Healthcare is the second-fastest-growing sector of the U.S. economy, employing over 12 million workers,¹ and is one of the most dangerous places to be employed. ² Compared to other sectors, healthcare workers sustain the second highest number of nonfatal injuries and illnesses. ^3,4 These workers face a wide range of hazards on the job, including a high risk for musculoskeletal disorders (MSDs), especially low back pain (LBP). Reports of LBP among nurses and other patient care workers range from 30–60%, ^5–8 and may contribute to the exodus of nurses from this profession. ^{6, 9}

LBP has been associated with inadequate physical activity and sleep deficiencies. ^10–17 The potential for synergistic impacts across these outcomes is apparent. Workers who sustain injuries are less able to be physically active during leisure time. ¹⁸ Conversely, sedentary behavior increases risk for LBP and injury ¹⁰ and among those already injured, prolongs disability and adds to the risk of further occurrence of LBP.^{19, 20} There is clear evidence that sedentary behavior is also associated with increased risk of all-cause and cardiovascular disease mortality.^21–26 National guidelines for physical activity recommend that adults engage in at least 30 minutes of moderate-intensity activity, five days per week, or 20 minutes of vigorous intensity activity, three days per week.²⁷ Nonetheless, in 2007, the percentage of U.S. adults classified as physically active was only 48.8%, including 50.7% of men and 47.0% of women, based on self-reports in telephone interview.²⁸ When physical activity is measured using accelerometers, estimates of adherence to these guidelines may be as low as 5%.²⁹ For workers in physically demanding jobs, being on one’s feet all day may contribute to fatigue and the need for recovery at the end of the day.³⁰ Contrary to workers’ perceptions, however, being in a physically demanding job does not necessarily contribute to meeting physical activity recommendations. For example, the physical demands of lifting patients do not provide a means of building cardiovascular fitness, as through the recommended levels of moderate to vigorous physical activity. Low levels of physical activity are also associated with absenteeism, reduced productivity, increased health care costs, and short-term disability. ^31–34

Similarly, research clearly points to the influence of work patterns, such as long work hours, on sleep, and underscores the hazards of work patterns that cause sleep deficiency (insufficient sleep duration and/or inadequate sleep quality).³⁵ Habitual patterns of insufficient sleep duration independently predict an increased risk of a fall or other injury requiring an emergency room visit.³⁶ In healthcare workers, sleep duration and extended shifts are related to healthcare workplace-associated injuries and patient safety-related errors, including motor vehicle crashes,³⁷ medical errors³⁸ and percutaneous injuries.³⁹ Working night or rotating shifts (i.e., sleeping during the daytime) has deleterious consequences not only for sleep cycles but for health outcomes as well.^40–43 In addition, for patient care workers, working nights and the associated sleep disruptions may contribute to increased risk of MSD’s, reduced physical activity, and compromised dietary patterns, often contributing to increased weight.⁴⁰

Prior research points to the important roles of job characteristics and the context of the work environment in risk of LBP, inadequate physical activity, and sleep deficiencies. In addition to the physically demanding nature of the work,^{44, 45} patient care workers’ increased risk for MSDs, including LBP, is associated with high work demands, low social support, and long work hours. ^46–49 Similar characteristics of the work environment may contribute to sleep deficiency.^{43, 50} and inadequate physical activity.^51–53 Despite the shared risks posed by the work environment, however, little research has systematically explored these cross-cutting pathways and their implications for improving the effectiveness of comprehensive worksite interventions to address the broad spectrum of worker health outcomes.⁵⁴

This paper examines the relationships among LBP, inadequate physical activity, and sleep deficiency among hospital patient care workers, which in combination, may pose an additive threat to worker health and wellbeing. In addition, we explore the relationships of characteristics of the work environment to these wellness outcomes, as illustrated in Figure 1. These findings may inform intervention design by helping to prioritize intervention targets; elements of the work environment that impact more than one outcome may be an especially high priority for workplace interventions. Specifically, we hypothesize that: (1) the three wellness outcomes -- presence of LBP, inadequate physical activity and sleep deficiency –are associated with one another; and (2) the three wellness outcomes are associated with common characteristics of the work environment, including job characteristics (i.e., social relations at work, job strain, use of a lifting device, work hours and schedule, and job title) and organizational context (i.e., the safety practices, ergonomic practices, a people-oriented culture, and work unit).

