Abstract
Objective:
Estimate the association of post-traumatic stress disorder (PTSD) and sleep latency among retired firefighters.
Methods:
Baseline health survey data collected from retried career Florida firefighters participating in an ongoing prospective cohort study from 2017–2021 was analyzed. Risk for PTSD was assessed using a 4-item primary care PTSD screening construct, and sleep onset latency was assessed by self-reported length of time to fall asleep.
Results:
Among the 500 participants, 8.0% screened positive for PTSD risk, 37.6% had prolonged sleep onset latency (≥20 minutes to fall asleep). Retired firefighters with PTSD risk were 2.7 times more likely (adjusted odds ratio=2.70 [95%Cl:1.27–5.75]) to have prolonged sleep latency compared to those without PTSD risk while controlling for covariates.
Conclusions:
Retired firefighters who screen positive for PTSD risk are three-time more likely to report delayed sleep onset latency.
Keywords: sleep latency, sleep disorders, post-traumatic stress disorder, retirement, firefighters
Sleep and mental health disorders are prevalent in the U.S. firefighter profession, a workforce typically engaged in long 24-hour work shifts. Firefighter duty rosters and individual shift length vary across fire departments, and epidemiologic studies indicate greater than half of U.S. firefighters report poor sleep and excessive sleepiness during their shifts.1–3 It is also common for firefighters, given the flexible duty rosters to have a second job and work extra hours for overtime pay. An observational study evaluating firefighter sleep disorders across 66 U.S. fire departments found 28.4% of firefighters screened positive for obstructive sleep apnea; 6.0% insomnia; 9.1% shift work disorder; and 3.4% restless legs syndrome.4 Furthermore, a significant proportion of firefighters suffer from undiagnosed sleep disorders, which can impair sleep quality, sleep duration and impact firefighter fatigue.1,5,6 While younger firefighters can better adapt to irregular and extended shift hours, changes in sleep and brain architecture throughout the life-course can limit older firefighters’ ability to adjust to shiftwork.7,8 Little is known about the sleep experience of older, retired firefighters once they are no longer exposed to the firefighter work environment.
Post-traumatic stress disorder (PTSD), a mental health condition that is prevalent in firefighters, can arise from exposure to a traumatic event such as structural fire burns, patient rescue, or car accidents. Other co-morbid health conditions including cardiovascular disease9, gastrointestinal disorders10,11, obesity12, and poor sleep quality13 have been associated with PTSD. Occupations such as military, frontline healthcare workers, policemen, and firefighters are at increased risk of developing PTSD due to the frequency of exposure to traumatic events.14 Prior research on the development of PTSD among incumbent firefighters has focused on traumatic events.15 A cross-sectional study among Australian firefighters found that firefighters with PTSD are more likely to have negative health outcomes (i.e., neurological, gastrointestinal, and cardiorespiratory symptoms) regardless of age.11 In a study on French firefighters, psychiatric disorders were independent risk factors for poor sleepy quality. A longitudinal study of 322 professional firefighter recruits found that they were exposed to approximately nine traumatic events during the first 3 years of service, of which 66% of events were in the line of duty.15 An estimated 20% of firefighters and healthcare workers fit a PTSD diagnosis thus further information is needed to characterize factors associated with PTSD in firefighters to develop strategies for intervention.16,17
Firefighters are concerned about their physical, mental, and emotional health and the impact sleep quality can have on their overall and long-term health.18,19 PTSD is shown to be associated with increased risk for other sleep disorders including sleep apnea20, insomnia18,21,22, and nightmares18,22. Limited information exists characterizing PTSD and the resultant negative health outcomes in retired firefighters. One study of 1,915 retired male firefighters who participated in the World Trade Center collapse found a 6% prevalence of diagnosed PTSD and 16% to 22% had an elevated risk for PTSD.23 There is a need to understand among firefighters, how sleep and mental health disorders evolve in retirement once exposure to the fire work environment ends. In the present study, we: 1) characterize self-reported sleep onset latency and risk for PTSD among a sample of retired career firefighters; and 2) examine the association of increased risk of PTSD and prolonged sleep onset latency. We hypothesize that retired firefighters with risk for PTSD will have longer sleep onset latency compared to retired firefighters without risk for PTSD.
