Central adiposity and protein intake are associated with arterial stiffness in overweight children

Adiposity and cardiac autonomic function in children with a family history of obesity

PURPOSE

Data on associations between adiposity and heart rate variability (HRV) in prepubertal children are limited. We examined the associations between adiposity indices and HRV, independent of lifestyle behaviors, comparing multiple indicators of adiposity, and explored differences between boys and girls.

METHODS

Data stem from 469 participants of the QUALITY cohort (630 children aged 8-10 years with a parental history of obesity). Adiposity indices included waist-to-height ratio, body mass index (BMI) percentiles and categories (overweight, obesity), dual-energy x-ray absorptiometry (DEXA) defined fat mass percentage and android/gynoid ratio. HRV indices in the frequency and the spectral domain were derived from a daytime 3-h Holter recording. Multivariable linear regression models were adjusted for age, sex, Tanner stage, physical activity, screen time, and fitness. Interactions between sex and adiposity were tested.

RESULTS

Greater adiposity was associated with decreased parasympathetic modulation and increased sympathetic dominance. Waist-to-height ratio was associated with lower parasympathetic activity: root mean square of the successive differences (RMSSD) [B =  -23.32, 95% confidence interval (CI) -42.42, -4.22], pNN50 (B =  -16.93, 95% CI - 28.58, - 5.27), LF/HF ratio (B = 1.83, 95% CI 0.97-2.70). Patterns of association were similar for android/gynoid ratio. Overweight was not associated with altered HRV. Obesity was negatively associated with RMSSD and pNN50 and positively with LF/HF ratio. Greater fat mass percentage was associated with lower RMSSD, pNN50, and HF, and increased LF/HF ratio. There were no differences between boys and girls.

CONCLUSIONS

Specific markers of adiposity relate to altered HRV in childhood, with waist-to-height ratio being potentially a more relevant marker of HRV than BMI and more pragmatic than percent body fat.

TRIAL REGISTRATION

NCT03356262, 11 November 2017.

Vascular ageing: moving from bench towards bedside

Prevention of cardiovascular disease (CVD) remains one of the largest public health challenges of our time. Identifying individuals at increased cardiovascular risk at an asymptomatic, sub-clinical stage is of paramount importance for minimizing disease progression as well as the substantial health and economic burden associated with overt CVD. Vascular ageing (VA) involves the deterioration in vascular structure and function over time and ultimately leads to damage in the heart, brain, kidney, and other organs. Vascular ageing encompasses the cumulative effect of all cardiovascular risk factors on the arterial wall over the life course and thus may help identify those at elevated cardiovascular risk, early in disease development. Although the concept of VA is gaining interest clinically, it is seldom measured in routine clinical practice due to lack of consensus on how to characterize VA as physiological vs. pathological and various practical issues. In this state-of-the-art review and as a network of scientists, clinicians, engineers, and industry partners with expertise in VA, we address six questions related to VA in an attempt to increase knowledge among the broader medical community and move the routine measurement of VA a little closer from bench towards bedside.

Effect of School-Based Educational Intervention on Promoting Healthy Dietary Habits in Danish Schoolchildren: The FOODcamp Case Study

The present study aimed to evaluate the effect of the school-based educational intervention "FOODcamp" on dietary habits among 6th-7th graders (aged 11-13 years), focusing on the food groups: fruits and vegetables, fish, meat, discretionary food, and sugar-sweetened beverages. In this cluster-based quasi-experimental controlled intervention study, 16 intervention classes (322 children) and 16 control classes (267 children) from nine schools were recruited during the school year 2019-2020. The children were asked to record their food intake for four consecutive days (Wednesday to Saturday) before (baseline) and after (follow-up) attending FOODcamp, using a validated self-administered web-based dietary record. Eligible dietary intake registrations from 124 and 118 children from the control and interventions classes, respectively, were included in the final statistical analysis. Hierarchical mixed model analysis was used to evaluate the effect of the intervention. No statistically significant effects of participating in FOODcamp were found on the average food intake of the food groups eaten regularly (vegetables, fruit, vegetables/fruit/juice combined, or meat) (p > 0.05). Among the food groups not eaten regularly (fish, discretionary foods, and sugar-sweetened beverages), a non-significant tendency to lower odds of consuming sugar-sweetened beverages from baseline to follow-up (OR = 0.512; 95% CI: 0.261-1.003; p = 0.0510) was seen among FOODcamp participants compared to control participants. In conclusion, this study found no effect of the educational intervention FOODcamp on the dietary intake of vegetables, fruit, vegetable/fruit/juice combined, meat, fish, or sugar-sweetened beverages. The intake frequency of sugar-sweetened beverages tended to decrease among FOODcamp participants.

Dietary Intake and Arterial Stiffness in Children and Adolescents: A Systematic Review

Arterial stiffness is a risk factor for cardiovascular disease that is affected by diet. However, research understanding how these dietary risk factors are related to arterial stiffness during childhood is limited. The purpose of this review was to determine whether various dietary factors were associated with arterial stiffness in the pediatric population. Five databases were systematically searched. Intervention studies, cross-sectional and cohort studies were included that investigated nutrient or food intake and outcomes of arterial stiffness, primarily measured by pulse wave velocity (PWV) and augmentation index (AIx), in the pediatric population (aged 0-18 years). A final 19 studies (six intervention and 13 observational) were included. Only two intervention studies, including a vitamin D and omega-3 supplementation trial, found protective effects on PWV and AIx in adolescents. Findings from observational studies were overall inconsistent and varied. There was limited evidence to indicate a protective effect of a healthy dietary pattern on arterial stiffness and an adverse effect of total fat intake, sodium intake and fast-food consumption. Overall, results indicated that some dietary factors may be associated with arterial stiffness in pediatric populations; however, inconsistencies were observed across all study designs. Further longitudinal and intervention studies are warranted to confirm the potential associations found in this review.

