48 SD).The median baseline BMI z-score was −0.24 (25th percentile −0.72; 75th percentile 0.58). After the intervention, the median BMI z-score increased by 0.06 (−0.17~0.37) in the Intervention Group and by 0.14 (−0.08~0.41) in the Control Group (p < 0.001). A higher increase in BMI was found in the Control Group than in the Intervention Group (1.20 vs. 0.94) during the 12-month period. Among participants whose parents’ educational attainment was above 9 years, the median BMI z-score increased by 0.07 (−0.17~0.37) in the Intervention Group and by 0.16 (−0.06~0.41) in the Control Group (p < 0.001). In a linear regression analysis adjusted for potential confounders, the BMI z-score decreased by 0.057 more in Level-Down than in Level-Up (95% CI: −0.103 to −0.012, p = 0.014). These results indicate that the decreased consumption of SSBs might have reduced the prevalence of overweight in schoolchildren in China, especially in students whose parents had high educational levels.

A longitudinal study investigating change in BMI z-score in primary school-aged children and the association of child BMI z-score with parent BMI

Background

This paper aims to explore change in BMI z-score through childhood and the association between parent BMI and child BMI z-score. This is important to understand for the development of effective obesity interventions.

Methods

Data from the longitudinal B-ProAct1v study (1837 participants) were analysed. A paired sample t-test examined changes in child BMI z-score between Year 1 and 4. Multivariable linear regression models examined the cross-sectional associations between child BMI z-score and parent BMI in Year 1 and 4. The influence of change in parental BMI between Year 1 and Year 4 on child BMI z-score in Year 4 was explored through regression analyses, adjusted for baseline BMI z-score.

Results

There was a strong association between child BMI z-score at Year 1 and 4. Child mean BMI z-score score increased from 0.198 to 0.330 (p = < 0.005) between these timepoints. For every unit increase in parent BMI, there was an increase in child BMI z-score of 0.047 in Year 1 (p = < 0.005) and of 0.059 in Year 4 (p = < 0.005). Parental BMI change was not significantly associated with Year 4 child BMI z-score.

Conclusion

The key indicator of higher child BMI at Year 4 is high BMI at Year 1. Further studies are needed to explore the impact of parental weight change on child BMI z-score and whether interventions targeted at overweight or obese parents, can improve their child’s BMI z-score.

What Change in Body Mass Index Is Required to Improve Cardiovascular Outcomes in Childhood and Adolescent Obesity through Lifestyle Interventions: A Meta-Regression

Background: Using meta-regression, this article aims at establishing the minimum change in BMI-standard deviation score (SDS) needed to improve lipid profiles and blood pressure in children and adolescents with obesity, to aid future trials and guidelines. Methods: Studies with participants involved in lifestyle interventions, aged 4-19 years, with a diagnosis of obesity according to defined BMI thresholds, were considered for inclusion in a large systematic review. Interventions had to report pre- and post-intervention (or mean change in) BMI-SDS, plus either systolic blood pressure (SBP), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and/or triglycerides (TGs). Random-effects meta-regression quantified the relationship between mean change in BMI-SDS and mean change in cardiovascular outcomes. Results: Seventy-one papers reported various cardiovascular measurements and mean change in BMI-SDS. Fifty-four, 59, 46, and 54 studies were analyzed, reporting a change in SBP, HDL, LDL, and TG, respectively. Reduction in mean BMI-SDS was significantly related to improvements in SBP, LDL, TG, and HDL (p < 0.05); BMI-SDS reductions of 1, 1.2, and 0.7 ensured a mean reduction of SBP, LDL, and TG, respectively, although an equivalent value for HDL improvement was indeterminate. Conclusion: Reductions in mean BMI-SDS of >1, >1.2, or >0.7 are likely to reduce SBP, LDL, and TG, respectively. Further studies are needed to clarify the optimal duration, intensity, and setting for interventions. Consistency is required regarding derived BMI values to facilitate future systematic reviews and meta-analyses.

