The effect of age on musculoskeletal injury compensation costs in South Australian professional urban firefighters: A cohort study

Abstract

BACKGROUND:

Firefighting is recognised as a physically demanding occupation involving exposure to hazardous environments and activities. An aging workforce combined with the age-related decline in physical fitness may result in increased future workers’ compensation expenditure for fire service organisations.

OBJECTIVE:

The objective of this research was to investigate the costs associated with musculoskeletal sprain and strain injury and the impacts of age and injury location on Workers’ Compensation claims submitted by professional urban firefighters.

METHODS:

Claim rates, direct costs, and days lost were extracted from a professional Fire Service organisation’s workers’ compensation claim database for financial years between 2011 to 2018.

RESULTS:

The mean cost per claim increased with age, with a mean claim cost of the 60–70-year-old group over 10 times more than the 20–29-year-old group. The mean days lost per claim were also higher for claims submitted by firefighters aged over 50.

CONCLUSIONS:

Older firefighters miss more workdays when injured and are associated with increased claims costs, particularly those in the 60–70-year group. With an aging workforce, Fire Service organisations must implement appropriate management and prevention strategies to reduce the potential risks associated with an aging workforce.

Keywords

Ageing workforce firefighter workers’ compensation sprain and strain injury

1 Introduction

Urban firefighting is a physically demanding occupation involving activities requiring high levels of muscular strength, power, and endurance, and high levels of cardiorespiratory fitness [1 –3]. Many firefighting activities are performed in extreme environmental conditions [4] which often necessitates the use of bulky and heavy (up to 25 kg) personal protective equipment (PPE) and breathing apparatus [5], which collectively augment the physical demands that must be routinely managed by firefighters.

Given the substantial physical demands and heavy external loads, it is not surprising that firefighters are at significantly higher risk of work-related injury than those in most other occupations. Australian firefighter’s injury rates have been reported as high as 177 injuries per 1000 full-time employees (FTE) which is substantially higher compared to office workers (15 injuries per 1000 FTE), healthcare workers, and trade workers (55 per 1000 FTE and 72 per 1000 FTE respectively) [6]. While numbers vary widely between studies, musculoskeletal (sprain or strain) injuries generally account for a significant proportion of firefighter injuries [7].

Aging may be an important consideration for work-related injuries. Previous examinations of claims in non—firefighting occupations have reported that the costs associated with musculoskeletal injuries increase with age [8, 9]. In the cross-sectional study conducted by Nelson, Bigley, and Mallon [8] the cohort was examined by 5-year age groups. The mean cost per claim increased for each age group, with the youngest age group (<20) displaying the lowest mean cost per claim ($333) while the oldest age group (≥65) displayed the greatest mean cost per claim ($1,652). It is estimated that the number of workers in Australian fire services aged 60 years and over will increase over the next 10–15 years, with only 7% projected to retire before the age of 60 years [10]. Thus, an aging workforce combined with high occupational physical demands may result in fire service organisations being more adversely impacted in injury prevalence and cost compared to less physically active occupations.

While injury and compensation claim rates have been comprehensively reported for firefighters [11], there is limited knowledge of the associated financial costs and organisational burden (days lost) with musculoskeletal injuries in urban fire service organisations. Additionally, the potential impact of aging on injury costs and duration has not been previously examined in this occupational setting. Therefore, we performed a retrospective analysis of workers’ compensation claims of South Australian urban firefighters to examine the financial burdens of musculoskeletal injuries including, the impact of bodily location of the injury and whether age may influence injury costs and the duration of the injury.

2 Methods

2.1 Setting

Data were obtained from an Australian Fire Service for the financial years between 2011 to 2018. This Fire Service operates in a metropolitan city of approximately 1.3 million people. As of April 2019, the organisation had an operational staff of 950, which included 926 males and 24 females with an average age of 46 years. The average length of service for personnel in the organisation is 17 years. Table 1 indicates the distribution of the operational workforce by age and gender.

