ABSTRACT
Background
Work and sleep patterns for commercial motor vehicle (CMV) drivers often include long working hours, shift work and diminished sleep duration and quality, which have been linked to overweight, obesity and other problems.
Aims
To explore possible connections between work, sleep and obesity among CMV drivers.
Methods
Survey and anthropometric data were collected from male long-haul CMV drivers in central North Carolina, USA, over a period of 6 months. Drivers’ body mass index (BMI) was used as a measure of total body obesity and sagittal abdominal diameter (SAD) as a measure of central adiposity.
Results
Among the 260 study subjects, mean BMI was 33.1 (64% were obese or morbidly obese) and mean SAD was 32.3cm, classifying 89% of drivers as being at high or very high cardiometabolic risk. About 83% of drivers worked an irregular daily schedule, 64% worked irregular total daily hours, 32% worked irregular days of the week and 46% reported getting <7h of sleep during work nights. Significant predictors of BMI included the number of hours worked daily (P < 0.05) and the age (P < 0.01) of the driver, while age was also a significant predictor for SAD (P < 0.05). Significant predictors of sleep quality included the extent of shift work (P < 0.05) and sleep duration (P < 0.001).
Conclusions
Work and sleep configurations appear to affect the weight status of CMV drivers. Shift work and sleep duration are both associated with the weight status of CMV drivers, and both appear to function as indicators of their sleep quality.
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First the authors provide some context based on previous research. It’s highlighted that:
- Long working hours, shift work and sleep duration and quality are all correlated with overweight and obesity.
- Long working hours, which includes working overtime and working >50 h per day, are all significantly correlated with higher total body obesity (via BMI…which as many know, has its limitations).
- An inverse relationship has been demonstrated between BMI and sleep duration and quality (i.e. as BMI goes up, sleep duration & quality go down and vice versa).
- Short sleep duration is linked with an increased risk of being overweight or obese, and for people with daily sleep durations <8 hours, “the increase in BMI is proportional to the reduction in sleep duration” (p726).
- Shift work schedules, is associated with less healthy sleep, higher rates of short sleep duration and higher BMI, and night shift workers have also been shown to have higher BMI.
Results from this study relating to commercial long-haul truckers found:
- The mean BMI of this sample was 33.1, with 64% classified as obese or morbidly obese.
- The multinomial logistic regression found hours worked daily and age to be significant predictors of BMI. Sleep duration and shift work were not significantly associated with either of the two obesity measures. The authors speculate that this may be due to the drivers over-reporting their amount of sleep due to perceived negative repercussions on employment.
- 71% of truck drivers worked >11 h per day, worked an irregular schedule (83%) and had irregular total daily hours (64%).
- Significant predictors of total body obesity were age of the driver, and number of hours worked daily. Longer working hours had the highest odds ratio with total body obesity (working >11 hours was over 7 times more likely with higher obesity than working < 11 hours).
- Significant predictors of sleep quality included sleep duration and the extent of shift work. The highest odds for poor sleep quality was drivers reporting short sleep duration. The odds for poor sleep quality increased as the extent of shift work increased.
- Further on sleep quality, nearly 10% of drivers reported that they never got a good night’s sleep, and 30% reported that they rarely got a good night’s sleep.
- Younger drivers were found to be at higher risk for health complications. As with the higher odds of working longer hours and central obesity, driver age was significantly linked with higher obesity (trending towards the younger age). The authors suggest that this may be due to younger drivers being more susceptible to the effects of sleep and work configurations in long-haul trucking, or it could be an artefact of a healthy worker syndrome whereby older drivers that are not resilient to these negative effects leave the industry (survivor population).
Being a cross-sectional design no causal association could be made between the variables. Also, many of the variables were self-declared (sleep length, quality etc.), which is a limitation.
Authors: Lemke, M.K., Hege, A., Perko, M., Sönmez, S., & Apostolopoulos, Y. (2015). Occup Med (Lond)
Study link: https://doi.org/10.1093/occmed/kqv080
Link to the LinkedIn article: https://www.linkedin.com/pulse/work-patterns-sleeping-hours-excess-weight-commercial-ben-hutchinson
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