Experience of nurses measuring preschool body mass index for the Health target: Raising Healthy Kids

INTRODUCTION Childhood obesity is a major health concern in New Zealand. Primary care nurses have been charged with body mass index (BMI) screening and initiating education or referral of 4-year-old children during the Before School Check (B4SC). Asking nurses about their BMI screening experiences when reporting is mandated by the Ministry of Health reveals valuable knowledge to inform the work of health professionals in this area. AIM To explore the experience of nurses performing the B4SC since the inclusion of the Raising Healthy Kids targets into the wellchild check. METHODS Five focus group discussions across New Zealand were conducted using the Nominal Group Technique. Nurses individually recorded their answers to the research question, 'What is your perception of performing the B4SC since the inclusion of the Raising Healthy Kids target in July 2016?'. Group discussion and establishing priorities followed. Researchers collated and analysed data. Results were obtained by adding up scores across groups to provide the final overall themes of: (i) communication; (ii) BMI as a measurement; (iii) cultural norms and socioeconomic situations; (iv) parenting and family structure; and (v) education. RESULTS Communication was the common theme across groups, but other priorities were more specific to the sociodemographic and cultural profile of the areas of practice. Mandatory reporting appears to have had the positive outcome of encouraging nurses to use positive and holistic discussion on health to families rather than concentrating on BMI. Nurses reported using tools to educate parents without implying judgement of their parenting and lifestyle. DISCUSSION Nurses worked hard to maintain relationships with families as they recognised the long-term value of keeping families engaged with health professionals. Where tools were useful, such as the BMI calculator, nurses used these to assist with positive communication. The mandatory nature of the BMI referral had enhanced their skills with difficult conversations.

Weight gain in mid-childhood and its relationship with the fast food environment

Background

Childhood obesity is a serious public health issue. Understanding environmental factors and their contribution to weight gain is important if interventions are to be effective.

Aims

The purpose of this research was to assess the relationship between weight gain in children and accessibility of fast-food outlets.

Methods

A longitudinal sample of 1577 children was created using two time points from the National Child Measurement Programme in South Gloucestershire (2006/7 and 2012/13). A spatial analysis was conducted using a weighted accessibility score on the number of fast-food outlets within a 1-km network radius of each child's residence to quantify access to fast food.

Results

The mean accessibility score for all children was 0.73 (standard deviation: 1.14). Fast-food outlets were more prevalent in areas of deprivation. A moderate association was found between deprivation score and accessibilty score (r = 0.4, P < 0.01). Children who had greater access to fast-food outlets were more likely (odds ratio = 1.89, P = 0.04) to gain significant weight (>50 percentile points) compared to children who had no access to fast-food outlets.

Conclusions

This paper supports previous research that fast-food outlets are more prevalent in areas of deprivation and presents new evidence on fast-food outlets as a potential contributor towards weight gain in mid-childhood.

The effect of childhood deprivation on weight status and mental health in childhood and adolescence: longitudinal findings from the Millennium Cohort Study

BACKGROUND

The study aims were to: (i) examine associations between deprivation at age 7 and health outcomes at age 7 and 14, (ii) determine whether a deprivation gradient to health outcomes exists at age 7 and 14, and (iii) assess the extent to which health outcomes at age 7 are associated with health outcomes at age 14.

METHODS

Data were from wave four and six of the Millennium Cohort Study. Health outcome measures were weight status, and Strengths and Difficulties Questionnaire measured mental health problems. Deprivation was determined using the 2004 English Indices of Multiple Deprivation. Adjusted logistic and multinomial logistic regressions were conducted.

RESULTS

A total of 6109 children (1890 girls) had complete data. Overweight, obesity and mental health problems were greatest among children in the highest deprivation decile at age 7 and 14 (P < 0.001). Health outcomes at age 7 were significantly associated with health outcomes at age 14 (P < 0.001).

CONCLUSIONS

A marked social gradient to weight status and mental health was evident at age 7 and 14, and no evidence of equalization was found. Weight status and mental health in childhood is strongly associated with weight status and mental health in adolescence.

