Impact of using national v. international definitions of underweight, overweight and obesity: an example from Kuwait

Towards standardised and valid anthropometric indicators of nutritional status in middle childhood and adolescence

Recognition of the importance of nutrition during middle childhood (age 5-9 years) and adolescence (age 10-19 years) is increasing, particularly in the context of global food insecurity and rising overweight and obesity rates. Until now, policy makers have been slow to respond to rapidly changing patterns of malnutrition across these age groups. One barrier has been a scarcity of consistent and regular nutrition surveillance systems for these age groups. What should be measured, and how best to operationalise anthropometric indicators that have been the cornerstone of nutrition surveillance in younger children and in adults, has been the topic of ongoing debate. Even with consensus on the importance of a given anthropometric indicator, difficulties arise in interpreting trends over time and between countries owing to the use of different terminologies, reference data, and cutoff points. In this Viewpoint we highlight the need to revisit anthropometric indicators across middle childhood and adolescence, a process that will require WHO and UNICEF coordination, the engagement of national implementors and policy makers, and partnership with research communities and donors.

Differences in Classification Standards For the Prevalence of Overweight and Obesity in Children. A Systematic Review and Meta-Analysis

The prevalence of childhood obesity has increased dramatically all over the world in recent years. While obesity in adults can be easily measured using the BMI calculation, determining overweight and obesity in children is more controversial. The aim was to compare the three most used international classification systems (WHO 2007, CDC 2000 and Cole-IOTF) to determine overweight and obesity in infant and adolescent populations. We performed a systematic review in accordance with the PRISMA 2020 guidelines of articles comparing any of the three classification systems. The main findings were that the WHO 2007 criteria show the highest prevalence of overweight and obesity in the child and youth population. The prevalence of childhood overweight and obesity was determined to be higher in boys than in girls in most studies, when analysing the classifications of the WHO 2007, CDC 2000 and Cole-IOTF together. However, there was a higher prevalence of overweight and obesity in girls than in boys when only the CDC 2000 and Cole-IOTF criteria were considered. Both the results of the review and the great heterogeneity found in the meta-analysis show that it is necessary to unify the criteria for the classification of childhood overweight and obesity. International standards are insufficient for working with the current population. A working group should be created to address this issue and agree on the unification of a gold standard, taking into account the geographical region, the ethnic groups and the age groups of the child and youth population and above all, the secular growth.

Prevalence of overweight and obesity among saudi children: A comparison of two widely used international standards and the national growth references

Objective

To compare three body mass index (BMI) classifications that are used to assess the prevalence of overweight and obesity among Saudi children aged 6-13 years: the International Obesity Task Force (IOTF) age and gender cutoffs, the World Health Organization (WHO) growth references for school-aged children, and the Saudi (KSA) national growth references.

Methods

The sample comprised 2,169 children (52.5% girls) derived from two cross-sectional studies conducted in Riyadh and Jeddah during the 2017 and 2019 school years, respectively. Body weight and height were measured, and BMI was calculated.

Results

The proportions (%) of the participants who were classified as underweight, overweight, and obese varied according to the reference used: IOTF reference (13.8, 18.4, and 12.7), WHO reference (17.2, 19.1, and 18.9), and KSA reference (7.0, 22.4, and 9.3), respectively, indicating higher values for overweight and obesity prevalence when the WHO references were used. Kappa agreement measures between the three references were found to be high, with the coefficients ranging from 0.936 (between the IOTF and KSA references) to 0.849 (between the IOTF and WHO references). In all three classifications, girls exhibited lower overweight or obesity prevalence than boys. Family income, but not paternal or maternal education, was significantly (p = 0.015) associated with overweight/obesity when using the IOTF standards. In addition, having a small family in the house was significantly (p < 0.05) associated with obesity, irrespective of the classification system.

Conclusion

Inconsistency was observed when estimating the prevalence of underweight, overweight, and obesity among Saudi children. However, when defining the overall prevalence of overweight plus obesity among Saudi children, the IOTF classification system performed in a similar way to the KSA references (31.1% versus 31.7%) compared to the WHO references (38.0%).