Table 1
Demographic summary of uniformed firefighters

Age (years) Number (%) Female (%) Male (%)

20–29 60 (6.3%) 2 58

30–39 198 (20.8%) 13 185

40–49 292 (30.7%) 7 285

50–59 297 (31.2%) 2 295

60–70 103 (10.8%) 0 103

Total 950 (100%) 24 (2.5%) 926 (97.5%)

Age (years)	Number (%)	Female (%)	Male (%)
20–29	60 (6.3%)	2	58
30–39	198 (20.8%)	13	185
40–49	292 (30.7%)	7	285
50–59	297 (31.2%)	2	295
60–70	103 (10.8%)	0	103
Total	950 (100%)	24 (2.5%)	926 (97.5%)

2.2 Data source

Prior to data extraction, the project was approved by the University of South Australia Human Research Ethics Committee (Protocol Number 202652). The fire service utilises a Workers’ Compensation database to record workers’ compensation claims as well as reporting to the State Workers’ Compensation body as part of the wider Australian National Data Set on compensation-based statistics. The database uses a modified version of the Type of Occurrence Classification System 3rd Edition (TOOCS3), with additional fields coded for Time Lost in days and Direct Cost of Workers’ Compensation payments in Australian dollars, cases were available for the 2011 to 2018 financial years. The database contained reports for all employees of the fire service inclusive of administrative roles and support staff such as mechanics and specialist technicians. The variables of interest in the dataset were: date of birth, report submission date, gender, occupation, description of the incident, treatment type, injury side, bodily location of the injury, nature of the injury, work time lost, and direct cost.

2.3 Analysis

The Workers’ Compensation database contained 904 workers’ compensation reports from firefighters and an additional 43 attributed to administrative and support staff which were excluded from subsequent analyses. Age, gender distributions, and injury natures were characterised using descriptive statistics. Days lost and direct cost by 10-year age group and bodily location of injury were also summarised. The database was filtered to include only sprain/strain injuries, resulting in 512 remaining cases. The distribution of observed claims by 10-year age group were compared to an expected distribution of claims proportional to the number of employees in each age group using a Chi-square test. Linear regression was used to examine the relationship between age, days lost, and direct costs. A generalised linear model including a post hoc lowest significant difference test was then used to examine the relationship between 10-year age groups, direct cost, and days lost. Descriptive statistics were analysed using Microsoft Excel (Microsoft Corporation, Washington, USA) with additional statistical analyses performed using IBM SPSS v25 (IMB Corp, New York, USA).

3 Results

3.1 Injury occurrence

There were 904 individual claims over the 7 years resulting in an annual rate of 136 claims per 1000 FTE. The median age of firefighters who submitted a claim was 50 years (IQR = 16 years). The distribution of claims submitted by gender was approximately proportional to the distribution of the workforce, with males submitting 97.7% of claims and females 2.3% of claims.

3.2 Nature of injury

Seventeen different injury natures were reported with the top 5 injury natures accounting for 86.2% of all injuries. Traumatic joint/ligament and muscle/tendon injuries, referred to as sprain/strain injuries were related to 56.6% of claims, 11.2% of claims were related to musculoskeletal and connective tissue diseases, 8.1% were related to neoplasms, 6.1% related to wounds, lacerations, amputations and internal organ damage and 4.2% related to nervous system/sense organ disease.

3.3 Direct costs

Over the 7-year period, sprain and strain injuries accounted for the second-highest amount of total direct expenditure with a cost of over $4.7 m.

There was a weak but statistically significant association between age and direct costs (F score (1,504) = 10.608, p = <0.05), with the model explaining 2.1% of the variance. When analysed by age categories (10-year age range), there was a significant difference in direct cost among groups (F score (4,462) = 3.51, p = 0.008), with post hoc analysis indicating that the 60–70-year age group was significantly different from all other age groups (p = <0.05), with no significant difference among the other groups (p = >0.05). For claims resulting in direct costs, there was a significant difference between the observed number of claims by the 10-year age groups and the number of claims proportional to the number of employees in each age category (X² (4, 462) = 37.84, p = <0.05)). The largest positive difference observed was in the 50–59-year age group, while in contrast, the largest negative difference was observed in the 60–70-year age group. Table 2 provides a summary of direct expenditure by 10-year age group.

