Body composition data show that high BMI centiles overdiagnose obesity in children aged under 6 years

The evolution of the understanding of obesity over the last 100 years

The definition of obesity has evolved significantly over the last century, from a simplistic view of excessive eating and laziness to a complex, multifactorial disease with profound health and societal implications. As science progresses, it is essential that we keep improving our knowledge about obesity, taking into consideration, factors like genetics, metabolism, body composition, and the social determinants of health. This article explores how our understanding of this condition has been shaped over the last 100 years considering historical and scientific factors. The history and usefulness of the body mass index (BMI), the development of other anthropometric markers and the evolution in the incorporation of body composition into clinical practice, among other aspects related to the definition of obesity, are discussed. The challenges posed by obesity can be better addressed and more effective strategies for prevention and treatment can be developed adopting a more personalized and holistic approach. Obesity is not only a matter of individual responsibility but a multifaceted public health problem that requires a multidisciplinary and inclusive strategy to address its complexities.

The Cross-Sectional Relation of Body Mass Index to Adiposity among 8- to 19-Year-Olds within Several Races and Ethnicities

OBJECTIVE

To assess the screening ability of a high body mass index (BMI) for high adiposity among 8- to 19-year-olds.

STUDY DESIGN

This cross-sectional study included 6454 National Health and Nutrition Survey participants from 2011 through 2018. Fat and lean mass were measured with dual-energy X-ray absorptiometry (DXA). We expressed adiposity as fat mass index (FMI, kg ÷ m2) and %fat.

RESULTS

Based on the Centers for Disease Control and Prevention 95th percentile, a high BMI correctly classified a high FMI for about 95% of participants in each racial and ethnic group. About 81% (Blacks) to 90% (Hispanics) of participants with a high BMI also had a high FMI. Further, children with a high BMI were 17 (Hispanics) to 46 (Blacks) times more likely to have a high FMI than those with a "normal" BMI. The screening ability of high BMI for high %fat was weaker because levels of %fat are influenced by both fat mass (numerator) and lean mass (denominator).

CONCLUSIONS

Despite differences in body composition, a high BMI is a very good screening tool for identifying high FMI not only among White 8- to 19-year-olds but also among Asians, Blacks, and Hispanics. Compared with %fat, FMI is likely a better adiposity metric among children and adolescents.

Waist-circumference-to-height-ratio had better longitudinal agreement with DEXA-measured fat mass than BMI in 7237 children

BACKGROUND

The absolute agreement of surrogate measures of adiposity with dual-energy X-ray absorptiometry (DEXA)-measured body composition was examined.

METHODS

Over a 15-year follow-up, 7237 (3667 females) nine-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) UK birth cohort were included. Total fat mass (FM) and trunk FM were serially measured with DEXA at ages 9, 11, 15, 17, and 24 years. BMI and waist circumference-to-height ratio (WHtR) were computed. Pearson's correlations, intraclass correlations (ICC), and area under curve (AUC) analyses were conducted.

RESULTS

Over 15 years, BMI, total FM, and trunk FM, increased but WHtR was relatively stable. WHtR provided a better longitudinal absolute agreement [males ICC 0.84 (95% CI 0.84-0.85); females 0.81 (0.80-0.82)] than BMI [(males (0.65 (0.64-0.66); females 0.72 (0.71-0.73)] with total FM as well as trunk FM from ages 9-24 years. WHtR cut-point for predicting excess total FM (75th-95th percentile) was 0.50-0.53 in males [AUC 0.86-0.94, sensitivity 0.51-0.79 and specificity 0.93-0.95]. WHtR cut-point for predicting excess total FM (75th-95th percentile) was 0.52-0.54 in females [AUC 0.83-0.95, sensitivity 0.38-0.68 and specificity 0.92-0.95]. Results were similar with trunk FM.

CONCLUSION

WHtR is an inexpensive alternative to BMI for predicting FM in pediatrics.

