Body mass index percentiles versus body composition assessments: Challenges for disease risk classifications in children

Background

Identifying at-risk children with optimal specificity and sensitivity to allow for the appropriate intervention strategies to be implemented is crucial to improving the health and well-being of children. We determined relationships of body mass indexes for age and sex percentile (BMI%) classifications to actual body composition using validated and convenient methodologies and compared fat and non-fat mass estimates to normative cut-off reference values to determine guideline reliability. We hypothesized that we would achieve an improved ability to identify at-risk children using simple, non-invasive body composition and index measures.

Methods

Cross-sectional study of a volunteer convenience sample of 1,064 (537 boys) young children comparing Body Fat Percentage (BF%), Fat Mass Index (FMI), Fat-Free Mass Index (FFMI), determined via rapid bioimpedance methods vs. BMI% in children. Comparisons determined among weight classifications and boys vs. girls.

Results

Amongst all subjects BMI% was generally correlated to body composition measures and indexes but nearly one quarter of children in the low-risk classifications (healthy weight or overweight BMI%) had higher BF% and/or lower FFMI than recommended standards. Substantial evidence of higher than expected fatness and or sarcopenia was found relative to risk status. Inaccuracies were more common in girls than boys and girls were found to have consistently higher BF% at any BMI%.

Conclusions

The population studied raises concerns regarding actual risks for children of healthy or overweight categorized BMI% since many had higher than expected BF% and potential sarcopenia. When body composition and FMI and FFMI are used in conjunction with BMI% improved sensitivity, and accuracy of identifying children who may benefit from appropriate interventions results. These additional measures could help guide clinical decision making in settings of disease-risks stratifications and interventions.

Impact of Pediatric Obesity on Diurnal Blood Pressure Assessment and Cardiovascular Risk Markers

Background: The prevalence of hypertension is increasing particularly among obese children and adolescents. Obese children and adolescents with hypertension are likely to remain hypertensive as they reach adulthood and hypertension is linked to an increased risk for cardiovascular disease. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has become one of the most important tools in diagnosing hypertension in children and adolescents and circadian patterns of blood pressure may be important disease-risk predictors. Methods: A retrospective chart review was conducted in patients aged 6-21 years who underwent 24-h ABPM at Kentucky Children's Hospital (KCH) from August 2012 through June 2017. Exclusion criteria included conditions that could affect blood pressure including chronic kidney disease and other renal abnormalities, congenital heart disease, cancer, and thyroid disease. Subjects were categorized by body mass index into normal (below 85th percentile), overweight (85th-95th percentile), stage I obesity (95th-119th percentile), stage II obesity (120th-139th) and stage III obesity (>140th). Non-dipping was defined as a nocturnal BP reduction of <10%. Results: Two hundred and sixty-three patients (156 male patients) were included in the analysis, of whom 70 were normal weight, 33 overweight, 55 stage I obesity, 53 stage II, and 52 stage III obesity. Although there was no significant difference between normal weight and obese groups for prevalence of hypertension, there was a greater prevalence of SBP non-dipping in obese patients as BMI increased (p = 0.008). Furthermore, non-dippers had a significantly elevated LVMI as well as abnormal lab values for uric acid, blood lipid panel, creatinine, and TSH (p < 0.05). Conclusions: These findings demonstrate that obese children and adolescents constitute a large proportion of hypertensive children and adolescents and the severity of pediatric obesity is associated with nocturnal BP non-dipping. Additionally, obesity in children is linked to several cardiovascular risk factors including left ventricular hypertrophy, dyslipidemia, and elevated uric acid levels. Further studies utilizing ABPM measures on risk stratification in this very high-risk population are warranted.

Maternal separation-induced increases in vascular stiffness are independent of circulating angiotensinogen levels

