BMI may underestimate the socioeconomic gradient in true obesity

Childhood obesity's influence on socioeconomic disparities in young adolescents' mental health

PURPOSE

We investigated whether socioeconomic inequalities in young adolescents' mental health are partially due to the unequal distribution of childhood obesity across socioeconomic positions (SEP), i.e. differential exposure, or due to the effect of obesity on mental health being more detrimental among certain SEPs, i.e. differential impact.

METHODS

We studied 4660 participants of the Generation R study, a population-based study in the Netherlands. SEP was estimated by mother's education and household income at age five of the child. We estimated the contribution of the mediating and moderating effects of high body fat percentage to the disparity in mental health. This was done through a four-way decomposition using marginal structural models with inverse probability of treatment weighting.

RESULTS

Comparing children with the least to most educated mothers and the lowest to highest household income, the total disparity in emotional problems was 0.98 points (95%CI:0.35-1.63) and 1.68 points (95%CI:1.13-2.19), respectively. Of these total disparities in emotional problems, 0.50 points (95%CI:0.15-0.85) and 0.24 points (95%CI:0.09-0.46) were due to the differential exposure to obesity. Obesity did not contribute to disparities in behavioural problems.

CONCLUSION

Addressing the heightened obesity prevalence among children in low SEP families may reduce inequalities in emotional problems in early adolescence.

Chronic exercise interventions for executive function in overweight children: a systematic review and meta-analysis

Objectives

To systematically evaluate the effectiveness of chronic exercise in physical activity (PA) as an intervention for executive functions (EFs) in children.

Methods

We conducted a systematic search in the following online databases: Web of Science, Cochrane Library, PubMed, Embase, and EBSCOhost. The timing is from database inception to July 2023, following PRISMA guidelines. Our inclusion criteria required studies reporting executive function (EF) levels in overweight children (age 0-18 years) before and after interventions. The Cochrane risk of bias tool assessed study bias, and Egger's test examined publication bias. Subgroup analyses considered three moderators: intervention duration, weekly frequency, and session length.

Results

The meta-analysis included a total of 10 studies with 843 participants. It revealed a statistically significant yet relatively small overall positive effect (g = 0.3, 95% CI 0.16-0.44, P < 0.01) of chronic exercise on EF in overweight children. Importantly, there was no significant heterogeneity (Q = 11.64, df = 12, P = 0.48; I2 = 0).

Conclusions

Chronic exercise interventions had a consistent positive impact on EF, irrespective of intervention duration, weekly frequency, or session length. However, given limitations in the number and design of studies, further high-quality research is needed to strengthen these conclusions.

Systematic Review Registration

PROSPERO identifier (CRD42023468588).

Physical activity and exercise alter cognitive abilities, and brain structure and activity in obese children

The prevalence of childhood obesity is increasing to such an extent that it has become a major global public health problem in the 21st century. Obesity alters children’s brain structure and activity and impairs their cognitive abilities. On the basis of these findings, it is necessary for educational and healthcare institutions to combat childhood obesity through preventive and therapeutic strategies. In general, exercise and physical activity are considered common but effective methods for improving physical, psychological, and brain health across the life span. Therefore, this review article mainly focuses on existing neuroimaging studies that have used magnetic resonance imaging (MRI), and functional magnetic resonance imaging (fMRI)to assess children’s brain anatomy and neural activity. We intended to explore the roles of physical activity and exercise in modulating the associations among childhood obesity, cognitive abilities, and the structure and activity of the brain.

