Prevalence and Associated Factors of Hypertension among Motorcycle Taxi Drivers in Kakonko District, Kigoma Region, Western Tanzania

Background: Hypertension is a significant cardiovascular risk factor and a public health concern in low-income and middle-income countries, including Tanzania. However, data on hypertension is scarce in Tanzania. We investigated the prevalence of hypertension and its associated factors among motorcycle taxi drivers in Kakonko district, Kigoma region western Tanzania.

Method: We conducted a descriptive and cross-sectional study among motorcycle taxi drivers between Agost and November 2024. We enrolled 312 eligible participants for data collection by purposive sampling. The independent variables (exposure) of interest were Age, alcohol consumption, cigarette smoking, family history of hypertension, duration of motorcycle driving, BMI, duration of sleeping, and eating (fruits/vegetables). The outcome variable of interest was hypertension defined as  systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg. Descriptive and logistic regression was used during statistical analysis.

Results: The prevalence of hypertension was 34.6%. Factors that were positively associated with increasing odds of hypertension  during both univariate and multivariate analysis were age above 30 years old, over weight and obesity.

Conclusion and Benefit of Results: The intervention for hypertension must also put much emphasis in addressing the problem of obesity and overweight. The results of this study are essential for the formulating health policies to improve the diagnosis, prevention and management of hypertension in Tanzania.

Introduction

Hypertension is a significant cardiovascular risk factor and a public health concern in low-income and middle-income countries, including Tanzania [1]. Hypertension is a key risk factor for heart failure, coronary artery diseases, atherosclerosis, stroke, and kidney failure [2], [3].

In the year 2015,1.13 billion adults were hypertensive, largely in Sub-Saharan Africa [4]. The prevalence rate between 16% to 44% has been reported in Sub-Saharan Africa [5]–[8]. Meanwhile, a meta-analysis in Sub-Sahara among adolescents (10–19 years old) found a prevalence rates of 45.9% and 54.1% among males and females respectively [8]. In Zimbabwe, a population-based survey among young people aged 18–24 years reported an overall prevalence of 7.4%, 8.7% in males and 6.6% in females, and it was found that male sex, increasing age, and obesity were associated factors for hypertension [9].

A study in Nigeria among young adults (18–40 years) reported an overall prevalence of 21.3%, 20.7% in the 18–19 years age group, 25.9% in the 30–40 years age group, 20.3% in females, and 24.3% in males [8]. In Tanzania, a prevalence rate between 3% to 79% has been reported [10]. A study by Mosha et al. in northwestern Tanzania has reported a prevalence of 8% among adults [11]. A study conducted among adolescents and youth (aged 15 to 24) in Tanzania and Uganda revealed a prevalence of 40% [12]. In a rural district of eastern Tanzania, a prevalence rate of 29.3% among young and middle-aged has been reported [13].

Several studies have reported that the risk factors for hypertension in adults and young adults are obesity, hyperlipidemia, smoking cigarettes, physical inactivity, and diabetes mellitus [14]–[16]. It is also known that rapid urbanization, population growth, and aging once interacted with traditional risk factors may attenuate the risk of hypertension [17], [18]. Besides, HIV is another risk factor for hypertension, due to HIV-induced atherosclerosis, opportunistic infections, immune response, and side effect of ant-retroviral drugs [19]–[21]. Despite that, the data on the prevalence of hypertension and its risk factors remains under-investigated in Tanzania including in our district.

Motorcycle taxis are the common sources of income and employment for young adults in Tanzania [22]. Most of the motorcycle taxi drivers are young adults between 18 to 45 years old. It is known that young adults are more likely to engage in harmful behaviors such as alcohol consumption and cigarette smoking, which are also known to be risk factors for hypertension [23]–[25]. However, little has been done investigating the influence of these established risk factors and other associated factors on hypertension among the population of motorcycle taxi drivers in Tanzania and in the Kakonko district.

We studied the prevalence of hypertension and its associated factors among young adults who are motorcycle taxi drivers in Kakonko district, Kigoma region, western Tanzania. The results of this study are essential for the formulating health policies to improve the diagnosis, prevention and management of hypertension in Tanzania.

