Mediators of socioeconomic differences in adiposity among youth: a systematic review

Association between Socioeconomic Position of the Family and Adolescent Obesity in Germany-Analysis of the Mediating Role of Familial Determinants

Background

Obesity's negative impact on young people's health has long been known. The family and its socioeconomic position (SEP) are key determinants in adolescent obesity. However, understanding which familial determinants explain the association remains limited.

Method

The analyses are based on data from the "German Health Interview and Examination Survey for Children and Adolescents" (KiGGS) (1,384 females and 1,332 males aged 11 to 17 years). Logistic regression models explored how familial determinants (family stress, family cohesion, parental smoking, parental sporting activity, and parental overweight) mediated the association between family SEP (parental education, occupational status, and household income) and adolescent obesity.

Results

Significant total effects for the associations between family SEP in childhood and adolescent obesity were found. Splitting the total effect of the family SEP on obesity into direct and indirect effects, all direct effects turned out to be significant. However, all associations involved also indirect effects of familial determinants, except for household income for female adolescents. Parental smoking and overweight were the most relevant mediators for males and females. For male adolescents, parental sporting activity additionally mediated the association between SEP and obesity.

Conclusion

A low SEP in childhood was associated with adolescent obesity. Parental health and health behaviors partly explained the association. For increasing health equality in adolescent health, the consideration of parental health behavior in the planning and implementation of health promotion programs seem to be important.

Socioeconomic Status and Obesity

Obesity is a pervasive public health problem that causes debilitating complications across the life course. One opportunity for preventing the onset of obesity is to focus on its social determinants. Socioeconomic status (SES), which includes factors such as income, educational attainment, occupational prestige, and access to resources, is a key determinant of obesity. In this scoping mini-review, we summarized review articles and meta-analyses of the SES-obesity association. From the 1980s to the present, cross-sectional studies have demonstrated a persistent socioeconomic gradient in obesity in which the association is negative in developed countries and positive in developing countries. Longitudinal studies have revealed the bidirectionality of the SES-obesity association; some studies demonstrate that socioeconomic adversity precedes the onset of obesity, while others provide evidence of reverse causality. While earlier studies relied on anthropometric assessments of weight and height to define obesity, the use of modern technologies like dual-energy x-ray absorptiometry and bioelectrical impedance have demonstrated that the socioeconomic gradient in obesity is robust across multiple indicators of body composition, including direct measures of lean and fat mass. More recently, examination of mediators and moderators of the SES-obesity association have highlighted causal pathways and potential intervention targets, with a focus on health behaviors, environmental conditions, psychological factors, and biological processes. We describe current gaps in knowledge and propose opportunities for future innovation to reduce the burden of obesity and related socioeconomic disparities.

Mediation by parent health literacy and behaviour of socioeconomic inequality in child overweight

BACKGROUND

Socioeconomic inequalities contribute to childhood overweight. Identifying mediators could help reduce these inequalities.

OBJECTIVE

We assessed to what extent and how parental health literacy and health behaviours mediate the relationship between parental socioeconomic status and childhood overweight.

METHODS

Data were taken from the multigenerational prospective Dutch Lifelines Cohort Study. We included 6683 children, baseline age 9.8 years (SD = 2.6), with an average follow-up of 36.2 months (SD = 9.3). Overweight was defined using age- and sex-specific cut-offs. Three indicators of socioeconomic status were included: education, income and occupation. We assessed the mediating role of parental health literacy and health behaviours (smoking, diet, physical activity and alcohol) using causal mediation.

RESULTS

Four additional years of education and an SD-increase in both income and occupation decreased the odds of childhood overweight by 42%, 12% and 20%, respectively. Only parental smoking independently mediated the relationship of both education (6.6%) and occupation (5.7%) with overweight. Parental health behaviours jointly explained 8.4% (education), 19.4% (income) and 9.8% (occupation) per relationship. Lastly, adding parental health literacy explained 10.8% (education), 27.4% (income) and 13.3% (occupation) of these relationships.

CONCLUSIONS

We found large socioeconomic inequalities in childhood overweight. Remarkably, parental smoking was a key mediator. Therefore, prevention targeting smoking may reduce socioeconomic inequalities in childhood overweight.

Breastfeeding duration and brain-body development in 9-10-year-olds: modulating effect of socioeconomic levels

OBJECTIVE

To investigate relationships of breastfeeding duration with brain structure and adiposity markers in youth and how these relationships are modified by neighborhood socioeconomic environments (SEEs).

METHODS

This was a cross-sectional study of youth enrolled in the Adolescent Brain and Cognitive Development (ABCD) Study® (n = 7511). Mixed effects models examined associations of breastfeeding duration with global brain measures and adiposity markers, adjusting for sociodemographic, pre- and post-natal covariates. Stratified analysis was performed by area deprivation index (ADI) tertiles.

RESULTS

Total cortical surface area (SA) (False Discovery Rate - FDR corrected P < 0.001), cortical (FDR corrected P < 0.001) and subcortical gray matter (GM) volume (FDR corrected P < 0.001) increased with increased breastfeeding duration. Body mass index (BMI) z-scores (FDR corrected P = 0.001), waist circumference (FDR corrected P = 0.002) and waist-to-height ratio (WHtR) (FDR corrected P = 0.001) decreased with increased breastfeeding duration. Breastfeeding duration was inversely associated with adiposity in youth from high- and medium- ADI neighborhoods, but positively associated with SA across ADI tertiles.

CONCLUSIONS

In this cross-sectional study, longer breastfeeding duration was associated with lower adiposity indices, particularly in youth from lower SEEs and greater SA across SEE levels. Longer breastfeeding duration showed long-term associations with brain and body development for offspring.

IMPACT

Building on previous findings that longer breastfeeding duration is associated with healthier weight gain, lower obesity risk, and brain white matter development in infancy, our results find longer breastfeeding duration to be associated with lower adiposity indices and greater cortical and subcortical gray matter volume, and cortical surface area during peri-adolescence. Children from lower socioeconomic environments (SEEs) demonstrated stronger negative associations of breastfeeding duration and adiposity indices, and children across SEEs showed positive relationships between breastfeeding duration and cortical surface area. Promoting breastfeeding, particularly among women from lower SEEs would confer long-term benefits to offspring.

