IJCS | Volume 33, Nº3, May / June 2020

211 Table 1 - Clinical and anthropometric characteristics of the population (n = 44) Variables COCG (n = 22) NCOCG (n = 22) p value Age (years) 23 ± 1.3 23 ± 2.0 0.98* Body mass index (kg/m 2 ) 22 ± 1.4 22 ± 1.0 0.37* Waist circumference (cm) 73 ± 7.8 70 ± 5.9 0.32* Systolic blood pressure (mmHg) 119 ± 10.1 107 ± 5.5 0.02* Diastolic blood pressure (mmHg) 77 ± 6.1 70 ± 10.6 0.18* C-reactive protein (mg/L) 1.8 (0.5 – 2.2) 0.7 (0.5 – 0.9) < 0.01# Glycemia (mg/dL) 82 ± 6.9 83 ± 5.7 0.57* COC use duration (years) 3.7 ± 2.3 - COCG: combined oral contraceptive group; NCOCG: group without combined oral contraceptive. * Two-way t-test for independent samples; # Bidirectional Mann-Whitney test. Table 2 - Comparison of fasting lipids (mg/dL) between the groups studied Variables COCG (n = 22) NCOCG (n = 22) p value Triglycerides (mg/dL) 88 (72 – 111) 49 (40 – 64) < 0.01# Total cholesterol (mg/dL) 207 ± 38.2 183 ± 29.7 0.02* HDL (mg/dL) 54 ± 13.0 48 ± 11.2 0.10* LDL (mg/dL) 134 ± 36.4 125 ± 27.2 0.34* COCG: combined oral contraceptive group; NCOCG: no combined oral contraceptive group; HDL: high-density lipoprotein; LDL: low-density lipoprotein; VLDL: very low-density lipoprotein. * Two-way t-test for independent samples; # Bidirectional Mann-Whitney test. Figure 1 shows the plasma renin value (ng/ml/h) in the groups evaluated. The median and the interquartile deviation of the NCOCG and COCG renin were 0.5 (0.1 – 1.0) and 3.0 (2 – 6), respectively, with significant difference (p < 0.01). There was also a strong positive correlation between CRP and renin (p < 0.01 and r = 0.68). The correlation between renin and lipid profile variables showed a moderate positive correlation with LDL (p = 0.01; r = 0.46). There was not any correlation of renin with the other lipid profile variables (p > 0.05). Discussion Based on the results of this research study, it is possible to suggest that the use of COC may chronically raise plasma renin values in women who use COC. Although the effects of the sociodemographic and nutritional variables of the study population were not evaluated in greater detail (with the quantity, frequency and types of food consumed), sample homogeneity, elimination of confounding factors in volunteer selection and the power obtained after analysis rule out the possibility of type I statistical error, strengthening the study findings. According to the 7 th Hypertension Guideline of the Brazilian Society of Cardiology, 1 the prevalence of systemic arterial hypertension (SAH) among women using COC is 5%. Since the 1990s, studies indicate that the prevalence of SAH is higher in women taking COC than in those who do not use it. 2,3 In our study, we found that SBP is higher in the group that uses COC, although the values are within normal limits. 1 The reasons why COC use increases BP are not well established. However, abnormalities may be caused by ethinyl estradiol and progestins in the renin-angiotensin- aldosterone system (RAAS). 4 Synthetic estrogens increase the hepatic synthesis of the renin substrate by inducing the expression of angiotensinogen mRNA. 5 This increase is also accompanied by enhanced renin activity. 6 This, therefore, increases the production of angiotensin II, which in turn is a potent direct and indirect vasoconstrictor, by inducing the production of vasopressin, when binding to the AT1 receptors in the hypothalamus. 7 In addition, angiotensin II, when converted to angiotensin III, induces the production of aldosterone by the adrenals, which in conjunctionwith increased production of the antidiuretic hormone (vasopressin) enhance the reabsorption of water through the renal tubules. Both vasoconstriction and increased water retention, induced by this system, favor an increase in systemic BP. 7 On the other hand, progestins, such as drospirenone, present an anti-mineralocorticoid diuretic effect, Oliveira et al. Plasma renin and use of oral contraceptives Int J Cardiovasc Sci. 2020; 33(3):208-214 Original Article