Method

Study Area

Kakonko district is located within the Kigoma region in western Tanzania close to the Burundi border. According to the Tanzania census of 2022, the district had a population of 178,419 of which female were 91,731 and male were 86,688, of which 24,675 are individuals aged 20–29 years,16,571 are aged 30–39, and 12,336 are aged 40–49 years [26].

Study Design and Population

We conducted descriptive and cross-sectional among a population of motorcycle taxi drivers in the Kakonko district between September and November 2024. Age was not an exclusion criterion; however, we included only males because there was no female motorcycle taxi driver during the period of data collection in the district. We excluded all those who refused to consent.

Motorcycle taxis are the most common sources of income for individuals aged 18 to 45 in the Kakonko district. Historically, Motorcycle taxis are believed to have begun in the year 2003 in Tanzania. It is a rapidly growing business in Sub-Sahara Africa, and a major source of employment to youth [22]. In Tanzania and other East African countries, they are famously known as Boda Boda. Its major means of transport carrying passengers from one point to another. Typically, one motorcycle cycle carries one passenger at a time and payment rate depend on the distance of travelling.

Sample Size, Sampling, and Sampling Techniques

We used the formula below to find out the minimum sample size.

We used a prevalence (P) of 21.3% from a study by Umegbolu and Ogamba [7] to estimate the sample size:

$$\begin{array}{r}N=P(1-P)\times {\left(\frac{Z}{E}\right)}^2\end{array}$$

where P is 21.3%.

$$\begin{array}{r}N=0.213(1-0.213)\times {\left(\frac{1.96}{0.05}\right)}^2=257.6\end{array}$$

Therefore, the minimum calculated sample size was 258. We used purposive sampling techniques to select 270 participants in 20 villages of Kakonko district.

Data Collection Tools and Instruments

We used a paper-based questionnaire to collect and record data on socio-demographic, behavioral, blood pressure and anthropometrics. We designed the questionnaire based on previous studies [15], [27]. The questionnaire comprises questions on Age, alcohol consumption, cigarette smoking, family history of hypertension, duration of motorcycle driving, BMI, duration of sleeping, and eating (fruits/vegetables). Data was collected at a nearby pre-determined office either at the health center, village office, or prepared location adjacent to a motorcycle taxi station. The written consent was taken before actual data collection. The participants were consecutively enrolled until the final sample size was attained.

Collection of Socio-Demographic and Behavioral Information

The socio-demographic and behavioral information was collected through face-to-face interviews by enumerators using a study questionnaire. The socio-demographic information collected included age, home address and behavior information including duration of sleeping, eating fruits/vegetables, smoking and drinking alcohol.

Measurement of Blood Pressure and Anthropometrics

The blood pressure (BP) and anthropometric was measured and recorded by trained enumerators using a study questionnaire. BP was measured using a mercury sphygmomanometer and listening for Korotkoff sounds with a stethoscope. BP was taken with a participant in a sitting and relaxed position with both arms raised at the level of the chest. Two readings were taken at the intervals of 5 minutes and an average from two readings was calculated. Body weight in Kg was taken with the participants in light clothing using a SECA scale. Height (to the nearest 0.5 cm) was measured using a stadiometer with participants wearing no shoes. Weight and height were used to calculate Body mass index (BMI) in kg/m².

Exposure and Outcome Variables

The dependent variable (outcome variable) was hypertension defined as systolic blood pressure (SBP) ≥ 140 mm Hg and or diastolic blood pressure (DBP) ≥ 90 mm Hg.

The independent variables (exposure) of interest were Age, alcohol consumption, cigarette smoking, family history of hypertension, duration of motorcycle driving, BMI, duration of sleeping, and eating (fruits/vegetables).

Statistical Analysis

We used Stata version 16 for data analyses. Hypertension was defined as SBP ≥ 140 mmHg and or DBP ≥90 mmHg using the average of two readings, BMI in kg/m² was defined according to WHO criteria as <18.5 kg/m² (underweight), 18.5—24.9 kg/m² (normal), 25.0—29.9 kg/m² (overweight), and ≥30.0 kg/m² (obesity).