Table 2
Distribution of claims and direct cost by operational age group for sprain/strain injuries

Age Group (yrs) 20–29 30–39 40–49 50–59 60–70 Total

Employees (n/%) 60 (6%) 198 (21%) 292 (31%) 297 (31%) 103 (11%) 950

Claims (n/%) 15 (3%) 98 (21%) 143 (31%) 187 (41%) 19 (4%) 462

Mean Direct Cost^* (SD) 1,881 (4,168) 7,594 (25,809) 7,466 (13,028) 11,389 (27,361) 26,648 (43,604) 9,689 (24,223)

Total Direct Cost ($AUD) 36,993 850,304 1,105,174 2,243,087 561,501 4,797,061

Age Group (yrs)	20–29	30–39	40–49	50–59	60–70	Total
Employees (n/%)	60 (6%)	198 (21%)	292 (31%)	297 (31%)	103 (11%)	950
Claims (n/%)	15 (3%)	98 (21%)	143 (31%)	187 (41%)	19 (4%)	462
Mean Direct Cost^* (SD)	1,881 (4,168)	7,594 (25,809)	7,466 (13,028)	11,389 (27,361)	26,648 (43,604)	9,689 (24,223)
Total Direct Cost ($AUD)	36,993	850,304	1,105,174	2,243,087	561,501	4,797,061

^*Figures reported in $AUD.

3.4 Days lost

Sprain/Strain injuries were responsible for the highest overall number of days lost at 5608. Linear regression revealed a weak but statistically significant association between days lost and age (F score (1,295) = 4.426, p = <0.05), with the model explaining 1.5% of the variance. When analysed by age, there was a significant difference between groups (F score (4,468) = 4.48, p = <0.05), with post hoc testing identifying that the 60–70-year age group was significantly different from all other groups (p = <0.05). No significant differences were observed among any other group (p = >0.05). There was a significant difference between the observed number of claims by age and the number of claims proportional to the number of employees in each age category (X² (4, 268) = 28.76, p < 0.05). The largest positive difference observed was in the 50–59-year age group, while the largest negative difference was observed in the 60–70-year age group. Table 3 provides a summary of days lost relative to age.

Table 3
Distribution of claims resulting in days lost by operational age group

Age Group (yrs) 20–29 30–39 40–49 50–59 60–70 Total

Employees (n) 60 (6%) 198 (21%) 292 (31%) 297 (31%) 103 (11%) 950

Claims (n) 3 (1%) 46 (17%) 100 (37%) 105 (39%) 14 (5%) 268

Mean Days Lost (SD) 1.7 (4.2) 9.1 (29.1) 8.8 (14.6) 11.1 (24.0) 34.7 (78.8) 10.7 (27.3)

Total Days Lost 32 1182 1300 2360 734 5,608

Age Group (yrs)	20–29	30–39	40–49	50–59	60–70	Total
Employees (n)	60 (6%)	198 (21%)	292 (31%)	297 (31%)	103 (11%)	950
Claims (n)	3 (1%)	46 (17%)	100 (37%)	105 (39%)	14 (5%)	268
Mean Days Lost (SD)	1.7 (4.2)	9.1 (29.1)	8.8 (14.6)	11.1 (24.0)	34.7 (78.8)	10.7 (27.3)
Total Days Lost	32	1182	1300	2360	734	5,608

3.5 Bodily location of injury of sprain/strain injuries

There were 512 cases of sprain/strain injury. A total of 23 different bodily locations of injury were coded in the database, 10 of which resulted in less than 1 injury annually per 1000 FTE. The four highest reported bodily locations accounted for 68.1% of overall injuries. The most frequently injured bodily location was the back, accounting for 25% of injuries, followed by the knee (23.2%), shoulder (11.7%) and lower leg (8.2%). Knee injuries were the most expensive, accounting for 44.2% of direct expenditure related to sprain and strain injuries. Shoulder injuries were the second most expensive (23.7%), followed by back injuries (23.5%). This trend was also reflected in the number of days lost by bodily location, with knee injuries accounting for 39.6% of days lost, followed by shoulder injuries (30%) and back injuries (19.8%). These results are summarised in Table 4.