A Systematic Review of the Associations of Adiposity and Cardiorespiratory Fitness With Arterial Structure and Function in Nonclinical Children and Adolescents

PURPOSE

To summarize the evidence on associations of adiposity and cardiorespiratory fitness (CRF) with arterial structure and function in nonclinical children and adolescents.

METHODS

Two researchers conducted a search in 5 electronic databases in April 2022 to find studies in nonclinical youth (age 5-17.9 y) reporting multivariable associations. Studies were eligible if adiposity and/or CRF were used as the predictor and arterial structure and/or function was the outcome. The Quality Assessment Tool for Quantitative Studies was used to assess methodological quality for experimental studies, and a modified version was used for observational studies.

RESULTS

Ninety-nine studies (72.7% cross-sectional) were included. Ninety-four assessed associations between adiposity and arterial outcomes, most using overall body proportion (n = 71), abdominal (n = 52), or whole-body adiposity (n = 40). Most evidence was inconsistent or nonsignificant, but 59 studies suggested higher abdominal adiposity and worse body proportion were associated with adverse arterial outcomes. Twenty-one assessed associations between CRF and arterial outcomes, with findings inconsistent. Most evidence was rated weak in quality.

CONCLUSION

While high adiposity may contribute to poor arterial outcomes, evidence is limited regarding CRF. Future studies should disentangle these associations by studying youth with healthy adiposity but poor CRF, or vice versa, using longitudinal or experimental study designs.

Correlation among Waist Circumference and Central Measures of Blood Pressure

BACKGROUND

Arterial stiffness is a strong predictor of cardiovascular disease (CVD). Body fat measures such as waist circumference (WC) have been associated with CVD in adulthood.

OBJECTIVES

The objective of this study was to evaluate the association of arterial stiffness, measured by applanation tonometry-Sphygmocor, with WC.

METHODS

Observational study with 240 participants who make routine consultations at the outpatient clinic of a university hospital. Participants were interviewed and had central blood pressure measurements (CBPM), anthropometric parameters, abdominal fat and visceral fat measured. Paired and unpaired t and chi-square tests were used. A significance level of 5% was adopted.

RESULTS

Of the 240 participants, 51.82% were male with a mean age of 59.71(±14.81) years and a mean WC of 99.87 (11.54) cm. Mean CBPM values were: Central arterial pressure (CAP) = 130.23 (91-223) mmHg, pulse wave velocity (PWV) = 9.8 (5.28-19.6)m/s and Augmentation Index [Amplification Index (AI)] = 29.45 (-14-60). PWV and CAP were highly correlated with WC with p<0.001 and p=0.02, respectively; however, the same positive correlation was not found between WC and AI (p=0.06).

CONCLUSION

The present study showed a positive association between WC and arterial stiffness, through the femoral carotid pulse wave velocity (cf-PWV) and AI, being stronger with cf-PWV, suggesting the evaluation of the effect of WC in vascular health as a method of aid in the early treatment of CVD and in the prevention of clinical outcomes.

Improved food literacy among schoolchildren as an effect of a food camp intervention: Results of a controlled effectiveness trial

Food literacy (FL) refers to an individual's prerequisites for their engagement with food. Schoolchildren's FL has been defined in terms of five competencies: "to know"(e.g food-related knowledge), "to do" (e.g cooking skills), "to sense" (e.g. less well-explored sensory experiences), "to care" (e.g. taking care of oneself and others) and "to want" (e.g. willingness to take a stand and act). A cluster-based quasi-experimental effectiveness trial on the effects of a school-based intervention, "FOODcamp," on FL, health literacy, and school well-being was conducted. A total of 640 school children in grades 6 and 7 (mean age = 12 years) attended this one-week camp and participated in different food-related classes and activities. Linear mixed models controlling for the nested structure of data showed small but significant effects for the following FL dimensions: "to do (E = 0.098, CI (0.035-0.161), p = 0.002), "to sense" (E = 0.152, CI (0.073-0.232), p < 0.001), and "to know" (E = 0.086, CI (0.022-0.150), p = 0.009) as well as for overall FL (E = 0.078, CI (0.034-0.122), p = 0.001). No effects were found for the dimensions "to want" or "to care". The intervention also had a small but significant effect on children's health literacy but not on school well-being. These findings demonstrate the value of FOODcamp and the positive impacts of a relatively brief intervention on children's FL.

Cardiometabolic Health and Carotid-Femoral Pulse Wave Velocity in Children: A Systematic Review and Meta-Regression

OBJECTIVE

To identify, in children the normal rate of carotid-femoral pulse wave velocity (cfPWV) progression, and whether presence of cardiometabolic risk factors is associated with cfPWV.

STUDY DESIGN

Electronic databases (PubMed, Google Scholar) were searched from inception to May 2018, for all studies which reported cfPWV in children (<19 years of age). Random effects meta-regression quantified the association between time (years) and cfPWV, and a systematic review was performed to determine whether cardiometabolic risk factors are associated with cfPWV.