We used both univariate and multivariate logistic regression to check whether there is an association between exposure and outcome variable of interest. We treated the outcome variable hypertension as dichotomous, and we considered 95% confidence interval and P value ≤ 0.05 as significant value.

Ethical Consideration

The study was approved by the National Health Research Ethics Committee (NatHREC), reference no: NIMR /HQ/R.8a/VOL.IX/4660.

Results

Baseline Characteristics

We included 312 male motorcycle taxi drivers in the final analysis. The mean age of the participants was 30.3 years. Majority of participants were aged ≤40 (84.5%), Smoking cigarrete (4.2%), drinking alcohol (26.0%), family history of hypertension (8.0%), either obese or overweight 108 (34.6%) duration of driving motorcycle >5 years (26.0%), sleeping duration <7 hours (26.6%), eating vegetable or fruits at least 5days per week (37.6%) (Table I).

Table I. Participant Characteristics

Characteristics	Population overall (N = 312)
Age groups (years)
18–29	175 (56.1%)
30–39	89 (28.5%)
40–49	39 (12.5%)
≥50	9 (2.9%)
Smoking cigarrete
No	299 (95.8%)
Yes	13 (4.2%)
Drinking alcohol
No	231 (74.0%)
Yes	81 (26.0%)
Family history of hypertension
No	287 (92.0%)
Yes	25 (8.0%)
Body mass index (kg/m2)
Underweight	3 (1.0%)
Normal	201 (64.4%)
Overweight	80 (25.6%)
Obesity	28 (9.0%)
Duration of driving boda-boda (years) a
≤5	231 (74.0%)
>5	81 (26.0%)
Eating vegetables/fruits b
No	194 (62.4%)
Yes	117 (37.6%)
Sleeping duration during night (hours)
7–9	229 (73.4)
<7	83 (26.6)

Prevalence of Hypertension

Out of all participants, 108 (34.6%) had hypertension defined as SBP ≥ 140 mmHg and DBP ≥ 90 mmHg. Among those with hypertension 81 (65.0%) were aged below 40 years old, and 54 (50.0%) were either obese or overweight (Table II).

Table II. Factors Associated with Hypertension

Characteristics	Prevalence (%)		Total (N = 312)
	Normotensive	Hypertensive
Age groups (years)
18–29	134 (65.7%)	41 (38.0%)	175 (56.1%)
30–39	49 (24.0%)	40 (37.0%)	89 (28.5%)
40–49	17 (8.3%)	22 (20.4%)	39 (12.5%)
≥50	4 (2.0%)	5 (4.6%)	9 (2.9%)
Smoking cigarettes
No	197 (96.6%)	102 (94.4%)	299 (95.8%)
Yes	7 (3.4%)	6 (5.6%)	13 (4.2%)
Drinking alcohol
No	155 (76.0%)	76 (70.4%)	231 (74.0%)
Yes	49 (24.0%)	32 (29.6%)	81 (26.0%)
Family history of hypertension
No	192 (94.1%)	95 (88.0%)	287 (92.0%)
Yes	12 (5.9%)	13 (12.0%)	25 (8.0%)
Body mass index (kg/m 2 )
Underweight	3 (1.5%)	0 (0.0%)	3 (1.0%)
Normal	147 (72.0%)	54 (50.0%)	201 (64.4%)
Overweight	41 (20.1%)	39 (36.1%)	80 (25.6%)
Obesity	13 (6.4%)	15 (13.9%)	28 (9.0%)
Duration of driving boda-boda (years)
≤5	151 (74.0%)	80 (74.1%)	231 (74.0%)
>5	53 (26.0%)	28 (25.9%)	81 (26.0%)
Eating vegetable/fruits a
No	124 (60.8%)	70 (65.4%)	194 (62.4%)
Yes	80 (39.2%)	37 (34.6%)	117 (37.6%)
Sleeping duration during night (hours) b
7–9	156 (76.5%)	73 (67.6%)	229 (73.4%)
<7	48 (23.5%)	35 (32.4%)	83 (26.6%)

Factors Associated with Hypertension

factors that were positively associated with hypertension and were statistically significant at 95% confidence interval and P value ≤ 0.05 during both univariate, and multivariate logistic regression were age above 30 years old, overweight and obesity (Tables III and IV).

