High Body Mass Index Percentile Accurately Reflects Excess Adiposity in White Girls

A body shape index and vascular structure and function in Spanish adults (MARK study): A cross-sectional study

A body shape index (ABSI) has been introduced as a marker of the relationship between body composition and all-cause mortality. However, until now, the relationships between ABSI and vascular structure and function have not been evaluated. The aim of this study was to investigate the association of ABSI with vascular structure and function in Spanish adults with intermediate cardiovascular risk. This cross-sectional study analyzed the data of 2354 subjects [age, 35-74 years (median, 62.0 years [range, 56.0-67.0 years]), 61.9% men] enrolled into the MediAte Risk management (MARK) study. ABSI was calculated by using the following formula: ABSI = waist circumference (m)/[body mass index × height (m))]. Vascular function was assessed by measuring cardio-ankle vascular index (CAVI) with the VaSera device and brachial ankle pulse wave velocity (baPWV) by using a validated equation. Vascular structure was assessed by measuring carotid intima-media thickness (IMT) by ultrasonography. Median value of ABSI was 0.083 (range, 0.081-0.090), mean CAVI was (8.5 ± 1.2), and median IMT was 0.727 (range, 0.672-0.799). The values of ABSI and CAVI were higher in men. After adjusting for confounders, ABSI was positively associated with CAVI, baPWV, and average mean IMT. Thus, for each unit increase in ABSI, CAVI increased by 0.16 units, baPWV by 0.25 m/s, and IMT by 0.033 mm. In the logistic regression analysis, the odds ratio of ABSI was > 1 for high CAVI ≥ 9, baPWV ≥ 15 m/s, and IMT ≥ 0.90 mm in the overall subject group, and in the sex- and age-specific (> 62 years, ≤ 62 years) subgroups, after adjusting for confounders. The area under the receiver-operating characteristic curve of the ABSI was 0.631 (95% confidence interval [CI], 0.608-0.654) for CAVI ≥ 9, and 0.617 (95% CI, 0.593-0.641) for high baPWV ≥ 15 m/s. ABSI showed a positive association with vascular structure and function, independent of other confounders that might influence weight and fat mass distribution in Spanish subjects at intermediate cardiovascular risk.Trial Registration: ClinicalTrials.gov Identifier: NCT01428934 (registered: September 2, 2011; last updated: September 8, 2016).

Differences in childhood body mass index between lesbian/gay and bisexual and heterosexual female adolescents: A follow-back study

Objective

To determine whether childhood body mass index (BMI), assessed in childhood, differs between lesbian/gay and bisexual (LGB) and heterosexual late adolescents, and whether childhood social stressors impact the association between sexual orientation and childhood BMI.

Methods

Participants included 2,070 late adolescents from the Pittsburgh Girls Study, of whom 233 (11.2%) identified as lesbian or bisexual and 1,837 (88.8%) as heterosexual at ages 17–20 years. Weight and height were used to calculate body mass index (BMI) at ages 10 through 14 years. Data were collected on child reported loneliness at ages 8 to 10 and peer victimization from 10 to 14 years.

Results

LGB females had higher BMIs and greater increases in BMI from ages 10–14 years compared to heterosexual females and reported higher levels of loneliness and peer victimization in childhood. Loneliness moderated the association between sexual identity and changes in BMI; for participants with loneliness scores in the upper quartile, the increase in BMI over time was approximately 30% higher for LGB females compared to heterosexual females. Child report of peer victimization mediated the association between sexual identity and changes in BMI, with nearly 18% of the total effect of sexual identity on BMI over time accounted for by peer victimization.

Conclusions

Lesbian and bisexual adolescents report greater loneliness and peer victimization as children than heterosexual adolescents; these stressors confer risk for higher BMI among LGB females. These data underscore the importance of research on the social determinants of health. The hypothesis that the social stressors may partially account for differences in BMI and other cardiometabolic risk factors between LGB and heterosexual females should be addressed in future research.

Adiposity measures and arterial stiffness in primary care: the MARK prospective observational study

BACKGROUND

The cardiovascular risk of obesity is potentially increased by arterial stiffness.

OBJECTIVE

To assess the relationship of adiposity measures with arterial stiffness in Caucasian adults with intermediate cardiovascular risk.

SETTING

Six Spanish health centres.

