HYPERTENSION AMONG UNDERGRADUATE STUDENTS FROM LUBANGO, ANGOLA

Se trata de un estudio descriptivo que tuvo como objetivo estudiar la presencia de la hipertensión arterial y los factores de riesgo entre universitarios de la ciudad de Lubango-Angola. Los resultados obtenidos según el Modelo de Campo de Salud fueron: a) biología humana: 61,3% en el intervalo de edad de 18 a 29 años; se estimó la presencia de la hipertensión entre 20,3 a 26,7%; 17,1% presentaban sobrepeso; 3,2%, obesidad; b) medio ambiente: 36,1% tenían dedicación exclusiva al estudio; 33,1% indicaron una renta familiar de hasta 250 dólares; c) estilo de vida: 86,2% realizaban actividad física; 60,6% indicaron preferencia por la ingestión de alimentos salados; 4,0% eran fumadores; 40,6% hacían uso de bebidas alcohólicas; d) atención de la salud: 82,8% ya habían verificado la presión arterial en alguna ocasión y el 65,4% de ellos no recordaba el valor encontrado.


INTRODUCTION
Hypertension has been appointed as the greatest risk factor for early morbidity and mortality caused by Cardiovascular Diseases (CD).
Framingham's studies show that increased blood pressure (BP) is associated to higher incidence of CD, which are an important problem for public health and are the main cause of death in most countries' adult population (1) .Data from the World Health Organization (WHO, 1997) indicate that they were the cause of about 30% of all deaths in the world, which corresponds to almost 15 million deaths each year, the majority (9 million) in developing countries.These data rank CD as a pandemic, whose treatment requires the adoption of effective primary and secondary preventive measures (2) .
Data from the VII Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure indicate that hypertension affects approximately 50 million people in the Unites States of America, and about 1 billion worldwide (3) .
Despite acknowledging that this group of diseases is of high severity, many African countries dedicate little attention to its prevention, since studies related to the prevalence of hypertension were not found in bibliographic research in some countries of the region, especially in Angola.
The primary prevention of hypertension is essential for the reduction of morbidity and mortality due to CD.Primary prevention aims to reduce or modify hypertension risk factors through the implementation of appropriate policies and educative programs in order to avoid or delay the development of the disease.Changes in the population's behavior (low consumption of salt or increased physical activity) can benefit individuals and contribute to BP control in the population (4)   .
The IV Brazilian Guidelines on Hypertension emphasize both the work of a multi-professional team in orientations to hypertensive patients and the importance of implementing strategies for the primary prevention of hypertension.Prevention is the most efficient means to fight hypertension.The reason is that it basically comprehends guidance aiming to introduce changes in life habits, to avoid elevated social costs, and to prevent difficulties related to treatment and control of complication in target organs, such as heart, brain and kidneys (5) .
Regarding risk factors for the hypertensive disease, these can be classified in constitutional, age, gender, genetic (race and family history) and environmental factors, including excessive consumption of salt, alcohol and fat in addition to smoking, and also those environmental factors linked to work and social class (6) .
The hypertension diagnosis is basically established by permanently high tensional levels, that is, above normal limits, when BP is determined through appropriate methods and conditions.Thus, BP is a key element in the establishment of the hypertension diagnosis.In Brazil, its measurement is a mandatory procedure that should be performed by physicians of all specialties and other properly trained health professionals, in every clinical evaluation of patients of both genders (5) .

THEORETICAL REFERENCE: THE HEALTH FIELD MODEL
The epidemiological model called "Health Field", determinant of diseases and death and proposed by Lalonde (7) , was the theoretical reference adopted in this study.This model was used in another Brazilian study involving women with acute myocardial infarction (8) .Body Mass Index (BMI) was computed by the formula: weight (kg/height 2 (m 2 ).The BMI classification criteria used were those provided by the World Health Organization (9) , which are: low-weight under 18.5kg/m 2 , normal weight 18.5 to 24.9kg/m 2 , overweight 25 to 29.9kg/m 2 , and obesity equal to or higher than 30kg/m 2 (level I -30 to 34.9kg/m 2 ; level II -35 to 39.9kg/m 2 , and level III ≥40kg/m 2 ).Waist and hip circumferences were measured with an inelastic metric tape, with the student in the upright position, arms along the body and feet together.The waist-hip ratio (WHR) was obtained by dividing the waist circumference by the hip circumference.

OBJECTIVES
To calculate the WHR, the cut-off points most used in studies of this kind were adopted, that is, equal or inferior to 0.80 for females and 0.90 for males (10)   , which define adequate values of WHR.
The cut-off points used for waist circumference were those recommended by WHO (9) , which classifies it as high when the value in centimeters is equal to or higher than 80cm for females, and equal to or higher than 94cm for males.A value equal to or higher than 88 cm for females and 102 cm for males is considered very high.