Prevalence of Childhood Overweight and Obesity in Liverpool between 2006 and 2012: Evidence of Widening Socioeconomic Inequalities

The primary aim of this study was to describe the prevalence of childhood overweight and obesity in Liverpool between 2006 and 2012. A secondary aim was to examine the extent to which socioeconomic inequalities relating to childhood overweight and obesity in Liverpool changed during this six-year period. A sample of 50,125 children was created using data from the National Child Measurement Program (NCMP) in Liverpool. The prevalence of overweight and obesity was calculated for Reception and Year 6 aged children in Liverpool for each time period by gender and compared against published averages for England. Logistic regression analyses examined the likelihood of children in Liverpool being classified as overweight and obese based on deprivation level for each time period. Analyses were conducted separately for Reception and Year 6 aged children and were adjusted for gender. The prevalence of overweight and obesity among Reception and Year 6 aged children in Liverpool increased between 2006 and 2012. During the same period, socioeconomic disparities in overweight and obesity prevalence between children living in the most deprived communities in Liverpool and those living in less deprived communities in Liverpool, widened. This study evidences rising rates of overweight and obesity among Liverpool children and widening socioeconomic health inequalities within Liverpool, England’s most deprived city between 2006 and 2012.

A scoping review protocol to map the evidence on interventions to prevent overweight and obesity in children

INTRODUCTION

Obesity has become one of the biggest public health problems of the 21st century. Prevalence of obesity in children and adolescents has increased dramatically worldwide over the last 20 years, and this trend is expected to continue. Obesity in childhood is concerning as it predicts obesity in adulthood, a common risk factor for a wide array of chronic diseases and poor health outcomes. Obesity is preventable and a vast but fragmented body of evidence on preventative interventions is now available. This article outlines the protocol for a scoping review of published literature reviews on interventions to prevent obesity in children. The scoping review addresses the broad research question 'What is the evidence on interventions to prevent childhood obesity?'. It aims to give an overview of the various interventions available, understand those which are effective and identify barriers and facilitators to their effectiveness.

METHODS AND ANALYSIS

The six-staged Arksey and O'Malley methodology framework is used to guide the scoping review process: following the definition of the research questions (stage 1); the eligibility criteria and search strategy are defined (stage 2); the study selection process based on the eligibility criteria identified will follow (stage 3); a framework developed for this review will then inform the extraction and charting of data from the included reviews (stage 4); results will be aggregated and summarised with criteria relevant for health professionals and policy-makers (stage 5); and the optional consultation (stage 6) exercise is not planned.

ETHICS AND DISSEMINATION

Since the scoping review methodology aims at synthetising information from available publications, this study does not require ethical approval. An article reporting the results of the scoping review will be submitted for publication to a scientific journal, presented at relevant conferences and disseminated as part of future workshops with professionals involved in obesity prevention.

Predicting future weight status from measurements made in early childhood: a novel longitudinal approach applied to Millennium Cohort Study data

BACKGROUND/OBJECTIVE

There are reports that childhood obesity tracks into later life. Nevertheless, some tracking statistics such as correlations do not quantify individual agreement, whereas others such as diagnostic test statistics can be difficult to translate into practice. We aimed to employ a novel analytic approach, based on ordinal logistic regression, to predict weight status of 11-year-old children from measurements at age 5 years.

SUBJECTS/METHODS

The UK 1990 growth references were used to generate clinical weight status categories of 12 076 children enrolled in the Millennium Cohort Study. Using ordinal regression, we derived the predicted probability (percent chances) of 11-year-old children becoming underweight, normal weight, overweight, obese and severely obese from their weight status category at age 5 years.

RESULTS

The chances of becoming obese (including severely obese) at age 11 years were 5.7% (95% confidence interval: 5.2 to 6.2%) for a normal-weight 5-year-old child and 32.3% (29.8 to 34.8%) for an overweight 5-year-old child. An obese 5-year-old child had a 68.1% (63.8 to 72.5%) chance of remaining obese at 11 years. Severely obese 5-year-old children had a 50.3% (43.1 to 57.4%) chance of remaining severely obese. There were no substantial differences between sexes. Nondeprived obese 5-year-old boys had a lower probability of remaining obese than deprived obese boys: -21.8% (-40.4 to -3.2%). This association was not observed in obese 5-year-old girls, in whom the nondeprived group had a probability of remaining obese 7% higher (-15.2 to 29.2%). The sex difference in this interaction of deprivation and baseline weight status was therefore -28.8% (-59.3 to 1.6%).

CONCLUSIONS

We have demonstrated that ordinal logistic regression can be an informative approach to predict the chances of a child changing to, or from, an unhealthy weight status. This approach is easy to interpret and could be applied to any longitudinal data set with an ordinal outcome.