Higher childhood weight gain, lower skeletal muscle mass, and higher cereal consumption in normal-weight Japanese women with high-percentage trunk fat: a subanalysis study

Normal-weight but high-percentage trunk fat phenotype was characterized in a setting where adiposity is not associated with educational and socioeconomic status. Body size trajectory since birth, current body composition measured using whole-body dual-energy X-ray absorptiometry, cardiometabolic traits, serum adipokines, and dietary intake were measured cross-sectionally in 251 normal weight Japanese female university students whose fasting triglyceride and homeostasis model assessment-insulin resistance (HOMA-IR) averaged 56 mg/dL and 1.2, respectively. They were grouped according to tertile of percentage trunk fat. Although HOMA-IR did not differ among three groups, high-percentage trunk fat was associated with higher triglyceride and apolipoprotein B, and lower HDL cholesterol and apolipoprotein A1. In multivariate logistic regression analyses, weight-adjusted skeletal muscle mass (OR: 0.13, 95% CI: 0.04-0.38, p < 0.001), weight gain from birth to age 12 years (OR: 1.214、95% CI: 1.008-1.463、p = 0.04), and cereal consumption (OR:1.008, 95% CI: 1.000-1.016, p = 0.04) were associated with high-percentage trunk fat independent of birthweight, HOMA-IR, adipose tissue-insulin resistance index (the product of fasting insulin and free fatty acid), triglyceride, HDL cholesterol, apolipoprotein A1 and B, leptin, adiponectin, blood pressure, and high-sensitivity C-reactive protein. Early childhood growth, lower skeletal muscle mass, and higher cereal consumption may be associated with normal-weight but high-percentage trunk fat phenotype in Japanese female university students in this subanalysis study. Atherogenic profile of lipids and apolipoproteins may be directly related to abdominal fat accumulation.

Effect of COVID-19 Pandemic Lockdowns on Body Mass Index of Primary School Children from Different Socioeconomic Backgrounds

BACKGROUND

Childhood obesity is associated with various health outcomes. Restrictive measures to contain the spread of the Coronavirus Disease 2019 (COVID-19) pandemic, like lockdowns and school closures, affected children's daily structure, physical activity, dietary habits, and sleep quality, possibly exacerbating risk factors for childhood obesity and higher body mass index (BMI) in children. Poor socioeconomic conditions may have led to relatively higher risk for elevated BMI levels following pandemic measures. In this study, the impact of measures related to the COVID-19 pandemic on the BMI of third graders was investigated regarding children's socioeconomic background (SEB).

METHODS

Data from 41,728 children (8.84 ± 0.56 years, 20,431 female) were collected in the context of a cohort study. Children were tested either before the pandemic (preCOVID: Sept2017-March2020, n = 26,314), or following the first (postLDI: Aug2020-Dec2020, n = 6657) or second lockdown in Germany (postLDII: Aug2021-Jan2022, n = 8757). SEB was based on the official school type classification of the state of Berlin. Outcome was BMI standard deviation scores (SDS).

RESULTS

Significant effects of Time and SEB revealed elevated BMIs in postLDI (M = 0.23, p = 0.011) and postLDII (M = 0.22, p = 0.011) compared to preCOVID (M = 0.17) cohorts and higher BMIs for children with lower SEB (b = - 0.13, p < 0.001). A significant Time × SEB interaction indicated that the effect of SEB on children's BMI increased in response to lockdowns, especially in postLDII (b = - 0.05, p = 0.006). Results suggest that the COVID-19-related measures lead to increased BMI in children, and that children of lower SEB were at particular risk for higher BMIs following lockdowns.

CONCLUSIONS

These findings highlight the dependency of children's BMI on societal circumstances. Over the course of two lockdowns in Germany, children have experienced BMI increments, particularly in low socioeconomic areas. Authorities are called into action to counteract increasing rates of childhood weight by promoting physical activity of children and establishing related post-pandemic offers.

Mental health in adolescents with obesity: conflicting views among physicians, a qualitative study

Mental health issues in adolescents with obesity are multifold, with no explicit screening recommendations. The aim of this research is to explore how this screening is performed by physicians and, thus, how it impacts adolescents' care pathways, offering insights into how to improve it through a qualitative study using interpretative phenomenological analysis. Twenty physicians (non-psychiatrist physicians and child and adolescent psychiatrists) involved at various stages in the care pathway were interviewed with semi-structured questionnaires. The findings connect 2 meta-themes. Non-psychiatrist physicians perceive widespread but ill-defined suffering in adolescents with obesity. Non-psychiatrist physicians see screening for mental conditions as mandatory. Unlike child and adolescent psychiatrists, they are not experts in distinguishing psychosocial suffering from psychiatric disorders. Screening is clinical. Adolescents' demand to lose weight in a context of shaming and alexithymia limits their access to psychiatric care. Child and adolescent psychiatrists then redefine the medical response to polymorphous symptoms. Psychiatric diagnoses mainly involve anxiety and depression symptoms, seldom eating disorders.    Conclusion: Physicians have overtly conflicting perspectives over the intensity of mental conditions. Non-psychiatrists, sensitive to perceived distress, seek to have it quickly appraised if they detect a significant suffering. Child and adolescent psychiatrists find appraisal complex to perform in the absence of means, interest, and/or experience. Improving screening requires training health professionals and using multidisciplinary assessment means. What is Known: • Mental health and eating disorders are contributing factors of obesity but their relationship remains complex between cause and consequence. • Mental health conditions and psychosocial suffering are the main complications among adolescents suffering from obesity with guilt, sadness, or stigma. What is New: • Non-psychiatric physicians express their need of a specialized diagnosis to define this suffering, but the lack of availability of psychiatrists and the necessity of time and of a multidisciplinary team lead to a delayed assessment. • For psychiatrists, this suffering is often not a psychiatric condition. Though requiring attention, this can lead to a misunderstanding between professionals.

The Association Between Socioeconomic Status and Use of Time in Australian Children and Adolescents

PURPOSE

There are well-known socioeconomic status (SES) gradients in children and adolescents' health which may be associated with time use. Our aim was to evaluate the association between Australian children's 24-hour time use and SES using four separate surveys from 2005 to 2021.

METHODS

Time use was assessed in 4526 8-19-year-olds from the 2005 Health of Young Victorians, 2007 National Children's Nutrition and Physical Activity, 2015 Child Health CheckPoint, and 2019-21 Life on Holidays study. Each survey used the same reliable, valid, 24-hour recall instrument. SES was quantified using tertiles of household income, education, and postcode-level measures. Compositional data analysis was used to compare 24-hour time use between SES categories, adjusting for age, sex, and puberty.

RESULTS

Time-use compositions differed significantly by SES in each survey. Relative to the lowest SES, children from the highest SES accumulated on average 31 min/day more School-related time, 6 min/day more Passive Transport and 6 min/day more Self-care. Conversely, they accumulated 30 min/day less Screen Time (which included computer time), 11 min/day less sleep, and spent 7 min/day less in Domestic/Social activities. There were only small differences in Quiet Time and Physical Activity.

DISCUSSION

SES-related differences in time use were robust across ages 8-19, a 16-year timespan, diverse Australian geographical regions, and using different SES metrics. The exchange of about 30 min/day between School-related activities and Screen Time amounts to >180 hours extra exposure to School-related activities annually in the highest SES category relative to the lowest, equivalent to >6 weeks of school time per year.