Table 4
Cost and days lost by bodily location for sprain/strain injuries

n Claims (Days Lost) Median Days Lost (IQR) Total Days Lost n Claims (Direct Cost) Median Direct Cost (IQR)^* Total Direct Cost^*

Back 86 4 (7) 986 127 2,225 (4,414) 962,938

Knee 78 12 (21) 1,974 118 8,238 (15,917) 1,815,122

Shoulder 37 24 (45) 1,395 59 4,488 (24,058) 974,110

Lower Leg 22 4 (6) 286 42 1,633 (3,209) 206,236

Ankle 12 3.5 (3) 95 27 1,053 (1,239) 59,654

	n Claims (Days Lost)	Median Days Lost (IQR)	Total Days Lost	n Claims (Direct Cost)	Median Direct Cost (IQR)^*	Total Direct Cost^*
Back	86	4 (7)	986	127	2,225 (4,414)	962,938
Knee	78	12 (21)	1,974	118	8,238 (15,917)	1,815,122
Shoulder	37	24 (45)	1,395	59	4,488 (24,058)	974,110
Lower Leg	22	4 (6)	286	42	1,633 (3,209)	206,236
Ankle	12	3.5 (3)	95	27	1,053 (1,239)	59,654

^*Figures reported in $AUD.

4 Discussion

There are three novel findings presented in the current investigation. First, this was the first investigation to report on the workers compensation burden associated with traumatic musculoskeletal injuries in Australian urban firefighters. The present study identified a trend for increasing claim costs with increases in chronological age, with the effect being most evident in firefighters aged 50 years and over. Second, firefighters aged 50–59 year old were most likely to be injured, being over represented with regards to the proportion of workers compensation claims submitted which resulted in either lost days or direct cost. While firefighters aged >60 or <30 were under represented. Third, while the most injured bodily location was the back, knee injuries imparted a substantially higher workers compensation burden, resulting in over twice as many lost days and almost twice as much direct costs.

The body location of injury findings observed in this current analysis supports those previously reported in firefighters, with back injuries being the most prevalent, followed by the knee and shoulder [12]. While back injuries were the most reported, knee injuries resulted in higher costs and a greater number of workdays lost. In both the present study and the previous report by Gray and Collie [12], the combined cost of back and knee injuries account for over 50% of the total cost of musculoskeletal injuries [12]. Thus, the underlying activities, protective equipment and movement patterns that contribute to back and knee injuries should be investigated as this may represent an important avenue in reducing workers’ compensation expenditure. Indeed, multiple studies investigating firefighter footwear have highlighted that boot design impacts several factors which may elevate the risk of lumbar and lower limb injuries [13 –15]. In general, heavier boots result in greater energy expenditure while boots with more flexible soles impart lower energy demands [13]. Heavier, more rigid footwear results in greater vertical impact forces and higher lumbar internal rotation angular velocities during landing tasks [14]. Higher boots, relative to knee height reduce knee and hip sagittal plane range of motion [15]. Therefore, the development and adoption of a lightweight flexible sole firefighting boot, with various boot height options based on foot size, may contribute to reducing costly knee and back injuries.

The mechanisms involved in sprain and strain injuries are complex with multiple physical and psychosocial factors contributing to this type of injury [16]. However, it has been shown that firefighters with low levels of muscular strength, endurance, flexibility, and cardiorespiratory fitness have a higher risk and greater costs associated with injury than those with higher levels of physical fitness [17–18]. Moreover, a lower physical fitness level pre-injury resulted in longer recovery times for Metropolitan Police suffering from whiplash [19], further highlighting the potentially important effect of physical fitness on musculoskeletal injury-related costs and recovery in first responder populations.