PARTICIPANTS

We enrolled 2354 adults (age range, 35-74 years; mean age, 61.4±7.7 years, 61.9% male).

METHODS

This is a cross-sectional study that analyses data from the baseline visit of the improving interMediAte RisK management (MARK) study. The main outcome variables were body mass index (BMI), waist-to-height ratio (WHtR), Clínica Universidad de Navarra-body adiposity estimation (CUN-BAE) body fat percentage and body roundness index (BRI). Vascular function was assessed by the cardio-ankle vascular index (CAVI) with the VaSera device; brachial-ankle pulse wave velocity (baPWV) was determined using a validated equation.

RESULTS

The mean adiposity measures were a BMI of 29.2±4.4, WHtR of 0.61±0.07, CUN-BAE of 35.7±1.7 and BRI of 5.8±1.7. The mean stiffness measures were a CAVI of 8.8±1.2 and baPWV of 14.9±2.5. In multiple linear regression analyses, all adiposity measures were negatively associated with CAVI and baPWV (p<0.01 for all) after adjustment for possible factors of confusion. The proportion of CAVI variability via the adiposity measures were 5.5% for BMI, 5.8% for CUN-BAE, 3.8% for WHtR and 3.7% for BRI. These were higher among diabetic, obese, younger (≤62 years) and non-hypertensive subjects who had similar activity and sedentary profiles.

CONCLUSIONS

Adiposity measures are negatively associated with arterial stiffness measures. The percentage of variation in CAVI explained by its relation to the different measures of adiposity ranges from 5.8% (CUN-BAE) to 3.7% (BRI). In the case of baPWV, it oscillates between 0.7% (CUN-BAE and BMI) and 0.1% (WHtR).

TRIAL REGISTRATION NUMBER

NCT01428934.

Simple tests for the diagnosis of childhood obesity: a systematic review and meta-analysis

There is a need to accurately quantify levels of adiposity in order to identify overweight and obesity in children. This systematic review aimed to identify all diagnostic accuracy studies evaluating simple tests for obesity and adiposity, including body mass index (BMI), skin-fold thickness and waist circumference, compared against high-quality reference tests. Twenty-four cohort studies including 25,807 children were included. BMI had good performance when diagnosing obesity: a sensitivity of 81.9% (95% confidence interval [CI]: 73.0 to 93.8) for a specificity of 96.0% (95% CI: 93.8 to 98.1). It was less effective at diagnosing overweight (sensitivity: 76.3%, 95% CI: 70.2 to 82.4; specificity: 92.1% 95% CI: 90.0 to 94.3). When diagnosing obesity, waist circumference had similar performance (sensitivity: 83.8%; specificity: 96.5%). Skin-fold thickness had slightly poorer performance (sensitivity: 72.5%; specificity: 93.7%). Few studies considered any other tests. There was no conclusive evidence that any test was generally superior to the others. BMI is a good simple diagnostic test for identifying childhood adiposity. It identifies most genuinely obese and adipose children while misclassifying only a small number as obese. There was no conclusive evidence that any test should be preferred to BMI, and the extra complexity of skin-fold thickness tests does not appear to improve diagnostic accuracy.

Comparison of methods to measure body fat in 7-to-10-year-old children: a systematic review

OBJECTIVE

To investigate methodological aspects in body fat (BF) measurements in 7-to-10-year-old children.

STUDY DESIGN

Systematic review of the literature.

METHODS

The studies were chosen from the PubMed and Scielo databases according to a protocol that defined: inclusion criteria; a search and quality-assessment strategy; and information extraction.

RESULTS

27 studies published from 2004 to 2014 were included. The literature describes skinfold measurements and dual energy X-ray absorptiometry (DEXA) as being the reference methods most widely used in the assessment of the ability of methods to identify BF. The most commonly-used statistical analyses were the Pearson correlation coefficient, and sensitivity and specificity performance analyses. The comparison between the tested methods and the references showed that body mass index (BMI) and waist circumference (WC) are strongly correlated to BF as calculated by bioelectrical impedance or skinfolds, and that there is a moderate positive correlation with percent body fat as calculated by DEXA, air-displacement plethysmography (ADP) or isotope dilution. There was a moderate positive correlation between waist-to-height ratio (WHtR) and BF, as estimated by ADP and skinfolds. Performance studies suggest that BMI and WC are very specific but less sensitive methods.