IMPACT

Waist circumference-to-height ratio (WHtR) is a better adiposity surrogate measure than body mass index (BMI) in predicting fat mass and discriminating lean mass from childhood through young adulthood. BMI has been used as an inexpensive surrogate measure of adiposity in children for several decades. However, emerging findings suggest that BMI fails to discriminate between fat mass adiposity and lean mass. This is the first-ever longitudinal study in over 7000 children followed up for 15 years that identified WHtR as an inexpensive accurate measure that discriminates fat mass from lean mass that could replace BMI measure of obesity in pediatrics.

Body composition and motor function in children born large for gestational age at term

BACKGROUND

This cross-sectional study compared body composition and motor function between children who were born large for gestational age (LGA) and those born appropriate for gestational age (AGA) and to investigate the association between gait quality and other variables.

METHODS

Body composition was determined using a bioelectrical impedance analyzer. Motor functions were assessed using one-leg standing time, timed up-and-go test, five times sit-to-stand test, and three-dimensional gait analysis. We compared the results between two groups. We performed multiple regression analysis to evaluate the association between gait deviation index and variables of LGA, fat mass index, and motor functions (adjusted for age and sex).

RESULTS

Children aged 6-12 years who were born LGA at term (n = 23) and those who were born AGA at term (n = 147) were enrolled. The LGA group had a higher fat mass index (2.9 vs. 2.2, p = 0.006) and lower gait deviation index (91.4 vs. 95.4, p = 0.011) than the AGA group. On multiple regression analysis, gait deviation index was associated with being LGA and fat mass index.

CONCLUSIONS

In school-aged children who were born LGA, monitoring increased fat mass index and decreased gait deviation index could lessen the risk of metabolic syndrome and reduced gait function.

IMPACT

Children aged 6-12 years who were born large for gestational age (LGA) at term showed a higher fat mass index and lower gait deviation index than those who were born appropriate for gestational age at term. No significant differences in balance function or muscle strength were observed between groups. On multiple regression analysis, gait deviation index was associated with being LGA at birth and fat mass index. In school-aged children who were born LGA, monitoring increased fat mass index and decreased gait deviation index could lessen the risk of metabolic syndrome and reduced gait function.

Occurrence of Body Posture Abnormalities in Overweight and Obese Children Aged 5-6 Years-Pilot Study

OBJECTIVES

The study aimed to assess the occurrence of body posture disorders and their changes under the influence of a physioprophylactic program in children depending on body weight.

METHODS

In the examined children, the general and segmental body composition and body posture were determined using a physiotherapeutic assessment based on the Kasperczyk method. Mass, overall, and segmental body composition were determined using the bioelectrical impedance method using a TANITA body composition analyzer. The study group of 76 children was divided due to body weight disorders into Group I (n = 51), in which BMI and fat mass values were within the normative limits for age and gender, and Group II (n = 19), comprising children whose body weight exceeded the norm and/or fat mass exceeded normative values. The examined children underwent a physioprophylactic. The program was conducted by qualified physiotherapists for 12 weeks, once a week for 30 min. The therapeutic program was focused on physioprevention of being overweight and the correction of body posture.

RESULTS

A distal distribution of fat mass was observed in the examined group. Asymmetry in the sagittal plane was found in 35% of children. No statistically significant differences were found in the presence of asymmetry in the sagittal plane between the groups. No statistically significant differences were found in the occurrence of posture irregularities between the groups.

CONCLUSIONS

There were no changes in the weight and body posture of the examined children under the influence of the physiotherapy program. The lack of correlation in the examined group between body weight and posture irregularities in 5-6-year-olds may suggest the acquisition of posture defects as a consequence of the persistence of overweight or obesity.

COVID-19 impact on overweight and obesity rates in Aotearoa | New Zealand 4-year-old children

BACKGROUND

COVID-19 has had profound societal impacts. This study estimated overweight, obesity, and extreme obesity rates in 4-year-old children over pre- and post-COVID-19 periods, and investigated differential changes between sex, ethnic and deprivation groups.