RESULTS

Data from 28 articles were eligible for inclusion, including 9 reference value (n = 13 100), 5 cardiovascular risk (n = 5257), 10 metabolic risk (n = 2999), and 8 obesity-focused (n = 8760) studies. Meta-regression findings (9 studies) showed that the increase in cfPWV per year (age) was 0.12 m/second (95% CI, 0.07-0.16 m/second) per year, and when stratified by sex the CIs overlapped. Systematic review findings showed that cardiometabolic risk factors were positively associated with cfPWV, including positive associations with blood pressure, impaired glucose metabolism, and metabolic syndrome. However, obesity was not consistently associated with cfPWV.

CONCLUSIONS

Arterial stiffness in children progresses with age and is associated with cardiometabolic risk factors. Although further longitudinal studies are warranted, the presented reference data will be valuable to epidemiologists tracking children, and to scientists and clinicians prescribing therapies to mitigate risk in a population that is increasingly more vulnerable to cardiovascular disease.

Truncal-to-leg fat ratio and cardiometabolic disease risk factors in US adolescents: NHANES 2003-2006

BACKGROUND

This study aims to describe patterns of truncal versus peripheral fat deposition measured by truncal-to-leg fat ratio (TLR) in adolescents and examine associations of TLR with cardiometabolic (CMD) risk factors.

METHODS

Data were from 3810 adolescents (12-19 years old) in the National Health and Examination Survey (NHANES) 2003-2006. Body fat was assessed by dual-energy X-ray absorptiometry, and CMD risk factors were determined by blood samples and physical examination. Linear and logistic regressions adjusted for BMI z-score and other covariates were used to examine associations of TLR with CMD risk factors as continuous and dichotomized outcomes, respectively.

RESULTS

Adolescents who were Mexican American, who have lower income, and with obesity had the highest mean TLR (all p < 0.05). In linear regression, increasing TLR was associated positively with homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides, total cholesterol, systolic blood pressure (BP), c-reactive protein, and alanine aminotransferase (ALT), and negatively with high-density lipoprotein (HDL) cholesterol in both sexes (p < 0.05). TLR was also associated with diastolic BP in boys and low-density lipoprotein cholesterol in girls (p < 0.05). A similar pattern of findings resulted from logistic regression. When further stratified by race/ethnicity, TLR was positively associated with high triglycerides, total cholesterol, and ALT for White and/or Mexican American (p < 0.05), but not Black adolescents, while associations with HOMA-IR and HDL were significant for all race/ethnicities.

CONCLUSIONS

In this cohort of adolescents, TLR was associated with several risk factors independent of BMI z-score, although some findings were sex or race/ethnicity specific. Body fat distribution may be an important determinant of future CMD.

Total Dairy, Cheese and Milk Intake and Arterial Stiffness: A Systematic Review and Meta-Analysis of Cross-sectional Studies

The aim of this review was to determine the relationship between dairy product consumption and arterial stiffness, measured by pulse wave velocity (PWV). We systematically searched the Medline, Embase and Web of Science databases until 30th January 2019 for cross-sectional data from studies addressing the association between dairy product consumption and PWV. This study was registered with PROSPERO (CRD42018110528). Both the inverse-variance fixed effects method and the DerSimonian and Laird method were used to compute pooled estimates of effect size (ES) and the respective 95% confidence intervals (CIs). Seven studies were included in the meta-analysis, with a total of 16,443 patients. Total dairy product (ES = -0.03; 95% CI [-0.04, -0.01]) and cheese (ES = -0.04; 95% CI [-0.07, -0.01]) consumption were weak, but significantly associated with lower PWV levels. Conversely, milk intake showed no significant association with PWV (ES = 0.02; 95% CI [-0.01, 0.05]). Heterogeneity in the ES was not important for the three groups of dairy products assessed. This systematic review and meta-analysis of seven studies found no detrimental effects of dairy product consumption on arterial stiffness measured by PWV. Due to the scarcity of studies, further investigations are warranted to clarify the role of dairy products on arterial stiffness.

Normal weight metabolically unhealthy phenotype in youth: Do definitions matter?

BACKGROUND

Normal weight metabolically unhealthy (NWMU) adults are at increased risk of cardiometabolic disease, however, little is known regarding NWMU children.

OBJECTIVES

We examined the associations between existing definitions of NWMU in children aged 8 to 10 years and insulin sensitivity (IS) and secretion 2 years later.

METHODS

Data stem from the Quebec Adipose and Lifestyle InvesTigation in Youth (QUALITY) cohort of 630 Caucasian youth, 8 to 10 years old at baseline, with at least one obese biological parent. Of these, 322 normal weight children were classified as NWMU using four definitions. At 10 to 12 years, IS was measured with the Matsuda-insulin sensitivity index; insulin secretion was measured with the ratio of the area under the curve (AUC) of insulin to the AUC of glucose over a 2-hour oral glucose tolerance test. Multiple linear regression models were used.

RESULTS

Because few children met the existing definitions of metabolic syndrome, associations were examined for less stringent definitions (eg, having two vs no risk factors). At baseline, IS was lower in NWMU children compared to children with no risk factors (virtually all definitions). Moreover, after 2 years, IS was 14.4-19.3% lower in NWMU children with one or more risk factors, and up to 29.7% lower in those with two or more risk factors compared to those with none. Insulin secretion was not predicted by components of the metabolic syndrome.

