The objective of this study was to determine the prevalence of musculoskeletal disorders (MSDs) among taxi drivers in Cameroon and the factors associated to them. We carried out an analytical cross-sectional study and the prevalence found was 86.8%. The most affected area of the body was the lower back. Frequent carrying of loads was associated with a higher frequency of MSDs. We did not find a significant association between the level of physical activity and MSDs.
The overall prevalence of MSDs among taxi drivers was 86.8%. This prevalence is found in the prevalence range of MSDs among professional drivers reported by the literature. Leonard et al. and Zulkarnain et al. in their respective reviews on MSDs in professional drivers found prevalences ranging between 43.1% and 93% [8, 10]. This large interval can be explained by the data collection method chosen. In some studies, participants having reported of pain or any other related complaint (limiting mobility or discomfort) frequently during the course of the year or who reported that the complaint lasted at least 24 consecutive hours were counted as having MSDs [13, 25]. In the above-mentioned studies, the overall prevalence was lower than those of studies which like ours, took into consideration any occasional musculoskeletal symptom reported by the professional driver. Knowing that before becoming chronic, the clinical picture of MSDs vary greatly with time and the prognostic factors are poorly known, it seemed important to us to report all the possible cases [22]. Abledu et al. [26] (2014) using an approach identical to ours found a prevalence of 70.5% among taxi drivers in Ghana. Similarly, Akinpelu et al. [22] (2011) found a prevalence of 89.3% among professional drivers (bus, taxi) in Nigeria. These two results are similar to ours. The high prevalence found in our study confirms the hypothesis that professional drivers are at high risk of developing MSDs.
The back region was the most affected region as described in the literature [8]. In professional drivers, the back region would be the major site because they have many risk factors for spinal pain compared to the general population, mainly due to vehicle vibrations and also a sedentary lifestyle [27]. Furthermore, in our study, we found a prevalence of 72.8%, which is higher than the 56% estimated in a meta-analysis carried out by Leonard et al. (2020) in a systematic review on the prevalence of MSDs among professional drivers in 04 continents [8]. Our result was different from those found in Ghana and Nigeria where their prevalences were 34.3% and 30% respectively [26, 28]. This difference can be explained by the fact that there were differences in the job tenures of the professional drivers in the different study populations. In the study carried out in Ghana, less than 2% of taxi drivers had worked for more than 12 years; in Nigeria, only 25% of the professional drivers had a job tenure of more than 15 years. Conversely, in our study, almost half of the taxi drivers (43%) had worked for more than 15 years. As MSDs result from chronic exposure to various risk factors, the cumulative exposure over the years to these factors present in our participants’ work environment would explain a higher incidence among them [27]. In addition, a majority of our participants were overweight (47.5%) and 25.8% were obese. This would also tend to explain the high prevalence of MSDs among our study participants. Overweight, in addition to being a cardiovascular risk factor, has been shown to increase the risk of back pain due to the increased physical load exerted on articular discs and the musculoskeletal system of the spine in particular [29, 30].
MSDs were also frequently reported in the neck and knee regions with their prevalences being 42.4% and 29.1% respectively. These results are similar to those of Szeto et al. who found prevalences of 55.6% and 35% among bus drivers in Japan [12]. Magnusson et al. in their study of taxi drivers in Switzerland found the prevalence MSDs of the neck to be 40% [15]. Raanas et al. found a prevalence of 57.8% in the neck region among taxi drivers in Norway [9]. Chen et al. found the prevalence of MSDs of the knee to be 19% in Taiwan [31]. All these results are similar to ours, and from this uniformity one could deduce that the different regions of the body would be subjected to the same exposures irrespective of the professional driver’s horizon.
In our study, 62% of participants had a low physical activity level. Similarly, Marcelo et al. (2014) in their study in Brazil reported that 69.84% of taxi drivers had a physical activity level below the WHO recommendations which recommend a minimum of 150 minutes of moderate physical activity or 75 minutes of intense physical activity per week in order to derive substantial health benefits [32]. This low physical activity level among professional drivers could be explained by their heavy workload, making them unavailable for sporting activities. In our study, 56.3% of taxi drivers worked daily and 58.3% were employed; the status of employee not conferring much decision-making power concerning the worker's schedule. Marcelo et al. (2014) also found that a great number of taxi drivers in Brazil worked every day (43.6%) and when asked the reason for their low physical activity level, the majority of them mentioned the heavy workload [32].
The physical activity level was not significantly associated with MSDs. In contrast, Wang et al. (2017) reported that taxi drivers who had at least one hour of daily physical activity had less back pain than the others and this difference was significant (OR = 2 p < 0.001) [33]. Similarly, Raanas et al. in 2008 found that a low physical activity level was associated with a high frequency of MSDs among taxi drivers in Norway (OR = 1.99 CI = 1.24–3.19) [9]. This disparity in results can be explained by the difference in sample size of the different studies. Indeed, these two studies that found an association, were done on large sample sizes, one of which was 719 and the other 929. However, in our study where this association was not found, the sample size was 151. This could explain the difficulty in highlighting an association. Studies should be performed on larger sample sizes in order to empirically clarify the role of physical activity in the prevention of MSDs.
Although not statistically significant, the habit of frequent naps increased the risk of having MSDs (OR = 4.5). Siestas in the taxi lead to poor postures. These poor postures lead to an excessive force exerted on the joints and the overload of adjacent muscles and tendons [34]. Ranas et al. (2008) found that taxi drivers who reported having frequent naps in the taxi had a higher prevalence of MSDs (OR = 1.63 CI = 1.17–2.26) [9]. It would therefore be wise for taxi drivers to limit naps in the taxi for better musculoskeletal health. Similarly, job tenure greater than 12 years was associated with MSDs (OR = 2.5) and this association was close to significance (p = 0.059). The cumulative effect of years of exposure is thought to be the cause [27]. Similarly, Zulkarnain et al. found in a systematic review among the 14 types of professional drivers including taxi drivers that seniority in the profession was associated with a higher prevalence of MSDs [10]. Other associated factors such as prolonged working hours, the carrying of loads, perceived work-related stress, and job dissatisfaction have been found in other studies but not in ours. This would probably be explained by the size of our sample which did not allow us to unveil some statistically significant associations.
This study has certain limitations. The type of study carried out as well as our sample size did not allow us to properly assess the effect of professional, personal and psychosocial factors in the incidence of musculoskeletal disorders.