Background to the Study
Hypertension remains a major global public health challenge that has been identified as the leading risk factor for cardiovascular morbidity and mortality (Kearney, Whelton, Reynolds, Muntner, Whelton & He, 2004). It increases hardening of the arteries, thus predisposing individuals to heart diseases, peripheral vascular diseases, stroke, heart failure and kidney failure. Hypertension is the commonest non-communicable disease in the world and all races are affected with variable prevalence. Castelli (2004) explained that its prevalence is on the increase in developing countries where adoption of western lifestyle and stress of urbanization, both of which are expected to increase morbidity associated with unhealthy lifestyle are not on the decline. Andreoli, Carpenter, Grigs and Loscalzo (2004) were of the opinion that hypertension produces disruptions in health, disability and death in the adult population worldwide. Ejike, Ezeanyika and Ugwu (2010) stated that hypertension causes one in every eight deaths worldwide, making it the third leading killer disease in the world. They also estimated that about one billion adults, the world over, had hypertension in the year 2010 and the number is expected to rise to 1.56 billion in the year 2025 if positive intervention programme is not made. Aram, George, Henry, Williams, Lee, and Joseph (2003) indicated that fifty million Americans have high blood pressure, approximately one in three adults.
In United States of America, approximately twenty eight (28) to thirty one per cent of adults have hypertension (Fields, Burt & Cutler (2004). Of this population, 90 to 95 per cent have primary hypertension (high blood pressure related to unidentified cause). The remaining five to ten per cent of this group have secondary hypertension (high blood pressure related to identified cause). In China, almost 130 million people aged 35-74 years are estimated to be hypertensive (Camel & Delene, 2006). Similarly in Ghana, studies revealed a hypertension prevalence of forty per cent among rural dwellers and eight per cent to thirteen per cent in the urban areas. In sub-Saharan Africa, it is the most rapidly rising cardiovascular disease and affecting over 20 million people (Kadiri, 2005). He also stated that in Nigeria, hypertension is the commonest non-communicable disease with over 4.3 million Nigerians above the age of fifteen years classified as being hypertensive.
Hypertension, also known as high blood pressure is the persistent blood pressure in the arteries above ninety millimeters of mercury (mmHg) between the heart beats (diastolic) or over 140 millimeters of mercury (mmHg) at the beats (systolic) (Aquilla, 2008). According to Hyman and Parlik (2003), hypertension is the persistent raised levels of blood pressure in which the systolic pressure is above 140 mmHg and diastolic pressure above 90 mmHg. The normal blood pressure is below 120/80 mmHg; blood pressure between 120/80 and 139/89 is called ‘Pre-hypertension, and a pressure of 140/90 or above is considered high (abnormal) blood pressure. According to Expert Committee on Non-Communicable Diseases (1993), blood pressure of 120/80 mmHg is considered normal for a 30 year old person, while blood pressure of 140 mmHg is considered high for such a person. Similarly, blood pressure of 150/90 mmHg is considered normal for a 60-year old person, while blood pressure of 160/100 mmHg is high for such a person. Hypertension is sometimes called “the silent killer” because people who have it are often symptom-free. In this study, hypertension is perceived as a systolic blood pressure greater than 140 mmHg and a diastolic blood pressure greater than 90 mmHg among adults. The top number which is the systolic pressure corresponds to the pressure in the arteries as the heart contracts and pumps blood forward into the arteries. The bottom number which is the diastolic pressure represents the pressure in the arteries as the heart relaxes after contraction. The diastolic pressure reflects the lowest pressure to which the arteries are exposed. Blood pressure is normally measured at the brachial artery with a sphygmomanometer (pressure cuff) in millimeters of mercury (mmhg) and given as systolic over diastolic pressure. Hypertension is classified into two namely; primary and secondary hypertension.
According to Stanler (2004), hypertension is categorized into primary and secondary hypertension. Primary hypertension has an unknown cause and accounts for ninety per cent to ninety five per cent of all hypertension cases (Chris, 2009). This type of hypertension is strongly associated with lifestyle. Usually, the patients do not have many signs and symptoms but may experience frequent headache, tiredness, dizziness or nose bleeds. Although the cause is not known, obesity, smoking, alcohol, diet and heredity play a role in essential or primary hypertension.
