Prevalence and pattern of hypertension and effect of body mass index on blood pressure in six communities of Biase LGA In Cross River , Nigeria

Introduction The era of increased prevalence of non-communicable disease is here with us. The burden of non-communicable disease like hypertension and diabetes mellitus is overwhelming in developing countries (1). Hypertension is the most common non-communicable disease and risk factor for heart failure, stroke, chronic kidney disease, and ischemic heart disease in Africa (2). It is a common and important major global public health problem. It is projected that, in a few years time, about 75% of all hypertensive patients in the world will be from developing countries (2). In Nigeria, it is the number one risk factor for stroke, heart failure, kidney failure and ischemic heart diseases (2). The prevalence of hypertension has increased significantly over the past two to three decades (2,3). Hypertension has been a disease of the affluent but this has changed in the last few years because of varying lifestyles (3-8). The awareness of hypertension ranges from 44% in Western Europe to 28% in North America (2). It has been documented as a threat to the health of people in sub-Saharan Africa and a major contributor to mortality and morbidity in the sub-Saharan region. In Nigeria, hypertension awareness ranges from 3.5% in Sokoto to 30% in Nsukka (2). This problem is worse in rural settings where availability and accessibility to quality health care is a mirage. The essence of this study was to assess the prevalence and pattern of hypertension and body mass index (BMI) in six rural communities in Biase, South–South Nigeria.


Introduction
The era of increased prevalence of non-communicable disease is here with us.The burden of non-communicable disease like hypertension and diabetes mellitus is overwhelming in developing countries (1).Hypertension is the most common non-communicable disease and risk factor for heart failure, stroke, chronic kidney disease, and ischemic heart disease in Africa (2).It is a common and important major global public health problem.It is projected that, in a few years time, about 75% of all hypertensive patients in the world will be from developing countries (2).In Nigeria, it is the number one risk factor for stroke, heart failure, kidney failure and ischemic heart diseases (2).The prevalence of hypertension has increased significantly over the past two to three decades (2,3).Hypertension has been a disease of the affluent but this has changed in the last few years because of varying lifestyles (3)(4)(5)(6)(7)(8).The awareness of hypertension ranges from 44% in Western Europe to 28% in North America (2).It has been documented as a threat to the health of people in sub-Saharan Africa and a major contributor to mortality and morbidity in the sub-Saharan region.In Nigeria, hypertension awareness ranges from 3.5% in Sokoto to 30% in Nsukka (2).This problem is worse in rural settings where availability and accessibility to quality health care is a mirage.The essence of this study was to assess the prevalence and pattern of hypertension and body mass index (BMI) in six rural communities in Biase, South-South Nigeria.

Methods
The study was conducted at the town hall of Adim village in Biase local government area of Cross River state of Nigeria.The Language spoken in Adim village includes the native language called "Arum" along with English and Efik.Biase make up one of the 18 local government areas in Cross River state, Nigeria.It has a population of about 15 000 people.Most of the people are peasant farmers and a few are working class people.It has a cottage hospital, few private clinics and few health centers for its teeming population.It is about 70 km away from Calabar, which is the capital of Cross River state.Adim Town Hall was the venue of the outreach.Many of the people recruited are peasant farmers by occupation.Participants were recruited randomly from six rural communities in Biase town and were aged 18-80 years.Permission was sought from the Cross River state Ministry of health and approval was given to carry out a medical outreach from which this study was done.The Village Head (Onun) also took time to encourage the villagers to attend the health outreach and was also intimated about the study and he gave consent to it.Willing participants made themselves available.Informed consent was sought from all participants and the procedures were well explained to each keen participant who was then given the questionnaire.Verbal informed consent was followed by the questionnaire administration.This was a cross-sectional community-based study done in a semi-rural area of South-South Nigeria.The standard operating procedure for verbal informed consent was followed by the questionnaire and anthropometrics according to local standard practice for participation in observational studies.An interviewer recorded the outcome of the consent procedure on behalf of the participants.A well-structured, detailed questionnaire was used with parameters covering demographic indices.The weight and height were assessed and taken appropriately.The BMI was calculated by dividing the weight in kg by the square of the height in meters.The blood pressure was obtained using appropriate cuff sizes and this was after the patient had been rested for a few minutes to ensure a resting cardiac value of blood pressure.The blood pressure was measured using an aneroid sphygmomanometer (UA767 PLUS, made by A and D Company Tokyo, Japan).This is a validated automatic blood pressure measuring device.Appropriate cuff-sizes were used.Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were the first and fifth Korotkoff sounds heard respectively.Each participant had blood pressure taken twice.The SBP and DBP were taken for the two readings and analyzed.Interviewers recorded the outcome of the data on behalf of the participants.Body weight, height, and blood pressure were done using standard methods.For each subject, temperature was measured using manual thermometer in the axilla.Next, a short history and physical examination was followed by the doctor.Drugs were prescribed according to the ailment and the questionnaire was collected.Height was measured by a graduated tape measure for each participant while weight was done by a weighing scale (Accosons, USA).A total of 5 doctors attended to the participants.In the overall, all the adults (males and females) from the six rural communities that were seen made up a total of 419 patients with ages ranging from 18-80 years.Pregnant women were excluded from this study since the etiology of pregnancy -induced hypertension is different.A total of 419 participants consented and enrolled for this study.Data were collected and analyzed by a statistician.All data were entered into Epi Info.All socio-demographic data were collected and recorded.Systolic and diastolic blood pressure were taken and mean values were calculated and given as mean ± standard deviation.Hypertension was defined as a measure of SBP >140 mm Hg and/or DSP >90 mm Hg.Isolated systolic hypertension was defined as SBP >140 mm Hg but ≤90 mm Hg of diastolic value.Isolated diastolic hypertension was defined as a DBP >90 mmHg and SBP ≤140 mm Hg.Participants who had controlled blood pressure (though known hypertensives) were those with systolic blood pressure less than 140 mm Hg and less than 90 mm Hg for diastolic value.These subjects were actually on blood pressure-lowering drugs.Data analysis was done by using EPI Info version 19.0 (Texas, USA).The prevalence of hypertension was done using relevant descriptive statistics (9).