The renin-angiotensin system (RAS) precursor angiotensinogen (AGT) has been implicated in the functional and mechanical alterations of the vascular wall in response to high-fat diet (HFD). Previously, we showed that HFD exacerbates angiotensin II-induced constriction in isolated aortic rings from male rats exposed to maternal separation (MatSep), a model of early-life stress. Thus, the aim of this study was to investigate whether MatSep increases AGT secretion promoting vascular stiffness in rats fed a HFD. Male Wistar-Kyoto MatSep offspring were separated (3 h/day, postnatal days 2-14), and undisturbed littermates were used as controls. At weaning, rats were fed for 17 wk a normal diet (ND) or a HFD, 18% or 60% kcal from fat, respectively. In plasma, there was a main effect of MatSep reducing AGT concentration (P < 0.05) but no effect due to diet. In urine, ND-fed MatSep rats displayed higher AGT concentrations that were further increased by HFD (P < 0.05 vs. control). AGT mRNA abundance and protein expression were increased in adipose tissue from HFD-fed MatSep rats compared with control rats (P < 0.05). No significant differences in liver and kidney AGT levels were found between groups. In addition, MatSep augmented vascular stiffness assessed on freshly isolated aortic rings from ND-fed rats (P < 0.05), yet HFD did not worsen vascular stiffness in either MatSep or control rats. There was no correlation between plasma AGT and vascular stiffness in ND-fed rats; however, this relationship was negative in HFD-fed MatSep rats only (P < 0.05). Therefore, this study shows that MatSep-induced increases in vascular stiffness are independent of diet or plasma AGT.NEW & NOTEWORTHY This study demonstrates that there was no correlation between circulating levels of angiotensinogen (AGT) and the development of vascular stiffness in rats exposed to early-life stress and fed a normal diet. This study also shows that early-life stress-induced hypersensitive vascular contractility to angiotensin II in rats fed a high-fat diet is independent of circulating levels of AGT and occurs without further progression of vascular stiffness. Our data show that early-life stress primes the adipose tissue to secrete AGT in a sex- and species-independent fashion.

Influence of BMI in nephrolithiasis in an Appalachian pediatric population: A single-center experience

INTRODUCTION

The prevalence of pediatric nephrolithiasis has increased significantly in the past 20 years. Metabolic abnormalities predisposing adults to nephrolithiasis in obese patients include increased urinary sodium and uric acid excretion as well as low urine pH; however, limited data are available in the pediatric population.

OBJECTIVE

The aim was to investigate whether obese pediatric patients presenting with nephrolithiasis have a unique metabolic profile similar to reported findings in obese adults with nephrolithiasis.

STUDY DESIGN

A retrospective chart review was performed in children aged 1-18 years seen at Kentucky Children's Hospital between 2010 and 2016. Inclusion criteria included all patients with documented stones confirmed by ultrasonography or computed tomography.

RESULTS

A total of 111 patient charts were reviewed in the study with a mean age of 11.8 ± 4.2 years. Seventy patients (63%) had a normal BMI and 41 patients (37%) were considered overweight/obese. There was no statistically significant relationship between BMI and stone recurrence. Obese patients had significantly decreased levels of urinary citrate, oxalate, magnesium, and potassium with significant elevations of urinary urea nitrogen, ammonia, and low urine pH compared with normal weight patients (Summary Figure).

DISCUSSION

Several groups have reported on metabolic findings within obese and non-obese pediatric patients. A Turkish study reported increased oxalate excretion and hypocitraturia in obese patients while a Korean study also reported increased rates of hypocitraturia in recurrent stone formers. Similar to these studies, we did find significant differences in citrate within our study population; however, we found significantly lower levels of urinary oxalate in obese patients. The majority of these studies do not report an association with BMI and urine pH although this has been reported in the adult population and our findings support an inverse relationship between body mass index (BMI) and pH. Our group found a higher level of calcium phosphate stones, supporting of Eisner's findings that high BMI is associated with increased supersaturation of calcium phosphate. Limitations of our study include being a single center and retrospective in nature.

CONCLUSION

Our study demonstrates differences in types of stones and urinary metabolites in an obese pediatric population suggestive of different metabolic profiles contributing to stone disease. We report similar association between BMI and urine pH, urinary potassium, and citrate. This study confirmed our primary hypothesis that obese pediatric patients would have a different urinary mineral profile as evidenced by lower levels of citrate and potassium and low urine pH; however, obese patients did not exhibit significantly elevated urinary sodium and uric acid when normalized to weight, as described in the adult population. Our study did not confirm our secondary hypothesis that stone composition would be associated with BMI status or stone recurrence.

A model of neglect during postnatal life heightens obesity-induced hypertension and is linked to a greater metabolic compromise in female mice

.: Exposure to early life stress (ELS) is associated with behavioral-related alterations, increases in body mass index and higher systolic blood pressure in humans. Postnatal maternal separation and early weaning (MSEW) is a mouse model of neglect characterized by a long-term dysregulation of the neuroendocrine system.