Table III. Univariate Analysis of Factors Associated with Hypertension

Characteristics	n	Odds ratios (95%CI)	P-value
Age groups (years)
18–29	Reference
30–39	89	2.6 (1.54–4.60)	<0.001
40–49	39	4.22 (2.05–8.71)	<0.001
≥50	9	4.09 (1.5–15.93)	0.043
Smoking cigarettes
No	Reference
Yes	13	1.66 (0.54–5.06)	0.376
Drinking alcohol
No	Reference
Yes	81	1.33 (0.79–2.25)	0.283
Family history of hypertension
No	Reference
Yes	25	2.19 (0.96–4.99)	0.062
Body mass index (kg/m 2 )
Underweight	Empty
Normal weight	Reference
Overweight	41	2.59 (1.51–4.43)	0.001
Obesity	28	3.14 (1.40–7.02)	0.005
Duration of driving boda boda (years)
≤5	Reference
>5	81	0.99 (0.59–1.69)	0.992
Eating vegetable/fruits a
No	Reference
Yes	117	0.82 (0.50–1.33)	0.423
Sleeping duration during night (hours) b
7–9	Reference
<7	83	1.56 (0.93–2.61)	0.093

Table IV. Multivariate Analysis of Factors Associated with Hypertension

Characteristics	n	Odds ratios (95%CI)	P-value
Age groups (years)
18–29	Reference
30–39	89	2.56 (1.41–4.65)	0.002
40–49	39	5.16 (2.27–11.71)	<0.001
≥50	9	6.76 (1.57–27.07)	0.010
Smoking cigarettes
No	Reference
Yes	13	1.71 (0.50–5.82)	0.388
Drinking alcohol
No	Reference
Yes	81	1.52 (0.84–2.75)	0.162
Family history of hypertension
No	Reference
Yes	25	2.07 (0.84–5.13)	0.116
Body mass index (kg/m 2 )
Underweight	Empty
Normal weight	Reference
Overweight	41	2.37 (1.31–4.26)	0.004
Obesity	28	2.42 (1.01–5.77)	0.047
Duration of driving boda boda (years)
≤5	Reference
>5	81	0.44 (0.23–0.86)	0.015
Eating vegetable/fruits a
No	Reference
Yes	117	0.89 (0.51–1.54)	0.667
Sleeping duration during night (hours) b
7–9	Reference
<7	83	1.72 (0.98–3.04)	0.059

As shown in Table IV, age group 30–39, (OR = 2.56 [1.41]–[4.65]), 40–49, (OR = 5.16 [2.27]–[11.71]), ≥50, (OR = 6.76 [1.57]–[27.07]), overweight, (OR = 2.37 [1.31]–[4.26]), Obesity, (OR = 2.42 [1.01]–[5.77]), were all associated with increasing odds of being hypertensive and the association was statistically significant. Also, smoking cigarette, (OR = 1.71 [0.50]–[5.82]), drinking alcohol, (OR = 1.52 [0.84]–[2.75]), family history of hypertension, (OR = 2.07 [0.84]–[5.13]), sleeping <7 hours, (OR = 1.72 [0.98]–[3.04]), were all positively associated with hypertension though the association was statistically insignificant. On the other side, eating vegetables or fruits at least 5 days per week is protective against hypertension (OR = 0.89 [0.51]–[1.54]).

Discussion

In this study of male motorcycle taxi drivers in Kakonko district, Kigoma region, western Tanzania we found a high prevalence of hypertension (nearly 35%). In our study, we found that hypertension was positively associated with increasing age and being overweight or obese.