Time trends of overweight and obesity among schoolchildren in Kuwait over a 13-year period (2007-2019): repeated cross-sectional study

OBJECTIVES

This study aimed to examine age-specific trends in the prevalence of overweight and obesity in schoolchildren in Kuwait over a 13-year period (2007 to 2019) using the WHO, the Centers for Disease Control and Prevention (CDC) and the International Obesity Taskforce (IOTF) definitions.

DESIGN

Using cross-sectional approach, Kuwait Nutrition Surveillance System (KNSS) objectively measured weight and height of schoolchildren over a 13-year period. Log-binomial regression models were used to examine age-specific trends of obesity and overweight over the study period.

SETTING

Public primary, middle and high schools in all provinces of Kuwait.

PARTICIPANTS

Schoolchildren aged 5-19 years (n 172 603).

RESULTS

According to the WHO definition, the prevalence of overweight and obesity in schoolchildren, respectively, increased from 17·73 % and 21·37 % in 2007 to 20·19 % and 28·39 % in 2019 (Pfor trend < 0·001). There is evidence that the obesity in females (but not males) has levelled off in the period 2014-2019 according to the three definitions of obesity, which is corroborated by a similar trend in the mean of BMI-for-age Z-score.

CONCLUSION

The prevalence of obesity and overweight in schoolchildren in Kuwait has risen over the last 13 years and trends are similar across all definitions. Obesity is no longer increasing at the same pace and there is evidence that the prevalence of obesity in females has plateaued. The current level of childhood overweight and obesity is too high and requires community-based and school-based interventions.

Comparison of International Growth Standards for Assessing Nutritional Status in Cystic Fibrosis: The GreeCF Study

OBJECTIVE

The aim of the study was to compare 3 international growth references and explore their differences in assessing growth in Greek school-aged patients with cystic fibrosis (CF).

METHODS

Sample included 114 patients (50 boys, age 11.5 ± 3.9 years), provided care at Aghia Sofia Children's Hospital, Greece. Anthropometrics and predicted forced expiratory volume in 1 second (FEV1%) were measured. Body mass index (BMI) and height z scores were computed according to the Centers for Disease Control and Prevention (CDC), World Health Organization (WHO), and International Obesity Task Force (IOTF) references. Agreement between methods was analyzed with kappa statistics, repeated-measures analysis of variance, and Bland-Altman analysis. The relationship between FEV1% and BMI was explored with linear regression.

RESULTS

Mean CDC BMI z score was the lowest (0.06 ± 1.08), followed by WHO (0.17 ± 1.14) and IOTF (0.35 ± 1.05) (P ≤ 0.001 for all). The CDC and WHO growth references highly agreed for most weight status strata and stunting; all other comparisons produced lower agreements. Except for CDC and IOTF BMI z scores, all other comparisons produced wide levels of agreement and proportional bias. CDC reference classified more children as attaining low or normal weight, against WHO or IOTF (P ≤ 0.001 for all). Lowest prevalence of ideal and excess weight was recorded by CDC, compared to all other standards (P ≤ 0.001 for all). All BMI z scores provided moderate associations with FEV1%.

CONCLUSION

Large variations across weight status classification were present when employing 3 growth standards in school-aged patients . Given than BMI z-scores from all references provided comparable associations with pulmonary function, our data indicate that no studied reference is better than others in assessing growth in CF.

Prevalence of obesity among school-age children and adolescents in the Gulf cooperation council (GCC) states: a systematic review

Background

The Gulf Cooperation Council (GCC) countries have among the highest prevalence of adult obesity and type 2 diabetes in the world. This study aimed to estimate the recent prevalence of obesity among school-age children and adolescents in the GCC States.

Methods

The literature search for obesity prevalence data was carried out in July 2017 in Google Scholar, Physical education index, Medline, SCOPUS, WHO, 2007-2017, and updated in November 2018.In addition, 22 experts from the GCC were contacted to check the search results, and to suggest studies or grey literature which had been missed. Eligible studies were assessed for quality by using the Joanna Briggs Institute (JBI) tool for prevalence studies. Conduct of the systematic review followed the Assessment of Multiple Systematic Reviews Tool (AMSTAR) guidance. A narrative synthesis was conducted.