CONCLUSION

Existing definitions of NWMU youth performed relatively similarly in predicting IS as youth entered puberty. Children with one or more components of metabolic syndrome-even when of normal weight-have significantly lower IS over time.

What Do We Know about Diet and Markers of Cardiovascular Health in Children: A Review

Chronic diseases such as cancer, diabetes, and cardiovascular diseases (CVD) are the main health concerns in the 21st century, with CVD as the number one cause of mortality worldwide. Although CVD hard endpoints such as stroke or heart attack do not usually occur in children, evidence shows that the manifestation of CVD risk factors begins in childhood, preceding clinical complications of CVD in adulthood. Dietary intake is a modifiable risk factor that has been shown to make a substantial contribution to the risk of CVD in adulthood. However, less is known about the association between dietary intake and markers of cardiovascular health in children. This review summarises the current evidence on the relationship between dietary intake and markers of cardiovascular health including traditional CVD risk factors, physical fitness, and indices of arterial stiffness and wave reflection in children. Original research published in English, between January 2008 and December 2018 fulfilling the objective of this review were screened and included. Findings show that adaptation of a healthy lifestyle early in life can be beneficial for reducing the risk of CVD later in life. Furthermore, keeping arterial stiffness low from a young age could be a potential CVD prevention strategy. However, limited studies are available on diet-arterial stiffness relationship in children, and future research is required to better understand this association to aid the development and implementation of evidence-based strategies for preventing CVD-related complications later in life.

Prospective Associations Between Play Environments and Pediatric Obesity

PURPOSE

To identify school typologies based on the availability of play equipment and installations. We also examined the associations between availability of play items and child adiposity.

DESIGN

Secondary analysis of longitudinal data.

SETTING

Elementary schools in Montreal, Canada.

PARTICIPANTS

We used data from the Quebec Adipose and Lifestyle Investigation in Youth study (QUALITY), an ongoing investigation of the natural history of obesity and type 2 diabetes in Quebec children of Caucasian descent.

MEASURES

The presence of play items was assessed in each child's school. A trained nurse directly assessed child anthropometric measurements to derive body mass index and waist circumference. Body fat composition was measured using DEXA Prodigy Bone Densitometer System.

ANALYSES

The final analytic sample comprised 512 students clustered in 296 schools (81% response). We used K-cluster analyses to identify school typologies based on the variety of play items on school grounds. Generalized estimation equations were used to estimate associations between school clusters and outcomes.

RESULTS

We identified 4 distinct school typologies. Children in schools with the most varied indoor play environments had lower overall body fat, B = -1.26 cm (95% confidence interval [CI], -2.28 to -0.24 cm), and smaller waist circumference, B = -4.42 cm (95% CI, -7.88 to -0.96 cm), compared to children with the least varied indoor play environment.

CONCLUSION

Our results suggest that policies regulating the availability of play items in schools may enrich comprehensive school-based obesity prevention strategies. Extending research in this area to diverse populations is warranted.

Utility of arterial stiffness assessment in children

Atherosclerotic cardiovascular disease is a leading cause of death and disability worldwide, and the atherosclerotic process begins in childhood. Prevention or containment of risk factors that accelerate atherosclerosis can delay the development of atherosclerotic cardiovascular disease. Although current recommendations are to periodically screen for commonly prevailing risk factors for atherosclerosis in children, a single test that could quantify the cumulative effect of all risk factors on the vasculature, thus assessing arterial health, would be helpful in further stratifying risk. Measurement of pulse wave velocity and assessment of augmentation index - measures of arterial stiffness - are easy-to-use, non-invasive methods of examining arterial health. Various studies have assessed pulse wave velocity and augmentation index in children with commonly occurring conditions including obesity, hypertension, insulin resistance, diabetes mellitus, dyslipidaemia, physical inactivity, chronic kidney disease, CHD and acquired heart diseases, and in children who were born premature or small for gestational age. This article summarises pulse wave velocity and augmentation index assessments and the effects of commonly prevailing chronic conditions on arterial health in children. In addition, currently available reference values for pulse wave velocity and augmentation index in healthy children are included. Further research to establish widely applicable normative values and the effect of lifestyle and pharmacological interventions on arterial health in children is needed.

Is arterial stiffening associated with adiposity, severity of obesity and other contemporary cardiometabolic markers in a community sample of adolescents with obesity in the UK?

BACKGROUND

Cardiovascular disease (CVD) prediction is problematic within groups of obese adolescents as measures such as adiposity and metabolic markers lack validation. Pulse wave velocity (PWV), a proxy for arterial stiffening, is a potential way to contemporaneously capture adolescents at greater risk of CVD.

OBJECTIVES

To investigate associations between PWV and 1) adiposity and 2) other conventional metabolic factors in a community sample of (>95th centile body mass index (BMI)).

DESIGN AND SETTING

Cross-sectional measurement and analysis in a hospital-based research centre drawn from a community sample of adolescents recruited to an obesity intervention at baseline.

PATIENTS

174 adolescents (12-19 years) with obesity (>95th centile BMI). 37% were male, while 66 (38%) were white, 53 (30%) black, 36 (21%) South Asian, 19 (11%) mixed/other. Participants with endocrine, genetic causes of obesity and chronic medical conditions (excluding asthma) were excluded.