The findings presented in the current study highlight a trend of increasing claim costs and lost work days with increasing age, consistent with broader South Australian workforce with the largest costs associated with those over 60 years [20]. Similar findings with regard to claim costs have also been seen among American construction workers [21]. However, in contrast to the findings presented in the current study, among predominantly male workers in the broader South Australian workforce, younger male workers displayed a higher rate of injury than those with ages exceeding 45 years [20]. This is consistent with findings from a previous study investigating traumatic musculoskeletal injuries in Australian firefighters, which found that younger firefighters (age < 40) sustained the largest proportion of musculoskeletal injuries [22]. The present study found that firefighters aged 50–59 sustained a greater number of injuries. These contrasting findings may be due to differences in operational, recruitment, or training practices.

The trend for firefighters aged 50–59 to sustain more frequent and more costly musculoskeletal injuries in this current study may highlight the significance of age-related declines in muscular strength and flexibility, and cardiorespiratory fitness, particularly in those adults over the age of 50 years [23 –25]. Previous works have reported that relatively short-term exercise programs (8 weeks) can effectively restore the age-related deterioration in certain indices of physical fitness [26 –28]. Therefore, it is plausible that the implementation of well-tailored exercise interventions may be an effective strategy in reducing the impact of musculoskeletal injuries in this workforce. Moreover, based on the current findings, it may be sensible to emphasize the benefits of exercise interventions in firefighters, particularly for those aged 50 years and older, specifically in this cohort.

There were several limitations of the current research. First, these data were part of an existing database that was not designed for academic research, and therefore, we were limited to the information entered as a part of the workers’ compensation reporting structure. Second, compensation claims can be submitted after employees have retired or transitioned to another occupation, which may have resulted in older workers being over-represented in the current analysis. Third, annual employment numbers for the period included in the database were not known and therefore, we based them on the current workforce distribution. Fourth, an insufficient sample size for female firefighters limited our ability to perform statistical analysis between subgroups. Fifth, presumptive cancer legislation was introduced in 2013, allowing an influx of historical claims. As a result, it is unlikely the figures regarding the rates and costs of neoplasm claims in this study reflect an ongoing trend for expenditure in this type of claim. Sixth, firefighters were given the same occupational code within the database regardless of rank or current role. As a result, it was not possible to examine the potential differences in job-task demands between different age groups. Lastly, while not directly examined in this research, an understanding of the specific occupational tasks and general movement patterns associated with strain and sprain injuries in firefighters may be critical for the development of occupation targeted injury prevention and management strategies.

5 Conclusion

In summary, increased chronological age was associated with higher costs and workdays lost due to sprain and strain injuries in urban firefighters. Thus, age and the associated changes in physical function should be a consideration when developing prevention and management strategies for musculoskeletal injuries. Additionally, knee and back injuries should be investigated as a priority to reduce the injury burden among Australian urban firefighters.

Ethical approval

This research was approved by the University of South Australia Human Research Ethics Committee, Protocol number 202652.

Informed consent

Not applicable.

Conflict of interest

None declared.

Footnotes

Acknowledgments

This research was part of the ‘Functional Fitness Research Project’ undertaken by the South Australia Metropolitan Fire Service. We would also like to thank the Chief Officer Michael Morgan and the team-members of Wellness and Safety Department for providing the data and facilitating the conduct of the study.

Funding

This study was funded by the Bushfire and Natural Hazards Cooperative Research Centre, the South Australian Metropolitan Fire Service and the Australian Government Research Training Program Scholarship.

Disclaimer

The views expressed in this article are those of the authors and are not an official position of the institution or funder. The funders had no involvement in the study design; analysis and interpretation of data; the writing of the manuscript.

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