Additive utility of family history and waist circumference to body mass index in childhood for predicting metabolic syndrome in adulthood

Waist circumference in children and adolescents correlate with metabolic syndrome and fat deposits in young adults

BACKGROUND & AIMS

To determine the relevance of waist circumference (WC) measurement and monitoring in children and adolescents as an early indicator of overweight, metabolic syndrome (MS) and cardiovascular problems in young adults in comparison with visceral and subcutaneous adiposity.

METHODS

A cohort study with 159 subjects (51.6% female) started in 1999 with an average age of 13.2 years. In 1999, 2006 and 2008 weight, height, and WC were evaluated. In 2006 blood samples for laboratory diagnosis of MS were added. In 2008 abdominal computed tomography (ACT) to quantify the fat deposits were also added.

RESULTS

The WC measured in children and adolescents was strongly correlated with body mass index (BMI) measured simultaneously. A strong correlation was established between WC in 1999 with measures of WC and BMI as young adults. WC strongly correlated with fat deposits in ACT. The WC in 1999 expressed more subcutaneous fat (SAT), while the WC when young adults expressed strong correlation with both visceral fat (VAT) and SAT. The correlation of WC with fat deposits was stronger in females. WC and not BMI in 1999 was significantly higher in the group that evolved to MS.

CONCLUSIONS

The WC in children and adolescents was useful in screening patients for MS. WC expressed the accumulation of abdominal fat; especially subcutaneous fat.

Components of the diet associated with child adiposity: a cross-sectional study

OBJECTIVE

This study sought to determine which components of youths' diets were related to adiposity while controlling for potential often-neglected confounders such as moderate to vigorous physical activity (MVPA) and dietary reporting error. Secondary goals of this study were to determine the extent to which MVPA confounded the associations between diet and adiposity and whether associations between diet and adiposity would differ depending on reporting error.

METHODS

An ethnically diverse urban sample of 342 children aged 9-10 years and 323 adolescents aged 17-18 years were recruited for this cross-sectional study. Body mass index (BMI) and waist circumference (WC) were measured in the school; dietary assessment included three 24-hour recalls via telephone in the evenings, and MVPA assessment included 5 days of accelerometry. Over (n = 68), under (n = 250), or plausible (n = 347) dietary intake reporters were identified with the Huang calculation method. Linear regression assessed the relationship between adiposity indicators (BMI z-score and WC) and components of the diet (energy intake, food groups, macronutrients) after controlling for reporting error, demographic variables, and MVPA.

RESULTS

When dietary reporting error and potential confounders such as MVPA and demographic variables were controlled, energy intake (EI), vegetables, refined grains, total fat, total protein, and total carbohydrate were positively related to BMI z-score and WC and artificially sweetened beverages to WC. MVPA was a significant confounder. For BMI z-score, but not WC, relationships and strength of these relationships differed depending on dietary reporting error group (plausible, underreporter, overreporter).

CONCLUSIONS

Among plausible reporters, as expected, EI, refined grains, and all macronutrients were positively related to adiposity; however, artificially sweetened beverages and vegetables, which are low-energy-dense foods, were also positively related to adiposity. Reporting error interfered with associations between diet and BMI z-score but not WC, suggesting WC is a more robust measure of adiposity in relation to diet.

Association between depressed mood and perceived weight in middle and high school age students: Texas 2004-2005

Research exploring the relationship between weight perception and depressed mood among adolescents is limited in the United States. The purpose of this study is to examine the association of perceived versus actual body weight and depressed mood in a representative sample of 8th and 11th grade public school students in Texas. Using data from the 2004-2005 School Physical Activity and Nutrition (SPAN) study, logistic regression analyses were conducted to assess the association of weight perception with depressed mood. Healthy weight students who perceived themselves to be a healthy weight were the reference group for all analyses. A high prevalence of misperception of body weight was observed. Overweight and obese 8th grade girls and boys who perceived themselves to be overweight had increased odds of depressed mood [Girls: OR 1.70 (95% CI: 1.07-2.69), Boys: OR 2.05 (95% CI: 1.16-3.62)]. Healthy weight 8th grade girls who perceived themselves to be overweight had 2.5 times greater odds of depressed mood (OR 2.63, 95% CI: 1.54-4.50). Healthy weight boys who perceived themselves to be underweight had more than twice the odds (OR 2.18, 95% CI: 1.23-3.89) of depressed mood. No weight category was significantly associated with depressed mood in boys or girls in 11th grade. The present study suggests that weight misperceptions are associated with depressed mood in young adolescents. Education about healthy body size is necessary to correct the common weight misperceptions observed. The high prevalence rates of depressed mood suggest a greater need for research into understanding factors that may contribute to depressed mood in adolescents.

General versus central adiposity and relationship to pediatric metabolic risk

BACKGROUND

The influence of moderate-to-vigorous physical activity (MVPA) and general versus central adiposity on pediatric metabolic risk is not well described.