MEASURES

BMI z-score (zBMI), waist z-score, fat mass index (FMI: measured using bioimpedance), sagittal abdominal dimension (SAD), cardiometabolic blood tests and resting blood pressure (BP) were collected. Carotid-radial PWV was measured by a single operator.

RESULTS

PWV was associated with age but not pubertal stage. PWV was positively associated with adiposity (zBMI: coefficient 0.44 (95% CI 0.08 to 0.79); FMI: coefficient 0.05 (95% CI 0.00 to 0.10); waist z-score: coefficient 0.27 (95% CI 0.00 to 0.53); SAD: coefficient 0.06 (95% CI: 0.00 to 0.12)). There was no association between PWV and BP, and few associations with cardiometabolic bloods. Associations between PWV and adiposity measures were robust to adjustment in multivariable models except for SAD. Participants with zBMI >2.5 SD and >3.5 SD had greater average PWV but overlap between groups was large.

CONCLUSIONS

In our sample, increasing adiposity was positively associated with arterial stiffness, however partitioning by severity was not reliable. Lack of associations between BP, cardiometabolic bloods and arterial stiffness questions the reliability of these factors for predicting CVD risk in adolescents with obesity.

The associations of cardiorespiratory fitness, adiposity and sports participation with arterial stiffness in youth with chronic diseases or physical disabilities

Background

The evidence on the associations of cardiorespiratory fitness, body adiposity and sports participation with arterial stiffness in children and adolescents with chronic diseases or physical disabilities is limited.

Methods

Altogether 140 children and adolescents with chronic diseases or physical disabilities participated in this cross-sectional study. Cardiorespiratory fitness was assessed using maximal exercise test with respiratory gas analyses either using shuttle run, shuttle ride, or cycle ergometer test. Cardiorespiratory fitness was defined as peak oxygen uptake by body weight or fat-free mass. Body adiposity was assessed using waist circumference, body mass index standard deviation score and body fat percentage. Sports participation was assessed by a questionnaire. Aortic pulse wave velocity and augmentation index were assessed by a non-invasive oscillometric tonometry device.

Results

Peak oxygen uptake/body weight (standardised regression coefficient β −0.222, 95% confidence interval (CI) −0.386 to −0.059, P = 0.002) and peak oxygen uptake/fat-free mass (β −0.173, 95% CI −0.329 to −0.017, P = 0.030) were inversely and waist circumference directly (β 0.245, 95% CI 0.093 to 0.414, P = 0.002) associated with aortic pulse wave velocity. However, the associations of the measures of cardiorespiratory fitness with aortic pulse wave velocity were attenuated after further adjustment for waist circumference. A higher waist circumference (β −0.215, 95% CI −0.381 to −0.049, P = 0.012) and a higher body mass index standard deviation score (β 0.218, 95% CI −0.382 to −0.054, P = 0.010) were related to lower augmentation index.

Conclusions

Poor cardiorespiratory fitness and higher waist circumference were associated with increased arterial stiffness in children and adolescents with chronic diseases and physical disabilities. The association between cardiorespiratory fitness and arterial stiffness was partly explained by waist circumference.

School food environments associated with adiposity in Canadian children

BACKGROUND/OBJECTIVES

Targeting obesogenic features of children's environment that are amenable to change represents a promising strategy for health promotion. The school food environment, defined as the services and policies regarding nutrition and the availability of food in the school and surrounding neighborhood, is particularly important given that students travel through the school neighborhood almost daily and that they consume a substantial proportion of their calories at school.

SUBJECTS/METHODS

As part of the Quebec Adipose and Lifestyle Investigation in Youth (QUALITY) cohort study, we assessed features of school indoor dietary environment and the surrounding school neighborhoods, when children were aged 8-10 years (2005-2008). School principals reported on food practices and policies within the schools. The density of convenience stores and fast-food outlets surrounding the school was computed using a Geographical Information System. Indicators of school neighborhood deprivation were derived from census data. Adiposity outcomes were measured in a clinical setting 2 years later, when participants were aged 10-12 years (2008-2011). We conducted cluster analyses to identify school food environment types. Associations between school types and adiposity were estimated in linear regression models.

RESULTS

Cluster analysis identified three school types with distinct food environments. Schools were characterized as: overall healthful (45%); a healthful food environment in the surrounding neighborhood, but an unhealthful indoor food environment (22%); or overall unhealthful (33%). Less healthful schools were located in more deprived neighborhoods and were associated with greater child adiposity.

CONCLUSIONS

Despite regulatory efforts to improve school food environments, there is substantial inequity in dietary environments across schools. Ensuring healthful indoor and outdoor food environments across schools should be included in comprehensive efforts to reduce obesity-related health disparities.

Effect of increased intake of skimmed milk, casein, whey or water on body composition and leptin in overweight adolescents: a randomized trial

BACKGROUNDS

Dairy proteins may support muscle protein synthesis and improve satiety in adults. However, there are limited studies using exact measures of body composition, especially in adolescents.

OBJECTIVES

This study investigates the effect of milk proteins and water on body composition and leptin in overweight adolescents.

METHODS

Subjects (n = 193) aged 12-15 years were randomized to drink 1 L d(-1) of skimmed milk, whey, casein (all milk-based drinks 35 g protein L(-1) ) or water for 12 weeks. Twenty participants dropped out. A pre-test control group of 32 adolescents was examined 12 weeks before start of intervention. Outcomes included leptin and dual-energy X-ray absorptiometry scanning. The effects of the milk-based drinks on body composition and leptin were compared with baseline, pre-test control and water.

