Pressão arterial elevada em crianças e adolescentes com excesso de peso: associação com biomarcadores hormonais e inflamatório

Abstract

INTRODUCTION: Childhood obesity is a concern and it is associated with the main metabolic and cardiovascular diseases. Its prevalence has been increasing, in all age groups, significantly so in developing countries, and has become a Public Health problem. The risk of a child or adolescent presenting hypertension is also associated with the degree of obesity, levels of leptin, insulin and high-sensitivity c- reactive protein. OBJECTIVES: To check on the prevalence of high blood pressure in obese or overweight children and adolescents and its association with leptin, insulin and high-sensitivity C-reactive protein. METHODOLOGY: A cross-sectional study with a sample of 200 children and adolescents aged between 2 and 18 years old, diagnosed as being overweight or obese. Anthropometric data were obtained: body mass index, waist circumference and blood pressure were measured. The systolic or diastolic blood pressure was classified as normal below the 90th percentile for gender, age and stature, and high at or above the 90 percentile. Laboratory tests on leptin, insulin and high-sensitivity c- reactive protein were conducted after the subjects had fasted for 12 hours. Insulin resistance was assessed using the homeostasis model assessment for insulin resistance (HOMA-IR) index, with HOMA-IR &#8805; 2.5 being considered abnormal. To evaluate the cardiovascular risk, high-sensitivity c-reactive protein was used, with values greater than 3mg/L considered as indicating a high risk of cardiovascular event. The systolic and diastolic blood pressures were divided into quartiles, and assessing the association between blood pressure, clinical and laboratory variables was conducted using the chi-square and ANOVA Oneway tests. Data were analyzed with an SPSS version 17 program and a confidence interval of 95% was considered. RESULTS: Of the 200 children and adolescents, 128 (64%) were female, 123 (61.5%) were adolescents, 132 (66%) had severe obesity and 159 (79.5%) had an abnormal waist circumference. Most of the 170 individuals (89%) had a history of hypertension. High systolic and/or diastolic blood pressure was observed in 141 (70.5%) of the population studied, the prevalence of high diastolic blood pressure (64.5%) being greater than high systolic blood pressure (37.5%). The average values of leptin and high-sensitivity c- reactive protein were significantly higher in adolescents with high systolic blood pressure than those with normal systolic blood pressure. High-sensitivity c-reactive protein > 3mg/dl was associated with high systolic blood pressure (p=0.031), in the adolescents, with a 2-fold greater chance of their having abnormal systolic blood pressure than those with normal high-sensitivity c-reactive protein [OR=2.350 (1.075 - 5.141)]. The average value of insulin (p=0.009), leptin (p <0.000), high-sensitivity c-reactive protein (p=0.058), and of HOMA-IR (p=0.006) increased significantly in accordance with the quartiles of systolic blood pressure, a fact which was not observed in those for diastolic blood pressure. CONCLUSION: High blood pressure was markedly present among overweight children and adolescents, indicating that the high level of body fat is altering the mechanisms responsible for the proper functioning of the cardiovascular system. Only systolic blood pressure was shown to be associated with hormonal biomarkers (leptin and insulin) and inflammatory ones (high-sensitivity c- reactive protein). Interventions to control obesity can represent one of the major actions aimed at preventing and controlling high BP, and thus at minimizing the cardiovascular consequences in this population.