Julio Alvarez

Added Impact of Obesity and Insulin Resistance in Nocturnal Blood Pressure Elevation in Children and Adolescents

The aim of the present study was to analyze the relationship between insulin resistance and the ambulatory blood pressure components in obese children and adolescents. Eighty-seven overweight and obese white children and adolescents of both sexes, of European origin from 6 to 18 years of age (mean age: 10.9±2.7 years), were selected. Obesity was defined on the basis of a threshold body mass index z score >2 (Coles least mean square method) and overweight with a body mass index from the 85th to 97th percentile. A validated oscillometric method was used to measure ambulatory BP (Spacelabs 90207) during 24 hours. Fasting glucose and insulin were measured, and the homeostasis model assessment index was calculated. Subjects were grouped into tertiles of homeostasis model assessment index. No significant differences in terms of age, sex, and body mass index z score distribution were observed among groups. When adjusted by age, sex, and height, nocturnal systolic blood pressure and heart rate were significantly higher in subjects in the highest homeostasis model assessment index tertile (>4.7) as compared with those of the other groups, whereas no differences were observed for awake systolic blood pressure or heart rate. Whereas body mass index z score was more closely related with blood pressure and heart rate values, waist circumference was strongly related with insulin resistance. Moreover, both waist circumference and insulin resistance were mainly associated with higher nocturnal but not with awake blood pressure. The early increment of nocturnal blood pressure and heart rate associated with hyperinsulinemia may be a harbinger of hypertension-related insulin resistance and may contribute to heightened cardiovascular risk associated with this condition.

Blood Pressure and Obesity Exert Independent Influences on Pulse Wave Velocity in Youth

The objective was to analyze pulse wave velocity (PWV) in normotensive, high-normal, and hypertensive youths by using aortic-derived parameters from peripheral recordings. The impact of obesity on vascular phenotypes was also analyzed. A total of 501 whites from 8 to 18 years of age were included. The subjects were divided according to BP criteria: 424 (85%) were normotensive, 56 (11%) high-normal, and 21 (4%) hypertensive. Obesity was present in 284 (56%) and overweight in 138 (28%). Pulse wave analysis using a SphygmoCor device was performed to determine central blood pressure (BP), augmentation index, and measurement of PWV. Among the BP groups, differences appeared in age, sex, and height but not in body mass index. Significant differences in peripheral and central systolic and diastolic BPs and pulse pressures were observed within groups. A graded increase in PWV was present across the BP strata without differences in augmentation index. Using a multiple regression analysis, age, BP groups, and obesity status were independently associated with PWV. Older and hypertensive subjects had the highest PWV, whereas, from normal weight status to obesity, PWV decreased. Likewise, PWV was positively related to peripheral or central systolic BP and negatively related to body mass index z score. For 1 SD of peripheral systolic BP, PWV increased 0.329 m/s, and for 1 SD of body mass index z score PWV decreased 0.129 m/s. In conclusion, PWV is increased in hypertensive and even in high-normal children and adolescents. Furthermore, obesity, the factor most frequently related to essential hypertension in adolescents, blunted the expected increment in PWV of hypertensive and high-normal subjects.

Influence of Concurrent Obesity and Low Birth Weight on Blood Pressure Phenotype in Youth

The aim of this study was to assess the impact of obesity and low birth weight on both office and ambulatory blood pressure (BP) values, as well as on aortic-derived parameters in youths. A total of 422 white youths, from 10 to 18 years of age, were included. Subjects were divided into 4 groups according to the presence (234; 55%) or the absence (188; 45%) of obesity and according to low (114; 27%) or normal (308; 73%, birth weight. Spacelabs 90207 was used to measure ambulatory BP during a 24-hour period. SphygmoCor radial/aortic transform software was used to estimate aortic pressure waveform. Office, 24-hour, daytime, and nighttime systolic BP values were significantly higher in those subjects with low birth weight who became obese. The lowest BP values were present in nonobese subjects in the absence of low birth weight. In the middle, with similar BP values, were nonobese subjects with low birth weight and obese subjects in the absence of low birth weight. No interaction existed between obesity and low birth weight in the office (P=0.165) or ambulatory (P=0.603) systolic BP values. Augmentation index, an estimate of the pulse wave reflection, was significantly higher in the nonobese low birth weight group when compared with the other groups after controlling for height, heart rate, and diastolic BP. A significant interaction between low birth weight and obesity (P<0.005) existed. In conclusion, although the low birth weight children who become obese have the highest systolic BP values, the presence of obesity blunts the increment of the reflecting wave observed in low birth weight subjects.