The relative roles of early life, physical activity, sedentarism and diet in social and economic inequalities in body mass index and obesity risk between 9 and 18

Background

Studies in many middle and high-income countries describe an increasing prevalence of adiposity and obesity among children and adolescents. Prevalence is higher among families of low socioeconomic position (SEP) and systematic reviews have identified relevant factors, but have not quantified their relative importance to SEP differentials. This paper examines the relative importance of different factors to Body Mass Index (BMI) and obesity trajectories from age 9 to age 17/18.

Methods

Multi-level models of child BMI/obesity risk trajectory by maternal education were conducted using a nationally representative cohort of children born in Ireland in 1998 and aged 9 at baseline (N = 8568), with follow-up at 13 and 17/18 years (88% and 73% response rate respectively). Models were stratified by sex and both time-varying (e.g. child physical activity, diet, sedentary activity) and time-invariant (e.g. early life) factors were tested.

Results

Significant inverse gradients in BMI and obesity risk by level of maternal education were present across both sexes and at each age; unadjusted absolute differentials in obesity risk between highest/lowest education groups increased by 56% for males and 42% for females between age 9 and 17/18. Early life factors accounted for 22% of the differential in obesity risk between the lowest and highest education groups among males at age 9, falling to 13% at 17/18. Among females the proportion fell from 33 to 23%. Unadjusted absolute high/low maternal education group differentials in BMI were 7.5 times higher among males and 11 times higher among females at 17/18 than at age 9.

Conclusions

Given the importance of early life exposures to subsequent differentials in BMI and obesity risk our findings suggest that policy makers should focus resources on primary prevention during the prenatal and early life period if they wish to reduce the prevalence of child and adolescent obesity.

Association between neighborhood health behaviors and body mass index in Northern Norway: evidence from the Tromsø Study

AIM

The prevalence of overweight and obesity has risen rapidly worldwide, and the ongoing obesity pandemic is one of the most severe public health concerns in modern society. The average body mass index (BMI) of people living in Northern Norway has also steadily increased since the late 1970s. This study aimed to understand how individuals' health behavior is associated with the general health behavior of the people in their neighborhood.

METHODS

Using the population-based Tromsø Study, we examined the life course association between average leisure time physical activity at the neighborhood level and the BMI of individuals living in the same neighborhood. We used a longitudinal dataset following 25,604 individuals living in 33 neighborhoods and performed a linear mixed-effects analysis.

RESULTS

The results showed that participants living in neighborhoods whose residents were more physically active during their leisure time, were likely to have a significantly lower BMI (-0.9 kg/m², 95% CI -1.5 to -0.4). Also, individuals living in neighborhoods whose residents were doing mainly manual work, had significantly higher BMIs (0.7 kg/m², 95% CI 0.4-1.0).

CONCLUSIONS

Our results showed a strong association between the average leisure time physical activity level of neighborhood residents and the higher BMI levels of residents of the same neighborhood.

Proportionate universalism intervention is effective for tackling nutritional social gradient in adolescents: the PRALIMAP-INÈS mixed randomised trial

OBJECTIVE

This study aimed to investigate the effectiveness of proportionate universalism intervention to reduce the slope of the nutritional social gradient in adolescents.

STUDY DESIGN

A mixed (experimental and quasi-experimental) multicentre trial.

METHODS

Data from 985 adolescents of the PRALIMAP-INÈS trial (North-eastern France, 2012-2015) were analysed. For this, adolescents were split into five social classes according to the Family Affluence Scale: Highly Less Advantaged (H.L.Ad; n = 33), Less Advantaged (L.Ad; n = 155), Intermediate (Int; n = 404), Advantaged (Ad; n = 324) and Highly Advantaged (H.Ad; n = 69). The overweight care management was a standard care for all and a strengthened one adapted to the social class of adolescents. The main outcome was the 1-year change of the body mass index z-score (BMIz) slope. Other nutritional outcomes were BMI, ΔBMI_p95 (BMI minus 95th percentile of the WHO reference), %BMI_p95 (percent of 95th percentile of the WHO reference), leisure-time sport, consumption of fruits and vegetables and consumption of sugary foods and drinks.

RESULTS

The inclusion data confirmed a weight social gradient expressed by a significant BMIz linear regression coefficient (β = -0.09 [-0.14 to -0.04], P < 0.0001). The higher the social class, the lower the BMIz. The 1-year BMIz linear regression coefficient was -0.07 [-0.12 to -0.02], corresponding to a significant weight social gradient reduction of 23.3% (β = 0.021 [0.001 to 0.041]; P = 0.04). Consistent results were found for other nutritional outcomes.

CONCLUSIONS

PRALIMAP-INÈS shows that proportionate universalism intervention is effective to reduce the adolescents' nutritional social gradient and suggests that equitable health programmes and policies are a realistic goal.

Childhood obesity is linked to putative neuroinflammation in brain white matter, hypothalamus, and striatum

Neuroinflammation is both a consequence and driver of overfeeding and weight gain in rodent obesity models. Advances in magnetic resonance imaging (MRI) enable investigations of brain microstructure that suggests neuroinflammation in human obesity. To assess the convergent validity across MRI techniques and extend previous findings, we used diffusion basis spectrum imaging (DBSI) to characterize obesity-associated alterations in brain microstructure in 601 children (age 9-11 years) from the Adolescent Brain Cognitive DevelopmentSM Study. Compared with children with normal-weight, greater DBSI restricted fraction (RF), reflecting neuroinflammation-related cellularity, was seen in widespread white matter in children with overweight and obesity. Greater DBSI-RF in hypothalamus, caudate nucleus, putamen, and, in particular, nucleus accumbens, correlated with higher baseline body mass index and related anthropometrics. Comparable findings were seen in the striatum with a previously reported restriction spectrum imaging (RSI) model. Gain in waist circumference over 1 and 2 years related, at nominal significance, to greater baseline RSI-assessed restricted diffusion in nucleus accumbens and caudate nucleus, and DBSI-RF in hypothalamus, respectively. Here we demonstrate that childhood obesity is associated with microstructural alterations in white matter, hypothalamus, and striatum. Our results also support the reproducibility, across MRI methods, of findings of obesity-related putative neuroinflammation in children.

Independent and Joined Association between Socioeconomic Indicators and Pediatric Obesity in Spain: The PASOS Study

Childhood obesity is a public health problem worldwide. An important determinant of child and adolescent obesity is socioeconomic status (SES). However, the magnitude of the impact of different SES indicators on pediatric obesity on the Spanish population scale is unclear. The aim of this study was to assess the association between three SES indicators and obesity in a nationwide, representative sample of Spanish children and adolescents. A total of 2791 boys and girls aged 8 to 16 years old were included. Their weight, height, and waist circumference were measured. SES was assessed using two parent/legal guardian self-reported indicators (educational level -University/non-University- and labor market status -Employed/Unemployed-). As a third SES indicator, the annual mean income per person was obtained from the census section where the participating schools were located (≥12.731€/<12.731€). The prevalence of obesity, severe obesity, and abdominal obesity was 11.5%, 1.4%, and 22.3%, respectively. Logistic regression models showed an inverse association of both education and labor market status with obesity, severe obesity, and abdominal obesity (all p < 0.001). Income was also inversely associated with obesity (p < 0.01) and abdominal obesity (p < 0.001). Finally, the highest composite SES category (University/Employed/≥12.731€ n = 517) showed a robust and inverse association with obesity (OR = 0.28; 95% CI: 0.16-0.48), severe obesity (OR = 0.20; 95% CI: 0.05-0.81), and abdominal obesity (OR = 0.36; 95% CI: 0.23-0.54) in comparison with the lowest composite SES category (Less than University/Unemployed/<12.731€; n = 164). No significant interaction between composite SES categories and age and gender was found. SES is strongly associated with pediatric obesity in Spain.