METHODS

A national screening programme of 4-year-old children undertaking B4 School Checks (B4SCs) between 1 January 2010 and 7 March 2023 was analysed. B4SCs include anthropometric measurements enabling sex-specific body mass index-for-age Z-scores (BMI z-scores) to be derived. Children with ≥85th, ≥95th, and ≥99.7th percentile BMI z-scores were classified as overweight, obese, and extremely obese.

RESULTS

The eligible sample included 656,038 children (48.8% girls). Overall, 210,492 (32.1%) children were overweight, 95,196 (14.5%) obese, and 19,926 (3.0%) extremely obese. While decreasing in the pre-COVID-19 period, annual prevalence estimates for overweight, obese, and extremely obese significantly (all p < 0.001) increased in the year after COVID-restrictions were implemented. However, after three years, overweight and obese prevalence estimates were no different to pre-COVID levels overall or stratified by sex for ethnicity and deprivation groups. Extreme obesity prevalence estimates also decreased but remained higher than pre-COVID levels.

CONCLUSION

The sharp and steep increases in prevalence estimates all dampened relatively quickly. The question remains whether these rates will continue to decrease in time.

IMPACT

Compared to pre-COVID-19 estimates, the prevalence of overweight, obesity and extreme obesity significantly and substantially increased for 4-year-old children in the immediate post-COVID-19 period. These post-COVID-19 prevalence estimates dampened relatively quickly, returning to pre-COVID-19 rates for overweight and obesity after 3 years. Inequities between ethnic and social deprivation groups in overweight and obesity prevalence estimates remained similar between pre- and post-COVID-19 periods.

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).

A differentiated approach to the diagnosis of overweight and obesity in children based on bioimpedance analysis of body composition

OBJECTIVE

Aim: The current study introduces a novel diagnostic algorithm employing bioimpedance analysis to comprehensively evaluate body composition in children, assessing fat content, skeletal muscle content, and fat distribution.

PATIENTS AND METHODS

Materials and Methods: Bioelectrical impedance measurements were obtained using the TANITA MC-780 MA analyzer. Indicators such as body weight, BMI, total fat content, absolute limb muscle mass, skeletal muscle strength, and waist-to-hip ratio (WHR) were assessed. A sample of 101 children aged 9 to 14 were studied using the proposed algorithm, refining BMI-based classifications.

RESULTS

Results: The algorithm comprises three steps, categorizing children based on fat content, presence of sarcopenia, and central fat distribution. It identified diverse somatotypes within the groups classified by BMI. Notably, it revealed prognostically unfavorable somatotypes, such as sarcopenic obesity with central fat distribution, highlighting potential health risks. Current BMI-centric diagnoses may misclassify cardiometabolic risks, making early detection challenging. The algorithm enables a detailed evaluation, unmasking metabolically unfavorable conditions like sarcopenic obesity. The incorporation of functional tests, such as a standardized hand-grip test, enhances diagnostic accuracy. The proposed WHR indicator for characterizing fat distribution provides a practical method for determining somatotypes in children.

CONCLUSION

Conclusions: This comprehensive algorithm offers an alternative to BMI-based classifications, enabling early detection of obesity and associated risks. Further validation through large-scale epidemiological studies is essential to establish correlations between somatotypes and cardiometabolic risks, fostering a more nuanced and individualized approach to pediatric obesity management.

The relative contributions of soft tissue mass components as risk or protective factors of non-alcoholic fatty liver disease in children

BACKGROUND/OBJECTIVE

Several body components are known to be associated with non-alcoholic fatty liver disease (NAFLD) in children. However, the relative contributions of soft tissue mass components as risk or protective factors of NAFLD are largely unknown because measurements of these components are often highly correlated. Therefore, we aimed to estimate levels of association between soft tissue mass components and NAFLD.