OBJECTIVES

Given the contribution of adrenal-derived hormones to the development of obesity, we hypothesized that exposure to MSEW could contribute to  the worsening of cardiometabolic function in response to chronic high-fat diet (HF) feeding by promoting adipose tissue expansion and insulin resistance.

SUBJECTS

MSEW was performed in C57BL/6 mice from postnatal days 2-16 and weaned at postnatal day 17. Undisturbed litters weaned at postnatal day 21 served as the control (C) group. At the weaning day, mice were placed on a low-fat diet (LF) or HF for 16 weeks.

RESULTS

When fed a LF, male and female mice exposed to MSEW display similar body weight but increased fat mass compared to controls. However, when fed a HF, only female MSEW mice display increased body weight, fat mass, and adipocyte hypertrophy compared with controls. Also, female MSEW mice display evidence of an early onset of cardiometabolic risk factors, including hyperinsulinemia, glucose intolerance, and hypercholesterolemia. Yet, both male and female MSEW mice fed a HF show increased blood pressure compared with controls.

CONCLUSIONS

This study shows that MSEW promotes a sex-specific dysregulation of the adipose tissue expansion and glucose homeostasis that precedes the development of obesity-induced hypertension.

Sex-specific effects of stress on metabolic and cardiovascular disease: are women at higher risk?

Cardiovascular disease (CVD) has traditionally been viewed as a male disease; however, the relative risk for obesity and hypertension morbidity and mortality, major risk factors for CVD, is higher for women in the United States. Emerging epidemiological data strongly support stressful experiences as a modifiable risk factor for obesity, insulin resistance, and heart disease in women at all ages. Therefore, primary prevention of these diseases may be associated with both identifying and increasing the knowledge regarding the sex differences in emotional functioning associated with physiological responses to stress. The purpose of this review is to highlight the growing body of clinical and experimental studies showing that stress, obesity-associated metabolic disturbances, and CVD comorbidities are more prevalent in females. Overall, this review reveals the need for investigations to decipher the early origins of these comorbidities. Targeting the sources of behavioral/emotional stress through the trajectory of life has the potential to reduce the alarming projected rates for chronic disease in women.

Developmental origins of cardiovascular disease: Impact of early life stress in humans and rodents

The Developmental Origins of Health and Disease (DOHaD) hypothesizes that environmental insults during childhood programs the individual to develop chronic disease in adulthood. Emerging epidemiological data strongly supports that early life stress (ELS) given by the exposure to adverse childhood experiences is regarded as an independent risk factor capable of predicting future risk of cardiovascular disease. Experimental animal models utilizing chronic behavioral stress during postnatal life, specifically maternal separation (MatSep) provides a suitable tool to elucidate molecular mechanisms by which ELS increases the risk to develop cardiovascular disease, including hypertension. The purpose of this review is to highlight current epidemiological studies linking ELS to the development of cardiovascular disease and to discuss the potential molecular mechanisms identified from animal studies. Overall, this review reveals the need for future investigations to further clarify the molecular mechanisms of ELS in order to develop more personalized therapeutics to mitigate the long-term consequences of chronic behavioral stress including cardiovascular and heart disease in adulthood.

Postnatal treatment with metyrapone attenuates the effects of diet-induced obesity in female rats exposed to early-life stress

Experimental studies in rodents have shown that females are more susceptible to exhibiting fat expansion and metabolic disease compared with males in several models of fetal programming. This study tested the hypothesis that female rat pups exposed to maternal separation (MatSep), a model of early-life stress, display an exacerbated response to diet-induced obesity compared with male rats. Also, we tested whether the postnatal treatment with metyrapone (MTP), a corticosterone synthase inhibitor, would attenuate this phenotype. MatSep was performed in WKY offspring by separation from the dam (3 h/day, postnatal days 2-14). Upon weaning, male and female rats were placed on a normal (ND; 18% kcal fat) or high-fat diet (HFD; 60% kcal fat). Nondisturbed littermates served as controls. In male rats, no diet-induced differences in body weight (BW), glucose tolerance, and fat tissue weight and morphology were found between MatSep and control male rats. However, female MatSep rats displayed increased BW gain, fat pad weights, and glucose intolerance compared with control rats (P < 0.05). Also, HFD increased plasma corticosterone (196 ± 51 vs. 79 ± 18 pg/ml, P < 0.05) and leptin levels (1.8 ± 0.4 vs. 1.3 ± 0.1 ng/ml, P < 0.05) in female MatSep compared with control rats, whereas insulin and adiponectin levels were similar between groups. Female control and MatSep offspring were treated with MTP (50 µg/g ip) 30 min before the daily separation. MTP treatment significantly attenuated diet-induced obesity risk factors, including elevated adiposity, hyperleptinemia, and glucose intolerance. These findings show that exposure to stress hormones during early life could be a key event to enhance diet-induced obesity and metabolic disease in female rats. Thus, pharmacological and/or behavioral inflection of the stress levels is a potential therapeutic approach for prevention of early life stress-enhanced obesity and metabolic disease.