Outcomes in children of women with type 2 diabetes exposed to metformin versus placebo during pregnancy (MiTy Kids): a 24-month follow-up of the MiTy randomised controlled trial

BACKGROUND

Metformin is increasingly being used during pregnancy, with potentially adverse long-term effects on children. We aimed to examine adiposity in children of women with type 2 diabetes from the Metformin in Women with Type 2 Diabetes in Pregnancy (MiTy) trial, with and without in-utero exposure to metformin, up to 24 months of age.

METHODS

MiTy Kids is a follow-up study that included infants of women who participated in the MiTy randomised controlled trial, receiving either oral 1000 mg metformin twice daily or placebo. Caregivers and researchers remained masked to the type of medication (metformin or placebo) mothers received during their pregnancy. Anthropometric measurements, including weight, height, and skinfold thicknesses, were taken at 3, 6, 12, 18, and 24 months. At 24 months, linear regression was used to compare the BMI Z score and sum of skinfolds in the metformin versus placebo groups, adjusted for confounders. Fractional polynomials were used to assess growth trajectories. This study is registered with ClinicalTrials.gov, NCT01832181.

FINDINGS

Of the 465 eligible children, 283 (61%) were included from 19 centres in Canada and Australia. At 24 months, there was no difference between groups in mean BMI Z score (0·84 [SD 1·52] with metformin vs 0·91 [1·38] with placebo; mean difference 0·07 [95% CI -0·31 to 0·45], p=0·72) or mean sum of skinfolds (23·0 mm [5·2] vs 23·8 mm [5·4]; mean difference 0·8 mm [-0·7 to 2·3], p=0·31). Metformin was not a predictor of BMI Z score at 24 months of age (mean difference -0·01 [95% CI -0·42 to 0·37], p=0·92). There was no overall difference in BMI trajectory but, in males, trajectories were significantly different by treatment (p=0·048); BMI in the metformin group was higher between 6 and 24 months. Children of women with type 2 diabetes were approximately 1 SD heavier than the WHO reference population.

INTERPRETATION

Anthropometrics were similar in children exposed and those not exposed to metformin in utero; hence, overall, data are reassuring with regard to the use of metformin during pregnancy in women with type 2 diabetes and the long-term health of their children.

FUNDING

Canadian Institute for Health Research.

Long-term benefits of breastfeeding on brain and body development among 9-10-year-olds: modulated by socioeconomic environment

Importance

It is yet unknown if breastfeeding (bf) benefits, to brain and body development of children, persist into peri-adolescence and vary by socioeconomic environments (SEEs).

Objective

We aim to investigate SEE-independent and SEE-modulated relationships between bf duration and child brain structure and adiposity markers during peri-adolescence.

Design setting and participants

This was a cross-sectional study of children aged 9-10 enrolled in the multi-center Adolescent Brain and Cognitive Development (ABCD) Study®.

Exposures

Bf duration was self-reported. Neighborhood-level SEE was assessed using area deprivation index (ADI).

Main Outcomes

T1-weighted magnetic resonance imaging was used to assess global brain measures: volumes of white, cortical, and subcortical gray matter (GM), cortical thickness, and surface area (SA). Adiposity markers included age- and sex-specific body mass index (BMI z- scores), waist circumference, and waist-to-height ratio (WHtR). Mixed effects models examined associations of bf duration with brain structure and adiposity markers controlling for sociodemographic, pre- and post-natal covariates. Stratified analysis was performed by tertiles of ADI.

Results

The sample consisted of 7,511 children (51.7% males; 18.8% no bf, 35.3% 1-6 months, 24.9% 7-12 months, 21.0% >12 months). Child's total SA (β (95% CI) = 0.053 (0.033, 0.074); FDR corrected P <0.001), cortical (β (95% CI) = 0.021 (0.010, 0.032); FDR corrected P <0.001) and subcortical GM volume (β (95% CI) = 0.016 (0.003, 0.030); FDR corrected P <0.001) increased monotonically with bf duration, after controlling for covariates. Child's BMI z -scores (β (95% CI) = -0.040 (-0.063, -0.016); FDR corrected P =0.001), waist circumference (β (95% CI) = -0.037 (-0.060, -0.014), FDR corrected P =0.002) and WHtR (β (95% CI) = -0.040 (-0.064, -0.018), FDR corrected P =0.001) decreased monotonically with increased bf duration, after controlling for covariates. Bf duration was inversely associated with adiposity in children from high- and medium-ADI neighborhoods. Bf duration was positively associated with SA across ADI tertiles.

Conclusions and Relevance

Our results imply that long-term benefits of bf on body and brain development in offspring increase as bf duration increases, particularly in children from low SEEs. Policies and social support aimed to incremental increases in bf duration among women from low SEEs would confer long-term benefits for offspring.

Key Points

Question: Do benefits of breastfeeding(bf), on children's brain and body development, persist long-term and are these benefits uniform across socioeconomic environments (SEEs)?Findings: Longer bf duration is associated with lower adiposity, greater cortical and subcortical gray matter volume, and cortical surface area in 9-10-year-old children. Children from lower SEEs showed stronger negative relationships between bf duration and adiposity. Children across all SEEs demonstrated positive relationships between bf duration and surface area.Meaning: Our results imply that long-term benefits to child brain and body development increase with bf duration; and children from lower SEEs benefited more from longer bf duration.

The role of energy balance related behaviors in socioeconomic inequalities in childhood body mass index: A comparative analysis of Germany, the Netherlands, the United Kingdom, and the United States

Socioeconomic inequalities in childhood Body Mass Index (BMI) are becoming increasingly more pronounced across the world. Although countries differ in the direction and strength of these inequalities, cross-national comparative research on this topic is rare. This paper draws on harmonized longitudinal cohort data from four wealthy countries-Germany, the Netherlands, the United Kingdom (UK), and the United States (US)-to 1) map cross-country differences in the magnitude of socioeconomic inequalities in childhood BMI, and 2) to examine cross-country differences in the role of three energy-balance-related behaviors-physical activity, screen time, and breakfast consumption-in explaining these inequalities. Children were aged 5-7 at our first timepoint and were followed up at age 8-11. We used data from the German National Educational Panel Study, the Dutch Generation R study, the UK Millennium Cohort Study and the US Early Childhood Longitudinal-Kindergarten Study. All countries revealed significant inequalities in childhood BMI. The US stood out in having the largest inequalities. Overall, inequalities between children with low versus medium educated parents were smaller than those between children with high versus medium educated parents. The role of energy-balance-related behaviors in explaining inequalities in BMI was surprisingly consistent. Across countries, physical activity did not, while screen time and breakfast consumption did play a role. The only exception was that breakfast consumption did not play a role in the US. Cross-country differences emerged in the relative contribution of each behavior in explaining inequalities in BMI: Breakfast consumption was most important in the UK, screen time explained most in Germany and the US, and breakfast consumption and screen time were equally important in the Netherlands. Our findings suggest that what constitutes the most effective policy intervention differs across countries and that these should target both children from medium as well as low educated families.

