Study Design and setting
A cross-sectional study was conducted from 15, April to 25, May 2020 in Sawula and Bulky towns. Sawula and Bulky towns are found 514 kilometers and 531 kilometers away from Addis Ababa (the capital city of Ethiopia), respectively. Based on the 2020 report obtained from the Sawula and Bulky towns’ health offices, Sawula town has ten kebele (the smallest administrative unit next to district) and Bulky town has five kebele. Sawula and Bulky towns had a total population of 46,957 and 25,000; and households 9,582 and 5,201 respectively [28, 29]. Sawula town has one government general hospital, one health center, twelve private clinics[28]. The bulky town has one health center and four private clinics[29]. A motorcycle is the common mode of transportation both in Sawula and Bulky towns. The towns were purposely selected considering factors like researchers’ familiarity with the study area and resource issues. Both towns are rapidly increasing in population size and economic growth among the towns of Gofa Zone, Southern Ethiopia.
Population and sampling
The source populations were all motorcycle drivers in Sawula and Bulky towns. Study populations were all randomly selected motorcycle drivers who were driving a motorcycle in the past three months before the study period. All motorcycle drivers who drive a motorcycle in the past three months before the study period were included in the study. Whereas, motorcycle drivers who were unable to communicate or severely ill during the data collection period and those who live in the study areas for less than six months were excluded.
The sample size was calculated using a single population proportion formula with the assumption of 50% proportion of helmet wearing (since the were no studies in Ethiopia that can address these objectives), 1.96 standard normal distribution curve value for 95% level of confidence, and 5% margin of error between the sample and the population. Finally, considering a non-response rate of 10%, the total sample size was calculated to be 422.
The participants of the study were selected as follows: First, the list of owners of motorcycles, their phone number, and motorcycles’ plate numbers were obtained from the registration books of Sawula and Bulky towns’ road and transportation offices to construct the sampling frame. Accordingly, 500 and 250 owners of motorcycles were identified in Sawula and Bulky town respectively. Then, the sample size was proportionally allocated to the two towns. Finally, computer-generated simple random sampling was used to identify the study participants. Their phone numbers were used to contact the participants. For those whose phone call was not working, their usual place of residence and working area was identified in collaboration with health extension workers. Since the possibility that a motorcycle may not be ridden by the owner and/or the existence of more than one rider for a single motorcycle; individuals who commonly drive the motorcycle during the last three months before data collection were selected after information from the owner of the motorcycle. In case when difficult to know who commonly drives the motorcycle, a lottery method was used to select them.
Data collection tools and procedures
An interviewer-administered structured questionnaire was adapted from different related literature [30-33]. It was initially prepared in English language and then translated to the local language (Gophigna and Amharic) and back-translated to English language by an independent translator to check for consistency of meaning. The questionnaire comprised of socio-demographic and economic characteristics, driving-related factors, substance use, and knowledge about helmet, perceived susceptibility, perceived severity, social pressure, and helmet wearing related questions. Perceived susceptibility, perceived severity, and social pressure were assessed using a five-scale response format, where: 1= strongly disagree, 2= Disagree, 3 = Neutral, 4= Agree, 5= strongly agree). Accordingly, perceived susceptibility and perceived severity were assessed by four items, and social pressure related to helmet wearing was assessed by five items. Knowledge about helmet was assessed by three items in ‘Yes or No’ format. A correct answer was coded as “1” and an incorrect answer was coded as “0”. Helmet wearing was assessed by two questions: One yes or No question (Have you used helmet prepared for motorcycle drivers in the past three months during driving?) and for those who answered “yes” to the first question, they were asked one additional three Likert scale question (How often do you wear?) with the response options of 1= Rarely, 2= Sometimes and 3= Always. A pretest was conducted on 5% of the total sample size in shefite town and some modifications were done based on the findings. The internal consistency of the items was checked using Cronbach’s alpha (α). Accordingly, the alpha of perceived susceptibility α = 0.98, perceived severity α = 0.85 and social pressure α = 0.91.
Six data collectors (four BSc Nurses and two diploma Nurses) and two supervisors (Health Officers) were involved in the study. One day intensive training was given to data collectors and supervisors on the aim of the study, data collection instruments, research ethics, and approaches to study participants. Data collection was conducted at the workplaces, main parking areas, and the area where traffic police monitor the drivers (police stations). Close supervision during data collection, daily feedback, and proper cleaning before and after entry, was made seriously. In addition to supervisors, the authors coordinated the data collection, made site visits, and oversaw the whole process and then if any inconsistency and errors were checked and solved immediately.
Operational Definitions and Measurements
In this study, motorcycle riders were considered as “wear helmet” if they were always wearing helmet for the sake of reducing motorcycle injuries while they drive in the last three months before the study period. That means, respondents who “hadn’t worn, wear rarely and wear sometimes” were considered as “Not wearing helmet” and those who “wear always” were considered as “Wearing helmet”.
To measure perceived susceptibility, perceived severity, and social pressure; subscale scores were computed by summing item scores and dividing by the total number of items. Then, dichotomization was made by taking mean as a cut of point. Scores above or equal to the mean scores were considered as “high” and scores below the mean score were considered as “low”. Knowledge about helmet was measured by computing a total score after summing up all three items together. Then, respondents were considered as “knowledgeable” if they scored above or equal to the mean value otherwise considered as “less knowledgeable”.
Social pressure: Any influence made on the motorcycle drivers from his friends and/or families and/or community to wear helmet.
Data analysis
The collected data were entered into Epidata version 3.1 and then exported to SPSS version 23 for analyses. Descriptive statistics like frequencies, proportions, means and standard deviations were done for different variables. Binary logistic regression analysis was carried out to select variables for multivariable regression analysis. Accordingly, variables with a p-value < 0.25 in the binary logistic regression analysis were taken as candidates for multivariable regression analysis. Finally, multivariable logistic regression analyses were performed to control for the possible confounding effect of the selected variables. Crude and adjusted odds ratio, and 95% CI were used to determine the magnitude of the association. Variables with a p-value of < 0.05 were taken as statistically significant determinants for wearing helmet. Model fitness was checked using Hosmer and Lemeshow goodness of a fit test and the model test P-value was found to be 0.10. Finally, results were presented in the form of tables, figures and narratives.
Ethical Approval
Ethical clearance was obtained from the Research and Ethical Review Committee of Jimma University. Permission letter was secured from Sawula and Bulky towns Health Offices, and road and transportation offices. Written informed consent was taken from each study participant. For participants under 18 years old, the written consent was obtained from their parents. All participants were informed about the purposes and benefits of the study. They were informed that participation in the study is voluntary and that they can refuse to participate or withdraw from the study without any penalties. Moreover, the participants were reassured that their responses were kept confidential.