Results

Out of 392 studies identified, 41 full-text reports were screened for eligibility; 11 of which were eligible and so were included, from 3 of the 6 GCC countries (United Arab Emirates, Kuwait, Saudi Arabia). Surveillance seems good in Kuwait in compared to other countries, with one recent national survey of prevalence. Quality of the eligible studies was generally low-moderate according to the JNBI tool: representative samples were rare; participation rates low; power calculations were mentioned by only 3/11 studies and confidence intervals around prevalence estimates provided by only 3/11 eligible studies; none of the studies acknowledged that prevalence estimates were conservative (being based on BMI-for-age). There was generally a very high prevalence of obesity (at least one quarter-one third of study or survey participants obese according to BMI-for-age), prevalence increased with age, and was consistently higher in boys than girls.

Conclusions

The prevalence of obesity among school-age children and adolescents appears to have reached alarming levels in the GCC, but there are a number of major gaps and limitations in obesity surveillance in the GCC states. More national surveys of child and adolescent obesity prevalence are required for the GCC states.

Trial registration

PROSPERO registration number CRD42017073692.

Overweight and Obesity Prevalence Among School-Aged Nunavik Inuit Children According to Three Body Mass Index Classification Systems

PURPOSE

Little is known about the suitability of three commonly used body mass index (BMI) classification system for Indigenous children. This study aims to estimate overweight and obesity prevalence among school-aged Nunavik Inuit children according to International Obesity Task Force (IOTF), Centers for Disease Control and Prevention (CDC), and World Health Organization (WHO) BMI classification systems, to measure agreement between those classification systems, and to investigate whether BMI status as defined by these classification systems is associated with levels of metabolic and inflammatory biomarkers.

METHODS

Data were collected on 290 school-aged children (aged 8-14 years; 50.7% girls) from the Nunavik Child Development Study with data collected in 2005-2010. Anthropometric parameters were measured and blood sampled. Participants were classified as normal weight, overweight, and obese according to BMI classification systems. Weighted kappa (κw) statistics assessed agreement between different BMI classification systems, and multivariate analysis of variance ascertained their relationship with metabolic and inflammatory biomarkers.

RESULTS

The combined prevalence rate of overweight/obesity was 26.9% (with 6.6% obesity) with IOTF, 24.1% (11.0%) with CDC, and 40.4% (12.8%) with WHO classification systems. Agreement was the highest between IOTF and CDC (κw = .87) classifications, and substantial for IOTF and WHO (κw = .69) and for CDC and WHO (κw = .73). Insulin and high-sensitivity C-reactive protein plasma levels were significantly higher from normal weight to obesity, regardless of classification system. Among obese subjects, higher insulin level was observed with IOTF.

CONCLUSIONS

Compared with other systems, IOTF classification appears to be more specific to identify overweight and obesity in Inuit children.

Agreement and Diagnostic Performance of FITNESSGRAM®, International Obesity Task Force, and Hungarian National BMI Standards

PURPOSE

This study examined agreement between all 3 standards (as well as relative diagnostic associations with metabolic syndrome) using a representative sample of youth from the Hungarian National Youth Fitness Study.

METHOD

Body mass index (BMI) was assessed in a field sample of 2,352 adolescents (ages 10-18.5 years) and metabolic syndrome status was assessed in a laboratory subsample of 373 youth. All youth were categorized into weight status groups based on the FITNESSGRAM®, International Obesity Task Force (IOTF), and Hungarian growth standards. Classification agreement was compared between all pairs of standards via cross-tabulation. Logistic regression was used to estimate the odds of metabolic syndrome by weight status.

RESULTS

The 3 BMI standards agreed on ≥  88% of cases, with better agreement on girls' standards than boys' standards. Kappa values ranged from .65 to .89. Using the Hungarian standards over the Fitnessgram or IOTF standards resulted in 5% to 10% more youth being classified as normal weight. The overweight/obesity groups were 4 times to 6 times more likely to have metabolic syndrome than those classified as normal weight regardless of the classification standards. These odds ratios increased to 8 times to 17 times when comparing the normal-weight/overweight groups to the obesity category. Odds ratios for boys tended to be slightly larger than those for girls.

CONCLUSIONS

All 3 standards provide similar information about weight status and metabolic syndrome classification. To more easily facilitate international comparisons, it may be of greater benefit to use the IOTF standards, which also had better agreement with the U.S. Fitnessgram thresholds.