Mediators of socioeconomic differences in overweight and obesity among youth in Ireland and the UK (2011–2021): a systematic review

Background

By 2025, adult obesity prevalence is projected to increase in 44 of 53 of European-region countries. Childhood obesity tracks directly onto adult obesity, and children of low socioeconomic position families are at disproportionately higher risk of being obese compared with their more affluent peers. A previous review of research from developed countries identified factors mediating this relationship. This systematic review updates and extends those findings specifically within the context of Ireland and the United Kingdom.

Objective

The aim of this systematic review is to summarise peer-reviewed research completed in Ireland and the United Kingdom between 2011–2021 examining mediators of socioeconomic differentials in adiposity outcomes for youth.

Design

An electronic search of four databases, Ovid MEDLINE, Embase, Web of Science and EBSCOhost was conducted. Quantitative studies, published in the English language, examining mediators of socioeconomic differentials in adiposity outcomes in youth, and conducted in Ireland and the United Kingdom between 2011–2021 were included. An appraisal of study quality was completed. The systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

Following screening, a total of 23 papers were eligible for inclusion. Results indicate socioeconomic differentials for Ireland and the United Kingdom follow similar patterns to other developed countries and have similar mediating factors including early life and parent-level factors. However, this review identified additional factors that mediate the relationship, namely access to green space and favorable neighborhood conditions. Identifying these factors present further opportunities for potential interventions and confirm the requirement for tailored and appropriate research and interventions for Ireland and the United Kingdom.

Conclusion

This review identified several modifiable factors that should be considered when planning interventions aimed at reducing socioeconomic differentials in adiposity among youth in Ireland and the United Kingdom. Support was found for interventions to be made as early as possible in an at-risk child’s life, with the prenatal and preschool periods considered the most efficacious. Results were equivocal about the role of physical activity in the risk of childhood overweight and obesity. While multi-country analyses provide excellent overviews, country- or area-specific research may produce more nuanced, and potentially more powerful findings, which can help better inform policy responses and interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14004-z.

Mediators of differences by parental education in weight-related outcomes in childhood and adolescence in Norway

Studies exploring mediators of socioeconomic inequalities in excess weight gain in early-life and subsequent overweight/obesity (OW/OB) among youth are limited. Thus, this study examined the mediating role of prenatal and early postnatal factors and child energy balance-related behaviours (EBRB) in the effects of parental education on (i) excess weight gain from birth to 2 years and (ii) OW/OB at 5, 8 and 14 years. The Norwegian Mother, Father and Child Cohort Study was used to include participants at the ages of 2 (n = 59,597), 5 (n = 27,134), 8 (n = 28,285) and 14 (n = 11,278) years. Causal mediation analyses using the inverse odds weighting approach were conducted. Children of low-educated parents had a higher conditional excess weight gain at 2 years compared to children of high-educated parents (total effect, RRTE = 1.06; 95% CI 1.01, 1.10). The joint mediation effects of the prenatal and early postnatal factors explained most of the total effect of low education on conditional excess weight gain at 2 years. Children of low-educated parents had a higher risk of OW/OB at 5, 8 and 14 years compared to children of high-educated parents. The mediators jointly explained 63.7%, 67% and 88.9% of the total effect of parental education on OW/OB among 5, 8 and 14 year-old-children, respectively. Of the total mediated effects at 5, 8 and 14 years, the prenatal and early postnatal mediators explained 59.2%, 61.7% and 73.7%, whereas the child EBRB explained 10.3%, 15.8.0%% and 34.8%. The mediators included were found to have a considerable mediating effect in the associations explored, in particular the prenatal and early postnatal factors. If truly causal, the findings could indicate potential targets for interventions to tackle socioeconomic inequalities in OW/OB from birth to adolescence.

Pathways of Parental Education on Children's and Adolescent's Body Mass Index: The Mediating Roles of Behavioral and Psychological Factors

Aim

The increasing body mass index (BMI) often followed by overweight and obesity is a global health problem of the 21st century. Children and adolescents with lower socioeconomic status are more affected than their counterparts. The mechanisms behind these differences must be well understood to develop effective prevention strategies. This analysis aims at examining the association of parental education as an indicator of the socioeconomic status on children's and adolescent's body mass index and the role of behavioral and psychological risk factors for a higher BMI longitudinally.

Methods

The analysis was based on a nationwide sample of N = 460 children and adolescents, aged 11 to 17 at baseline (2009-2012), who took part in the representative BELLA study, the mental health module of the German National Health Interview and Examination Survey among Children and Adolescents (KiGGS). A follow-up was conducted 5 years later. Using mediation analyses, the mediating effects of breakfast consumption, consumption of sugar-sweetened beverages, screen time, physical activity, mental health problems (Strengths and Difficulties Questionnaire), and health-related quality of life (KIDSCREEN-10) on the association of parent's years of education on their children's BMI were investigated.

Results

A lower level of parental education was significantly associated with a higher BMI in children and adolescents 5 years later. The association was partially mediated by breakfast consumption and total screen time, with breakfast consumption mediating 16.7% and total screen time 27.8% of the association. After controlling for age, gender, and migration status, only breakfast consumption remained a partial mediator (8.5%). Other included variables had no mediating effects.

Conclusions

Preventive measures should be mainly targeted at children and adolescents of parents with lower educational levels. Tailored strategies to prevent the development of overweight and obesity in this population among children and adolescents should promote daily breakfast consumption at home and reducing screen time.

Associations between family structure and adolescents' food habits

OBJECTIVE

To investigate family structure differences in adolescents' consumption of fruit, vegetables, sweets and sugar-added soft drinks with adjustments for socio-demographic and socio-economic variables.

DESIGN

Cross-sectional data from the Health Behaviour in School-aged Children survey.

SETTING

Norwegian primary and secondary schools.

PARTICIPANTS

Adolescents (n 4475) aged 11, 13, 15 and 16 years.