Family socioeconomic status and childhood adiposity in Europe - A scoping review

Childhood obesity is a considerable public health problem worldwide. In Europe, lower parental socioeconomic status (SES) relates to higher childhood adiposity. This scoping review strives to discover, which SES indicators are the most commonly used and meaningful determinants of childhood adiposity (greater level of continuous adiposity indicator, e.g. body mass index z-score, or overweight or obesity categorized by established definitions). The review focused on studies about European general populations from the 21st century (January 2000-April 2021) considering children and adolescents aged 0-17 years. PubMed and reference lists of articles were searched in February-April 2021. Total of 53 studies with 121 association analyses between different SES indicators and adiposity indicators, were identified and reviewed. Different SES indicators were grouped to 25 indicators and further to six indicator groups. The most used indicator was mother's education (n of association analyses = 24) and the most used indicator group was parental education (n of association analyses = 51). Of all association analyses, 55% were inverse, 36% were non-significant, and 8% were positive. Composite SES (80%), parental education (69%) and parental occupation (64%) indicators showed most frequently inverse associations with obesity measures (i.e. lower parental SES associating with higher adiposity), while parental income (50% inverse; 50% non-significant) and property and affluence (42% inverse; 50% nonsignificant) indicators showed approximately even number of inverse and non-significant associations. Instead, majority of parental employment (60%) indicators, showed non-significant associations and 33% showed positive associations (i.e. higher parental SES associating with higher adiposity). Despite some variation in percentages, majority of the associations were inverse in each age group and with different outcome categorizations. In girls and in boys, non-significant associations predominated. It seems that children with parents of higher SES have lower likelihood of adiposity in Europe. Parents' employment appears to differ from other SES indicators, so that having an employed parent(s) does not associate with lower likelihood of adiposity. Positive associations seem to occur more frequently in poorer countries. Criteria for uniform childhood SES and adiposity measures should be established and used in studies in order to be able to produce comparable results across countries.

Socioeconomic position and body composition in childhood in high- and middle-income countries: a systematic review and narrative synthesis

BACKGROUND

The relation between socioeconomic position (SEP) and obesity measured by body mass index (BMI), a measure of weight for height, has been extensively reviewed in children, showing consistent associations between disadvantaged SEP and higher BMI in high-income countries (HICs) and lower BMI in middle-income countries (MICs). Fat mass (FM), a more accurate measure of adiposity, and fat-free mass (FFM) are not captured by BMI, but have been shown to track from childhood to adulthood, and be important for cardiovascular health and functional outcomes in later life. It is not clear whether body composition is associated with SEP. We systematically reviewed the association between SEP and body composition in childhood.

METHODS

A systematic review was carried out following PRISMA guidelines. The protocol was pre-registered with PROSPERO (CRD42019119937). Original studies in the English language, which examined the association between SEP and body composition in childhood, were included. An electronic search of three databases was conducted. Two independent reviewers carried out screening, data extraction and quality assessment. Due to heterogeneity in results, a narrative synthesis was conducted. Heterogeneity in findings according to SEP, sex, body composition measure and country income level was investigated.

RESULTS

50 papers were included, the majority from HICs. No papers were from low-income countries. Disadvantage in childhood was associated with greater FM and lower FFM in HICs, but with lower FM and lower FFM in MICs. When measures of FFM indexed to height were used there was no evidence of associations with SEP. In HICs, more studies reported associations between disadvantaged SEP and higher FM among girls comparative to boys.

CONCLUSIONS

Inequalities in FM are evident in HICs and, in the opposite direction, in MICs and follow similar trends to inequalities for BMI. Inequalities in height are likely important in understanding inequalities in FFM.

Early life disadvantage and adult adiposity: tests of sensitive periods during childhood and behavioural mediation in adulthood

BACKGROUND

Early exposure to socioeconomic disadvantage is associated with obesity. Here we investigated how early, and conducted mediation analyses to identify behavioural factors in adulthood that could explain why.

METHODS

Among 931 participants in the New England Family Study, we investigated the associations of family socioeconomic disadvantage measured before birth and at age 7 years with the following measures of adiposity in mid-adulthood (mean age = 44.4 years): body mass index (BMI), waist circumference and, among 400 participants, body composition from dual-energy X-ray absorption scans.

RESULTS

In linear regressions adjusting for age, sex, race and childhood BMI Z-score, participants in the highest tertile of socioeconomic disadvantage at birth had 2.6 additional BMI units in adulthood [95% confidence interval (CI) = 1.26, 3.96], 5.62 cm waist circumference (95% CI = 2.69, 8.55), 0.73 kg of android fat mass (95% CI = 0.25, 1.21), and 7.65 higher Fat Mass Index (95% CI = 2.22, 13.09). Conditional on disadvantage at birth, socioeconomic disadvantage at age 7 years was not associated with adult adiposity. In mediation analyses, 10-20% of these associations were explained by educational attainment and 5-10% were explained by depressive symptoms.

CONCLUSIONS

Infancy may be a sensitive period for exposure to socioeconomic disadvantage, as exposure in the earliest years of life confers a larger risk for overall and central adiposity in mid-adulthood than exposure during childhood. Intervention on these two adult risk factors for adiposity would, if all model assumptions were satisfied, only remediate up to one-fifth of the excess adult adiposity among individuals born into socioeconomically disadvantaged households.

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.