CONCLUSIONS

The results of this systematic review show favourable evidence for the use of anthropometric indicators - above all BMI and WC- in the measurement of BF, when more accurate techniques such as DEXA and ADP are not feasible. They also demonstrate features that make them advantageous for epidemiological studies in a child population, since they are easy and safe to obtain and well tolerated by the children.

The use of measures of obesity in childhood for predicting obesity and the development of obesity-related diseases in adulthood: a systematic review and meta-analysis

BACKGROUND

It is uncertain which simple measures of childhood obesity are best for predicting future obesity-related health problems and the persistence of obesity into adolescence and adulthood.

OBJECTIVES

To investigate the ability of simple measures, such as body mass index (BMI), to predict the persistence of obesity from childhood into adulthood and to predict obesity-related adult morbidities. To investigate how accurately simple measures diagnose obesity in children, and how acceptable these measures are to children, carers and health professionals.

DATA SOURCES

Multiple sources including MEDLINE, EMBASE and The Cochrane Library were searched from 2008 to 2013.

METHODS

Systematic reviews and a meta-analysis were carried out of large cohort studies on the association between childhood obesity and adult obesity; the association between childhood obesity and obesity-related morbidities in adulthood; and the diagnostic accuracy of simple childhood obesity measures. Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and a modified version of the Quality in Prognosis Studies (QUIPS) tool. A systematic review and an elicitation exercise were conducted on the acceptability of the simple measures.

RESULTS

Thirty-seven studies (22 cohorts) were included in the review of prediction of adult morbidities. Twenty-three studies (16 cohorts) were included in the tracking review. All studies included BMI. There were very few studies of other measures. There was a strong positive association between high childhood BMI and adult obesity [odds ratio 5.21, 95% confidence interval (CI) 4.50 to 6.02]. A positive association was found between high childhood BMI and adult coronary heart disease, diabetes and a range of cancers, but not stroke or breast cancer. The predictive accuracy of childhood BMI to predict any adult morbidity was very low, with most morbidities occurring in adults who were of healthy weight in childhood. Predictive accuracy of childhood obesity was moderate for predicting adult obesity, with a sensitivity of 30% and a specificity of 98%. Persistence of obesity from adolescence to adulthood was high. Thirty-four studies were included in the diagnostic accuracy review. Most of the studies used the least reliable reference standard (dual-energy X-ray absorptiometry); only 24% of studies were of high quality. The sensitivity of BMI for diagnosing obesity and overweight varied considerably; specificity was less variable. Pooled sensitivity of BMI was 74% (95% CI 64.2% to 81.8%) and pooled specificity was 95% (95% CI 92.2% to 96.4%). The acceptability to children and their carers of BMI or other common simple measures was generally good.

LIMITATIONS

Little evidence was available regarding childhood measures other than BMI. No individual-level analysis could be performed.

CONCLUSIONS

Childhood BMI is not a good predictor of adult obesity or adult disease; the majority of obese adults were not obese as children and most obesity-related adult morbidity occurs in adults who had a healthy childhood weight. However, obesity (as measured using BMI) was found to persist from childhood to adulthood, with most obese adolescents also being obese in adulthood. BMI was found to be reasonably good for diagnosing obesity during childhood. There is no convincing evidence suggesting that any simple measure is better than BMI for diagnosing obesity in childhood or predicting adult obesity and morbidity. Further research on obesity measures other than BMI is needed to determine which is the best tool for diagnosing childhood obesity, and new cohort studies are needed to investigate the impact of contemporary childhood obesity on adult obesity and obesity-related morbidities.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013005711.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Diagnostic performance of body mass index to identify obesity as defined by body adiposity in children and adolescents: a systematic review and meta-analysis

BACKGROUND

The ideal means of identifying obesity in children and adolescents has not been determined although body mass index (BMI) is the most widely used screening tool.

OBJECTIVE

We performed a systematic review and meta-analysis of studies assessing the diagnostic performance of BMI to detect adiposity in children up to 18 years.

METHODS

Data sources were EMBASE, MEDLINE, Cochrane, Database of Systematic Reviews Cochrane CENTRAL, Web of Science and SCOPUS up to March 2013. Studies providing measures of diagnostic performance of BMI and using body composition technique for body fat percentage measurement were included.

