Introduction

Occupation and health interact with one another. The work environment and the nature of job contribute significantly in the causation of diseases. Professional driving is associated with long hours in a single body posture, under exposure to vibration, vehicle exhaust, and noise. Furthermore, the work is performed in an environment that demands constant vigilance. There are, however, many specific diseases for which significantly increased risks of mortality and morbidity have been reported. In a retrospective cohort study of incident cancers among Danish bus and tram drivers during 1943-92, increased risks were reported for cancer in the lung, larynx, pharynx, bladder, kidney, skin, rectum, and liver. ¹ Among lorry drivers an increased mortality has been found for multiple myeloma, ² colon cancer, laryngeal cancer, lung cancer, diabetes, non-alcohol related cirrhosis, and motor vehicle accidents. ³ Professional driving has also been associated with a high relative risk for ischemic heart disease (IHD), ⁴ , ⁵ , ⁶ stroke, prolapsed lumbar disc, ⁷ prolapsed cervical disc, ⁸ pain in neck and back, ⁹ , ¹⁰ gastrointestinal disorders, ¹¹ , ¹² , ¹³ , ¹⁴ and chronic obstructive pulmonary disease (COPD). ¹³

Several studies has been conducted among professional drivers to identify occupational diseases. ¹⁰ , ¹¹ , ¹² , ¹³ Low back pain is a major cause of disability among these working population and has a significant socioeconomic impact. To identify occupational diseases, many investigators have examined the effects of occupational activities. A review of the literature showed that results regarding effects of occupational activities, such as lifting heavy loads sedentary work or physically hard work and driving motor vehicles, were fairly consistent indicating that exposure to these factors increased the risk of occupational health diseases. ² , ¹⁴ , ¹⁵

Population-based surveys have also shown associations between work factors and musculoskeletal disorders. Some have focused on physical factors, for example, sitting, driving, lifting, awkward postures, and vibration in an Ontario provincial survey. ¹⁴ Others have included psychosocial items at work, such as job dissatisfaction in a Belgian national survey. ¹⁵ More comprehensive surveys have included both physical and psychosocial work factors-for example, associations between back pain and each of physically heavy, monotonous, and repetitive work among adults. ¹⁶ , ¹⁷ , ¹⁸ , ¹⁹ There are few studies in Nigeria that have examined occupational health diseases among professional drivers. This study was, therefore, designed to screen for and describe common occupational health diseases among professional drivers in Sagamu, Nigeria.

Methods

Study design

This study is an analytical cross-sectional study. The information was collected from professional drivers in the five interstate motor parks including the cement factory [WAPCO] in Sagamu local government area in Ogun State from February 25, 2007 to March 15, 2008.

The study area

The study was conducted in Sagamu local government area (SLGA) in Ogun state, which is located in the South Western part of Nigeria. Sagamu local government area is one of the 20 local government area in Ogun state. It was carved out of the former Ijebu Remo local government in 1991 and has a total land area of 68.03 km ². It is bounded on the west by the Obafemi Owode local government area, on the east by both Ikenne and Odogbolu local government area, and also shares a boundary with Ikorodu local government area of Lagos state in the south.

According to the 2006 census, the area has a population of 253,412 inhabitants which consists of mainly remo-speaking people of Ogun state. Other ethnic groups like the Hausas, Igbos, and the Benue people are well represented. Most of the towns are either semi-urban or rural. Other major towns in the local government besides Sagamu include Ogijo, Sotubo, Ode-lemo, Emuren, and Simawa. The local government has 15 political wards, 12 of which fall within the Sagamu metropolis. This area is a major transit region between the southwest, southeast, and the northern part of Nigeria.

Sampling technique

This study is a cross-sectional study. Total sample of all the consenting professional drivers in the five interstate motor parks including the cement factory [WAPCO] in the local government area were recruited into the study. An interviewer administered structured questionnaire was administered by trained health workers and respondents were screen for common occupational health problems.

Sampling size determination

The sample size was calculated using Epi-Info version 6.0 statistical software. The result of a previous study ⁴ that showed prevalence of condom use among PLWAs was used.

The sample size used for this study was calculated with the formula

n = z ²pq/d ²

n = 1.96 ²× 0.35 × 0.65/0.05 ²= 350

However, a total of four hundred participants {400} were recruited into the study.

Study instrument

The factors examined in the study include socio-demographic characteristics (age, sex, income, education, religion, marital status, occupation, place of residence), illness related factors, service related factors, psycho-social factors, and behavioural factors.

Screening for health condition was carried out by physicians. Hypertension was screen for using sphygmomanometers, Short sightedness using Snellen′s chart, etc.

The Questionnaire was pre-tested on 20 transport workers in Ikenne local govt area and necessary adjustments were made. Trained data collectors explained the aim of the study, obtained informed consent, and interviewed each respondent privately. All information was obtained under anonymity.

Ethical considerations

Ethical clearance was obtained from the Olabisi Onabanjo Teaching Hospital Ethics Board. Confidentiality on candidate′s information was maintained. Permission of the Chairman of the road transport workers in Sagamu local government area was obtained before the commencement of the study.