Socioeconomic position and childhood-adolescent weight status in rich countries: a systematic review, 1990-2013

Background

Childhood obesity is a major problem in rich countries due to its high prevalence and its harmful health consequences. An exploratory analysis conducted in the PubMed database highlighted that the number of papers published on the relationship between socioeconomic position (SEP) and childhood-adolescent weight status had risen substantially with respect to an earlier review which had covered the period 1990–2005.

Methods

To describe the findings on the relationship between SEP and childhood-adolescent weight status in papers published in rich countries from 1990 through 2013, studies were identified in the following databases: PubMed; Web of Knowledge (WOK); PsycINFO; Global Health; and Embase. We included observational studies from the 27 richest OECD countries, which covered study populations aged 0 to 21 years, and used parental education, income and/or occupation as family SEP indicators. A total of 158 papers met the inclusion criteria and reported 134 bivariable and 90 multivariable analyses.

Results

Examination of the results yielded by the bivariable analyses showed that 60.4 % of studies found an inverse relationship, 18.7 % of studies did not found relationship, and 20.9 % of studies found a relationship that varied depending on another variable, such as age, sex or ethnic group; the corresponding percentages in the multivariable analyses were 51.1, 20.0 and 27.8 %, respectively. Furthermore, 1.1 % found a positive relationship.

Conclusion

The relationship between SEP and childhood-adolescent weight status in rich countries is predominantly inverse and the positive relationship almost has disappeared. The SEP indicator that yields the highest proportion of inverse relationships is parents’ education. The proportion of inverse relationships is higher when the weight status is reported by parents instead using objective measurements.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-015-0443-3) contains supplementary material, which is available to authorized users.

Development of socioeconomic inequalities in obesity among Dutch pre-school and school-aged children

OBJECTIVE

To investigate the emergence of the inverse socioeconomic gradient in body mass index (BMI) in the first 6 years of life. Furthermore, associations of socioeconomic position (SEP) with BMI and total fat mass (%) were assessed at age 6, and potential mediating factors in the pathway between SEP and children's body composition were investigated.

METHODS

Nearly 3,656 Dutch children participating in a prospective cohort study in Rotterdam, the Netherlands, were included from 2002 to 2006. Maternal educational level and net household income were used as indicators of SEP. BMI and fat mass were both outcome measures. Associations and mediation analyses were investigated using linear mixed models and linear regression analyses.

RESULTS

The lowest SEP groups showed a larger increase in BMI over time as compared to the highest SEP groups (P < 0.001), which resulted in the emergence of the inverse SEP gradient around 3-4.5 years of age. In 6-year-old children, both BMI and total fat mass were significantly higher for children of low educated mothers (difference in BMI SDS: 0.24; 95% CI 0.15, 0.33; and in total fat mass (%): 2.68; 95% CI 2.19, 3.17), which was also shown for children with a low household income. This was mainly explained by parental BMI and prenatal smoking.

CONCLUSIONS

The inverse socioeconomic gradient in obesity emerges during the preschool period, and widens with increasing age. A public health strategy aimed at tackling the development of inequalities in obesity in early childhood needs to start before birth and should include the prevention of prenatal smoking and obesity of parents.

Anthropometric measurements in Canadian children: a scoping review

OBJECTIVE

The objective of the current study was to identify what forms of anthropometric measurement are currently being utilized with Canadian children and youth and what are the gaps in the literature on this topic.

METHODS

The current study utilized a scoping review methodology in order to achieve the study objectives. Online databases Medline and PubMed and CINAHL were used to search articles from the last decade (2002-2012) that addressed Canadian children aged 2-18 years.

SYNTHESIS

50 studies were included in this review. A variety of anthropometric measurements were identified, including body mass index, waist circumference, hip-to-waist ratio, among others. Six of the included studies (12%) utilized nationally representative data from large-scale studies. BMI was the most reported form of measurement with 88% of studies collecting it. Waist circumference was a distant second with 20% of studies reporting it. Several gaps in the literature exist with regards to First Nations (FN) research; many of the measurement methods were not used. Additionally, FN accounted for only 2.5% of the study's sample. The majority of studies took place in Quebec (29%) and Ontario (27%).

CONCLUSION

Body mass index is the most reported method of anthropometric measurement used for children. Efforts should be taken by health care practitioners and researchers to collect other forms of measurement in order to assist in understanding the validity of other measures and their value when used with children. Furthermore, attention needs to be focused on utilizing and studying various forms of anthropometric measurement across all Canadian regions and populations.