MATERIALS AND METHODS
Study Design
The Advancing Epidemiology of Retired Firefighters Aging Longitudinally (AERIAL) study is a prospective longitudinal cohort study of retired career firefighters, established in April 2017, with the primary research goal to collect uniform firefighter-specific annual survey information on topics such as preventive health practices, healthcare access and utilization, and health risk behaviors that are linked to cancer diagnosis, cancer risk, chronic diseases, and injuries. Firefighters initially learn about the study procedures and protocol with research staff, address study questions, complete a written informed consent, and subsequently complete the baseline AREIAL cohort health survey. Each year, on the anniversary date of their enrollment in the cohort, the retired firefighters are invited to complete a follow up survey.
Study Population and Sample
Retired firefighters and firefighters in the Deferred Retirement Option Plan (DROP) were invited to complete the AERIAL baseline and follow up surveys. Firefighters in the DROP were incumbent firefighters working at a fire department that are between 1- and 5-years from official retirement. The DROP was designed to keep firefighters from retiring too early and putting a strain on the fire department to hire and train new firefighters. United States firefighters who were retired from the fire service or are in the DROP were recruited using a fire department’s e-mail listserv of retirees and other retiree venues/activities such as local firefighter union meetings and retiree events. The research team visited these events to recruit DROP-eligible and retired firefighters to encourage participation in the study. The study observation period for this analysis included baseline health surveys collected from retired and DROP Florida firefighters between April 2017 through October 2021 (n=646).
Data Collection Process & Study Baseline Questionnaire
Following the study overview and informed consent process, participants were provided with the choice of completing the AERIAL baseline questionnaire at the visited site via smart tablets or they can elect to be sent an email with a link to the survey so they can complete it in a place of privacy or convenience. Every year on the anniversary date from the completed baseline survey, participants were sent a link to their follow-up survey. The baseline and follow-up surveys collect participant socio-demographics, personal and family cancer history, and other physical/mental injuries, illnesses, or diseases continuing into retirement. All questions are voluntary. The consent form, baseline survey and follow up survey were all administered using the Research Electronic Data Capture (REDCap) software that provides a browser-based survey collection mechanism to monitor and follow-up longitudinal data collection. All study data was collected and managed using REDCap electronic data capture tools.24,25
Post-Traumatic Stress Disorder and Sleep Latency Measures
The baseline AERIAL survey includes questions pertaining to sleep disorders, sleep conditions and a Primary Care Post-Traumatic Stress Disorder (PC-PTSD) screener.26 Sleep-onset latency (the main study outcome) is the amount of time it takes to transition from being fully awake to sleep however there is limited consensus of normative values for sleep latency.27,28 Participants estimated their own sleep duration when responding to the following question: “currently, how long does it take you to fall asleep”. For this analysis, prolonged sleep onset latency was defined based on the Multiple Sleep Latency Test (MSLT) definition where an individual taking on average 20 or more minutes to fall asleep.25 Survey responses to the sleep latency question were then categorized into prolonged (≥20 minutes to fall asleep) or normal sleep latency. The PC-PTSD, shown to be a reliable psychometric operator, is a 4-item question screener that can be used in a primary care setting to assist with identifying individuals that are at risk for PTSD and may need intervention. Each PC-PTSD item has a binary outcome of 1 (yes) or 0 (no). Item responses are summed and scores can range from 0 to 4, with a score of 3 or more used to identify individuals with a probable PTSD diagnosis.