RESULTS

After adjusting for covariates, living in a single-mother family was associated with lower vegetable consumption (OR 0·76, 95 % CI 0·63, 0·91) and higher soft drink consumption (OR 1·29, 95 % CI 1·06, 1·57). Living in a mother and stepfather family was negatively associated with fruit (OR 0·71, 95 % CI 0·54, 0·95) and vegetable (OR 0·72, 95 % CI 0·54, 0·97) consumption. Living in a single-father family was associated with lower sweets consumption (OR 0·48, 95 % CI 0·32, 0·72). No significant interactions were demonstrated between family structure and socio-demographic or socio-economic covariates.

CONCLUSIONS

The study suggests that an independent association between family structure and adolescents' food habits exists.

Alternative pediatric metabolic syndrome definitions impact prevalence estimates and socioeconomic gradients

BACKGROUND

There is no consensus regarding the definition of pediatric metabolic syndrome (MetS). This study assessed the impact of alternative definitions on the prevalence, children identified, and association with socioeconomic status (SES).

METHODS

Data were from the prospective multigenerational Dutch Lifelines Cohort Study. At baseline, 9754 children participated, and 5085 (52.1%) with average follow-up of 3.0 (SD = 0.75) years were included in the longitudinal analyses; median ages were 12 (IQR = 10-14) and 14 years (IQR = 12-15), respectively. We computed MetS prevalence according to five published definitions and measured the observed proportion of positive agreement. We used logistic regression to assess the SES-MetS association, adjusted for age and sex. Longitudinal models were also adjusted for baseline MetS.

RESULTS

MetS prevalence and positive agreement varied between definitions, from 0.7 to 3.0% and from 0.34 (95% CI: 0.28; 0.41) to 0.66 (95% CI: 0.58; 0.75) at baseline, respectively. We consistently found a socioeconomic gradient; in the longitudinal analyses, each additional year of parental education reduced the odds of having MetS by 8% (95% CI: 1%; 14%) to 19% (95% CI: 7%; 30%).

CONCLUSIONS

Alternative MetS definitions had differing prevalence estimates and agreed on 50% of the average number of cases. Additionally, regardless of the definition, low SES was a risk factor for MetS.

IMPACT

Little is known about the impact of using different definitions of pediatric metabolic syndrome on study results. Our study showed that the choice of pediatric metabolic syndrome definition produces very different prevalence estimates. We also showed that the choice of definition influences the socioeconomic gradient. However, low socioeconomic status was consistently a risk factor for having pediatric metabolic syndrome. In conclusion, studies using different definitions of metabolic syndrome could be reasonably compared when investigating the association with socioeconomic status but not always validly when comparing prevalence studies.

Socioeconomic inequalities in children's weight, height and BMI trajectories in Norway

Studies exploring when social inequalities in body mass index (BMI) and its composites emerge and how these evolve with age are limited. Thus, this study explored parental income and education related inequalities in children's weight, height, weight velocity and body mass index among Norwegian children from 1 month to 8 years. The study population included 59,927 family/children pairs participating in the Norwegian Mother, Father, and Child Cohort Study. Growth was modelled using the Jenss-Bayley model and linear mixed effects analyses were conducted. Maternal and paternal educational differences in children's weight and BMI trajectories emerged during infancy, continuing to age 8 years. Parental income-related inequalities in children's weight were observed from the age of 1 month to 4 years for maternal and up to 1 year for paternal income-related differences but then disappeared. Parental income-related inequalities in child's BMI were observed from 18 months to 8 years for maternal income, and from 9 months to 8 years for paternal income-related differences. These results suggest that social inequalities in children's BMI present early in infancy and continue to 8 years of age. The inequalities sometimes differed by indicator of socioeconomic position used. Interventions to combat these inequalities early in life are, thus needed.

Association between Breakfast Skipping and Body Weight-A Systematic Review and Meta-Analysis of Observational Longitudinal Studies

Globally, increasing rates of obesity are one of the most important health issues. The association between breakfast skipping and body weight is contradictory between cross-sectional and interventional studies. This systematic review and meta-analysis aims to summarize this association based on observational longitudinal studies. We included prospective studies on breakfast skipping and overweight/obesity or weight change in adults. The literature was searched until September 2020 in PubMed and Web of Science. Summary risk ratios (RRs) or β coefficients with a 95% confidence interval (CI), respectively, were estimated in pairwise meta-analyses by applying a random-effects model. In total, nine studies were included in the systematic review and three of them were included in the meta-analyses. The meta-analyses indicated an 11% increased RR for overweight/obesity when breakfast was skipped on ≥3 days per week compared to ≤2 days per week (95% CI: 1.04, 1.19, n = two studies). The meta-analysis on body mass index (BMI) change displayed no difference between breakfast skipping and eating (β = −0.02; 95% CI: −0.05, 0.01; n = two studies). This study provides minimal evidence that breakfast skipping might lead to weight gain and the onset of overweight and obesity.

Socioeconomic Status and Childhood Obesity: a Review of Literature from the Past Decade to Inform Intervention Research

PURPOSE OF REVIEW

This is a review of the patterns, conceptualization, and suggested mechanisms underlying the relationship of socioeconomic status (SES) to obesity in childhood and the implications of these data for interventions going forward.

RECENT FINDINGS

Adiposity and SES are negatively associated in high-income countries and positively associated in medium to low-income countries. Several mechanisms, such as early introduction of solid food and parental behaviors, which may explain the association of SES and adiposity, have been identified. Parental education and adiposity and early pediatric nutrition appear to be particularly salient SES-related effectors on adiposity. There is a clear association of SES and adiposity which is affected by population affluence. Evaluation of the relationship of SES and obesity in children are complicated by the complexity of SES and lack of common definition. A number of SES-related interventional targets have been identified. Intervention research should ensure they are addressing SES-associated issues in the study population.

Health-Related Behaviors in Adolescents Mediate the Association between Subjective Social Status and Body Mass Index

The aim of this study was to explore the association between adolescent subjective social status (SSS) and body mass index (BMI) at two different time points and to determine whether this association was mediated by health-related behaviors. In 2002 (n = 1596) and 2017 (n = 1534), tenth-grade students (15-16 years old) in schools in the District of Oppland, Norway, completed a survey. Four categories of perceived family economy were measured as SSS, and structural equation modeling was performed, including a latent variable for unhealthy behavior derived from cigarette smoking, snuff-use, and alcohol-drinking as well as dietary and exercise as mediators. No linear association was found between SSS and BMI in 2002 (standardized ß -0.02, (95% confidence interval (CI) -0.07, 0.03)). However, an association was present in 2017 (standardized ß -0.05 (95% CI -0.10, -0.001)), indicating that BMI decreased by 0.05 standard deviations (0.05 × 3.1 = 0.16 BMI unit) for every one-category increase in SSS. This association was mediated by exercise (standardized ß -0.013 (95% CI -0.02, -0.004) and unhealthy behavior (standardized ß -0.009 (95% CI -0.002, -0.04)). In conclusion, a direct association between SSS and BMI was found in 2017 in this repeated cross-sectional survey of 15-16-year-old Norwegian adolescents. This association was mediated through health-related behavior.

