Article Text

Original article
Work-related musculoskeletal disorders among construction workers in the United States from 1992 to 2014
1. Xuanwen Wang1,
2. Xiuwen Sue Dong1,
3. Sang D Choi2,
4. John Dement3
1. 1CPWR—The Center for Construction Research and Training, Silver Spring, Maryland, USA
2. 2Department of Occupational & Environmental Safety & Health, University of Wisconsin—Whitewater, Whitewater, Wisconsin, USA
3. 3Division of Occupational and Environmental Medicine, Duke University Medical Center, Durham, North Carolina, USA
1. Correspondence to Dr Xiuwen Sue Dong, CPWR—The Center for Construction Research and Training, 8484 Georgia Avenue, Suite 1000, Silver Spring, MD 20910, USA; SDong{at}cpwr.com

## Abstract

Objectives Examine trends and patterns of work-related musculoskeletal disorders (WMSDs) among construction workers in the USA, with an emphasis on older workers.

Methods WMSDs were identified from the 1992–2014 Survey of Occupational Injuries and Illnesses (SOII), and employment was estimated from the Current Population Survey (CPS). Risk of WMSDs was measured by number of WMSDs per 10 000 full-time equivalent workers and stratified by major demographic and employment subgroups. Time series analysis was performed to examine the trend of WMSDs in construction.

### supplementary table

Number and incidence rate of WMSDs and nonfatal injuries in construction, median days away from work and total annual lost wages due to WMSDs, 1992–2014

Figure 1

Number and rate of work-related musculoskeletal disorders in construction, 1992–2014. FTEs, full-time equivalent workers; WMSDs, work-related musculoskeletal disorders.

Demographically, the percentage of WMSDs among construction workers aged 45 to 64 years rose from 27.6% between 2003 and 2007 to 38.1% between 2011 and 2014, reflecting an ageing workforce in this industry (table 1). Specifically, the proportion of WMSD cases for workers aged 55 to 64 years increased by 80%, from 6.4% to 11.5%, during the same time period. Across the years, the proportion of WMSDs shared by Hispanic construction workers remained at about 15%.

Table 1

Distribution of WMSDs in construction by age group and race/ethnicity, 2003–2014

In general, the rate of WMSDs increased with age until age 55 years, and then declined among older age groups (table 2). Overall, those aged 35–44 years and 45–54 years had a higher rate of WMSDs than other age groups (51.3 and 50.8 per 10 000 FTEs, respectively), while those aged 65 years and older had the lowest rate (14.1 per 10 000 FTEs). On average, white workers had a higher rate of WMSDs than Hispanic workers between 2003 and 2014 (52.6 vs 32.5 per 10 000 FTEs, respectively).

Table 2

Incidence rate of WMSDs in construction by age group and race/ethnicity, 2003–2014

When stratified by occupation, construction labourers, the largest trade in construction, had the highest number of WMSDs, accounting for 18.7% of WMSDs among all construction occupations from 2011–2014 (table 3), followed by carpenters (12.5%), heating and air-conditioning mechanics (8.2%) and plumbers (8.2%). While helpers had a small number of WMSD cases, they had the highest incidence rate of WMSDs among the selected occupations (100.9 per 10 000 FTEs), and more than twice the average risk of all construction occupations combined (39.5 per 10 000 FTEs). Other high-risk occupations with a risk index ≥2 include heating and air-conditioning mechanics, cement masons and sheet metal workers.

Table 3

Number and incidence rate of WMSDs in construction, selected occupations, 2011–2014

By body part affected by WMSDs, the back ranked at the top for the construction industry and for all industries as well (42.5% and 41.6%, respectively; table 4). The event and exposure that led to the most WMSDs was overexertion involving outside sources for both construction and for all industries (65.3% and 67.8%, respectively). The number of WMSDs increased with length of service for both construction and for all industries combined. In particular, working over 5 years accounted for the highest percentage of WMSDs in construction (35.6%) and for all industries (40.3%). The major source of WMSDs was ‘persons/plants/animals/minerals’, which for WMSDs is associated with body reaction, repetitive motion or sustained viewing with no impact involved.

Table 4

Case characteristics of WMSDs, construction versus all industries, 2011–2014 total

## Discussion

This study examined the trends and patterns of WMSDs among construction workers in the USA from 1992 to 2014. During the study period, the number and rate of WMSDs in construction decreased significantly, following the overall injury trends. However, the average rate of WMSDs in construction was continually higher than that for all industries combined. At the same time, the median days away from work (ie, a key measure of severity for the injury or illness) for WMSDs have increased. In addition, the proportion of WMSD cases for workers aged 55 to 64 years almost doubled in the past decade, and workers aged 35 to 54 years had a higher rate of WMSDs than any other age group. While construction labourers made up the largest proportion of WMSDs, construction helpers experienced the highest risk of WMSDs among construction occupations. This study also found that the major event and exposure of WMSDs among construction workers was overexertion; and the back was the primary body part affected by WMSDs, accounting for more than 40% of the WMSDs in construction. Moreover, the study suggests that WMSDs are costly; the estimated wage loss for private wage-and-salary construction workers was \$46 million in 2014.