National Adolescent Treatment Trial for Obesity in Kuwait (NATTO): project design and results of a randomised controlled trial of a good practice approach to treatment of adolescent obesity in Kuwait

BACKGROUND

Few randomised controlled trials (RCTs) of interventions for the treatment of adolescent obesity have taken place outside the western world. This RCT tested whether a simple 'good practice' intervention for the treatment of adolescent obesity would have a greater impact on weight status and other outcomes than a referral to primary care (control) in adolescents in Kuwait City.

METHODS

We report on an assessor-blinded RCT of a treatment intervention in 82 obese 10- to 14-year-olds (mean age 12.4, SD 1.2 years), randomised to a good practice treatment or primary care control group over 6 months. The good practice intervention was intended as relatively low intensity (6 hours contact over 24 weeks, group-based), aiming to change sedentary behaviour, physical activity, and diet. The primary outcome was a change in body mass index (BMI) Z score; other outcomes were changes in waist circumference and blood pressure.

RESULTS

The retention of subjects to follow up was acceptable (n = 31 from the intervention group, and n = 32 from the control group), but engagement with both the intervention and control treatment was poor. Treatment had no significant effect on BMI Z score relative to control, and no other significant benefits to intervention were observed.

CONCLUSIONS

The trial was feasible, but highlights the need to engage obese adolescents and their families in the interventions being trialled. The trial should inform the development of future adolescent obesity treatment trials in the Gulf States with the incorporation of qualitative assessment in future intervention trials.

TRIAL REGISTRATION

RCT Registered as National Adolescent Treatment Trial for Obesity in Kuwait (NATTO): http://www.controlled-trials.com/ISRCTN37457227, 1 December 2009.

Health related quality of life of obese adolescents in Kuwait

Background

Obesity impairs health related quality of life (HRQL) in adolescents, but most evidence in this area has mostly come from western societies. We wanted to test the hypothesis that obesity impairs HRQL in Kuwaiti adolescents, and to test for differences in HRQL assessed by self-report and parent-proxy report.

Methods

In 500 Kuwaiti 10–14 year olds HRQL was assessed using the Peds QL^TM with both adolescent self-reports (n = 500) and parent-proxy reports (n = 374).

Results

Obesity was not significantly associated with HRQL in regression analysis. In a paired comparison of 98 pairs of obese adolescents vs. 98 healthy weight peers, impairment of HRQL reached significance only for physical score (95% CI = −1.5, -9.4), not for psychosocial score or total score. In a paired comparison of parent-proxy vs. self-reports for the obese adolescents, total score (95% CI = −4.9, -10.9), physical score (95% CI = −3.2, -11.0), and psychosocial score (95% CI = −4.2, -10.8) were all significantly lower in the parent reports.

Conclusions

Obesity is not associated with marked impairment of HRQL in adolescents in Kuwait, in contrast to studies in western societies. This may reflect cultural differences in attitudes towards obesity.

Body fatness or anthropometry for assessment of unhealthy weight status? Comparison between methods in South African children and adolescents

OBJECTIVE

A variety of methods are available for defining undernutrition (thinness/underweight/under-fat) and overnutrition (overweight/obesity/over-fat). The extent to which these definitions agree is unclear. The present cross-sectional study aimed to assess agreement between widely used methods of assessing nutritional status in children and adolescents, and to examine the benefit of body composition estimates.

DESIGN

The main objective of the cross-sectional study was to assess underweight, overweight and obesity using four methods: (i) BMI-for-age using WHO (2007) reference data; (ii) BMI-for-age using Cole et al. and International Obesity Taskforce cut-offs; (iii) weight-for-age using the National Centre for Health Statistics/WHO growth reference 1977; and (iv) body fat percentage estimated by bio-impedance (body fat reference curves for children of McCarthy et al., 2006). Comparisons were made between methods using weighted kappa analyses.

SETTING

Rural South Africa.

SUBJECTS

Individuals (n 1519) in three age groups (school grade 1, mean age 7 years; grade 5, mean age 11 years; grade 9, mean age 15 years).

RESULTS

In boys, prevalence of unhealthy weight status (both under- and overnutrition) was much higher at all ages with body fatness measures than with simple anthropometric proxies for body fatness; agreement between fatness and weight-based measures was fair or slight using Landis and Koch categories. In girls, prevalence of unhealthy weight status was also higher with body fatness than with proxies, although agreement between measures ranged from fair to substantial.