Increasing attention has been given to the multiple risks workers face related to hazards on the job as well as individual health behaviors. A growing literature points to the need for integrated interventions that can effectively coordinate efforts to address multiple outcomes influencing worker health and wellness.^{54, 65, 66} In the analyses presented here, we examined the relationships among three important wellness outcomes among hospital patient care workers: LBP, inadequate physical activity, and sleep deficiency. We hypothesized that these outcomes would be associated with one another, posing increased risk to health and wellbeing for these workers. We found that sleep deficiency, common among these workers, was significantly associated with inadequate physical activity. Unexpectedly, however, LBP was not associated with either physical activity or sleep deficiency in these cross-sectional data. We also hypothesized that the three outcomes would be associated with common characteristics of the work environment, as illustrated in Figure 1. In multivariable analyses, we found several important themes in the nature of the relationships of these outcomes to job characteristics (i.e., social relations at work, job strain, use of a lifting device, work hours and schedule, and job title) and organizational context (i.e., safety practices, ergonomic practices, a people-oriented culture, and patient care work unit).

Our finding of the relationship between inadequate physical activity and sleep deficiency is consistent with prior reports in the literature.⁶⁷ Indeed, research has indicated that improved fitness can improve sleep.⁶⁸ The lack of association of either sleep or physical activity to LBP is contrary to our hypothesis and is in contrast to prior research which has shown a relationship between sedentary behavior and increased risk for MSDs of both the low back and neck. ⁶⁹ In addition, others have reported that among those already injured, physical inactivity prolongs disability and adds to the risk of further occurrence of musculoskeletal pain.^{70, 71} Prior research has also found that workers who sustain injuries are less able to be physically active during leisure time. ^{10, 30, 72–74} These results are also inconsistent with prior studies that have shown that adequate restorative sleep improves long-term pain.⁷⁵ For patient care workers, working nights and the associated sleep disruptions contribute to increased risk of MSDs and predict a decreased probability of returning to work.⁷⁶ The discrepancies between prior research and the findings presented here may reflect the cross-sectional nature of our data, the focus on LBP rather than other MSDs, or the specific work experiences of these patient care workers employed in acute care settings. Further research exploring the nature of these relationships, particularly for patient care workers, is warranted.

We found several cross-cutting associations with the work environment among the three outcomes in our multivariable analyses. Harassment on the job and low supervisor support were significantly associated with both LBP and sleep deficiency. The importance of these central indicators of social relationships on the job is of clear relevance to efforts to improve the work environment. Being a staff nurse or patient care associate as compared to other occupations also increased risk of LBP and sleep deficiency. In addition, core indicators of job strain played an important role: Low decision latitude was significantly associated with inadequate physical activity, and high job demands increased the risk of LBP. In addition, poor ergonomic practices were associated with sleep deficiency.

Other studies have underscored importance of experiences at work as important determinants of worker health and wellbeing.^77–81 For example, consistent with our findings, in a study of nurses aids, Eriksen, Burrsgaard and Knardahl⁸² found that LBP was associated not only with ergonomic exposures, but also with working night shift, lack of support from one’s superior, and work culture. Others have also shown the importance of workplace abuse or harassment in workplace injuries and other worker health outcomes. ^{83, 84} Prior studies have also reported that risk of injury on the job is associated with the pace of work and a sense of time urgency, staffing patterns and resulting workload that may be associated with them, the degree of perceived control over work, and the nature of job tasks, such as the extent to which high physical exertion is a requirement of the job.^{44–49, 79, 81, 85–89}

