7th Brazilian Guideline of Arterial Hypertension: Chapter 1 - Concept, Epidemiology and Primary Prevention

 [bib_ref] Diferencas regionais na transicao da mortalidade por doencas cardiovasculares no Brasil, Guimaraes [/bib_ref] 

## Prevalence of arterial hypertension
The prevalence of HA in Brazil varies according to the population studied and the assessment method [fig_ref] Table 1 -: Prevalence of AH according to different approaches [/fig_ref].
In the meta-analysis by Picon et al., the 40 cross-sectional and cohort studies included showed a reduction trend in AH prevalence in the last three decades, from 36.1% to 31.0%. [bib_ref] Trends in prevalence of hypertension in Brazil: a systematic review with meta-analysis, Picon [/bib_ref] A study with 15,103 government employees from six Brazilian capitals has reported a 35.8% AH prevalence, with predominance of men (40.1% vs 32.2%). [bib_ref] Prevalence, awareness, treatment and influence of socioeconomic variables on control of high..., Chor [/bib_ref] Data from VIGITEL (2006 to 2014) indicate that the self-reported AH prevalence among individuals aged 18 years and over, living in the capitals, ranged from 23% to 25%, respectively, with no difference in the period assessed, not even regarding sex. The self-reported AH prevalence varied among adults according to age groups as follows: 18 -29 years, 2.8%; 30 -59 years, 20.6%; 60 -64 years, 44.4%; 65 -74 years, 52.7%; and  75 years, 55%. The Southeastern region showed the highest self-reported AH prevalence (23.3%), followed by the Southern (22.9%) and West-Central (21.2%) regions. The Northeastern and Northern regions had the lowest rates, 19.4% and 14.5%, respectively.In 2014, the Brazilian National Health Survey (PNS) measured the BP of selected dwellers from drawn residences, using calibrated digital semi-automated devices. Three BP measurements were taken at two-minute intervals, considering the mean of the last two measurements, inserted in smartphone. The overall prevalence of BP 140/90 mm Hg was 22.3%, with predominance among men (25.3% vs 19.5%), ranging from 26.7% in Rio de Janeiro to 13.2% in Amazonas, with predominance in the urban area as compared to the rural one (21.7% vs 19.8%).

## Knowledge, treatment and control
A review 7 has shown a wide variation of BP knowledge (22% to 77%), treatment (11.4% to 77.5%) and control (10.1% to 35.5%) rates, depending on the population studied [fig_ref] Table 2 -: Blood pressure knowledge, treatment and control in 14 Brazilian population-based studies published... [/fig_ref].

## Prehypertension
Prehypertension (PH) is characterized by systolic BP (SBP) between 121 and 139 and/or diastolic BP (DBP) between 81 and 89 mm Hg.The world prevalence of PH has ranged from 21% to 37,7% in population-based studies, except for Iran (52.1%) [fig_ref] Figure 4 -: Prevalence of prehypertension [/fig_ref]. 14 Prehypertension associates with a higher risk of developing AH [bib_ref] Incidence of hypertension in Porto Alegre, Brazil: a population-based study, Moreira [/bib_ref] [bib_ref] Asia Pacific Cohort Studies Collaboration. Effects of prehypertension and hypertension subtype on..., Arima [/bib_ref] and cardiac abnormalities. [bib_ref] Prehypertension is associated with abnormalities of cardiac structure and function in the..., Santos [/bib_ref] Approximately one third of the cardiovascular (CV) events attributed to BP elevation occur in individuals with PH. [bib_ref] Impact of lower range of prehypertensionon cardiovascular events in a general population:..., Fukuhara [/bib_ref] Meta-analyses of the incidence of CVD, IHD and stroke in prehypertensive individuals have shown a higher risk among those with BP levels between 130 and 139 or 85 and 89 mm Hg than among those with BP levels between 120 and 129 or 80 and 84 mm Hg [fig_ref] Figure 5 -: Meta-analysis of the risk of the incidence of cardiovascular disease [/fig_ref]. [bib_ref] Prehypertension-prevalence, health risks, and management strategies, Egan [/bib_ref] The clinical implication of that epidemiological evidence is that the BP of prehypertensive individuals should be monitored closely, because a significant proportion of them will develop AH and its complications. 2

## Risk factors for arterial hypertension

## Age
There is a direct and linear association between aging and AH prevalence related to the increase: i) in life expectancy of the Brazilian population, currently 74.9 years; ii) in the elderly population  60 years in the past decade (2000 to 2010), from 6.7% to 10.8%.A meta-analysis of studies performed in Brazil including 13,978 elderly has shown a 68% AH prevalence. 20

## Sex and ethnicity
The 2013 Brazilian National Health Survey (PNS) showed a self-reported AH prevalence statistically different between sexes, being higher among women (24.2%) and black

## Overweight and obesity
In Brazil, the 2014 VIGITEL data revealed, between 2006 and 2014, an increase in the prevalence of overweight (BMI  25 kg/m 2 ), 52.5% vs 43%. In that same period, obesity (BMI  30 kg/m 2 ) increased from 11.9% to 17.9%, predominating among 35-to-64-year-old individuals and women (18.2% vs 17.9%), but remained stable from 2012 to 2014.