Environmental Interventions to Reduce the Consumption of Sugar-Sweetened Beverages: Abridged Cochrane Systematic Review

BACKGROUND

Regular consumption of sugar-sweetened beverages (SSB) can increase the risk for obesity, type 2 diabetes, cardiovascular disease, and dental caries. Interventions that alter the physical or social environment in which individuals make beverage choices have been proposed to reduce the consumption of SSB.

METHODS

We included randomised controlled, non-randomised controlled, and interrupted time series studies on environmental interventions, with or without behavioural co-interventions, implemented in real-world settings, lasting at least 12 weeks, and including at least 40 individuals. Studies on the taxation of SSB were not included, as these are subject of a separate Cochrane review. We used standard Cochrane methods for data extraction, risk of bias assessment, and evidence grading and synthesis. Searches were updated to January 24, 2018.

RESULTS

We identified 14,488 unique records and assessed 1,030 full texts for eligibility. We included 58 studies comprising a total of 1,180,096 participants and a median length of follow-up of 10 months. We found moderate-certainty evidence for consistent associations with decreases in SSB consumption or sales for the following interventions: traffic light labelling, price increases on SSB, in-store promotion of healthier beverages in supermarkets, government food benefit programs with incentives for purchasing fruits and vegetables and restrictions on SSB purchases, multi-component community campaigns focused on SSB, and interventions improving the availability of low-calorie beverages in the home environment. For the remaining interventions we found low- to very-low-certainty evidence for associations showing varying degrees of consistency.

CONCLUSIONS

With observed benefits outweighing observed harms, we suggest that environmental interventions to reduce the consumption of SSB be considered as part of a wider set of measures to improve population-level nutrition. Implementation should be accompanied by evaluations using appropriate methods. Future studies should examine population-level effects of interventions suitable for large-scale implementation, and interventions and settings not yet studied thoroughly.

Correlates of screen time and mediators of differences by parental education among adolescents

Background

Existing literature shows that there is an inverse association between socioeconomic position and screen time among adolescents. What is less known is the mechanism behind these differences. The study aimed to explore individual, interpersonal and neighborhood environmental correlates of total screen time (TST) among adolescents and to assess their mediating role in the association between parental education and TST.

Methods

A cross-sectional study including 706 adolescents (mean age of 13.6 (SD = 0.3)) was used to collect data at schools through an online questionnaire. Multiple regression analyses were used to explore factors associated with TST. Mediation analyses were conducted to assess whether these factors mediated the association between parental education and TST.

Results

Multiple linear regression analyses, adjusted for gender and age, showed that parental modelling of TV and movie streaming, TV/movie streaming during dinner and access to screens were positively related to TST. Self-efficacy towards limiting TV and movie streaming, self-efficacy towards limiting computer/electronic game use, and the perceived opportunities for physical activity in the neighborhood were inversely related to total screen time. All of these factors except self-efficacy towards limiting TV and movie streaming mediated the association between parental education and TST.

Conclusions

The study identified several modifiable factors at the individual, interpersonal and neighborhood environmental levels that can be targeted in interventions aimed at decreasing screen time among youth in general and among those with a low socioeconomic position in particular.

Influence of early-life risk factors on socioeconomic inequalities in weight gain

Background

Previous research has examined the role of early-life risk factors on childhood weight gain.The extent to which these factors drive socioeconomic differences in weight is unclear. We aimed to quantify the influence of early-life risk factors on the development of socioeconomic inequalities in children's body mass index (BMI) z-score at 10-11 years.

Methods

Overall, 2186 children from the Longitudinal Study of Australian Children were examined. Socioeconomic position (SEP) was measured as a continuous composite of parent's education, occupation and income. The Product of Coefficients mediation method was used to quantify the contribution of maternal smoking during pregnancy, gestational diabetes, prematurity, caesarean section, birthweight, not being breastfed, early introduction of solid food, maternal BMI and paternal BMI to the relationship between SEP and BMI z-score.

Results

Each increasing decile of SEP (higher SEP) was associated with a 0.05 unit lower (95% CI: -0.06, -0.03) BMI z-score at 10-11 years. In total, 83.5% of these differences in BMI z-score could be explained by socioeconomic differences in maternal smoking during pregnancy (26.9%), maternal BMI (39.6%) and paternal BMI (17.0%).

Conclusions

Interventions to reduce socioeconomic inequalities in excess weight gain during childhood should support the attainment of a healthy parental weight and prevent smoking during pregnancy.

Associations Between Boys' Early Childhood Exposure to Family and Neighborhood Poverty and Body Mass Index in Early Adolescence

OBJECTIVE

To test relations between exposure to poverty, in the forms of family income and neighborhood deprivation, during three developmental stages, and children's body mass index (BMI) in early adolescence.

METHODS

Data came from a longitudinal sample of racially diverse, urban, low-income boys. Interactions between family income to needs and census-derived neighborhood deprivation at three developmental stages-early childhood (18 and 24 months), preschool-to-school entry (3.5 and 6 years), and school-age (8 and 10 years)-were tested in relation to BMI at age 11.

RESULTS

There was a significant interaction whereby higher income predicted lower BMI only in the context of low levels of neighborhood deprivation in early childhood. In high-deprivation neighborhoods, higher income was associated with risk for overweight/obesity in early adolescence. This pattern was found to be specific to income and neighborhood deprivation measured in early childhood.

CONCLUSIONS

Findings have implications for policy relevant to obesity prevention. More research on associations between early exposure to poverty and later risk for obesity on low-income samples is warranted, as the relationship is likely complex and influenced by many different factors, including the family and neighborhood food environments and child health behaviors.

Gender-specific mediators of the association between parental education and adiposity among adolescents: the HEIA study

Identifying the mechanisms behind socioeconomic inequalities in adiposity among youth is vital for efforts aimed at combating these inequalities. The study explored whether a broad range of behavioral and familial factors mediated the associations between parental education and indicators of adiposity among adolescents. Baseline data from a school-based intervention study conducted in 2007 among 11-year-old adolescents were used. Anthropometric outcomes, physical activity and sedentary time among adolescents were objectively measured. Other behavioral variables and parental waist circumference were self-reported. Mediation analyses were conducted. Among boys, maternal waist circumference (WC), paternal WC and TV viewing mediated 16%, 11.5% and 13% of the association between parental education and adolescent WC. The respective proportions when body fat percentage was used as the outcome variable were 22.5%, 16% and 21%. Among girls, maternal and paternal WC mediated 20% and 14% of the association between parental education and WC. The respective proportions when body fat percentage was used as the outcome variable were 14% and 10%. Other included variables did not play any mediating role. Parental WC was found to be a mediator of socioeconomic differences in adiposity in both genders; underlying mechanisms were however not investigated. Among boys, reducing TV time could contribute to the reduction of social inequalities in adiposity.