The significant drop in the number and incidence rate of WMSDs as well as in the overall non-fatal injuries during the study period may reflect continuous intervention efforts in the US construction industry. However, work-related injuries and illnesses, in particular MSDs, could be underestimated due to various reasons. For example, the numbers reported in this study are less likely to cover MSDs caused by accumulative job exposures since it is more difficult to establish work-relatedness for such cases than for cases from acute and traumatic injuries. In fact, many cases of MSDs may have no clear causal relations to an individual's work, especially for construction workers who are mobile and can work for a number of employers at different locations within a short time period. In addition, employers and employees may under-report MSDs willingly or unwillingly.26 ,27 Moreover, the OSHA recordkeeping regulation changes may partially contribute to the injury decline during the study period.28

The study found that the rate of WMSDs increased with age until age 55 years, and then declined among older age groups (table 3). Other studies have observed a similar pattern with age.9 One of the explanations could be that older workers who continue employment in the construction industry might move to positions such as foreman, with reduced work exposures and WMSD risk. Moreover, the possibility of a healthy worker survivor effect in construction should be considered as some older workers might have left the construction workforce due to health concerns, such as work-related disability or inability to perform the demanding tasks associated with construction; or those older workers who remain in their jobs have coped better with their tasks/work than younger ones.13

The growing proportion of WMSDs among older workers reflects the ageing workforce in the construction industry. Coupled with the increasing overall median days away from work due to WMSDs suggests a pattern consistent with longer recovery times among older workers experiencing WMSDs.29 Research has found that MSDs were the leading reason for occupational disability in all age categories and a strong trend in the risk of disability with increasing age.30 A review of the literature highlighted that older workers are more susceptible to WMSDs than younger workers because of decreased functional capacity, and the risk of injury was more related to the difference between the demands of work and the worker's physical work capacity rather than age.31 While this study did not analyse costs by age group, previous research found that delayed return to work following an injury among older workers increased compensation costs.32 ,33 Given the continuing trends of the ageing workforce,34 preventative ergonomic interventions should target older workers in construction to promote healthy ageing at work.

Ergonomic interventions should meet the needs of workers through redesigned tools, adjusted tasks and improved working environments.35 ,36 Since ergonomic hazards vary from job to job as well as site to site, ergonomic solutions must be job-specific and site-specific. Such solutions range from simple tool modifications such as ergonomic tool belts (http://www.cpwrconstructionsolutions.org) and full-fingered antivibration gloves,37 ,38 to elaborate ergonomic material handling/lifting devices or automation of construction processes.1 ,8 ,37 Resources for practical ergonomic interventions, for example, Solutions for Home Building Workers,6 Simple Solutions: Ergonomics for Construction Workers (http://www.cdc.gov/niosh/docs/2007–122/pdfs/2007–122.pdf), CPWR's Handouts and Toolbox Talks (http://www.cpwr.com), and many other available ergonomic work practices, should be widely promoted through training, campaigns and other intervention programmes.

Previous research has shown that keeping workers physically fit has many benefits, including lower injury rates and insurance costs.36 Furthermore, OSHA requires that employers must provide all workers with a safe, healthy place to work (https://www.osha.gov/SLTC/ergonomics/). Therefore, the role of employers is extremely important for reducing WMSDs and overall work-related injuries and illnesses. For example, construction employers can establish a task-specific programme that may limit the weight an individual should lift or carry at one time and the maximum carry distance and adjust it accordingly for older workers and those with medical conditions (http://www.hse.gov.uk/msd/faq-manhand.htm#manual).

As with other WMSD studies, this study has strengths and limitations. A major strength was the use of large nationally representative data sets that had a better representation of construction trades and age groups than small samples. In addition, the long study period provided a relatively comprehensive picture of the WMSDs in construction over time. The stratified analysis identified workers with a higher risk of WMSDs, as well as found issues related to ageing, which may provide a basis for future research and prevention priorities of WMSDs.

Using national survey data also has limitations. Although the missing values for race/ethnicity from the SOII were adjusted in this study, misclassification could exist if the data were not missing at random. In addition to the potential underestimate aforementioned, undercounting may be more common among Hispanic workers,39 which might partially explain the lower rate of WMSDs among Hispanic construction workers reported in this study. While the number of WMSDs could be under-reported, the FTEs from the CPS may be overestimated; each could result in underestimating the real risk of WMSDs in construction. In addition, self-employed workers are excluded from this study. Previous research shows that self-employed workers are much older than wage-and-salary workers in construction on average,2 yet the risk of WMSDs for those self-employed workers remains unknown. Moreover, owing to the strict confidentiality rules, this study did not have access to the research files of the SOII, thereby restricting data analyses (eg, unable to provide age-adjusted rates of WMSDs). Finally, there is evidence suggesting that use of work-related injury data sources for the surveillance of WMSDs may underestimate the burden of these disorders as many cases are treated through private health insurance and not reported.40

Despite the limitations, this study highlights the importance of preventing WMSDs among construction workers, in particular for high-risk workers. Given the prevalence of WMSDs at worksites and the increasingly ageing workforce in the USA, the significance of this study would encompass the construction industry and beyond.

## Acknowledgments

The authors would like to thank Deronta Renard Spencer and Alissa Fujimoto for their contributions to this manuscript.

## Footnotes

• Contributors XW was involved in acquisition, analysis and interpretation of data, drafting the manuscript, and approved the final version. XSD was involved in research, conception and design, data interpretation, drafting the article and revising it critically for important intellectual content and approved the final version of the manuscript. SDC and JD was involved in research, conception, data interpretation, drafting the article and approved the final version.

• Funding This study is funded by the National Institute for Occupational Safety and Health (NIOSH) grant U60OH009762. The contents of this study are solely the responsibility of the authors and do not necessarily represent the official views of NIOSH.

• Competing interests None declared.

• Provenance and peer review Not commissioned; externally peer reviewed.