Study design and site
The study was a community- based cross sectional study. Recruitment and data collection were conducted in July 2019, at Moshi Municipal, situated in Kilimanjaro region in the northern Tanzania.
Kilimanjaro is one of the 31 regions found in northern zone of Tanzania. It is the home of 1.64 million people according to 2012 census. Moshi municipal is one of the seven district of Kilimanjaro region. It has 21 wards and covers an area of 59 km2. The municipal has a population of 184,292 where males are 89,174 and females are 95,118 according to 2012 census.
Study population, sampling and data collection procedures
Population
The study population was men aged at least 18 years in selected wards of Moshi Municipal and consented to participate in the study. The study excluded men who are not permanent residents in the study area.
Sample size
Sample size for this study was estimated by using the formula for precision
$$ \mathrm{N}={\mathrm{Z}}^2\mathrm{p}\ \left(1-\mathrm{p}\right)/{\upvarepsilon}^2 $$
Where N is estimated minimum sample size; Z is confidence level at 95% (standard value is 1.96); P is proportion of ED in population based on study by Pallangyo et al., where the prevalence of ED was 24% [12] and ε is precision at 95% CI = 0.05.
The minimum sample that was required for this study was 346 men. Addition of 10% for non-response gave a minimum sample of 381 men aged at least 18 years.
Sampling
Multistage sampling technique was used to obtain men who participated in the study. The multistage sampling techniques involved the following stages. Stage 1: 4 out of 21 wards that make up the municipal were randomly selected. Stage 2: Two streets from each of the selected ward were randomly selected: At Majengo ward, Shauri moyo and Sokoni streets, were randomly selected. At Mji Mpya ward, Sokoni and Langoni streets were randomly selected. At Kiboriloni ward, mnazi mmoja and Kilimanjaro District Council (KDC) streets were randomly selected. At Rau ward, Saba saba and Karikacha streets were randomly selected. From these streets, men aged 18 years and above who consented to participate in this study were recruited.
Study procedures
Ethical clearance was obtained from the Kilimanjaro Christian Medical University College (KCMUCo) Ethical committee before starting the research. The ethical clearance was delivered to District Medical Officer (DMO) of Moshi Municipal, where permission to conduct the study was sought from the DMO office. DMO gave us introductory letter that was presented to Ward and streets leaders. The ward and street leaders were all informed about their key role of introducing researchers to the community and help to inform adult males about the study prior to the beginning of the study.
After reaching to the center which was established, at respective wards those who were eligible and consented to participate were interviewed. The interviews were conducted by three medical students who were in their 4th year of training and have rotated in the urology department for four weeks. They underwent training by the consultant urologist (OM) for 3 days before commencement of data collection. This was followed by general clinical examination and measurement of the blood pressure (BP), anthropometric measurements and taking blood for Random blood glucose level (RBG) measurement. The interviews and clinical examination were conducted in private room which was either a ward executive officer office or room at a local clinic. After the test participants were informed the results of BP, overweight/obesity and RBG on the same day.
Those found with confirmed either diabetes or hypertension were informed about their results and then referred to the nearby health centre. Those with erectile dysfunction were referred at KCMC referral hospital urology clinic where there is expertise to manage the condition. The physician responsible was then informed about their health status through a referral letter. They were also given advice on diet, physical activity, on salt and alcohol intake.
Data collection tool and methods
Data collection tools
Data was collected using a questionnaire which had both open and closed ended questions and was in Swahili language. The questionnaire had three sections, the first part collected information on socio-demographic characteristics, and the second part assessed the behavioural characteristics of the participant. The third part was clinical examination. The validated Swahili-translated 5-item version of the international index of erectile function (IIEF-5) scale was used to assess erectile dysfunction.
Data collection methods
Face to face interview was used to collect information from the consented participant. Blood pressure was measured twice before and after the interview. Weight (kg), height (cm), blood sample (finger prick) was collected to check for random blood glucose (RBG). Data collection process took place privately in a selected room (i.e. ward executive office).
Anthropometric measurement
Weight in kg was measured using weighing machine (SECA brand) participants were requested to remove shoes, extra clothing like jackets and anything in pockets before measurements. Height was measured with a height stadiometer where by individual stood upright with no shoes and the ruler hook was placed such that it just touches the head then the height in cm was recorded. Body Mass Index (BMI) was calculated by a ratio of weight (in kilograms) to height (in meters) squared. BMI cut-off values of World Health Organization (WHO) were used.
Blood pressure measurements
Blood pressure was measured by manual BP machines. BP was recorded from the left arm using an appropriate size cuff that covers two – third of the upper arm after the participant rested for at least five minutes and no smoking or caffeine 30 min before measurements, with the arm supported at the level of the heart, palm facing upward. Two measurement were taken at the start of interview and at the end in a sitting position while the participant rested quietly, then the average of the two measurement was recorded.
Blood glucose measurements
Random Blood glucose was measured using a blood glucose monitor (GlucoPlus brand). Blood sample was collected through finger pricking and dropped on glucometer strip to give the reading.
Data analysis
The data was entered and analysed using SPSS 20. Before analysis, data was cleaned by running frequency of each variable. Categorical variables were summarized into frequency and percent while continuous variables were summarized using measures of central tendency and their respective measure of dispersion. Odds ratio with their 95% confidence interval were used to measure the strength of association between age, alcohol drinking, tobacco use, physical activities, overweight/obesity, hypertension, diabetes mellitus and erectile dysfunction. Multivariable logistic regression analysis was conducted to control for confounders and get independent predictors for erectile dysfunction. P-value of < 0.05 was considered statistically significant.
Categorization of variables
ED was assessed using IIEF with 5 questions each with scale of 5. Maximum possible score is 25 and minimum score is 5. The IIEF-5 scale categorizes ED into five categories depending on the score i.e. 22–25: no ED, 17–21: mild ED, 12–16: mild to moderate ED, 8–11: moderate, 5–7: severe ED.
A systolic blood pressure (SBP) < 120 mmHg and a diastolic blood pressure (DBP) < 80 mmHg was defined as normotensive. Pre- hypertension was defined as SBP of 120–139 mmHg or DBP of 80–89 mmHg, while SBP ≥140 mmHg or DBP ≥90 mmHg indicated hypertension.
Diabetes was defined as RBG ≥11.1 mmol/L. Prediabetes was defined as RBG of 7.8–11.0 mmol/L.
WHO BMI cut-off values were used. Underweight was defined as BMI of < 18.5 Kg/m2, normal was defined as BMI of 18.5–24.9 Kg/m2, overweight was defined as BMI of 25–29.9 Kg/m2 and obese was defined as BMI of ≥30 Kg/m2.
Physical inactivity was defined as having less than 150 min of moderate to vigorous -intensity physical activity throughout the week.