Data Analysis and Sensitivity Analysis
The total baseline AERIAL surveys (n= 646) available during the study observation period (April 2017 through October 2021), was reduced to a final analytic dataset of 500 retired firefighters. Approximately 22.6% of available records had missing data on the main outcome measure and predictor, sleep onset latency and PTSD risk, respectively. Participants dropped and retained in the analysis due to missingness on the main outcome and the main predictor were compared with respect to their age, gender, race, ethnicity, tenure as a firefighter and health conditions to determine whether there are systematic differences on these characteristics. There were no significant differences noted among these covariates between the two groups. We then calculated descriptive statistics for continuous variables, expressed as means with its standard deviation, and for categorical variables, expressed as frequency and percent of the sample. Bivariate association between main outcome of sleep onset latency and the potential categorical confounder were tested with either chi-square or Fisher’s exact test and corresponding p-values are calculated. Differences between the two study groups were studied using chi-square test for categorical variables and t test for continuous variables. Univariable and multivariable binary logistic regression models for having prolonged sleep onset latency were fit to determine the magnitude of the association between sleep onset latency and PTSD risk controlling for potential confounders. Unadjusted (uOR) and adjusted odds ratios (aOR) with corresponding 95% confidence intervals (95%CI) were calculated. An alpha level of 0.05 was considered statistically significant. All analyses were performed using IBM SPSS Statistics for Windows, version 26 (IBM Corp., Armonk, NY). The study protocol was reviewed and approved by the Institutional Review Board of the University.
RESULTS
The baseline sample characteristics of retired firefighters who participated in the AERIAL cohort survey stratified by sleep onset latency are shown in Table 1. Participant age ranged from 45 to 84 years with a mean age of 60.3 ± 7.1 years. Approximately 37.6% of retired and DROP-eligible firefighters had an prolonged sleep latency time period, reporting 20 minutes or longer to fall asleep. Compared to retired firefighters with normal sleep latency periods, retired firefighters with prolonged sleep latency were significantly more represented in the 50–59-year age group (43.8% versus 35.9%; p=.008), female (15.4% vs 4.5%; p=.001), and among those with PTSD risk (12.2% vs. 5.4%; p=.007).
Table 1.
Socio-demographic, sleep latency and risk of Post-traumatic stress disorder among retired and Deferred Retirement Option Plan (DROP)-eligible participants of the Advancing Epidemiology of Retired fIrefighters Aging Longitudinally (AERIAL) Cohort (April 2017 -October 2021)
| Characteristics | Total Samplen (%)* | Normal Sleep Latencyn (%)* | Prolonged Sleep Latencyn (%)* | p-value* |
|---|---|---|---|---|
| Row Total | 500 (100.0) | 312 (62.4) | 188 (37.6) | |
| Age Groups (years) | 0.008 | |||
| 40–49 | 20 (4.2) | 7 (2.3) | 13 (7.4) | |
| 50–59 | 185 (38.8) | 108 (35.9) | 77 (43.8) | |
| 60–69 | 214 (44.9) | 146 (48.5) | 68 (38.6) | |
| 70 and older | 58 (12.2) | 40 (13.3) | 18 (10.2) | |
| Gender | <0.001 | |||
| Male | 457 (91.4) | 298 (95.5) | 159 (84.6) | |
| Female | 43 (8.6) | 14 (4.5) | 29 (15.4) | |
| Race | ||||
| White | 479 (96.4) | 304 (97.7) | 175 (94.1) | 0.103 |
| Black | 7 (1.4) | 3 (1.0) | 4 (2.2) | |
| Other | 11 (2.2) | 4 (1.3) | 7 (3.8) | |
| Ethnicity | 0.419 | |||
| Hispanic | 49 (9.8) | 28 (9.0) | 21 (11.2) | |
| Non-Hispanic | 449 (90.2) | 283 (91.0) | 166 (88.8) | |
| Education | 0.270 | |||
