Physical Work Demands of Home Care workers and Onshore Maintenance Petroleum Workers in Norway: Observational Studies Utilizing Sensor Technology

Abstract

It has been suggested that high physical work demands is an important contributor to musculoskeletal disorders, sickness absence, eligibility for disability pension, and early withdrawal from work. Home care workers and onshore maintenance petroleum workers are considered to have a high prevalence of work tasks requiring monotonous, repetitive, awkward, and demanding body postures. What constitutes a health-promoting workday and the thresholds for what should be defined as excessive work-related physical activity are still not well known or understood, due to most evidence being based on self-reported data, which can be unreliable. However, through the implementation of device-based measurements, we are now able to gain a more precise understanding of how physical exposures impact our health. Considering the accelerating changes in demography, leaving fewer individuals of productive age, there is a need for a work environment that promotes health and enables workers to stay productive for longer. However, to achieve this, it is first crucial to assess the physical work demands by using precise measurement tools. This would lead to better understanding of work conditions, which in turn could enable the implementation of more accurate and appropriate occupational health and safety measures in home care and in the petroleum industry. Furthermore, few studies have developed classification models for classifying kneeling and squatting accurately. Hence, there is a need to develop classification models for the lower extremities, allowing development of exposure thresholds, and hence provide knowledge about dose-response relationships between time spent kneeling and squatting, long-term sickness absence and about musculoskeletal disorders and pain. The aims of this PhD-work were: 1) To develop and validate a rule-based model for classification of kneeling and squatting, adapted to working populations using personal protective equipment. 2) To assess physical work demands in home care workers with wearable sensors in a large Norwegian municipality. 3) To assess objectively the physical work demands of maintenance workers on onshore petroleum facilities in Norway. For Paper I, my co-authors and I developed and validated a rule-based model for classification of kneeling and squatting. This was done by including 15 healthy individuals (8 males and 7 females) and using three AX3 accelerometers (Axivity Ltd) to detect acceleration of their body segments. The sensors were attached just below the head of the fibula, on the distal and anterior region of the femur, and below the iliac crest of the hip. A GoPro camera was used to record the postures for validation, and data from the accelerometers and annotated video recordings were synchronized by using custom software. We found that the sensitivity and specificity for classification of kneeling on one or both sides of the body was above 0.98 in both cases, while for squatting it was above 0.96 and 0.91, respectively. The positive predictive value was 98% for kneeling and 57% for squatting. We also found that our model performed slightly less accurately when sensors were mounted on only one side of the body. For Paper II, my co-authors and I assessed the physical work demands of 114 of 169 eligible home care workers from six home care units (71% females and 29% males), who had an average age of 36.7 years. All workers filled in a questionnaire regarding work and healthrelated factors, performed a submaximal aerobic test, kept a diary of their work hours, and for up to six consecutive days wore five triaxial accelerometers placed in standardized positions on the calf, thigh, hip, upper back, and upper arm, and a one-channel ECG-based heart rate sensor. Our results revealed that 8% of the home care workers did ≥ 60° of the arm elevations while on their feet for ≥ 37 minutes during the workday and that 85% home care workers had forward bending of the trunk of up to ≥ 60° for more than 10 minutes while on their feet during working hours. These amounts of arm-elevation and forward bending have been associated with a risk of long-term sickness absence. Other important findings from our data were that 20% of the home care workers spent more than 30% of the workday in static standing position. Our results also revealed high interindividual variation in physical work demands, with 42% of the home care workers spending 50–76% of the workday engaged in work-related physical activity. For Paper III, my co-authors and I assessed the physical work demands of 46 out of 69 eligible maintenance workers (37 mechanics and 9 process technicians) from three onshore petroleum facilities in Norway. The workers consisted of 83% males and 17% females, and the average age of the sample was 29.8 years. Identical measurement procedures were carried out as done for Paper Ⅱ. The analysis of the data showed that 74% of the onshore maintenance petroleum workers had ≥ 60° arm elevation while on their feet for ≥ 37 minutes during the course of the workday. Moreover, we found that 48% of the workers were bent forward > 60° while on their feet for 10 minutes or more during working hours. Another finding of importance was that 26% of the onshore maintenance petroleum workers spent more than 30% of the workday in a static standing position. Additionally, we found a high interindividual variation in physical work demands, with 35% of the workers engaged in 50–73% work-related physical activity throughout the workday. Thus, our findings indicate that some home care workers and onshore maintenance petroleum workers could be at risk of adverse health effects, which in turn indicates a need for preventive measures in these occupational groups.