Effects of Weight Loss on Vascular Function in Obese Subjects

Rio de Janeiro State Research Supporting Foundation (FAPERJ), Conselho Nacional de Desenvolvimento Científico e Tecnológico

To evaluate the effect of weight loss on vascular function in obese with poor cardiovascular health. The investigators will evaluate the effects of weight loss on total and central body adiposity, blood pressure, central hemodynamic parameters, arterial stiffness, endothelial function, apnea-hypopnea index, insulin resistance and inflammatory markers.

Excessive adipose tissue is associated with adverse metabolic effects and is an important risk factor for chronic diseases. According to the American Heart Association, most cardiovascular events can be prevented by adhering to healthy practices, reflecting cardiovascular health as poor, intermediate, and ideal. Methods: Both sexes, aged between 40 and 70 years, with body mass index ≥ 30 and < 40 kg/m² will be included and clinical, anthropometric, body composition and laboratory tests will be assessed. In vascular tests, the investigators will evaluate the sympathetic tone using a frequency meter (Polar® RS800), oscillometric pulse wave analysis by Mobil-O-Grah®, post-occlusive microvascular reactivity and carotid ultrasound to measure intimamedia thickness. In the sleep study, the investigators will analyze the presence and degree of obstructive sleep apnea (OSA) through the home polysomnography device (WatchPAT 200®). The first visit will be for screening, clinical and anthropometric evaluation. On the second visit, the vascular tests, instructions and device delivery for sleep study will be performed. Patients will return the following day to return the WatchPAT and to receive the hypocaloric nutritional intervention (800kcal reduction of daily total energy value), which should be followed for 16 weeks. Eight weeks after the beginning of the nutritional intervention a new visit will be scheduled for clinical, nutritional assessment and dietary adjustment. After completing 16 weeks, the patients will return for clinical, laboratory, nutritional, vascular and sleep tests.

Obesity, Weight loss, Cardiovascular diseases, Sleep Apnea Syndromes, Arterial stiffness, Endothelial dysfunction

The participants do not know if they are classified as poor or intermediate/ideal cardiovascular health.

Cardiovascular health is said to be ideal by the presence of optimal health behaviors (non-smokers, adequate BMI, physical activity level and healthy eating pattern) and ideal health factors (blood pressure, total cholesterol and blood glucose). Poor cardiovascular health is considered for two or less metrics.

Cardiovascular health is said to be ideal by the presence of optimal health behaviors (non-smokers, adequate BMI, physical activity level and healthy eating pattern) and ideal health factors (blood pressure, total cholesterol and blood glucose). Ideal cardiovascular health is considered for those with five or more metrics within this qualification, and intermediate for the presence of three or four metrics.

The total energy value (TEV) of the diet prescribed for each study participant will be determined by subtracting 800 kcal / day from the total daily energy expenditure, which will be based on Dietary Reference Intake (DRI) recommendations. The distribution of macronutrients will be as follows: protein 15 to 20% of TEV, lipids 25 to 30% of TEV and carbohydrates 50 to 60% of TEV.

Inclusion Criteria: Patients of both sexes; Age between 40 and 70 years; Body mass index (BMI) ≥ 30 kg/m² and <40 kg/m². Exclusion Criteria: Systolic blood pressure ≥ 160 and/or diastolic blood pressure ≥ 100 mmHg; Diabetes mellitus; Hormone replacement therapy; Evidence of secondary hypertension; Clinically evident changes in thyroid function; Acute or chronic kidney or liver disease; History of cancer in the last 5 years; Clinically evident coronary disease with a history of acute myocardial infarction and/or myocardial revascularization, clinical signs of heart failure, cardiac arrhythmia or clinically significant valve disease; Previous stroke;