Data analysis

To describe respondent′s characteristics, we calculated proportions and medians. For categorical variables, we compared proportions using Chi-square tests and, when appropriate, Fisher′s exact test. For continuous variables, we compared medians using the Wilcoxon Rank-Sum Test. Chi-square was used to determine association between categorical variables and a P value of less than 0.05 was considered significant. Data was presented in tabular form.

Results

Socio-demographic characteristics of respondents

A total of 400 professional drivers were recruited into the study. The age of the respondents ranged from 21 to 62 years, (mean 41.07 ± 6.13 years). About half, 208 [52.0%] of the respondents were married, 126 [31.5%] were never married, 21 [5.3%] were separated, 22 [5.5%] divorced, and 23 [5.8%] were widower. More than half, 59.3% of the respondents were Christians, 39.3% were Muslims, and 1.3% were traditional worshippers. Fifty-eight percent {232] were of the Yoruba tribe, 18.0% were Igbos, 10.8% were Hausas, and 13.3% were from other tribes. About 10.5% of the respondents had a post secondary education, 38.0% have completed a secondary education, 40.3% had a primary education, and 11.3% had no education at all. This is as shown in Table 1.{Table 1}

More than half, 232 [58.0%] of the respondents work for about 12 hrs daily while 82 [20.5%] work for less than 6 hrs daily and 86 [21.5%] work for between 6-11 hrs daily. Few, 30 [7.5%] of the respondents had worked for more than 10 yrs, 154 [38.5%] for 6-10 yrs and 226 [54.0%] for less than 5 yrs. This is as shown in Table 2.{Table 2}

Majority, 313 [78.3%] of the study participants had multiple sexual partners with 241 [60.3%] of these respondents using condom regularly. Only 55 [13.8%] have ever tested for HIV/AIDS. Among 352 [88.0%] professional drivers, myalgia was the most prevalent occupational health problem. This was followed by hypertension 90 [22.5%], then road traffic accident in the last one year 52 [13.0%], and short sightedness 41 [10.3%]. Others were upper respiratory tract infection 20 [5.0%], sexually transmitted diseases 15 [3.8%], and hearing problems 4 [2.8%]. This is as shown in Table 3.{Table 3}

Discussion

Among 352 [88.0%] professional drivers, musculo-skeletal pain/injury was the most prevalent occupational health problem. Several studies have reported similar findings. ²⁰ , ²¹ , ²² , ²³ , ²⁴ , ²⁵ , ²⁶ , ²⁷ Driving has been found to be a major occupational risk factor for musculoskeletal injuries. Occupational exposures including vibrations affecting the whole body, physically hard work, frequently twisting or bending, standing up, and concentration demands are risk factors for musculoskeletal pain, which is a major cause of disability among the working population and has a significant socioeconomic impact. ²⁸ , ²⁹ Health education to the professional drivers should ensure education on prevention and care of musculo-skeletal injuries with adequate attention to their health seeking behaviour.

The study suggests an increased risk for hypertension and other heart diseases such as myocardial infarction. This has been reported in several studies done among professional drivers ³⁰ , ³¹ , ³² but there are also some studies where this was not found. ³³ , ³⁴ The evidence for an increased risk of hypertension and myocardial infarction seems to be stronger among bus drivers than among other groups of drivers. A combination of high psychological demands and low control at work (job strain) has been proposed as being associated with an increased risk of developing coronary heart disease. This theory, the Karasek-Theorell hypothesis, has gained support from several epidemiological studies.

The study shows that the long distance professional drivers in Western Nigeria were a high risk group for sexually transmitted diseases. This has been reported by several studies. ³⁵ , ³⁶ , ³⁷ This implies that correct attitude towards HIV and other sexually transmitted diseases should be encouraged. Campaigns on safer sex practices and the use of condom should be embarked upon by the various bodies responsible for monitoring the activities of the professional drivers.

The study shows that the long distance professional drivers were a high risk group for short sightedness. Short sightedness has been identified as a risk factor for road traffic accident and may be responsible for a considerable number of accidents which occurred among the study participants. This may imply that the prevention and control of this common disease among the drivers will lead to reduction of road traffic accidents in Western Nigeria and other low income countries. We suggest that periodic examination of drivers should be embarked upon by the road safety officials in order to reduce the incidence of road traffic accident among these professional drivers.

The results of this study should be interpreted cautiously. First, the study was conducted at the motor-parks. This setting may stimulate study participants and overestimate risk perception and positive mental attitude towards these diseases. The study was also limited in that it relied on self-report, and is, therefore, subject to reporting bias. This will have implications for interventions focused on educating professional drivers in a typical African population on occupational diseases associated with their profession and sensitize them to its prevention.

Conclusions

The study concludes that common occupational diseases among long distance professional drivers in Western Nigeria were myalgia, upper respiratory tract infection, hypertension, short sightedness, sexually transmitted diseases, and RTA. Prevention and control of these common diseases among the drivers will lead to reduction of road traffic accidents in Western Nigeria and other low income countries.