Data related to health care
Initially, all participants were inquired about whether their BP had ever been measured before and which value had been found.Of the 667 interviewees, 552 (82.8%) reported it had been measured once, with 428 (77.5%) in the same year of the study; (10.1%) had it measured two years before; 49 (8.9%) more than two years ago; 19 (3.4%) did not remember when it had been measured, and the majority, 361 (65.4%), were not able to inform the BP value found at the time.
All students were asked whether they suffered from hypertension and answers were: 60 (9.0%) knew they had hypertension; 329 (49.3%) denied they had the disease, and 278 (41.7%) did not know whether or not they had the disease, despite the fact that many of them had their BP measured sometime before.Only 16 (26.7%), of the 60 students who acknowledged their hypertension, followed some kind of treatment to control the disease.
Damage caused by obesity is clearly known and described by several authors.Obese people have a higher prevalence of hypertension than non-obese, and reducing body weight leads to reduced levels of BP (12)   .
The association of BMI and hypertension is also stressed in the studies of Framingham, who observed that an excess of 20% in the ideal weight increases the incidence of hypertension eight times (13) .
Reducing body weight is the most effective nonpharmacological way to control hypertension, because even moderate reduction of body weight significantly reduces BP (14) .
Family history of the hypertensive disease should be taken into account in studies on the prevalence of the disease because hypertension is a disease in which the genetic heritage element is of great importance.
Regarding the family structure of the population studied, it was observed that the majority (54.1%) was single, explained by the fact that the predominant age range was of young individuals, between 18 and 29 years old, though the majority (51.3%) had children.

Socioeconomic conditions have been
appointed by some authors as risk factors for the development of some diseases, which influences mortality.
Regarding the students' life style, the physical activity reported by the great majority (86,2%) deserves to be highlighted.It is a positive fact, since regular physical activity provides multiple benefits to health, even reducing the incidence of CD, such as those due to coronary arteriosclerosis (15) .
Data showed that the study population had some healthy habits, such as physical activities, which contribute to prevent some diseases caused by physical inactivity.However, despite the majority reporting the practice of physical activities, there is still a share of this population who does not, and others who do not follow requirements, that is, 30 to 60 minutes of activity at least three times per week (5) .
thist indicates the need to program and implement educative actions, aiming to inform individuals about the need to practice regular physical activity.
Regarding eating patterns, the findings show that the most consumed foods were carbohydrates and proteins, and the least consumed foods were fruits, greens and vegetables.The consumption of fruits and greens is advised because there is evidence of their protective effect against CD and CVA.The favorable effects of consuming fruits and greens for BP have been reported in innumerous studies (16) .It is known that a balanced diet is essential for the maintenance of health and that it should include the main nutritional sources: carbohydrates, proteins, fat, vitamins and fibers.
In relation to the consumption of salt, information obtained indicates that the participants did not have a clear understanding of the harmful effects of excessive ingestion of this ion.Several authors stress that saline restriction should be part of anti-hypertension therapy and is one of the first recommendations given to hypertensive patients and their families, aiming to prevent it.
Therefore, the dissemination of information aiming to prevent BP is crucial because, as several studies have shown, reducing the consumption of salt is one of the most effective measures to prevent the disease.It promotes lower elevation of BP and pressure decrease proportional to the decreased level of sodium.In this perspective, the consumption of salt up to 6 grams/day is recommended, as well as to avoid the use of a salt container on the table, and the non-ingestion of industrialized food because it presents high levels of salt (5) .
Despite the small number of smokers (4.0%), this habit deserves attention because smoking is a risk factor for cardiovascular and cancer diseases and is one of the main evitable causes of death in the world.In relation to the consumption of alcohol, several studies report the association between its excessive consumption and hypertension and/or CD. were not able to inform the value found at that time.

FINAL CONSIDERATIONS
Results from this study indicate the need for orientation programs to inform the population on chronic degenerative diseases in general and especially hypertension.

First, the research
project was sent to the Research Ethics Committee of the University of Sao Paulo at Ribeirão Preto College of Nursing (EERP-USP), because there are no Ethics Committees in Angola.The data collection was carried out after the committee's approval.Data were obtained through individual interviews, after signature of the free and informed consent term, based on Resolution 196/96 of the Brazilian Health Council (CNS).Height was inferred with an inelastic metric tape of 150 cm of length, fixed upside down with adhesive tapes on a flat wall with no baseboard, positioned 50 cm above the floor.Body weight was obtained through a portable anthropometrical scale with a 150-kilogram capacity, arranged on a leveled floor and previously calibrated.
In the analysis of risk factors for hypertensive disease grouped in the four elements of the Health Field model, in the human biology element, modifiable (high prevalence of hypertension and a considerable percentage of overweight students) and nonmodifiable factors (age, race, gender, family history of hypertension) were highlighted.In terms of environment, the socio-economic level (low income and family structure) was verified, whereas self-raised habits (excessive consumption of salt and alcohol, expressive in this population) are found in relation to life style.And finally, a fact related to health services deserves attention.Although many participants indicated blood pressure measurement sometime in their life, they The struggle against hypertension and other chronic diseases is a great challenge to the State as well as to professionals, because it depends on the establishment of public policies and investment in human resources, which would allow health professionals and teachers to attend education and training programs.Communication means and society as a whole should link up with these professionals, aiming to disseminate information, with a view to changes in citizens' educative process.The most viable alternatives include continuing education courses, training, informative booklets, lectures, seminars, among many other means of enriching and/or consolidating knowledge.