Exercise protects against PCB-induced inflammation and associated cardiovascular risk factors

Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that contribute to the initiation of cardiovascular disease. Exercise has been shown to reduce the risk of cardiovascular disease; however, whether exercise can modulate PCB-induced vascular endothelial dysfunction and associated cardiovascular risk factors is unknown. We examined the effects of exercise on coplanar PCB-induced cardiovascular risk factors including oxidative stress, inflammation, impaired glucose tolerance, hypercholesteremia, and endothelium-dependent relaxation. Male ApoE(-/-) mice were divided into sedentary and exercise groups (voluntary wheel running) over a 12-week period. Half of each group was exposed to vehicle or PCB 77 at weeks 1, 2, 9, and 10. For ex vivo studies, male C57BL/6 mice exercised via voluntary wheel training for 5 weeks and then were administered with vehicle or PCB 77 24 h before vascular reactivity studies were performed. Exposure to coplanar PCB increased risk factors associated with cardiovascular disease, including oxidative stress and systemic inflammation, glucose intolerance, and hypercholesteremia. The 12-week exercise intervention significantly reduced these proatherogenic parameters. Exercise also upregulated antioxidant enzymes including phase II detoxification enzymes. Sedentary animals exposed to PCB 77 exhibited endothelial dysfunction as demonstrated by significant impairment of endothelium-dependent relaxation, which was prevented by exercise. Lifestyle modifications such as aerobic exercise could be utilized as a therapeutic approach for the prevention of adverse cardiovascular health effects induced by environmental pollutants such as PCBs.

Intimal Neovascularisation is a Prominent Feature of Atherosclerotic Plaques in Diabetic Patients with Critical Limb Ischaemia

INTRODUCTION

Neovascularisation of atherosclerotic plaques correlates with increased plaque instability and subsequent risk of vascular complications. Diabetics have widespread atherosclerotic involvement of the arterial tree and a more aggressive form of the disease culminating in increased plaque instability. This results in a greater incidence of ischaemic sequelae than in non-diabetics. Previous studies have examined neovascularisation as a marker of plaque instability in both the carotid and coronary territories and revealed a greater degree in both symptomatic and diabetic patients. This is the first study to examine intimal neovascularisation in lower limb peripheral arterial disease.

METHODS

Arterial specimens were taken from 20 patients, ten of whom were type 2 diabetics, undergoing major lower limb amputation for unreconstructable critical ischaemia. Sections were stained with H&E for morphological assessment and inflammatory cell characterisation. Additional sections underwent immunohistochemical staining for CD31 and von-Willebrand Factor (vWF) and the number of intimal vessels per four 40x magnification fields assessed.

RESULTS

There was a more prominent inflammatory infiltrate in diabetic subjects compared to non-diabetic controls. Diabetic patients had a greater degree of intimal neovascularisation compared to controls with a median of 11.5 and 2.0 vessels per field respectively (P<0.05). Sub-group analysis revealed that diabetic patients medicating with HMG-CoA Reductase inhibitors (Statins) had a greater degree of neovascularisation compared to those not taking this class of medication.

CONCLUSION

Diabetic patients with critical limb ischaemia requiring amputation demonstrate a greater degree of plaque intimal neovascularisation and inflammatory infiltrate compared to their non-diabetic counterparts. This may explain the greater plaque instability and subsequent cardiovascular complications seen in these patients.

Expression of growth factors and growth factor receptor in non-healing and healing ischaemic ulceration

OBJECTIVES

To characterise the histological and cytokinetic characteristics of purely ischaemic ulcers and the processes that underpin healing following successful revascularisation.

DESIGN

Prospective observational study.

MATERIALS AND METHODS

Biopsies were taken immediately pre- and 6 weeks following successful revascularisation of solely ischaemic ulceration. They were evaluated for morphological differences using H&E staining for the platelet derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR), TGFbeta receptorIII (TGFbetaRIII), transforming growth factor beta 1 and 3 (TGFbeta1 and TGFbeta3) and von Willebrand factor (vWF) expression using immunohistochemistry. Localisation and quantification of these growth factors and receptors was assessed systematically by three independent investigators who were blinded to the timing of biopsy.

