IJCS | Volume 33, Nº3, May / June 2020

209 US nurses with a four-year follow-up (between 1989 and 1993), the relative risk of developing hypertension was 50% higher for current COC users compared to new users and 10% higher compared to long-term users. 8 Translating these into absolute numbers, this increase means 41 cases in every 10,000 women using COC/year. However, at that time, the COCs were not yet of lowdose. More recent studies, which did not aim to assess blood pressure (BP), did not find any statistical difference between the BP of women who used and did not use COC, although systolic and diastolic pressure was higher in women on COC. Despite these results, studies have not yet evaluated the subclinical response of hormonal changes that influence the blood pressure​ of women taking COC. Some aspects such as endothelial dysfunction due to reduced nitric oxide intake and changes in the functioning of the renin-angiotensin aldosterone system (RAAS) influence the development of hypertension. RAAS is presented as an endocrine axis in which each component of a cascade is produced by different organs. An arrangement that provides an example of interaction of several organic systems, engaged to maintain hemodynamic stability. 9 Therefore, the objective of the present study was to test the hypothesis that there is a difference between the plasma renin levels ​of women who use and do not use COC, as well as to determine their relationshipwith CRP. Methods The present study follows the same data collection protocol from previous studies conducted by our research group. 10 The study is characterized as a comparative cross-sectional observational study inwhich 44 irregularly active women aged 20 to 30, eutrophic, nulliparous, using COC for at least one year or not using COC were evaluated for at least six months to one year. COCs were considered low dose if they contained 15–30 microgram ethinyl estradiol associated with progestin. To determine whether the volunteer was irregularly active, the International Short-Form Physical Activity Questionnaire developed by the WHO and the Centers for Disease Control and Prevention (CDC) was used. This questionnaire was used because it has the following advantages: it can be performed in two forms (short and long form), it allows estimating caloric expenditure, presents a more detailed classification, into sedentary, irregularly active, active and very active, besides making it possible to draw comparisons and adjustments to the Brazilian reality. 11 Exclusion criteria were the presence of diabetes mellitus, dyslipidemia, hepatic dysfunction, glycemia above 99 mg/dL, systemic arterial hypertension, hypo or hyperthyroidism, renal diseases, polycystic ovary syndrome, use of anabolic or dietary supplements, hypo or hyperlipidic diet, history of alcoholism, smoking, use of lipid-lowering drugs, corticoids, diuretics or beta- blockers. For this study, those with total cholesterol > 220 mg/dL, low-density lipoprotein > 160 mg/dL or triglycerides > 150 mg/dLwere considered dyslipidemic. Ethical Criteria Firstly, the research study was carried out in the Physiotherapy course of Faculdade Social da Bahia. All women who were willing to participate in the study were initially evaluated and those who agreed with the inclusion criteria and did not present any exclusion criteria were included in the study. All of the research steps, such as the study objectives and the risks and benefits involved in the procedures, were explicitly detailed to the volunteers in a reader- friendly manner. The volunteers signed an informed consent form. Throughout the study, the human research guidelines of the Declaration of Helsinki and Resolution 466/12 of the National Health Council were observed. This study was submitted and approved by the Research Ethics Committee with CAAE number 79549517.3.0000.5654. Data Collection Protocol Participants were divided into two groups. One group using COC (COCG) and one group without COC use (NCOCG). Initially, the volunteers answered a standard questionnaire andwere submitted tophysical examination. Bothwere conducted inorder to collect general information about the sample characteristics. Physical examination included determination of resting BP, total body mass, height and waist circumference measurements. To determine BP, the American Heart Association recommendations were followed, using a medium-sized tensiometer for the average adult, duly calibrated by the National Institute of Metrology (INMETRO) and a BD- brand duo-sonic stethoscope. Height was measured using a professional Sanny stadiometer with 0.1 cm precision. Measurement was Oliveira et al. Plasma renin and use of oral contraceptives Int J Cardiovasc Sci. 2020; 33(3):208-214 Original Article