## Salt intake
The excessive consumption of sodium, one of the major RF for AH, associates with CV and renal events. [bib_ref] Dietary factors associated with hypertension, Zhao [/bib_ref] [bib_ref] Reducing population salt intake worldwide: from evidence to implementation, He [/bib_ref] In Brazil, data of the Survey on Family Income (POF), collect from 55,970 dwellings, have shown home availability of 4.7g of sodium/person/day (adjusted for the consumption of 2,000 kcal), exceeding more than twice the maximum recommended consumption (2 g/day), lower in the urban area of the Southeastern region, and higher in the rural area of the Northern region. [bib_ref] Alcohol consumption and risk of hypertension in men and women: a systematic..., Briasoulis [/bib_ref] The impact of the sodium-rich diet estimated in the 2014 VIGITEL data showed that only 15.5% of the individuals interviewed acknowledged high or extremely high salt content in their meals. 12

## Alcohol intake
A chronic and high consumption of alcoholic beverages increases BP consistently. A meta-analysis of 2012, including 16 studies with 33,904 men and 19,372 women compared the consumption intensity between non-drinkers and drinkers. [bib_ref] Prevalencia de hipertensao arterial autorreferida na populacao brasileira: analise da Pesquisa Nacional..., Andrade [/bib_ref] For women, there was a protective effect with doses lower than 10g of alcohol/day, and risk for AH with a consumption of 30-40g of alcohol/day. For men, the increased risk for AH became consistent from 31g of alcohol/day onwards.
The 2006-2013 VIGITEL data showed that abusive alcohol consumption -at least four doses for women, or at least five doses for men, of alcoholic beverages on the same occasion, within the past 30 days -is stable in the adult population, around 16.4% (24.2% for men and 9.7% for women). For both sexes, abusive alcohol consumption was more often among youngsters, and increased with schooling. 25

## Sedentary lifestyle
A population-based study in the city of Cuiaba, Mato Grosso State, (n = 1,298 adults  18 years) has revealed a 75.8% overall prevalence of sedentary lifestyle (33.6% during leisure time; 19.9% at work; 22.3% during both). A significant association of AH was observed with age, male sex, overweight, central adiposity, sedentary lifestyle during leisure time and work, less than 8 years of schooling, per capita income < 3 minimum wages. [bib_ref] Hipertensao arterial e atividade fisica em uma capital brasileira, Scala [/bib_ref] Brazilian National Health Survey (PNS) data indicate that insufficiently active individuals (adults not practicing at least 150 minutes per week of physical activity including leisure, work and displacement time) represent 46.0% of the adults, the percentage being significantly higher among women (51.5%). The frequencies of insufficiently active individuals differed between age groups, mainly among the elderly (62.7%) and the adults with no formal education and those with incomplete elementary education (50.6%). 27

## Socioeconomic factors
Adults with lower schooling (no formal education or incomplete elementary education) have a higher prevalence of self-reported AH (31.1%). The proportion decreases among those with complete elementary education (16.7%), being 18.2% among those with complete higher education. [bib_ref] Hipertensao arterial e atividade fisica em uma capital brasileira, Scala [/bib_ref] However, the ELSA Brazil Study, performed with employees of six Brazilian universities and university-affiliated hospitals with higher schooling, has shown a 35.8% AH prevalence, higher among men. 11

## Genetics
Brazilian studies assessing the impact of genetic polymorphisms in the quilombola population could not identify a more prevalent pattern, showing the strong impact of miscegenation, and hindering the identification of a genetic pattern for the elevation of BP levels. [bib_ref] Multilocus family-based association analysis of seven candidate polymorphisms with essential hypertension in..., Kimura [/bib_ref] [bib_ref] Genomic ancestry of rural African-derived populations from Southeastern Brazil, Kimura [/bib_ref] Strategies for the implementation of preventive measures
The strategies for preventing the development of AH comprise public policies for health in combination with action from the medical societies and communication media. They should be aimed at stimulating early diagnosis, continuous treatment, control of BP and associated RF, by use of lifestyle changes and/or regular use of medications.
[fig] Figure 1 -: Mortality rate in Brazil due to cardiovascular diseases (CVD) and distribution according to cause in 2013. IHD: ischemic heart disease; CbVD: cerebrovascular disease; HD: hypertensive disease; CHF: congestive heart failure. Arq Bras Cardiol 2016; 107(3Suppl.3):1-83 [/fig]
[fig] Figure 2 -Figure 3 -: Mortality rate in Brazil due to CVD from 2000 to 2013. Source: Information System on Mortality. Health Surveillance Secretariat, Brazilian Ministry of Health. Hospitalization rate in Brazil per 100,000 inhabitants, per geopolitical region, from 2010 to 2012. [/fig]
[fig] Figure 5 -: Meta-analysis of the risk of the incidence of cardiovascular disease (CVD) in individuals with prehypertension (PH). [/fig]
[fig] Figure 4 -: Prevalence of prehypertension (PH). Arq Bras Cardiol 2016; 107(3Suppl.3):1-83 [/fig]
[table] Table 1 -: Prevalence of AH according to different approaches [/table]
[table] Table 2 -: Blood pressure knowledge, treatment and control in 14 Brazilian population-based studies published from 1995 to 2009. 7 [/table]