Development and validation of a search filter to identify equity-focused studies: reducing the number needed to screen

Background

Health inequalities, worse health associated with social and economic disadvantage, are reported by a minority of research articles. Locating these studies when conducting an equity-focused systematic review is challenging due to a deficit in standardised terminology, indexing, and lack of validated search filters. Current reporting guidelines recommend not applying filters, meaning that increased resources are needed at the screening stage.

Methods

We aimed to design and test search filters to locate studies that reported outcomes by a social determinant of health. We developed and expanded a ‘specific terms strategy’ using keywords and subject headings compiled from recent systematic reviews that applied an equity filter. A ‘non-specific strategy’ was compiled from phrases used to describe equity analyses that were reported in titles and abstracts, and related subject headings. Gold standard evaluation and validation sets were compiled. The filters were developed in MEDLINE, adapted for Embase and tested in both. We set a target of 0.90 sensitivity (95% CI; 0.84, 0.94) in retrieving 150 gold standard validation papers. We noted the reduction in the number needed to screen in a proposed equity-focused systematic review and the proportion of equity-focused reviews we assessed in the project that applied an equity filter to their search strategy.

Results

The specific terms strategy filtered out 93-95% of all records, and retrieved a validation set of articles with a sensitivity of 0.84 in MEDLINE (0.77, 0.89), and 0.87 (0.81, 0.92) in Embase. When combined (Boolean ‘OR’) with the non-specific strategy sensitivity was 0.92 (0.86, 0.96) in MEDLINE (Embase 0.94; 0.89, 0.97). The number needed to screen was reduced by 77% by applying the specific terms strategy, and by 59.7% (MEDLINE) and 63.5% (Embase) by applying the combined strategy. Eighty-one per cent of systematic reviews filtered studies by equity.

Conclusions

A combined approach of using specific and non-specific terms is recommended if systematic reviewers wish to filter studies for reporting outcomes by social determinants. Future research should concentrate on the indexing standardisation for equity studies and further development and testing of both specific and non-specific terms for accurate study retrieval.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0567-x) contains supplementary material, which is available to authorized users.

The Potential Cost-Effectiveness and Equity Impacts of Restricting Television Advertising of Unhealthy Food and Beverages to Australian Children

Television (TV) advertising of food and beverages high in fat, sugar and salt (HFSS) influences food preferences and consumption. Children from lower socioeconomic position (SEP) have higher exposure to TV advertising due to more time spent watching TV. This paper sought to estimate the cost-effectiveness of legislation to restrict HFSS TV advertising until 9:30 pm, and to examine how health benefits and healthcare cost-savings differ by SEP. Cost-effectiveness modelling was undertaken (i) at the population level, and (ii) by area-level SEP. A multi-state multiple-cohort lifetable model was used to estimate obesity-related health outcomes and healthcare cost-savings over the lifetime of the 2010 Australian population. Incremental cost-effectiveness ratios (ICERs) were reported, with assumptions tested through sensitivity analyses. An intervention restricting HFSS TV advertising would cost AUD5.9M (95% UI AUD5.8M⁻AUD7M), resulting in modelled reductions in energy intake (mean 115 kJ/day) and body mass index (BMI) (mean 0.352 kg/m²). The intervention is likely to be cost-saving, with 1.4 times higher total cost-savings and 1.5 times higher health benefits in the most disadvantaged socioeconomic group (17,512 HALYs saved (95% UI 10,372⁻25,155); total cost-savings AUD126.3M (95% UI AUD58.7M⁻196.9M) over the lifetime) compared to the least disadvantaged socioeconomic group (11,321 HALYs saved (95% UI 6812⁻15,679); total cost-savings AUD90.9M (95% UI AUD44.3M⁻136.3M)). Legislation to restrict HFSS TV advertising is likely to be cost-effective, with greater health benefits and healthcare cost-savings for children with low SEP.

Socioeconomic inequalities in childhood and adolescent body-mass index, weight, and height from 1953 to 2015: an analysis of four longitudinal, observational, British birth cohort studies

BACKGROUND

Socioeconomic inequalities in childhood body-mass index (BMI) have been documented in high-income countries; however, uncertainty exists with regard to how they have changed over time, how inequalities in the composite parts (ie, weight and height) of BMI have changed, and whether inequalities differ in magnitude across the outcome distribution. Therefore, we aimed to investigate how socioeconomic inequalities in childhood and adolescent weight, height, and BMI have changed over time in Britain.

METHODS

We used data from four British longitudinal, observational, birth cohort studies: the 1946 Medical Research Council National Survey of Health and Development (1946 NSHD), 1958 National Child Development Study (1958 NCDS), 1970 British Cohort Study (1970 BCS), and 2001 Millennium Cohort Study (2001 MCS). BMI (kg/m2) was derived in each study from measured weight and height. Childhood socioeconomic position was indicated by the father's occupational social class, measured at the ages of 10-11 years. We examined associations between childhood socioeconomic position and anthropometric outcomes at age 7 years, 11 years, and 15 years to assess socioeconomic inequalities in each cohort using gender-adjusted linear regression models. We also used multilevel models to examine whether these inequalities widened or narrowed from childhood to adolescence, and quantile regression was used to examine whether the magnitude of inequalities differed across the outcome distribution.

FINDINGS

In England, Scotland, and Wales, 5362 singleton births were enrolled in 1946, 17 202 in 1958, 17 290 in 1970, and 16 404 in 2001. Low socioeconomic position was associated with lower weight at childhood and adolescent in the earlier-born cohorts (1946-70), but with higher weight in the 2001 MCS cohort. Weight disparities became larger from childhood to adolescence in the 2001 MCS but not the earlier-born cohorts (pinteraction=0·001). Low socioeconomic position was also associated with shorter height in all cohorts, yet the absolute magnitude of this difference narrowed across generations. These disparities widened with age in the 2001 MCS (pinteraction=0·002) but not in the earlier-born cohorts. There was little inequality in childhood BMI in the 1946-70 cohorts, whereas inequalities were present in the 2001 cohort and widened from childhood to adolescence in the 1958-2001 cohorts (pinteraction<0·05 in the later three cohorts but not the 1946 NSHD). BMI and weight disparities were larger in the 2001 cohort than in the earlier-born cohorts, and systematically larger at higher quantiles-eg, in the 2001 MCS at age 11 years, a difference of 0·98 kg/m2 (95% CI 0·63-1·33) in the 50th BMI percentile and 2·54 kg/m2 (1·85-3·22) difference at the 90th BMI percentile were observed.

INTERPRETATION

Over the studied period (1953-2015), socioeconomic-associated inequalities in weight reversed and those in height narrowed, whereas differences in BMI and obesity emerged and widened. These substantial changes highlight the impact of societal changes on child and adolescent growth and the insufficiency of previous policies in preventing obesity and its socioeconomic inequality. As such, new and effective policies are required to reduce BMI inequalities in childhood and adolescence.

FUNDING

UK Economic and Social Research Council, Medical Research Council, and Academy of Medical Sciences/the Wellcome Trust.