| Grade 12 or GED | 17 (3.4) | 11 (3.5) | 6 (3.2) | |
| Some college or technical school | 311 (62.2) | 202 (64.7) | 109 (58.0) | |
| College graduate | 172 (34.4) | 99 (31.7) | 73 (38.8) | |
| Marital Status | 0.113 | |||
| Married | 418 (83.6) | 269 (86.2) | 149 (79.3) | |
| Divorced/Widowed/Separated | 70 (14.0) | 36 (11.5) | 34 (18.1) | |
| Never Married | 12 (2.4) | 7 (2.2) | 5 (2.7) | |
| Body Mass Index | 0.775 | |||
| Normal(18.5 to <24.9 kg/m2) | 70 (14.2) | 41 (13.1) | 29 (15.4) | |
| Overweight(25 to 29.9kg/m2) | 243 (48.0) | 153 (49.0) | 90 (47.9) | |
| Obese(>30kg/m2) | 187 (37.8) | 118 (37.8) | 69 (36.7) | |
| Retirement Status | 0.614 | |||
| Retired | 446 (89.2) | 285 (89.9) | 166 (88.3) | |
| Currently in DROP | 54 (10.8) | 32 (10.1) | 22 (11.7) | |
| Post-traumatic stress disorder | 0.007 | |||
| Yes | 40 (8.0) | 17 (5.4) | 23 (12.2) | |
| No | 460 (92.0) | 295 (94.6) | 165 (87.8) | |
| Sleep Disorders | ||||
| Yes, >=1 disorder | 133 (26.6) | 83 (26.6) | 50 (26.6) | 0.999 |
| No | 367 (73.4) | 229 (73.4) | 138 (73.4) | |
| Combating Fires (years) | ||||
| mean ± SD | 26.8 ± 7.5 | 27.0 ± 7.5 | 26.5 ± 7.4 | 0.879 |
| Sleep Latency Period (minutes) | <0.001 | |||
| mean ± SD | 27.4 ± 30.1 | 11.0 ± 5.6 | 54.4 ± 34.3 |
Differences in sub-total population sample due to item non-response or missing; SD=Standard Deviation; GED= High School Equivalency Diploma
Diagnosed sleeping disorders were reported by this sample of retired firefighters, including sleep apnea (24.0%), insomnia (2.8%), restless leg syndrome (2.4%), and other sleeping disorders (1.0%); Table 2). In the prior 12-months to baseline survey administration, retired firefighters reported sometimes to always snoring while sleeping (56.8%), and snorting, gasping or stop breathing while asleep (24.2%). In the 30 days prior to the baseline survey administration, retired firefighter reported experiencing, sometimes to almost always the following sleep conditions: waking up too early in morning or being unable to get back to sleep (54.0%); feeling unrested during the day, no matter total hours slept (50.8%); feeling excessively/overtly sleepy during day (42.4%); not getting enough sleep (48.8%); and taking sleeping pills/other medications to get sleep (24.0%). Approximately 39.3% of retired firefighters reported speaking to a health professional about having trouble with their sleep.
Table 2.
Sleep condition and sleep quality reported among retired career Florida firefighters participating in the 2017–2021 Advancing Epidemiology of Retired Firefighters Aging Longitudinally (AERIAL) Cohort Study, n=500.
| Sleep Characteristics | Total Sample n (%)* | Normal Sleep Latency n (%)* | Prolonged Sleep Latency n (%)* | p-value |
|---|---|---|---|---|
| Row Total | 500 (100.0) | 312 (62.4) | 188 (37.6) | |
| Sleep Disorders (Ever diagnosed) | ||||
| Sleep Apnea | 120 (79.5) | 79 (85.9) | 41 (69.5) | 0.218 |
| Insomnia | 14 (9.3) | 3 (3.3) | 11 (18.6) | 0.002 |
| Restless Legs Syndrome | 12 (7.9) | 8 (8.7) | 4 (6.8) | 0.757 |
| Other | 5 (3.3) | 2 (2.2) | 3 (5.1) | 0.299 |
| Sleep Symptoms (past 12 months) | ||||
| Snore while sleeping | ||||
| Never/Rarely | 201 (43.2) | 123 (42.1) | 78 (45.1) | 0.533 |
| Sometimes to Almost always | 264 (56.8) | 169 (57.9) | 95 (54.9) | |
| Snort, gasp, or stop breathing whileasleep | ||||
| Never/Rarely | 329 (75.8) | 212 (77.1) | 117 (73.6) | 0.411 |
| Sometimes to Almost always | 105 (24.2) | 63 (22.9) | 42 (26.4) | |
| Sleep Complaints (past month) | ||||
| Wake up too early in morning / Unable to get back to sleep | ||||
| Never/Rarely | 230 (46.0) | 164 (52.6) | 66 (35.1) | <0.001 |
| Sometimes to Almost always | 270 (54.0) | 148 (47.4) | 122 (64.9) | |
| Feel unrested during day, no matter total hours slept |