Diagnosis and Treatment of Hypertension in Children

Hypertension is a global problem, affecting both developed and developing nations. In children and adolescents, hypertension has gained ground in cardiovascular medicine, thanks to the progress made in several areas of pathophysiologic and clinical research. Childhood hypertension is often asymptomatic and is easily missed, even by health professionals. Target organ damage is detectable in children and adolescents. Management of hypertension includes lifestyle changes and pharmacologic treatment. In the case of secondary hypertension, pharmacologic treatment usually is required. In essential hypertension, assessment of early organ damage provides a useful tool for treatment decisions.

Sexual Dimorphism in the Transition From Masked to Sustained Hypertension in Healthy Youths

The risk and factors related to the development of hypertension among healthy youths with elevated ambulatory and normal conventional blood pressure, masked hypertension, have not been established. We performed a long-term follow-up study assessing how hypertension develops over time in healthy, masked hypertensive youths. The potential sex dimorphism in the incidence and timing of the development of hypertension has been analyzed. In a long-term follow-up study (median follow-up, 36 months), we enrolled 272 healthy conventional normotensive youths (aged 6–18 years; 55.8% girls) of whom 39 had masked hypertension at baseline. Development of sustained hypertension (hypertension in both conventional and ambulatory measurement) was recorded. The daytime systolic blood pressure increased from baseline to last available follow-up in boys (3.5 mm Hg; P<0.001) but not in girls (0.7 mm Hg; P=0.23), leading to a significant between-sex difference (P=0.0022). The incidence of sustained hypertension was 7.0/100 subjects/y (n=12) in masked hypertensives and 0.6/100 subjects/y (n=4) in normotensives. Masked hypertensive boys more frequently proceeded to sustained hypertension as compared with masked hypertensive girls (50.0% versus 17.4%; P=0.041). Masked hypertension at baseline (hazard ratio, 15.6; 95% confidence interval, 4.91–49.7; P<0.0001) and male sex (hazard ratio, 3.25; 95% confidence interval, 1.12–9.39; P=0.0295) were independent factors associated with the incidence of sustained hypertension during the follow-up. In youth, masked hypertension is a precursor of sustained hypertension. The risk of developing sustained hypertension is higher in boys than it is for girls. The fact that masked hypertension is not prognostically innocent increases the importance of the diagnosis at an early age.

Prevalence and factors related to urinary albumin excretion in obese youths.

Objectives: The aim of the present study is to assess whether obesity is associated with urinary albumin excretion and what the main determinants are. Methods: One hundred and thirty-four obese white children and adolescents of both sexes, ranging from 9 to 18 years of age (mean age 12.6 ± 2.0), were included in the study. Obesity was defined on the basis of a threshold BMI z-score of more than 2 (Coles LMS method) and overweight with a BMI from the 85th to 95th percentile. Office blood pressure was measured using a mercury sphygmomanometer. Urinary albumin excretion was measured in the first voiding urine of the morning and expressed in albumin/creatinine ratio in mg/g. Reproducibility of the urinary albumin excretion was studied by the Bland and Altman technique in a subgroup. Triglycerides, uric acid, fasting glucose and insulin were measured and the homeostatic model assessment (HOMA) index was calculated. Results: The prevalence of microalbuminuria was 2.4%. No differences in the prevalence of microalbuminuria were observed when the different groups of obesity degree were compared (0, 2.2 and 0% in overweight, moderate and severe obese, respectively). A significant relationship emerged between the Log urinary albumin excretion and BMI z-score, waist circumference, Log triglycerides, fasting insulin and HOMA index, adjusted by age and sex. In a multiple regression analysis, the main determinants of Log urinary albumin excretion were sex, waist circumference and Log triglycerides. In 17% of the individuals who fulfil criteria for metabolic syndrome, urinary albumin excretion was significantly higher than those without. Conclusion: The prevalence of elevated urinary albumin excretion is not prominent in obese children, and when it is increased, it depends mainly on metabolic factors.

Ambulatory Blood Pressure Monitoring in Children and Adolescents: Coming of Age?

Over the last years, ambulatory blood pressure monitoring has been introduced into the pediatric population, contributing to a significant increase in the bulk of knowledge of crucial clinically relevant issues. Guidelines have established the currently known conditions where ambulatory blood pressure monitoring is useful and where it will provide additional information in children and adolescents. How common and important the intra-individual differences are within clinical and ambulatory blood pressure is the keystone to the use of ambulatory blood pressure monitoring as a diagnostic tool. By using not only office, but also ambulatory blood pressure, four possible situations arise. Two of these have values in agreement for normotension or hypertension. Two have values that are discrepant. The latter two are known as white coat and masked hypertension. The relationship with hypertension-induced organ damage, the prognostic value and the assessment of treatment goals are key issues of ambulatory blood pressure monitoring. In children, the accurate identification of hypertension at the earliest possible age would, therefore, give health-care providers the opportunity to initiate preventive measures, thereby reducing the chance of developing end-organ damage and its attendant morbidity and mortality.