RESULTS

Lean mass index (LMI) increased compared to baseline (all 95% confidence intervals 0.05-0.50 kg m(-2) , all P ≤ 0.009) and the pre-test control group (0.044-0.247 kg m(-2) , P ≤ 0.002) for all four test drinks. Fat mass index (FMI) increased only for milk-based drink groups compared with baseline (0.15-0.67 kg m(-2) , P < 0.001) and also compared with water (0.029-0.255 kg m(-2) , P ≤ 0.011). For pre-test control, there was no change in FMI or LMI. Leptin increased in the casein (1.016-3.246 ng mL(-1) , P < 0.001; 0.952-3.294 ng mL(-1) , P < 0.001) and whey groups (0.135-2.273 ng mL(-1) , P = 0.027; 0.069-2.322, P = 0.038) compared with water and pre-test control group, respectively.

CONCLUSIONS

Although milk proteins increased LMI in overweight adolescents, there was a concurrent increase in FMI and leptin, whereas water only resulted in increased LMI. Thus, increased water intake may be beneficial for body composition in overweight adolescents.

Effects of protein intake on blood pressure, insulin sensitivity and blood lipids in children: a systematic review

High protein intake in early childhood is associated with obesity, suggesting possible adverse effects on other cardiometabolic outcomes. However, studies in adults have suggested beneficial effects of protein intake on blood pressure (BP) and lipid profile. Whether dietary protein intake is associated with cardiovascular and metabolic health in children is unclear. Therefore, we aimed to systematically review the evidence on the associations of protein intake with BP, insulin sensitivity and blood lipids in children. We searched the databases Medline, Embase, Cochrane Central and PubMed for interventional and observational studies in healthy children up to the age of 18 years, in which associations of total, animal and/or vegetable protein intake with one or more of the following outcomes were reported: BP; measures of insulin sensitivity; cholesterol levels; or TAG levels. In the search, we identified 6636 abstracts, of which fifty-six studies met all selection criteria. In general, the quality of the included studies was low. Most studies were cross-sectional, and many did not control for potential confounders. No overall associations were observed between protein intake and insulin sensitivity or blood lipids. A few studies suggested an inverse association between dietary protein intake and BP, but evidence was inconclusive. Only four studies examined the effects of vegetable or animal protein intake, but with inconsistent results. In conclusion, the literature, to date provides insufficient evidence for effects of protein intake on BP, insulin sensitivity or blood lipids in children. Future studies could be improved by adequately adjusting for key confounders such as energy intake and obesity.

Importance of android/gynoid fat ratio in predicting metabolic and cardiovascular disease risk in normal weight as well as overweight and obese children

Numerous studies have shown that android or truncal obesity is associated with a risk for metabolic and cardiovascular disease, yet there is evidence that gynoid fat distribution may be protective. However, these studies have focused on adults and obese children. The purpose of our study was to determine if the android/gynoid fat ratio is positively correlated with insulin resistance, HOMA2-IR, and dislipidemia in a child sample of varying body sizes. In 7-13-year-old children with BMI percentiles ranging from 0.1 to 99.6, the android/gynoid ratio was closely associated with insulin resistance and combined LDL + VLDL-cholesterol. When separated by sex, it became clear that these relationships were stronger in boys than in girls. Subjects were stratified into BMI percentile based tertiles. For boys, the android/gynoid ratio was significantly related to insulin resistance regardless of BMI tertile with and LDL + VLDL in tertiles 1 and 3. For girls, only LDL + VLDL showed any significance with android/gynoid ratio and only in tertile 2. We conclude that the android/gynoid fat ratio is closely associated with insulin resistance and LDL + VLDL-, "bad," cholesterol in normal weight boys and may provide a measurement of metabolic and cardiovascular disease risk in that population.

Increased circulating inflammatory markers may indicate that formula-fed children are at risk of atherosclerosis

AIM

The aim of this study was to determine whether formula-fed children have higher serum monocyte chemoattractant protein-1 (MCP-1) and uric acid levels than breast-fed children and to evaluate the association between these inflammatory markers and breastfeeding duration.

METHODS

The study group consisted of 87 patients aged between five and 32 months. Participants were divided into breast-fed and formula-fed groups and into age groups of ≤12 months and >12 months. MCP-1 was measured by the commercial immunoenzymatic ELISA kit, and uric acid was assessed using the colorimetric method.

RESULTS

Children in the formula-fed group had statistically significant higher serum MCP-1 and uric acid levels than breast-fed children (p < 0.01 and p < 0.05, respectively). Anthropometric parameters were comparable in both groups. Serum MCP-1 and uric acid levels were negatively correlated with duration of breastfeeding (p < 0.01 and p < 0.05). There was a positive relationship between serum MCP-1 and uric acid concentrations (r = 0.27, p < 0.05).

CONCLUSION

Increased circulating inflammatory markers may indicate that formula-fed children are at risk of atherosclerosis. However, further studies are needed.

Effect of milk proteins on linear growth and IGF variables in overweight adolescents

OBJECTIVE

Milk may stimulate growth acting via insulin-like growth factor-I (IGF-I) secretion but the effect in adolescents is less examined. This study investigates the effect of milk proteins on linear growth, IGF-I, IGF binding protein-3 (IGFBP-3) and IGF-I/IGFBP-3 ratio in overweight adolescents.

