ABC | Volume 113, Nº4, October 2019

Original Article Santiago et al. Prevalence of hypertension and associated factors Arq Bras Cardiol. 2019; 113(4):687-695 The data used in the present investigation derived from a study entitled “Evaluation of food and nutritional security in urban and rural communities affected by drought in the semi-arid region of Pernambuco” (certificate of presentation for ethical approval: 38878814.9.0000.5208; certificate of approval: 897.655). All participants received information about the study and signed the informed consent form. Statistical analysis All data were entered twice with the Epi Info™ software, version6.04 (CDC/WHO, Atlanta, GE, USA), with the subsequent use of the VALIDATE module to check data consistency. We grouped the explanatory variables into the following four hierarchically ordered levels from distal to proximal: 1) biological factors; 2) demographic and socioeconomic factors; 3) behavioral factors, and 4) biochemical and nutritional factors (proximal level). Based on a conceptual model to determine hypertension, we assumed that predisposing factors imply different hierarchical levels of determination. We conducted univariate statistical analysis with either Pearson’s chi-square test or the chi-square test for trend to establish associations between explanatory variables and the outcome. Variables with a p-value < 0.20 were incorporated into themultivariate analysis using Poisson regression with robust variance. Results of the univariate analysis were expressed as percentages and respective 95% confidence intervals (95%CI) and of the multivariate analysis were described as prevalence ratios and respective 95%CI. A p-value < 0.05 in the final model was considered indicative of a statistically significant association. All analyses had the aid of the Statistical Package for Social Sciences (SPSS), version 13.0 (IBM Analytics, NC, USA) and Stata, version 14.0 (StataCorp, TX, USA). Results The final sample consisted of 416 adults with a median age of 35.0 (interquartile range of 28.0 to 48.0) years. Most of the sample was female (64;9%, 95%CI: 60.1 to 69.5), of black/ multiracial ethnicity (78.4%, 95%CI: 74.0 to 82.2), and lived in urban areas (57.9%, 95%CI: 53.0 to 62.7). A total of 19.7% (95%CI: 16.1 to 23.9) of the sample had the habit of consuming alcoholic beverages, 23.3% (95%CI: 19.4 to 27.7) smoked actively, 16.3% (95%CI: 13.0 to 20.3) smoked passively, and 71.5% (95%CI: 65.6 to 76.9) were sedentary or insufficiently active. Moreover, 10.1% (95%CI: 7.5 to 13.5) of the sample reported adding salt to food after preparation sometimes or nearly always. The prevalence of hypertension was 27.4% (95%CI: 23.2 to 32.0). Table 1 shows the distribution of the condition according to demographic and socioeconomic variables. We found a statistically significant association between higher prevalence of hypertension and increasing age and lower levels of schooling and income. Regarding behavioral variables (Table 2), hypertension was more frequent among active smokers/ex-smokers and passive smokers. With respect to the health and nutritional profile (Table 3), hypertension was associated with overweight, determined by the BMI, and an increased weight-to-height ratio. Hypertension was also associated with the following biochemical variables: reduced glucose tolerance/DM and high total cholesterol (Table 4). After statistical adjustments in the hierarchical model, the explanatory variables that remained significantly associated with hypertension were age, economic class, active smoking, BMI, and fasting blood glucose (Table 5). Discussion Hypertension is one of the most common conditions among older adults, but it also affects a considerable portion of the adult population (20 to 59 years), striking more than 30 million individuals in this age range in Brazil alone. 6 Thus, addressing this condition in the adult population is necessary. Although slightly lower than the estimated national average of 30%, 6 the prevalence of hypertension among adults in the semi-arid region of Pernambuco was high, confirming that this is a serious public health problem. This finding was expected, given the low socioeconomic development of the mesoregion and its possible association with the high prevalence of chronic non-communicable diseases. 10 We underline, however, that some individuals classified as hypertensive may actually have “white coat hypertension,” which was not evaluated and could be considered a limitation of the present study. According to Andrade et al., 8 the prevalence of self- reported hypertension among adults in Northeastern Brazil is 19.4% (95%CI: 18.4 to 20.5), which is lower than the rate found in the present study. This divergence may be explained by one of the limitations of using self-reports, which, although validated in population-based studies, might underestimate prevalence rates. 21 This aspect is influenced by the access to and use of health care services by the part of the population investigated, as self-reported hypertension would require a previous medical diagnosis. 21 The greater susceptibility to hypertension with the increase in age found in the present study has been reported in the specialized literature, and there is a consensus on the direct, linear relationship between BP and age. 6 This relationship results from the development of atherosclerosis, with the stiffening of the arteries leading to an elevation in pressure levels, which is normally caused by physiological changes stemming from the aging process. 22 The association between economic class and hypertension in the present study supports the conjecture that individuals with low status are more vulnerable to the development of the disease. 23 Furthermore, despite the association with a low level of schooling having lost its significance in the multivariate model, it could represent a more evident risk factor than income. 23 Thus, it is important to increase the monitoring of and care for these more vulnerable groups. Being a smoker or ex-smoker was also associated with the prevalence of hypertension, which corroborates data from other population-based studies conducted in Brazil and a review study by Passos et al. 21 This result is consistent with experimental evidence that smoking can cause hypertension and other cardiovascular diseases. 24 In the first decade of the 21 st century, 11% of worldwide deaths from cardiovascular diseases were attributed to smoking, 25 making this habit an important risk factor to address in health promotion and disease prevention actions. 689