Cardiovascular Journal of Africa: Vol 27 No 6 (November/December 2016)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 6, November/December 2016

AFRICA

359

of the population had no formal education, limiting their access

to quality information about healthy lifestyles. Although the

government is putting efforts into increasing awareness in these

rural and semi-urban settlements,

17,18

health education is still

largely inadequate.

Estimates from our study showed that 55.5% of the adults

had hypertension, with SDH being the commonest subtype.

This prevalence was much higher than the 29.7% reported

by Adedoyin

et al.

in south-western Nigeria, and the 46.4%

reported by Ejim

et al.

in south-eastern Nigeria. This higher

prevalence may have been related to participants being older in

our study compared to these other studies (61.6 vs 41.5 years and

61.6 vs 59.8 years, respectively).

Many studies have recorded a high prevalence of hypertension

among elderly participants. For example, Peltzer

et al.

in a

study among the elderly in 2008 recorded a high prevalence of

hypertension (77.3%, mean age 65 years). Other studies reported

higher prevalence rates of hypertension among older adult

population surveys in Tanzania in 2010 (69.9%, mean age 76

years), Tunisia in 2003 (69.3%, mean age 69 years) and Senegal in

2009 (65.4%, mean age 69.5 years).

22-24

Similar to Banegas

et al.

and Onwubere

et al.

a larger percentage of participants in our

study had ISH compared to IDH. ISH was also more common

in those above 60 years of age, compared to IDH.

Age is known to significantly influence the prevalence and

pattern of elevated blood pressure, therefore SBP tends to

increase with advancing age as a result of loss of arterial

compliance, while DBP tends to plateau or decrease after 50

years of age. The decrease in compliance results in higher SBP.

An increase in peripheral resistance is also known to result

in elevated DBP, whereas loss of elasticity in the large vessels

causes a reduction with increasing age. Therefore the net effect of

these opposing factors may results in a normal or near-normal

DBP,

27,28

depending on the predominant factor.

The prevalence of ISH obtained in this study is much

higher than in a study by Tesfaye

et al.

Our study showed

that only 26% of individuals with hypertension had been

diagnosed previously, 10.9% were on antihypertensive treatment,

while 22% were controlled (BP

≤

140/90 mmHg). This finding

demonstrates a high proportion of undiagnosed, untreated and

poorly controlled hypertension in Nigeria, a problem that has

been reported by others. For instance, good hypertension control

could only be achieved in 24.2% of the patients seen in a Port

Harcourt hospital.

Ekwunife

et al.

also found only 23.7 and

17.5% of males and females, respectively, with hypertension were

on antihypertensive treatment, while 5.0% of males and 17.5% of

females with hypertension were controlled.

In the present study, participants with IDH were significantly

younger than those with ISH. This is in keeping with a similar

study done by Adeoye

et al.

who found subjects with IDH to be

significantly younger among the hypertensive patients in Ibadan.

The strength of this study is in its relatively moderate sample

size that was spread across many communities. It however has

some limitations. Many of the participants were illiterate with

no recorded biodata, so the age given may not be accurate. Also,

participation in this study was voluntary, which might have

influenced the results.

Conclusion

The estimate of prevalence of hypertension obtained in this

study was higher than in most other studies in Nigeria, which

is contrary to the existing trend of low prevalence found

many years ago in semi-urban communities. The predominant

patterns of hypertension observed were both SDH and ISH.

The prevalence of hypertension was found to increase with age,

therefore age was a significant predictor of hypertension among

these subjects.

Hypertension, because of its high prevalence, deserves to be

the health priority of policy makers. Therefore policy makers

and other stakeholders in the health sector need to urgently

institute community-based strategies towards creating awareness

of hypertension, encouraging health-seeking behavioural habits,

and educating people on the main risk factors such as unhealthy

diet, high salt intake and sedentary lifestyles. It is important that

the findings of this study prompt appropriate response at state

and national levels, towards improved detection, control and

management of hypertension in Nigeria.

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Table 3. Comparison of sociodemographic and clinical characteristics

according to hypertension subtypes

Variable

Both

(

198)

IDH

(

37)

ISH

(

181)

-value

Age (years)

68.2 (13.7)

61.4 (18.4)

64.4 (17.6)

0.014

Gender

Male,

(%)

51 (25.8)

15 (40.5)

59 (32.6)

0.117

Female,

(%)

147 (74.2)

22 (59.5)

122 (67.4)

Educational level

None

133 (67.2)

18 (48.6)

110 (60.8)

0.199

Primary

38 (19.2)

10 (27.0)

37 (20.4)

Secondary

17 (8.6)

4 (10.8)

24 (13.3)

Tertiary

10 (5.1)

5 (13.5)

10 (5.5)

Income (Naira)

20 000

174 (87.9)

29 (78.4)

151 (83.4)

0.512

20 000–40 000

18 (9.1)

7 (18.9)

21 (11.6)

41 000–60 000

4 (2.0)

1 (2.7)

6 (3.3)

61 000–100 000

1 (0.5)

0 (0.0)

3 (1.7)

100 000

1 (0.5)

0 (0.0)

Mean BMI (kg/m

)

23.4 (5.3)

24.1 (5.1)

23.7 (7.3)

0.823

Mean WC (cm)

87.3 (11.2)

88.9 (10.5)

86.5 (12.7)

0.483

Mean WHR

0.94 (0.15)

0.95 (0.05)

0.92 (0.07)

0.109

Mean SBP (mmHg)

169.8 (25.3)

125.5 (9.1)

158.3 (17.2)

0.001

Mean DBP (mmHg)

98.9 (9.9)

92.4 (4.4)

78.6 (7.8)

0.001