Results
A total of 419 subjects agreed to participate in this study.They were all adults whose ages ranged between 18 years and 80 years.The mean age was 46.80 ± 17.96 years.Of all the 419 participants, about 58.9% (247) were adult females and 41.1% (172) were adult males (see Figure 1).Hence, more adult females turned out for the outreach than adult males (ratio 1.4:1).A total of 137 subjects had elevated blood pressure (SBP >140 mm Hg, DBP >90 mm Hg).This amounted to 32.7% of the people screened.Of all the hypertensives, about 86 (62.8%) were females and 51 (37.2%) were males (see Figure 2).The people with hypertension in this study were seen to be higher than 40 years for most of them and increasing age was seen here as a major risk factor for hypertension in both sexes.The mean SBP and DBP values were 144.5 ± 27.3 mm Hg and 89.13 ± 17.96 mm Hg respectively.Stage 2 hypertension (moderate hypertension) was the commonest type of presentation.This is defined as a SBP of between 160 and 179 mm Hg and a diastolic value of 100 to 109 mmHg.The mean BMI was 25.5 ± 5.8 and 24.6 ± 4.8 for females and males respectively (P = 0.1149).A total of 66 people (16%) were obese, while 92 people (22%) were overweight and the rest were of normal BMI (Figure 3).Majority of the people with obesity and overweight were hypertensive.More women were obese (50 women) as opposed to the men (16 women) (P < 0.05).Similarly, more women were more overweight than men (P < 0.05).There was a strong correlation between overweight, obesity and high blood pressure given as correlation coefficient: r 2 = 0.02.And in all, more females were screened, and more females were hypertensive.

Discussion
The major risk factors identified here as the causes of hypertension are increasing age, overweight and obesity; however, other social factors may be contributory.More women are seen here to have an increased blood pressure compared to the males.Also, females have a higher BMI and are more overweight and obese than males.The people with obesity and overweight had higher values of blood pressure.Also, of all the hypertensive, only about 29 (21.2%)knew they were hypertensive and were on medications.The rest of them (78.8%) did not have awareness of their health status in regard to their blood pressure.Hence, increased awareness and emphasis on screening for hypertension be enhanced as well as emphasizing on the importance of maintaining a normal BMI through right dieting and lifestyle modification.Historically, hypertension and its complications were said to be rare among Africans, but adoption of western lifestyle, dietary change and sedentary lifestyle have led to an increased in this non-communicable disease (4-9).In Africa, there is an increasing urbanization of lifestyles among individuals with attendant cardiovascular morbidity and mortality on the increase (10).Before now, hypertension was thought to be rare among Africans; however, many studies have proved this to be wrong (11,12).This scourge includes also Nigerian in both urban and rural areas.Many studies done in Nigeria to ascertain the prevalence of hypertension over the years have focused attention at the north and south western Nigeria (13)(14)(15).In this study, the prevalence of hypertension was 32.7%.This finding is consistent with some other researchers (15)(16)(17), but lower than that of some other researchers who carried out similar studies among the Ibibios and Efiks (8) but higher than results from Osun (18), Ghana (12) and South Eastern Nigeria (19).The occurrence of hypertension was higher in females (65.2%) compared to males (34.8%) (see Figure 4) which also agrees with earlier studies (20), but contrary to findings of prior awareness of hypertension by patients; which was extremely low (21).This also agrees with works done by Andy et al (8).Currently, the awareness of hypertension is very low among Nigerians in both urban and rural area (7,14,22).Myriads of complications are associated with poorly controlled or uncontrolled hypertension, hence there is a need to assess the prevalence, risk factors and pattern of blood pressure and BMI among rural dwellers in Nigeria.

Conclusion
The prevalence of hypertension in this community was high, based on this study.Many Nigerians live in the rural setting, and with this pattern of high prevalence of hypertension, aggressive and adequate steps must be

Ethical issues
This study was done after obtaining clearance from the State Ministry of Health, Calabar, Cross River State.

Figure 1 .
Figure 1.Sex distribution of participants for the study.

Figure 2 .
Figure 2. The prevalence of hypertension.