Similarly, prior research has found that insomnia and poor sleep quality are associated with high job demands, low influence over decisions on the job, and other work-related factors.^{17, 90, 91} The role of supervisor support has also been demonstrated. For example, supervising managers of healthcare workers who are inflexible about their employee’s work-family conflicts have employees with measured sleep duration about one half hour shorter per night, on average, than employees with more flexible managers.⁴²

We also found that job decision latitude was associated with physical activity. This finding is consistent with prior literature demonstrating that physical activity is positively associated with job control, and inversely related with both job demands and generalized occupational stress.^{15–17, 51–53, 80, 90–95} Nonetheless, others have reported stronger associations between the work organization and physical activity levels, compared to the findings we reported here. Although we found that in bivariate analyses, inadequate physical activity was additionally associated with lower people-oriented culture and lower coworker support, only the association with decision latitude remained significant in multivariate analyses. The nature of patient care work may indeed involve a different dynamic in these pathways, and further research may help to elucidate these pathways.

Knowledge about the co-occurrence of risks associated with exposures on the job and health behaviors is clearly relevant to understanding the patterns of risks. For example, consistent evidence underscores the pattern of increased risk of both MSDs and risk-related behaviors by socio-economic position, with higher risk among workers in lower status service positions and with lower levels of education.^{96, 97} In our findings, staff nurses and patient care assistants were at elevated risk for LBP relative to other workers, although these occupational differences did not hold in multivariate analyses for the other two outcomes.

We recognize that in general the magnitudes of the odds ratios we found to be statistically significant may not be seen as “clinically relevant.” Others have observed, however, that small changes in risk at a population level have meaningful public health implications. ^{98, 99} Indeed, while the associations observed here may have limited implications for the treatment of individual workers, they represent an opportunity for health professionals and others to work with hospital leadership on organizational changes to optimize wellness and wellbeing in the workforce. The combined impact of these work factors suggests in addition that worksite interventions target multiple factors in the work environment for optimal impact.

These findings rely on a cross-sectional survey; as with any cross-sectional assessment, it is not possible to determine the temporal sequence in these relationships, and we therefore do not infer causality. Data were collected from two academic teaching hospitals in the greater Boston area; we acknowledge that findings from this setting may not be generalizable to other patient care settings. Findings reported here are based on self-reports from the survey, and accordingly are subject to recall and social-desirability bias. Additionally, while we controlled for workload by grouping similar units, we recognize that work on patient care units is highly variable and unknown confounders or work characteristics may impact the outcomes. Despite these limitations, it is important to note the high response rate to this survey (79%) and the use of multiple indicators of work experiences.

In conclusion, these findings point to important shared pathways in the work environment that jointly influence multiple wellness outcomes for patient care workers. In particular, low supervisor support and harassment on the job had implications for two of the three outcomes studied here. Efforts to improve the organization of work and social relations at work may contribute to improvements in worker health across multiple dimensions. Interventions intended to independently reduce LBP, sleep deficiency, or inadequate physical activity may benefit from synergy and coordination. These findings underscore the importance of attending to these key domains of social relationships and control over decisions at work as part of these intervention efforts. Simply put, from a public health perspective, focusing on both workplace hazards and worker health behaviors is important because it provides a more complete assessment of the risks workers face, compared to attending to one domain (e.g. physical hazards on the job) to the exclusion of another (e.g.., health behaviors). ¹⁰⁰ Understanding the shared influences of the work environment on multiple wellness outcomes has clear implications for interventions. There is increasing recognition that an integrated approach, that attends to workers’ health behaviors as well as the potential for exposures on the job, holds promise for bolstering the impact of interventions. An integrated approach recognizes that the workplace acts as both an accelerator and preventer of chronic disease and as a key determinant of individual health behaviors, through physical, social, organizational and psychosocial mechanisms. ⁵⁴