METHODS

Secondary analyses on pediatric participants from the National Health and Nutrition Examination Survey, 2003-2006 (n=2,155). MVPA (min/day) and adherence to MVPA recommendations were assessed objectively by accelerometers. Body mass index (BMI) z-score and waist circumference (WC) were measured by standard protocols. The main dependent variables included an overall metabolic risk score and clinical tests related to metabolic risk. A series of linear regression analyses were used to examine BMI z-score versus WC as a mediator of the relationship between MVPA and the metabolic risk score or the individual components, controlling for sociodemographic covariates. All analyses with BMI z-score as an independent variable controlled for WC and vice versa. The product-of-coefficients method was used to test for mediation.

RESULTS

MVPA adherence was inversely associated and WC was positively associated with the metabolic risk score (all P<0.05). MVPA was inversely associated with systolic blood pressure and positively associated with high-density lipoprotein cholesterol (HDL-C) (all P<0.05). WC was inversely associated with HDL-C and positively associated with C-reactive protein (CRP), glycohemoglobin, fasting triglycerides, and fasting insulin (all P<0.05). WC mediated the relationship between MVPA and CRP or HDL-C (both P<0.05).

CONCLUSIONS

MVPA correlated with pediatric metabolic risk and this relationship was mediated by central adiposity for CRP and HDL-C. This finding suggests the need for programs to screen for and improve children's MVPA and WC.

Development of youth percent body fat standards using receiver operating characteristic curves

BACKGROUND

Few studies have identified health-related criterion standards of percent body fat (%BF) in U.S. youth. Further, existing standards are static thresholds (e.g., 25%, 30%) and do not account for normal growth and maturation.

PURPOSE

The purpose of this study was to identify thresholds of %BF in youth linked to metabolic syndrome in a large sample of U.S. children and adolescents.

METHODS

Percent fat was derived from the skinfold thicknesses of those aged 12-18 years, from the National Health and Nutrition Examination Survey (NHANES [1999-2004, N=1966]). Metabolic syndrome was classified using previously published standards based on the National Cholesterol Education Program/Adult Treatment Panel III adult values at age 20 years. Using %BF z-scores as the test and metabolic syndrome as the criterion, receiver operating characteristic (ROC) curve analysis was used to identify %BF thresholds.

RESULTS

ROC analysis indicated that %BF can be used with moderate accuracy to identify metabolic syndrome in adolescents. %BF thresholds of 22.3% and 35.1% in boys and 31.4% and 38.6% in girls (at age 18 years) were found to be indicative of "low" and "high" metabolic syndrome risk.

CONCLUSIONS

Age- and gender-specific %BF thresholds for creating separate risk groups were identified in relation to metabolic syndrome status. The selected thresholds identify adolescents with unfavorable metabolic profiles. These values could be extrapolated to younger children using previously created %BF centiles, which potentially allows for earlier identification and intervention of at-risk youth if tracking of current %BF was maintained.

Childhood obesity and cardiovascular disease: links and prevention strategies

The prevalence and severity of pediatric obesity have dramatically increased since the late 1980s, raising concerns about a subsequent increase in cardiovascular outcomes. Strong evidence, particularly from autopsy studies, supports the concept that precursors of adult cardiovascular disease (CVD) begin in childhood, and that pediatric obesity has an important influence on overall CVD risk. Lifestyle patterns also begin early and impact CVD risk. In addition, obesity and other CVD risk factors tend to persist over time. However, whether childhood obesity causes adult CVD directly, or does so by persisting as adult obesity, or both, is less clear. Regardless, sufficient data exist to warrant early implementation of both obesity prevention and treatment in youth and adults. In this Review, we examine the evidence supporting the impact of childhood obesity on adult obesity, surrogate markers of CVD, components of the metabolic syndrome, and the development of CVD. We also evaluate how obesity treatment strategies can improve risk factors and, ultimately, adverse clinical outcomes.

Behind and beyond the pediatric metabolic syndrome

The growing use of the Metabolic Syndrome in pediatric age need a critical approach, on the basis of recent concerns on definition and usefulness for individual management in clinical practice. We reviewed these aspects from a pediatric point of view, providing a set of questions about what the Metabolic Syndrome means in a clinical setting. The new proposed pediatric definition by IDF was discussed, by outlying how it does not fully consider the peculiarities of children and adolescents. The comparison between two cases of obese children was used in order to show how this diagnosis could be confusing for a correct management. We stressed the need for health-related limits for each component of the Metabolic Syndrome instead of percentile-derived cut-points, as well as the opportunity to extend the estimation to other family or individual risk factors by means of a multiple-items screening form. In conclusion, Metabolic Syndrome use in pediatric age suffers at present from important limitations (i.e., adult derived definition, possibility to rule-in but not to rule-out the individual metabolic risk, instability of MetS during adolescence, poor usefulness of the diagnosis for specific treatment). Consequently, a prudent use of Metabolic Syndrome for children and adolescents seems to be the best and honest position for paediatricians, waiting for long term, longitudinal follow-up studies that could clarify the entire question.