SUBJECTS/METHODS

We collected the medical records of 555 Chinese children (aged 3-18 years). Five mutually exclusive and exhaustive components of soft tissue mass were measured using dual energy X-ray absorptiometry. NAFLD was diagnosed with abdominal B-ultrasound scan. We fit Dirichlet regression and multivariate linear regression models wherein age and NAFLD were used as predictors of the proportional measurements of soft tissue mass components.

RESULTS

The proportion of android fat was significantly higher in children with NAFLD than in those without NAFLD (ratio of proportions ranged from 1.18 to 1.30), whereas proportions of trunk lean and limb lean were significantly lower (ratio of proportions ranged from 0.87 to 0.92 for trunk lean and from 0.82 to 0.91 for limb lean). The proportion of gynoid fat was slightly higher in boys with NAFLD than in those without NAFLD (ratio = 1.05), but this proportion was not significantly higher in girls. The association between the proportion of android fat and NAFLD appeared to be somewhat greater than the associations between proportions of trunk lean or limb lean components and NAFLD.

CONCLUSION

Our findings suggest that lowering fat mass and increasing lean mass can both be used to combat NAFLD in children and that more studies are needed to determine the association between gynoid fat and NAFLD.

Rapid infant weight gain or point-in-time weight status: Which is the best predictor of later obesity and body composition?

OBJECTIVE

The aim of this study was to determine which growth indicator (weight, weight-for-length, BMI) and time frame (6- or 12-month intervals between 0 and 24 months) of rapid infant weight gain (RIWG) best predicted obesity risk and body composition at 11 years of age.

METHODS

RIWG (increase ≥0.67 z scores between two time points) was calculated from weight and length/height at birth, 0.5, 1, 1.5, and 2 years. The predictive value of each measure and time frame was calculated in relation to obesity (BMI ≥95th percentile) and body fat (fat mass index [FMI], dual-energy X-ray absorptiometry scan) at 11 years.

RESULTS

The sensitivity (1.5% to 62.1%) and positive predictive value (12.5% to 33.3%) of RIWG to predict obesity varied considerably. Having obesity at any time point appeared a stronger risk factor than any indicator of RIWG for obesity at 11 years. Obesity at any age during infancy consistently predicted a greater FMI of around 1.1 to 1.5 kg/m2 at 11 years, whereas differences for RIWG were inconsistent.

CONCLUSIONS

A simple measure of obesity status at a single time point between 6 and 24 months of age appeared a stronger risk factor for later obesity and FMI than RIWG assessed by any indicator, over any time frame.

BMI-based obesity classification misses children and adolescents with raised cardiometabolic risk due to increased adiposity

OBJECTIVE

To assess how inaccurately the body mass index (BMI) is used to diagnose obesity compared to body fat percentage (BF%) measurement and to compare the cardiometabolic risk in children and adolescents with or without obesity according to BMI but with a similar BF%.

METHODS

A retrospective cross-sectional investigation was conducted including 553 (378 females/175 males) white children and adolescents aged 6-17 years, 197 with normal weight (NW), 144 with overweight (OW) and 212 with obesity (OB) according to BMI. In addition to BMI, BF% measured by air displacement plethysmography, as well as markers of cardiometabolic risk had been determined in the existing cohort.

RESULTS

We found that 7% of subjects considered as NW and 62% of children and adolescents classified as OW according to BMI presented a BF% within the obesity range. Children and adolescents without obesity by the BMI criterion but with obesity by BF% exhibited higher blood pressure and C-reactive protein (CRP) in boys, and higher blood pressure, glucose, uric acid, CRP and white blood cells count, as well as reduced HDL-cholesterol, in girls, similar to those with obesity by BMI and BF%. Importantly, both groups of subjects with obesity by BF% showed a similarly altered glucose homeostasis after an OGTT as compared to their NW counterparts.

