Rationale – Bus drivers are well documented to have higher rates of bodily injury, psychological disorders and increased prevalence of hypertension. Yet, the specific causes of these health outcomes are still not well understood particularly with regard to obesity, and cardiovascular illnesses. Drivers are exposed to multiple risk factors on the job while driving that impact their health including noxious chemicals, demanding schedules, potentially dangerous environments including both driving and passengers, as well as a number of psychosocial work stressors such as job strain (work high in demands and low in control) inter alia. (See Special Issue of Studies of Urban Mass-Transit Operators of the Journal of Occupational Health Psychology Vol 3 Nº2, April 1998).
We are particularly interested in the role of work hours, scheduling, deadlines, constraints and organizational psychosocial stressors as they might contribute to fatigue, mental exhaustion, obesity, elevated blood pressure and safety issues. We believe the presence of many of these stressors negatively impacts on the drivers mental functioning and ability to carry out their jobs properly thus contributing to accidents.
I. Possible Goals of this proposed research project
1) To identify and compare the prevalence of accidents, cardio-metabolic risks factors and psychosocial work factors among the country participants
2) To examine the associations between work stressors, in particular psychosocial stressors and accidents, cardio-metabolic risks factors in bus drivers samples from Colombia, México, Switzerland, Poland and the USA.
3) To determine the statistical contribution of different aspects of work, individual factors, job stress (e.g. as explained by the job strain and effort-reward imbalance models) in accidents and cardio-metabolic indicators (e.g. obesity, blood pressure, heart rate) in bus drivers from different countries.
Question to discuss:
It is understood among us that the research goals in each country will reflect the specific problems and needs of each particular country. Nonetheless, the challenge for us is it possible to define a common goal (or goals) for all participant researchers that will allow valuable comparisons between countries. What exposures and outcomes as well as methods should be selected as common? This would be a central issue for discussion at our meeting Saturday am May 18th at 8am.
II. Possible Methods and Procedures
A common design for the International Study could be a cross-sectional study.
A, Outcomes of Interest:
1) Accidents. This variable could be measured by records of the organization or self-report of bus drivers
2) Fatigue and Emotional Exhaustion
3) Metabolic Syndrome: Includes Obesity, Blood Pressure, Glucose, Triglycerides and Cholesterol (depending of selected criteria). Self reported and objective measures of these variables should be discussed.
4) Hearth rate, HRV cardiovascular symptoms.
5) Self reported health and compensation and health insurance claims.
B. Exposures of interest:
1) Universal work place stressors: Job strain, ERI, Job insecurity
Specific work stressors: route, clerical requirements, type of passengers, etc.
2) Work hours
C. Methods of common interest
A. Qualitative methods including focus groups.
B. Ambulatory monitoring
One approach we wish to explore with transit drivers would involve ambulatory monitoring of bus drivers including measuring cortisol, blood pressure, heart rate, heart rate variability and activity with simple and inexpensive monitors that can be worn during working hours.
For this procedure a feasibility study should be carried out or could be completed in sub-samples if it is not possible to do it in the complete sample.
Example of a Bus Driver Feasibility Pilot Study :
Goal: Demonstrate feasibility defined as safety and comfort of collecting ambulatory physiological data in a small group of firefighters.
1) Ambulatory bp (Spacelabs or Omron devices)
2) Cortisol (oral swab)
3) Activity monitor (worn on body)
4) Heart rate and heart rate variability (chest strap). This methodology is highly recojmmended due to ease of use and value of outcome data.
We would need 5-10 volunteers per project to wear equipment.
Key question. Can a Spacelabs ambulatory BP monitor be worn safely while driving?
1) Safety – automated monitor will grab and squeeze are for 45 seconds
2) Can Spacelab’s device obtain a reliable reading while driving?
Need 5-8 readings in a workday of blood pressure to get a reliable estimate of an individual’s bp.
An alternative a to Spacelab’s device would be an automated wrist device. This could be put on, triggered and bp collected in 60 seconds. Would need a repeated window during the day in which to obtain these readings. Drivers would need to be trained in its use. When do such opportunities present themselves during the day? Red lights, traffic jams, rest breaks (how many of these occur during the work day). If they occur every 2 hours this is not enough intervals to collect 5-8 readings.