DESIGN

The trial included 193 overweight adolescents aged 12-15 years. They were randomized to drink 1L/day of: skimmed milk, whey, casein or water for 12 weeks; all milk-based drinks contained 35 g protein/L. A subgroup of 32 adolescents was examined 12 weeks before they were randomized into the groups and started the intervention (pre-test control group). Examinations included anthropometry, diet registration and blood samples which were analyzed for IGF-I and IGFBP-3 by chemiluminescence methods. The effects of milk-based drinks on linear growth, IGF-I, IGFBP-3 and IGF-I availability, calculated as the IGF-I/IGFBP-3 ratio, were compared with baseline, the pre-test control group and water.

RESULTS

IGF-I increased with skimmed milk (P=0.015) and tended to increase with casein (P=0.075) compared to the pre-test control group. IGFBP-3 but not IGF-I increased with skimmed milk (P=0.006) and casein (P=0.001) compared to water. There was no difference in height or height Z-score for any of the milk-based test drink groups compared to water or compared to the pre-test control group. However, height Z-score decreased within the whey group.

CONCLUSIONS

Skimmed milk and casein may have a stimulating effect on the IGF-I system whereas there was no positive effect on height in overweight adolescents during this 12 week intervention.

NMR-based metabolomic profiling of overweight adolescents: an elucidation of the effects of inter-/intraindividual differences, gender, and pubertal development

The plasma and urine metabolome of 192 overweight 12–15-year-old adolescents (BMI of 25.4 ± 2.3 kg/m²) were examined in order to elucidate gender, pubertal development measured as Tanner stage, physical activity measured as number of steps taken daily, and intra-/interindividual differences affecting the metabolome detected by proton NMR spectroscopy. Higher urinary excretion of citrate, creatinine, hippurate, and phenylacetylglutamine and higher plasma level of phosphatidylcholine and unsaturated lipid were found for girls compared with boys. The results suggest that gender differences in the metabolome are being commenced already in childhood. The relationship between Tanner stage and the metabolome showed that pubertal development stage was positively related to urinary creatinine excretion and negatively related to urinary citrate content. No relations between physical activity and the metabolome could be identified. The present study for the first time provides comprehensive information about associations between the metabolome and gender, pubertal development, and physical activity in overweight adolescents, which is an important subject group to approach in the prevention of obesity and life-style related diseases. While this study is preliminary, these results may have the potential to translate into clinical applicability upon further investigations; if biomarkers for Tanner stage can be established, these might be used for identification of individuals susceptible to an early pubertal development.

Casein improves brachial and central aortic diastolic blood pressure in overweight adolescents: a randomised, controlled trial

Arterial stiffness, blood pressure (BP) and blood lipids may be improved by milk in adults and the effects may be mediated via proteins. However, limited is known about the effects of milk proteins on central aortic BP and no studies have examined the effects in children. Therefore, the present trial examined the effect of milk and milk proteins on brachial and central aortic BP, blood lipids, inflammation and arterial stiffness in overweight adolescents. A randomised controlled trial was conducted in 193 overweight adolescents aged 12-15 years. They were randomly assigned to drink 1 litre of water, skimmed milk, whey or casein for 12 weeks. The milk-based test drinks contained 35 g protein/l. The effects were compared with the water group and a pretest control group consisting of thirty-two of the adolescents followed 12 weeks before the start of the intervention. Outcomes were brachial and central aortic BP, pulse wave velocity and augmentation index, serum C-reactive protein and blood lipids. Brachial and central aortic diastolic BP (DBP) decreased by 2·7% (P = 0·036) and 2·6 % (P = 0·048), respectively, within the casein group and the changes were significantly different from those of the pretest control group (P = 0·040 and P = 0·034, respectively). There was a significant increase in central aortic DBP, and in brachial and central systolic BP in the whey group compared with the water group (P = 0·003, P = 0·009 and P = 0·002, respectively). There were no changes in measures of arterial stiffness or blood lipid concentrations. A high intake of casein improves DBP in overweight adolescents. Thus, casein may be beneficial for younger overweight subjects in terms of reducing the long-term risk of CVD. In contrast, whey protein seems to increase BP compared with drinking water; however, water may be considered an active control group.

Infant macronutrient composition is associated with differences in cardiovascular structures and function in childhood

Early-life nutrition may influence cardiovascular development. Not much is known about the associations between dietary composition and cardiovascular risk factors in childhood. We examined the associations of infant macronutrient intake with cardiovascular structures and function in 2882 children participating in a prospective, population-based cohort study. Information on macronutrient intake at the age of 14 mo was obtained from food-frequency questionnaires completed by a parent. Systolic and diastolic blood pressure, carotid-femoral pulse wave velocity (PWV), fractional shortening, and left cardiac structures (left atrial diameter, aortic root diameter, and left ventricular mass) were measured at the age of 6 y. Linear regression analyses were performed by using energy-adjusted macronutrient intakes, adjusted for maternal, child, and other dietary factors. Higher total fat intake was associated with higher carotid-femoral PWV (P-trend = 0.03), whereas higher intakes of total carbohydrate and mono- and disaccharides were associated with lower carotid-femoral PWV. No consistent associations were observed for macronutrient intake with systolic blood pressure, diastolic blood pressure, fractional shortening, and aortic root diameter. Higher intakes of total, saturated, monounsaturated, and polyunsaturated fat were associated with lower left atrial diameter (all P-trend ≤ 0.01), and higher total carbohydrate and mono- and disaccharide intakes were associated with higher left atrial diameter (P-trend < 0.01 and 0.02, respectively). Furthermore, the third tertile of mono- and disaccharide intake was associated with a higher left ventricular mass (difference: 1.01 g; 95% CI: 0.18, 1.85 g; P = 0.02). Dietary macronutrient composition in infancy may lead to developmental differences in cardiovascular structures and function in childhood. Further studies are needed to investigate whether these differences have consequences for the risk of future cardiovascular disease.