RESULTS

Thirty-seven eligible studies that evaluated 53 521 patients, with mean age ranging from 4 to 18 years were included in the meta-analysis. Commonly used BMI cut-offs for obesity showed pooled sensitivity to detect high adiposity of 0.73 (confidence interval [CI] 0.67-0.79), specificity of 0.93 (CI 0.88-0.96) and diagnostic odds ratio of 36.93 (CI 20.75-65.71). Males had lower sensitivity. Moderate heterogeneity was observed (I(2) = 48%) explained in meta-regression by differences across studies in race, BMI cut-off, BMI reference criteria (Center for Disease Control vs. International Obesity Task Force) and reference standard method assessing adiposity.

CONCLUSION

BMI has high specificity but low sensitivity to detect excess adiposity and fails to identify over a quarter of children with excess body fat percentage.

Systematic review to identify and appraise outcome measures used to evaluate childhood obesity treatment interventions (CoOR): evidence of purpose, application, validity, reliability and sensitivity

BACKGROUND

Lack of uniformity in outcome measures used in evaluations of childhood obesity treatment interventions can impede the ability to assess effectiveness and limits comparisons across trials.

OBJECTIVE

To identify and appraise outcome measures to produce a framework of recommended measures for use in evaluations of childhood obesity treatment interventions.

DATA SOURCES

Eleven electronic databases were searched between August and December 2011, including MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations; EMBASE; PsycINFO; Health Management Information Consortium (HMIC); Allied and Complementary Medicine Database (AMED); Global Health, Maternity and Infant Care (all Ovid); Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost); Science Citation Index (SCI) [Web of Science (WoS)]; and The Cochrane Library (Wiley) - from the date of inception, with no language restrictions. This was supported by review of relevant grey literature and trial databases.

REVIEW METHODS

Two searches were conducted to identify (1) outcome measures and corresponding citations used in published childhood obesity treatment evaluations and (2) manuscripts describing the development and/or evaluation of the outcome measures used in the childhood intervention obesity evaluations. Search 1 search strategy (review of trials) was modelled on elements of a review by Luttikhuis et al. (Oude Luttikhuis H, Baur L, Jansen H, Shrewsbury VA, O'Malley C, Stolk RP, et al. Interventions for treating obesity in children. Cochrane Database Syst Rev 2009;1:CD001872). Search 2 strategy (methodology papers) was built on Terwee et al.'s search filter (Terwee CB, Jansma EP, Riphagen II, de Vet HCW. Development of a methodological PubMed search filter for finding studies on measurement properties of measurement instruments. Qual Life Res 2009;18:1115-23). Eligible papers were appraised for quality initially by the internal project team. This was followed by an external appraisal by expert collaborators in order to agree which outcome measures should be recommended for the Childhood obesity Outcomes Review (CoOR) outcome measures framework.

RESULTS

Three hundred and seventy-nine manuscripts describing 180 outcome measures met eligibility criteria. Appraisal of these resulted in the recommendation of 36 measures for the CoOR outcome measures framework. Recommended primary outcome measures were body mass index (BMI) and dual-energy X-ray absorptiometry (DXA). Experts did not advocate any self-reported measures where objective measurement was possible (e.g. physical activity). Physiological outcomes hold potential to be primary outcomes, as they are indicators of cardiovascular health, but without evidence of what constitutes a minimally importance difference they have remained as secondary outcomes (although the corresponding lack of evidence for BMI and DXA is acknowledged). No preference-based quality-of-life measures were identified that would enable economic evaluation via calculation of quality-adjusted life-years. Few measures reported evaluating responsiveness.

LIMITATIONS

Proposed recommended measures are fit for use as outcome measures within studies that evaluate childhood obesity treatment evaluations specifically. These may or may not be suitable for other study designs, and some excluded measures may be more suitable in other study designs.

CONCLUSIONS

The CoOR outcome measures framework provides clear guidance of recommended primary and secondary outcome measures. This will enhance comparability between treatment evaluations and ensure that appropriate measures are being used. Where possible, future work should focus on modification and evaluation of existing measures rather than development of tools de nova. In addition, it is recommended that a similar outcome measures framework is produced to support evaluation of adult obesity programmes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.