Secondary hypertension has a known cause and accounts for five per cent to ten per cent of all hypertension cases. Chris (2009) maintained that the most common cause of secondary hypertension is an abnormality in the arteries supplying blood to the kidneys. Other causes include airway obstruction during sleep, stress, diseases and tumors of the adrenal glands, lifestyle, spinal cord injury, hormone abnormalities (oral contraceptive estrogen replacement), thyroid disease, toxemia of pregnancy, renal problems such as vascular lesion of renal arteries, diabetic neuropathy, pains as well as anxiety and hypoglycemia. There are some factors which predispose adults to hypertension.
The risk factors of hypertension are genetic factor which can be inherited from parents, age which when the body does not retain the amount of elasticity as it used to in the early years of life, obesity which is an increase in weight of over ten per cent above normal body index due to
generalized deposition of fat in the body, excessive salt intake which increases blood pressure, stress which produces chemical substances that cause generalized vasoconstriction, oral contraceptive which contains estrogen that causes salt retention that increases the volume of blood, sedentary lifestyle which has the tendency of increasing body weight and directly raises blood pressure, elevated levels of plasma lipids particularly cholesterol, excessive alcohol consumption which increases blood pressure and tobacco use (cigarette smoking) that contains nicotine which causes constriction of the blood vessels.
The signs and symptoms of hypertension recognized by Thatch and Schultz (2004) include occipital headache, dizziness, restlessness, failing vision, shortness of breath, and rapid increased heartbeat. Adults should possess the knowledge of risk factors in order to prevent hypertension. This will help them recognize and prevent or treat hypertension when these signs occur.
Knowledge is used to cover such related terms as facts, information, understanding, awareness, insight, wisdom, reasons, comprehension, meaning, concept and experience (Albelum, 1987). It is an organized body of knowledge shared by people. Nnachi (2007) conceptualized knowledge as the ability to understand or comprehend phenomena, the acquisition of positive information by the exercise of some capacity which humans presumably have in common. Health knowledge could be said to mean putting into reality the art of mobilization of resources by an individual, intellectually, physically and emotionally. Hamburg and Russell (2000) opined that health knowledge and understanding of related factors have a favourable effect on quality of overall well-being. They went further to state that one’s exposure to proper health knowledge will influence positively the person’s health attitude and practice, and thus, one could rightly say that knowledge is the key to optimum well-being. Umaru (2003) pointed out that knowledge comes about as a result of learning through cognitive, affective and psychomotor domains. In this study, knowledge is referred to as all understanding and familiarity gained by learning and experience that will enable adults to recognize risk factors as well as recognizing and use of preventive measures of hypertension. Knowledge of hypertension is an important prerequisite for an individual to implement desirable behavioural practices towards its prevention. Lack of such knowledge will lead to aggravated health problems. Adults should therefore, possess adequate knowledge of risk factors of hypertension in order to prevent the disease.
Risk factors are defined by Lothar, Gottfried and Heide (2011) as individual characteristics which affect the person’s chances of developing a particular disease or group of diseases within a defined future time period. According to Lucas and Gilles (2003), risk factor is anything that has been identified as increasing an individual’s chances of getting a disease or developing a condition. They will be considered to be at risk of developing hypertension, those with habits or characteristics which increase the likelihood of developing hypertension. Risk factors in this study, refers to the characteristics, conditions or behaviors such as excess salt intake and smoking which increase the probability of hypertension to occur. When risk factors are related to hypertension, they are known as risk factors of hypertension. Risk factors of hypertension are of two types: those ones that can be changed and those that cannot be changed. The risk factors that can be changed are obesity, excess salt intake, smoking, environmental stress, oral contraceptives, sedentary lifestyle, elevated levels of plasma lipids and unregulated secretion of aldosterone. Risk factors that cannot be changed are genetic predisposition, age and gender. Adults should have adequate knowledge of the risk factors to be able to prevent hypertension.