The high prevalence observed in our study is similar to previous studies among the population of young adults [7], [12], [13]. However, the study population in our current study was male motorcycle taxi drivers while previous studies recruited young adults either students or from the general population and both sexes were included.

Our study has demonstrated that hypertension is of great concern at a tender age. Out of all 44 participants with hypertension, 19 participants were aged below 40 years. This reflects the increasing burden of hypertension among the population of young adults, similar to what has been reported in previous studies of young adults. Evidence has shown that untreated hypertension in young adults in most cases will progress into adulthood [7]. This emerging data are of great concern hence additional efforts are required to address the burden of hypertension among the population of young adults. To be specific, more efforts are required, especially on screening programs, health education, treatment of hypertension and further research. This will reduce hypertension-related mortality and morbidity in later years of life.

We observed a positive association between BMI and hypertension. Motorcycle taxi drivers who are Obese and overweight are more likely to have hypertension (Table IV). The influence of obesity and overweight on hypertension has been established before [15], [28]. In sub-Saharan Africa including Tanzania, the life systyle has changed over the past few decades where people are enjoying a sedentary lifestyle which might contribute to increasing the burden of hypertension [29]. Therefore, intervention for hypertension must also put much emphasis on addressing the problem of obesity and overweight.

Our study has also shown a positive association between the duration of sleep and hypertension. The odds of being hypertensive among those who sleep less than 7 hours was 1.72 (0.98–3.04) compared to those sleeping 7–9 hours (Table IV), though the association was statistically insignificant. The findings in our current study are similar to previous studies [30]–[32]. Because of their job, some motorcycle taxi drivers spend most of their time (days and nights) working to generate income to feed their families. This might lead them to sleep less, hence increasing their risk for hypertension. Although underlying mechanisms of which short sleep causes hypertension have not been fully established but have been linked to increased sympathetic activity and reduced parasympathetic activity during sleep [33], [34].

Although we established a positive association between a family history of hypertension, smoking cigarettes, drinking alcohol, and hypertension, the association remains statistically insignificant in our current study (Table IV) possibly because of underreporting smoking cigarettes and drinking alcohol fear of social stigma and social disapproval. The family history of hypertension may have been underreported because of difficulty with recalling past information and the difficulty for family members to share their health information with one another. Also, the majority of families in our district are unaware of their hypertension status, therefore it is unlikely for a member of the family to tell exactly whether there is a positive history of hypertension in the family or not. To address this, community-based screening of Blood pressure is required and establishing hypertension registry and clinics at the primary health care. Both family history of hypertension, smoking cigarettes, and drinking alcohol are well-documented predictors of hypertension [5], [15], [16].

In addition, our current study demonstrated the protective effect of eating vegetables or fruits on hypertension (Table IV). This finding is similar to previous studies [12], [35]. However, compared to previous studies, our current study recruited only male participants while previous studies recruited both sexes. Despite the difference, both studies demonstrated a protective effect of eating vegetables or fruits to hypertension. Fruits and vegetables contain high levels of potassium which can reduce blood pressure [35]. Also, fruits and vegetables can reduce overweight and obesity, the two strongest risk factors for hypertension [35]. We recommend further studies, especially cohorts, to investigate the influence of fruit and vegetable consumption on the risk of hypertension.

Our study had some strengths and limitations. The strength of this study is that we successfully enrolled in a population of motorcycle taxi drivers, the majority being young adults aged below 40 years. We successfully investigated and reported the prevalence of hypertension among this population group, hence contributed to a growing body of literature.

The limitation is that being cross-sectional it is impossible to establish causality. Also underreporting behavioral factors such as smoking and drinking alcohol was more likely because of social stigma and social disapproval. Sex comparison was impossible because the study recruit only male participants.

Conclusion

The prevalence of hypertension among male motorcycle taxi drivers in Kakonko district, Kigoma region, western Tanzania is high. Both increasing age, overweight and obesity are strongest predictors of hypertension. The interventions for hypertension must also put much emphasis on addressing the problem of obesity and being overweight. longitudinal studies are required to investigate more hypertension and associated factors among the population of young adults.