||||
| Never/Rarely | 246 (49.2) | 180 (57.7) | 66 (35.1) | <0.001 |
| Sometimes to Almost always | 254 (50.8) | 132 (42.3) | 122 (64.9) | |
| Feel Excessively/overtly sleep during day | ||||
| Never/Rarely | 288 (57.6) | 204 (65.4) | 84 44.7) | <0.001 |
| Sometimes to Almost always | 212 (42.4) | 108 (34.6) | 104 (55.3) | |
| Not get enough sleep | ||||
| Never/Rarely | 256 (51.2) | 194 (62.2) | 62 (33.0) | <0.001 |
| Sometimes to Almost always | 244 (48.8) | 118 (37.8) | 126 (67.0) | |
| Take Sleeping pills/other medication to get sleep |
||||
| Never/Rarely | 379 (76.0) | 256 (82.3) | 123 (65.4) | <0.001 |
| Sometimes to Almost always | 120 (24.0) | 55 (17.7) | 65 (34.6) | |
| Told Health Professional they have trouble sleeping | ||||
| Yes | 192 (39.3) | 88 (28.8) | 104 (56.8) | <0.001 |
| No | 297 (60.7) | 218 (71.2) | 79 (43.2) | |
| Hours Slept (mean ± SD) | ||||
| Average 24-hour period | 7.0 ± 1.3 | 7.3 ± 1.2 | 6.6 ± 1.3 | 0.016 |
Differences in sub-total population sample due to item non-response or missing. SD: Standard deviation
In the univariable binary logistic regression analyses (Table 3), PTSD risk was significantly associated with prolonged (≥20 minutes to fall asleep) sleep latency periods relative to retired firefighters without PTSD (un-adjusted odds ratio, UOR =2.42; 95% Confidence Interval, CI, [1.26–4.66]). Prolonged sleep latency was also significantly associated with age group 40–49 years (UOR=4.13 [1.41–12.08]), female sex (UOR=3.88 [1.99–7.56]), and sometimes to almost always taking sleeping pills (UOR=2.46 [1.62–3.74]). In the multivariable model, PTSD risk was still significantly associated with prolonged sleep latency times (Adjusted odds ratio, AOR =2.70; 95% CI [1.27–5.75]) even after controlling for covariates. However, individuals 40–49 years old vs. 70 and older (AOR = 3.84 [1.15–12.80]), female vs. males, (AOR= 3.03 [1.43–6.43), and taking sleeping pills sometimes to almost always vs. never/rarely (AOR=2.36 [1.48–3.77]) were significantly more likely to report prolonged sleep latency periods.
Table 3.
Univariable and multivariable binary logistic regression models of prolonged sleep latency (≥20 minutes to fall asleep) (vs. Normal sleep latency) among retired and DROP-eligible Florida firefighters participating in the 2017–2021 Advancing Epidemiology of Retired Firefighters Aging Longitudinally (AERIAL) Cohort Study, n=500.
| Characteristics | Unadjusted Odds Ratio (UOR) [95% Confidence Interval] |
Adjusted Odds Ratio (AOR) [95% Confidence Interval] |
|---|---|---|
| Post-traumatic stress disorder Risk (ref= No) | ||
| Yes | 2.42 [1.26–4.66] | 2.70 [1.27–5.75] |
| Age Groups (ref=70 and older) | ||
| 40–49 year olds | 4.13 [1.41–12.08] | 3.84 [1.15–12.80] |
| 50–59 year olds | 1.58 [0.85–2.97] | 1.32 [0.65–2.66] |
| 60–69 year olds | 1.04 [0.55–1.94] | 0.85 [0.43–1.67] |
| Gender (ref=Male) | ||
| Female | 3.88 [1.99–7.56] | 3.03 [1.43–6.43] |
| Race (ref= White) | ||
| Black | 2.32 [0.51–10.47] | 2.52 [0.46–13.71] |
| Other | 3.04 [0.88–10.53] | 2.43 [0.62–9.48] |
| Ethnicity (ref= non-Hispanic) | ||
| Hispanic | 1.28 [0.70–2.32] | 1.07 [0.51–2.24] |
| Education (ref=High school graduate/GED) | ||
| Some college or technical school | 0.99 [0.36–2.75] | 0.94 [0.31–2.79] |
| College graduate | 1.35 [0.48–3.82] | 1.12 [0.36–3.48] |
| Marital Status (ref=Never Married) | ||
| Married | 0.99 [0.36–2.75] | 0.63 [0.16–2.56] |
| Divorced/Widowed | 1.35 [0.48–3.82] | 0.91 [0.20–4.05] |
| Body Mass Index (ref=Normal) | ||
| Overweight | 0.83 [0.48–1.43] | 0.84 [0.45–1.55] |
| Obese | 0.83 [0.47–1.45] | 0.93 [0.48–1.78] |
| Retirement Status (ref=Retired) | ||
| In the DROP | 1.16 [0.65–2.06] | 0.65 [0.32–1.34] |
| Combatting Fires (Years) | 0.99 [0.97–1.02] | 1.01 [0.99–1.05] |