CONCLUSIONS

Results from the present study suggest increased cardiometabolic risk factors in children and adolescents without obesity according to BMI but with obesity based on BF%. Being aware of the difficulty in determining body composition in everyday clinical practice, our data show that its inclusion could yield clinically useful information both for the diagnosis and treatment of overweight and obesity.

Examining the Double Burden of Underweight, Overweight/Obesity and Iron Deficiency among Young Children in a Canadian Primary Care Setting

There is little evidence on the prevalence of the double burden and association between body mass index (BMI) and iron deficiency among young children living in high-income countries. We conducted a cross-sectional study of healthy children, 12-29 months of age, recruited during health supervision visits in Toronto, Canada, and concurrently measured BMI and serum ferritin. The prevalence of a double burden of underweight (zBMI < -2) and iron deficiency or overweight/obesity (zBMI > 2) and iron deficiency was calculated. Regression models examined BMI and serum ferritin as continuous and categorical variables, adjusted for covariates. We found the following in terms of prevalence among 1953 children (mean age 18.3 months): underweight 2.6%, overweight/obesity 4.9%, iron deficiency 13.8%, iron-deficiency anemia 5.4%, underweight and iron deficiency 0.4%, overweight/obesity and iron deficiency 1.0%. The change in median serum ferritin for each unit of zBMI was -1.31 µg/L (95% CI -1.93, -0.68, p < 0.001). Compared with normal weight, we found no association between underweight and iron deficiency; meanwhile, overweight/obesity was associated with a higher odds of iron deficiency (OR 2.15, 95% CI 1.22, 3.78, p = 0.008). A double burden of overweight/obesity and iron deficiency occurs in about 1.0% of young children in this high-income setting. For risk stratification and targeted screening in young children, overweight/obesity should be added to the list of important risk factors.

Maternal vitamin D status and risk of childhood overweight at 5 years of age in two Nordic cohort studies

Introduction

Maternal vitamin D status during pregnancy has been suggested to have a role in childhood adiposity development, but results are conflicting. Our aims were to investigate [1] the relationships between maternal 25-hydroxyvitamin D (25OHD) during pregnancy and the child's body mass index (BMI) and risk of overweight at 5 years of age, and [2] maternal pre-pregnancy BMI as effect modifier for these associations.

Methods

Data sources included a subsample from the Norwegian Mother, Father and Child Cohort Study (MoBa sub-cohort; N = 2,744) and the Swedish GraviD cohort study (N = 891). Maternal 25OHD was analyzed in gestational week 18 in the MoBa sub-cohort and week 10 in the GraviD cohort. In the MoBa sub-cohort, parents reported their child's documented measures of weight and length or height from the health card at routine check-up. In the GraviD cohort, this information was collected directly from medical records. Childhood overweight (including obesity) was identified using the International Obesity Task Force cut-offs. Linear and logistic regression models were used to investigate the association between maternal 25OHD and child's BMI and risk of overweight at 5 years of age in each cohort separately, and in a pooled dataset.

Results

In the pooled analysis, maternal 25OHD <30 nmol/L was associated with lower BMI in children at 5 years of age, but not with risk of overweight. Interaction analysis showed that the association was predominant among children of mothers with pre-pregnancy BMI ≥25 kg/m2.

Conclusion

Low maternal vitamin D status, particularly in mothers with overweight or obesity, predicted lower BMI in their five-year-old children. However, there was no evidence of an effect on overweight in these children.