Triglyceride to HDL-C ratio and increased arterial stiffness in children, adolescents, and young adults

BACKGROUND AND OBJECTIVE

Lipid levels are linked to early atherosclerosis. Risk stratification may be improved by using triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), which relates to arterial stiffness in adults. We tested whether TG/HDL-C was an independent predictor of arterial stiffness in youth.

METHODS

Subjects 10 to 26 years old (mean 18.9 years, 39% male, 56% non-Caucasian, n = 893) had laboratory, anthropometric, blood pressure, and arterial stiffness data collected (brachial distensibility, augmentation index, carotid-femoral pulse-wave velocity). Subjects were stratified into tertiles of TG/HDL-C (low, n = 227; mid, n = 288; high, n = 379).

RESULTS

There was a progressive rise in cardiovascular (CV) risk factors and arterial stiffness across TG/HDL-C ratio. The high TG/HDL-C ratio group had the stiffest vessels (all P < .03 by analysis of variance). TG/HDL-C as a continuous variable was an independent determinant of brachial distensibility in CV risk factor adjusted model and for carotid-femoral pulse-wave velocity in obese subjects, with trend for higher augmentation index.

CONCLUSIONS

TG/HDL-C, an estimate of small, dense low-density lipoprotein cholesterol, is an independent determinant of arterial stiffness in adolescents and young adults, especially in obese youth. These data suggest that use of TG/HDL-C may be helpful in identifying young adults requiring aggressive intervention to prevent atherosclerotic CV diseases.

Association of arterial stiffness with obesity in Australian women: a pilot study

This study investigated the arterial stiffness status in overweight/obese Australian women compared with their lean counterparts. Twenty-six Caucasian women were designated into one of two groups: overweight/obese (body mass index [BMI] 25-34.9 kg/m2 [ n=12]) and lean (BMI 18.5-24.9 kg/m2 [n=14]) groups. Participants were assessed for clinical, anthropometric, metabolic, and augmentation index (AIx) measurements. Age was similar between groups (P=.482). BMI was significantly higher in overweight/obese compared with lean participants (30.26±1.09 vs 21.62±0.52 kg/m2, P=.001) as well as the percentage of body fat (40.60±2.43 vs 21.57±1.13, P=.001), waist circumference (91.47±2.77 vs 70.67±1.60, P=.001), and waist/hip ratio (0.81±0.04 vs 0.71±0.03, P=.036). Overweight/obese group showed higher total cholesterol, triglyceride, low-density lipoprotein cholesterol, and fasting glucose levels compared with the lean group (all P<.05). Both systolic (122.92±3.18 mm Hg vs 108.14±2.42 mm Hg, P=.001) and diastolic (83.58±2.43 mm Hg vs 72.43±1.29 mm Hg, P=.0001) blood pressures, as well as AIx (50.08±4.7 vs 120.79±2.17, P=.001) were significantly higher in the overweight/obese group compared with the lean group. AIx was positively associated with measurements of body composition (P<.05), triglycerides (r=0.361, P=.035) and glucose levels (r=0.371, P=.031), and systolic and diastolic blood pressure (r=0.793 and r=0.718, respectively; P=.0001). This data suggests that arterial stiffness is associated with obesity, along with other metabolic abnormalities in Australian women.

Skim milk, whey, and casein increase body weight and whey and casein increase the plasma C-peptide concentration in overweight adolescents

In adults, dietary protein seems to induce weight loss and dairy proteins may be insulinotropic. However, the effect of milk proteins in adolescents is unclear. The objective was to test whether milk and milk proteins reduce body weight, waist circumference, homeostatic model assessment, plasma insulin, and insulin secretion estimated as the plasma C-peptide concentration in overweight adolescents. Overweight adolescents (n = 203) aged 12-15 y with a BMI of 25.4 ± 2.3 kg/m(2) (mean ± SD) were randomized to 1 L/d of skim milk, whey, casein, or water for 12 wk. All milk drinks contained 35 g protein/L. Before randomization, a subgroup of adolescents (n = 32) was studied for 12 wk before the intervention began as a pretest control group. The effects of the milk-based test drinks were compared with baseline (wk 0), the water group, and the pretest control group. Diet and physical activity were registered. Outcomes were BMI-for-age Z-scores (BAZs), waist circumference, plasma insulin, homeostatic model assessment, and plasma C-peptide. We found no change in BAZ in the pretest control and water groups, whereas it was greater at 12 wk in the skim milk, whey, and casein groups compared with baseline and with the water and pretest control groups. The plasma C-peptide concentration increased from baseline to wk 12 in the whey and casein groups and increments were greater than in the pretest control (P < 0.02). There were no significant changes in plasma C-peptide in the skim milk or water group. These data suggest that high intakes of skim milk, whey, and casein increase BAZs in overweight adolescents and that whey and casein increase insulin secretion. Whether the effect on body weight is primary or secondary to the increased insulin secretion remains to be elucidated.