RESULTS

Pre-operatively, small vessel vasculitis, necrosis and infection with a profuse neutrophil and macrophage infiltrate was observed in all samples. Post-operative biopsies revealed a proliferation of new capillaries in and around the ulcer edge and base. vWF staining confirmed an endothelial layer within these new vessels. Following successful revascularisation there was less infection and inflammation with minimal vasculitis. These newly formed capillaries had increased staining for TGFbeta3, PDGFR and TGFbetaRIII with staining for PDGFR also localised to dermal fibroblasts which were larger and more numerous. Accelerated epithelial cell proliferation was observed with detachment from the underlying dermis.

CONCLUSIONS

Healing of purely ischaemic ulcers is characterised by vasculogenesis associated with increased presence of the proangiogenic cytokines PDGF and TGFbeta3. These findings show promise for the use of growth factor manipulation to aid healing in ischaemic ulcers.

Colonic epithelial apoptosis during conventional and endoluminal aortic surgery

Background

This study characterized the initial modes of colonic mucosal injury during aneurysm surgery and correlated these with proinflammatory cytokine release into the colonic and systemic circulations.

Methods

Twenty-four patients undergoing conventional open aortic aneurysm repair and ten who had endovascular aneurysm repair (EVAR) were recruited. Mucosal biopsies were taken from the sigmoid colon immediately before and after surgery, for histological examination. Inferior mesenteric vein (IMV) and peripheral blood from patients who had conventional surgery was assayed for interleukin (IL) 1β, IL-6 and tumour necrosis factor (TNF) α. Only peripheral blood from patients who had EVAR was assayed.

Results

Conventional aneurysm repair resulted in a threefold increase in columnar epithelial apoptosis. There was a 26-fold increase in IL-6 in IMV blood within 5 min of reperfusion, with an equivalent rise in peripheral blood after 30 min. A 20-fold rise in peripheral blood TNF-α was observed after surgery. Splanchnic IL-6 correlated positively with cross-clamp time and increased apoptosis. No histological changes were seen after EVAR. There were no intraoperative cytokine changes during EVAR, although a postoperative increase in IL-6 and TNF-α was observed.

Conclusion

The lack of columnar epithelial apoptosis following EVAR reflects the relatively minor ischaemic injury incurred during this procedure.

The Influence of Asymptomatic Significant Carotid Disease on Mortality and Morbidity in Patients Undergoing Coronary Artery Bypass Surgery

OBJECTIVES

Controversy exists regarding the optimal management of patients with coexisting coronary and extracranial carotid artery disease. This study investigates the incidence of death, cerebrovascular events and myocardial infarction (MI) in patients with asymptomatic significant carotid artery disease undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective cohort.

METHODS

Fifty patients with asymptomatic carotid stenoses > or =70% associated with cervical bruits undergoing CABG without prophylactic carotid endarterectomy (CEA) were followed up over a median period of 68 months following surgery cerebrovascular events, MI and mortality were recorded. All patients received optimal secondary prevention for cardiovascular disease unless contraindicated.

RESULTS

No cerebrovascular events occurred within 30 days of surgery. One patient suffered an ipsilateral transient ischaemic attack (TIA) 14 months after CABG. Two patients died within 30 days; one from an MI, the other from pancreatitis. Three deaths occurred after 30 days; one from MI, one from primary lung cancer and one following rupture of an abdominal aortic aneurysm. No non-fatal MIs occurred.

CONCLUSIONS

In this patient group the overall risk of death, cerebrovascular events and MI was 4% during the first 30 days postoperatively and 8% thereafter. This compares favourably with published series for staged or combined CEA-CABG procedures. For asymptomatic significant carotid disease, prophylactic CEA prior to CABG does not appear to confer any advantage over CABG alone.

Transient neonatal pustular melanosis

A black male infant had congenital lesions that consisted of pigmented macules, many of which had a peripheral collarette of scale, and vesicopustules. The appearance of this patient fit the clinical syndrome of transient neonatal pustular melanosis, a newly described vesicopustular disease of the newborn. Differential diagnosis in this patient included the following conditions: erythema toxicum neonatorum, staphylococcal pyoderma, and herpes simplex.