Physiological and Environmental Factors Affecting Cancer Risk and Prognosis in Obesity

Obesity results from a chronic excessive accumulation of adipose tissue due to a long-term imbalance between energy intake and expenditure. Available epidemiological and clinical data strongly support the links between obesity and certain cancers. Emerging clinical and experimental findings have improved our understanding of the roles of key players in obesity-associated carcinogenesis such as age, sex (menopause), genetic and epigenetic factors, gut microbiota and metabolic factors, body shape trajectory over life, dietary habits, and general lifestyle. It is now widely accepted that the cancer-obesity relationship depends on the site of cancer, the systemic inflammatory status, and microenvironmental parameters such as levels of inflammation and oxidative stress in transforming tissues. We hereby review recent advances in our understanding of cancer risk and prognosis in obesity with respect to these players. We highlight how the lack of their consideration contributed to the controversy over the link between obesity and cancer in early epidemiological studies. Finally, the lessons and challenges of interventions for weight loss and better cancer prognosis, and the mechanisms of weight gain in survivors are also discussed.

Prevalence of low and high BMI during the first 3 years of life: using New Zealand national electronic health data

BACKGROUND

Data on body mass index (BMI) in infants and toddlers worldwide are lacking, relative to older age groups.

OBJECTIVES

To describe the growth (weight, length/height, head circumference, and BMI z-score) of New Zealand children under the age of 3 years, and examine differences by sociodemographic characteristics (sex, ethnicity, and deprivation).

METHODS

Electronic health data were collected by Whānau Āwhina Plunket, who provide free 'Well Child' services for approximately 85% of newborn babies in New Zealand. Data from children under the age of 3, who had their weight and length/height measured between 2017 and 2019, were included. The prevalence of BMI (WHO child growth standards) ≤2nd, ≥85th, and ≥95th percentiles were determined.

RESULTS

Between 12 weeks and 27 months of age, the percentage of infants ≥85th BMI percentile increased from 10.8% (95% CI, 10.4%-11.2%) to 35.0% (34.2%-35.9%). The percentage of infants with high BMI (≥95th percentile) also increased, particularly between 6 months (6.4%; 95% CI, 6.0%-6.7%) and 27 months (16.4%; 15.8%-17.1%). By contrast, the percentage of infants with low BMI (≤2nd percentile) appeared steady between 6 weeks and 6 months, and declined at older ages. The prevalence of infants with a high BMI appears to increase substantially from 6 months across sociodemographic characteristics, with a widening prevalence gap by ethnicity occurring from 6 months, mirroring that of infants with a low BMI.

CONCLUSIONS

The number of children with high BMI increases rapidly between 6 months and 27 months of age, suggesting this is an important timeframe for monitoring and preventive action. Future work should investigate the longitudinal growth trajectories of these children to determine if any particular patterns predict later obesity and what strategies could effectively change them.

Childhood BMI and other measures of body composition as a predictor of cardiometabolic non-communicable diseases in adulthood: a systematic review

OBJECTIVE

There is growing evidence that childhood malnutrition is associated with non-communicable diseases (NCD) in adulthood and that body composition mediates some of this association. This review aims to determine if childhood body composition can be used to predict later-life cardiometabolic NCD and which measures of body composition predicts future NCD.

DESIGN

Electronic databases were searched for articles where: children aged under 5 years had body composition measured; cardiometabolic health outcomes were measured a minimum of 10 years later.

SETTING

The databases Embase, Medline and Global Health were searched through July 2020.

PARTICIPANTS

Children aged under 5 years with a follow-up of minimum 10 years.

RESULTS

Twenty-nine studies met the inclusion criteria. Though a poor proxy measure of body composition, body mass index (BMI) was commonly reported (n 28, 97 %). 25 % of these studies included an additional measure (ponderal index or skinfold thickness). Few studies adjusted for current body size (n 11, 39 %).

CONCLUSIONS

Many studies reported that low infant BMI and high childhood BMI were associated with an increased risk of NCD-related outcomes in later life but no conclusions can be made about the exact timing of child malnutrition and consequent impact on NCD. Because studies focussed on BMI rather than direct measures of body composition, nothing can be said about which measures of body composition in childhood are most useful. Future research on child nutrition and long-term outcomes is urgently needed and should include validated body composition assessments as well as standard anthropometric and BMI measurements.

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.