Preventive measures are interventions directed to avert the emergence of specific disease, reducing their incidence and prevalence in population. Starfield, Hyde, and Gervas (2007) defined preventive measures as all measures that limit the progression of a disease at any stage of its course. In this study, preventive measures is referred to as all the activities whose primary purpose is to promote, restore and maintain health, and those practices which are directed towards preventing hypertension among adults. There are two types of preventive measures; primary and secondary. Primary prevention is the intervention that averts the occurrence of a disease or actions taken prior to the onset of disease which removes the possibility that a disease will occur. It signifies intervention in the pre-pathogenesis phase of a disease or health problem. It may be accomplished by measures designed to promote general health and well-being, and quality of life of adults (health promotion) or by specific protective measures (specific protection). Secondary prevention is action which slows the progression of a disease at its incipient stage and prevents complication. Salama (2011) opined that the specific intervention in secondary prevention is early detection of hypertension which involves screening test. It attempts to arrest the disease process, restore health by seeking out unrecognized disease and treating it before irreversible pathological changes take place especially among adults.
Adulthood is the longest period of a man’s life. Hornby (2001) defined an adult as a person who has grown to full size or strength, intellectually and emotionally mature, and legally a person old enough to vote or marry. Ebiringa and Nwagbo (1997) defined an adult as someone who has reached the age of maturity, who covers his nakedness, who lives on his own, who can answer a village call and who is taxable. They went further to state that an adult is someone who has developed a sense of perspective, more balanced in thinking, and is responsible for his own actions and that of others. Samuel (2006) defined adulthood as the period whereby an individual has acquired all the adolescent developmental tasks, reached accepted age bracket and is responsible for his actions without parental or social restrictions. Samuel (2006) also categorized adults into three stages; young adulthood (21- 40), middle adulthood (41-65) and older adulthood (65 years and above). Young adulthood which commences at around 21 to 40 years is the period when full physical fitness is generally experienced. It is a stage of critical transition. Adults in this age group are filled with vitality and enthusiasm. Middle adults falls within the ages of 41 to 65 years which is a period of pleasant plateau (Ejifugha, 2003). Adults within this group are at a stage of physical and psychological development. Adults in this group tend to eat too much and may fail to take regular exercise. Many are overweight and actually obese. Psychological stress causes adults in this group to smoke, drink and abuse drugs. Older adults are between the ages of 65 years and above. The factors in ageing set in to influence the individual gradually which may cause cardiovascular diseases like hypertension. In this study, an adult is referred to as an individual who has reached the age of maturity and falls within the age bracket of thirty five years and above.
There are many variables that may impinge on knowledge of hypertension. Literature shows that studies on knowledge of hypertension examined socio-demographic factors of age, race, level of education, parity, gender, income, location, occupation and marital status (Hamdan, Saeed, Kutbi, Choudhry & Nooh, 2010). However the present study is concerned with demographic factors of age, gender, location, and level of education.
Age has been identified as a strong factor that that can limit the ability of adults to acquire adequate knowledge of hypertension. Age determines growth, development, maturity and death. Age brings about maturity and maturity puts one in a position to rationalize, concretize, accept or reject concept, information, habit, attitude and practice (Ejifugha, 2003). It is believed that the more one add years to life, the more knowledge he acquires and the more exposed to situations that can cause health problems including hypertension. Adults because of their exposure and experience must have come to understand the concept of hypertension, signs and symptoms, risk factors and preventive measures of hypertension and because of lack of exposure or experience may not adequately acquire the knowledge of diseases (Bagunyoke, 2003) such as hypertension.
Gender has influence on knowledge of hypertension. Akinkugbe (2003) observed that women have more hypertension than men. However, after menopause, the incidence of hypertension due to arteriosclerosis in women rapidly increases than in men and even become higher in old age. From adolescence through 54 years, men have a much greater risk of developing hypertension compared with women of the same age. The reverse is the case after 54 years. Women then are seen to have more incidence of hypertension due to the disappearance of female stronger hormone that provides protective effect against hypertension.
Location is an environmental factor which may limit the ability of adults to seek adequate knowledge of hypertension. Hamdan, Saeed, Kutbi, Choudhry and Nooh (2010) indicated that hypertension was significantly associated with age, gender, geographical location. Similarly, Lech and Piotr (2009), stated that hypertension was more frequently diagnosed among rural than urban adults. The adults in urban areas have more opportunities and access to attend seminars, health talks, workshops and medical check ups on hypertension (accessibility to health information). Unfortunately, those in the rural areas may not have such opportunities as such programmes may not exist in the rural areas. These programmes are in most cases accessible to a smaller privileged group in the society, who are living in well developed towns, at the expense of greater majority who wallow up in diseases and ignorance in rural areas.