Cardiovascular fitness in youth: association with obesity and metabolic abnormalities

UNLABELLED Therapies currently implemented for obesity are focused on nutritional aspects and on physical activity. In order to make physical activity a positive therapy instead of triggering disabilities it is relevant to accurately assess cardiovascular fitness. OBJECTIVE To assess the cardiovascular fitness by measuring the peak oxygen consumption and to asses their relationship with classical cardiometabolic parameters. METHODS A modified Balke protocol was applied to one hundred and twenty-six Caucasians (60% males), ranging between 9 and 16 years old, who underwent an assessment of obesity. The non-obese group consisted of healthy age and sex matched subjects who were invited to participate from the general population. RESULTS Significant differences in consumption of oxygen peak between non-obese and obese individuals were observed. In contrast, no significant differences existed between the categories of obesity. Furthermore in obese subjects consumption of oxygen peak was inversely correlated with parameters of cardiometabolic risk, particularly insulin and HOMA index. In addition, two predictive equations of consumption of oxygen peak, with an R2 of 0.74 and 0.84, respectively, have been developed. CONCLUSION The consumption of oxygen peak is a relevant clinical parameter that should be included in the routine clinical assessment of obese subjects. Therefore, it is crucial to make exercise tests more affordable which can be achieved by employing predictive equations.

Ubiquitous monitoring and assessment of childhood obesity

Childhood obesity is a significant health problem in current societies that is increasing at an alarming way among population of all ages. To date, studies on the effectiveness of treatments for childhood obesity in the medium and long term suggest a moderate effect on weight loss and maintenance, which has led to suggestions that early interventions have a preventive nature on adult obesity. The long-term recovery of the weight lost is often associated with a lack of adherence to recommendations for changing life habits. Then, obesity becomes a chronic problem, difficult to approach, and the main difficulty lies in promoting and ensuring adherence to a change in lifestyle. A system known as ETIOBE has been developed to improve the treatment adherence, to promote the mechanisms of self-control in patients and to prevent relapses. An important part of the ETIOBE system is the ubiquitous monitoring platform since it enables the clinician to obtain relevant information from patients (contextual, physiological and psychological), which enables treatment customization and adaptation, depending on the patient’s evolution. The aim of this paper is to describe the monitoring platform which is intended to establish a sensor network whose focus is the obese children under clinical treatment, and the various elements that compose it: electronic PDA records to establish diet habits, HAS: home ambulatory system (data integration of biomedical devices; blood pressure to study hypertension; pulse oximeter to detect Sleep Disorders; and electronic t-shirt to detect physical activity). This paper presents the first validations of the electronic PDA records and the electronic t-shirt. These validations suggest that the monitoring platform can help to achieve the goals previously mentioned, by offering constant support and increasing motivation to change.

Determinants of Cardiometabolic Risk Factors in the First Decade of LifeNovelty and Significance: A Longitudinal Study Starting at Birth

The present prospective study assessed the association of birth weight (BW) and growth pattern on cardiometabolic risk factors in a cohort followed from birth to 10 years of age. One hundred and forty-five subjects (73 girls) who fulfilled the inclusion criteria and had all their data recorded at birth and at 5 years were enrolled. Of these, 100 (52 girls) also recorded data at 10 years. Anthropometric measurements, office and 24-hour blood pressure, and metabolic parameters were obtained. At 5 years, both BW and current weight were determinants of blood pressure and metabolic parameters; however, as the subjects got older, the impact of body size increased. Higher BW and maternal obesity increased the risk of becoming obese at 5 years while this was reduced if breastfeeding. Maternal obesity was the only factor associated with becoming obese at 10 years. Twenty-two children at 10 years had insulin values ≥15 U/L, some of whom were persistent from 5 years while in others it increased afterward. Subjects with insulin values ≥15 U/L showed significant higher values of office systolic blood pressure, triglycerides, and uric acid and lower values of high-density lipoprotein than did those with normal insulin values. Highest weight gain from 5 to 10 years and lowest BW were the main determinants of high insulin levels. In conclusion, although BW was a proxy of the events during fetal life and projected its influence later, the influence of gaining weight was a key determinant in the risk to develop obesity and metabolic abnormalities.