CONCLUSIONS

Methods for defining under- and overnutrition should not be considered equivalent. Weight-based measures provide highly conservative estimates of unhealthy weight status, possibly more conservative in boys. Simple body composition measures may be more informative than anthropometry for nutritional surveillance of children and adolescents.

Obesity and metabolic syndrome in adolescent survivors of standard risk childhood acute lymphoblastic leukemia in Saudi Arabia

BACKGROUND

This study estimated prevalence of unhealthy weight status and metabolic syndrome (MS) amongst Saudi survivors of standard risk ALL.

PROCEDURE

We recruited 56 survivors, mean age 13.4 years (SD 4.1), a mean of 9.1 years (SD 4.1) post-diagnosis. The BMI for age was used to define weight status relative to national (Saudi) and international (Cole et al., Cole-IOTF, WHO, and CDC) reference data. We measured body composition by dual-energy X-ray absorptiometry (DXA), waist circumference, blood pressure, lipid profile (HDL-C, Triglycerides), fasting glucose and insulin.

RESULTS

According to international definitions based on BMI for age, around half of the sample had unhealthy weight status. All of the approaches based on BMI for age underestimated overfatness, present in 27/51 (53%) of the sample according to DXA. Prevalence of MS was 7.1% (3/42 of those over 9-years old) and 5.4% (3/56) by applying the International Diabetes Federation (IDF) definition and National Cholesterol Education Program Third Adult Treatment panel Guidelines (NCEP III), respectively. However, MS by the NCEP III definition was present in 19% of the overweight and obese survivors and 7.1% of the sample had at least two of the components of MS.

CONCLUSION

Unhealthy body weight and overfatness may be common amongst adolescent Saudi survivors of standard risk ALL, though overweight and obesity may be no more common than in the general Saudi adolescent population. Defining weight status using BMI underestimates overfatness. Ideally, body composition and cardiometabolic risk factors should be monitored at late effects clinics.

Evidence-based obesity prevention in childhood and adolescence: critique of recent etiological studies, preventive interventions, and policies

Prevention of obesity in childhood and adolescence remains a worthwhile and realistic goal, but preventive efforts have been beset by a number of problems, which are the subject of this review. The review draws on recent systematic reviews and evidence appraisals and has a United Kingdom (UK) perspective because there is a rich evidence base in the United Kingdom that may be helpful to obesity prevention researchers elsewhere. Recent evidence of a leveling off in child and adolescent obesity prevalence in some Western nations should not encourage the belief that the obesity prevention problem has been solved, although a better understanding of recent secular trends might be helpful for prevention strategy in future. An adequate body of evidence provides behavioral targets of preventive interventions, and there are frameworks for prioritizing these targets logically and models for translating them into generalizable interventions with a wide reach (e.g., school-based prevention interventions such as Planet Health). An improved understanding of the "energy gap" that children and adolescents experience would be helpful to the design of preventive interventions and to their tailoring to particular groups. In the United Kingdom, some recent etiological evidence has been taken as indicative of the need for paradigm shifts in obesity prevention, but this evidence from single studies has not been replicated, and paradigm shifts probably occur only rarely. Ensuring that the evidence base on etiology and prevention influences policy effectively remains one of the greatest challenges for childhood obesity researchers.

High prevalence of metabolic syndrome among Kuwaiti adults--a wake-up call for public health intervention

The socio-economic development which followed the discovery of oil resources brought about considerable changes in the food habits and lifestyle of the Kuwaiti population. Excessive caloric intake and decreased energy expenditure due to a sedentary lifestyle have led to a rapid increase in obesity, diabetes and other non-communicable chronic diseases in the population. In this paper, we examine the prevalence of the Metabolic Syndrome (MetS) among Kuwaiti adults (≥20 years) using data from the first national nutrition survey conducted between July 2008 and November 2009. The prevalence of MetS was 37.7% in females and 34.2% in males by NCEP criteria, whereas the values were 40.1% in females and 41.7% in males according to IDF criteria. Prevalence of MetS increased with age and was higher in females than males. The high prevalence of the MetS in Kuwaiti adults warrants urgent public health measures to prevent morbidity and mortality due to cardiovascular complications in the future.