Studies have indicated that level of education is associated with knowledge, which may include the risk factors and preventive measures of hypertension. According to Hamdan, Saeed, Kutbi, Choudhry and Nooh (2010) observed that adults who were more knowledgeable adopted positive lifestyles, while the iliterate adults adopted unhealthy lifestyles. The higher the educational attainment, the higher the acquisition of knowledge, attitude and behaviour, while the lower the level of education, the lower increase in knowing risk factors and prevention measures of hypertension. Similarly, Myo, Thaworn, Janthila, Nongluk , Suchart , Wilawan , Phatchanan , Puangpet, Nara , and Apiradee (2012) reported that those with primary school education were likely to be aware of hypertension than those who did not have primary school education. The variables of age, gender, location and level of education were examined in the study. Knowledge of hypertension by adults will surely influence their health behaviour. Therefore, some behaviour change theories will be applied to explain knowledge of hypertension.
This study was anchored on three theories. These are the critical knowledge theory, health belief model, theory of reasoned action. According to Diagnam (1992), Critical knowledge theory states that when an individual is ignorant or holds a belief about a health matter, the health educator attempts to change or ascertain the individual’s level of knowledge towards the health matter or concept through questioning the respondent.
The health belief model has its focus on explaining and predicting preventive health
behaviour by focusing on the attitudes and beliefs of individuals (Rosenstock, Strecher and Beckar, 1999). This is useful because the model examined the perceptions, beliefs and behaviours of adults and to provide information on the lifestyle practices related to preventing hypertension. Adults who believe that certain lifestyles such as excess salt intake and inactivity can predispose them to hypertension will achieve good health by avoiding such lifestyles.
Theory of reasoned action show how attitude impacts on behaviours. It states that a person’s attitude towards a particular behaviour is influenced by belief outcome of the behavior. Adults who develop positive attitude towards high salt intake, excess alcohol and inactivity consumption are likely going to develop hypertension; conversely, those who have negative attitude may not get hypertension. The study was carried out in Owerri Senatorial Zone of Imo State.
Owerri senatorial zone is in Imo state located in the South Eastern part of Nigeria. The senatorial zone covers around 1,700sqkm and shares common boundaries with Abia State by the east, and Rivers State by the south. It also shares common boundaries with Ohaji Egbema, Orlu, Obowo, Ihitte-Uboma, and Mbano local government areas all of which are in Orlu and Okigwe zones of Imo State. There are nine local government areas which make up Owerri Senatorial Zone (see Appendix A). The inhabitants are engaged in agriculture, businesses and civil service works. These activities occupy much of their time with little or no time left for them to have rest and take care of their health, and they undergo lots of stress which can lead to hypertension. Furthermore, there are places which serve as tourist attractions in the zone such as Mbari exhibition centre, Imo Concorde hotel and lots of hotels and guest houses where people come for relaxation. These places expose adults to excessive alcohol consumption. Owerri Municipal which is the major urban area is cosmopolitan being the Imo State Capital and commercial nerve centre. These activities made the location to qualify for the study.
Hypertension has been shown to have series of consequences, and adequate knowledge of risk factors can help in the prevention of hypertension. Therefore, adults in Owerri Senatorial Zone need to have the knowledge of hypertension to reduce the prevalence of hypertension disease, improve health and optimum well-being. But it is likely that adults in the area may or may not have adequate knowledge of hypertension. Evidence regarding the knowledge of hypertension does not seem to exist. Therefore, this study on knowledge of hypertension becomes necessary.
Despite effective therapies and lifestyle interventions, optimal prevention of hypertension remains very health challenge to health professionals especially in most developing countries like Nigeria. Kadiri (2005) noted that 4.3 million Nigerians are suffering from this silent killer disease called hypertension. The inability to adequately prevent or manage hypertension in Nigeria can be attributed to inadequate knowledge of hypertension. Thus reaching the healthy people vision 2020 objective may be difficult if necessary actions are not taken to prevent this disease. If health promotion programmes are to be appropriate and effective, adults’ knowledge of hypertension need to be identified. Therefore, the researcher was motivated to determine the level of knowledge of hypertension possessed by adults in Owerri senatorial zone of Imo state. This became necessary against the backdrop that identification of gaps in adults’ knowledge of hypertension is capable of aiding the development of adequate information to enhance the knowledge of hypertension.
Statement of the Problem