| Sleep Disorders (ref= None) | ||
| >=1 doctor diagnoses sleep disorder | 1.00 [0.66–1.51] | 0.96 [0.60–1.55] |
| Takes Sleeping Pills (ref= Never/Rarely) | ||
| Sometimes to Almost always | 2.46 [1.62–3.74] | 2.36 [1.48–3.77] |
UOR= Unadjusted odds ratio, the 95% confidence interval, CI.
AOR = Adjusted odds ratio, its 95% CI is shown in this table.
DISCUSSION
In this study of retired career firefighters, we found those who were at risk for PTSD were almost three times more likely to report a prolonged sleep initiation, at least 20 minutes or more, compared to retired firefighters without PTSD risk. These findings are consistent with a study using electroencephalogram (EEG) in a sample of traumatized police officers and military veterans, with and without PTSD.29 de Boer found that participants with PTSD had a notable decrease in sleep efficiency, characterized by a tendency toward longer sleep latency compared to participants without PTSD. This is an important finding for retired firefighters, given that sleep disturbances have been shown to play a significant role in the development and maintenance of PTSD.30 An individual’s sleep patterns, and sleep quality directly impacts memory consolidation and emotional regulation. During the retirement phase, it appears these retried firefighters who are no longer exposed to the hazardous firefighter work environment, experience sleep quality issues, including prolonged sleep latency, particularly among those at risk for PTSD.
Approximately 8.0% of retired firefighters in this study had a score higher than 3 on the Primary Care Post-Traumatic Stress Disorder (PC-PTSD) screener, which indicates a probable PTSD diagnosis. Similarly, Harvey et. al (2016) found 8% of Australian incumbent firefighters received a score indicating a probable PTSD diagnosis using a self-reported questionnaire based on PTSD Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria.31 Another epidemiologic study on firefighter mental health among Greek incumbent firefighters found that 13.1% of firefighters had a probable PTSD diagnosis.32 Much of the prior research evaluating PTSD in the U.S. fire service has highlighted associations with traumatic events, specifically involving early career personnel15,33. In theory, years of trauma exposure combatting fires and rescue could result in more traumatic experiences, however our findings suggest there was no association between years of combatting fires with prolonged sleep latency or PTSD. This warrants further investigation into other workplace exposures that may be associated with an increased risk of PTSD diagnosis.
Poor sleep quality was prevalent among retired U.S. firefighters with approximately 39.4% of firefighters in this sample reporting having told a health professional they have trouble sleeping and 37.6% reporting a prolonged sleep latency. We documented that younger retired firefighter (40–49 years old) and female firefighters with PTSD were more likely to report prolonged sleep latency. Previous occupational research on U.S. incumbent firefighters has reported ranges between 37% and 73% of personnel having reported poor sleep quality with occupational shift work often highlighted as a root cause.1,2,4 An analysis of data from the Wisconsin Sleep Cohort, a longitudinal cohort study of sleep habits and disorders, found that sleep onset latency for healthy males (mean age 59 years) was on average 11.2 minutes and females (mean age 56 years) was 13.9 minutes.34 We found, in the present analysis, a greater mean average of sleep onset latency in a cohort of which suggests that these firefighters take longer to initiate sleep compared to the general U.S. population. Our findings also suggest, in conjunction with existing research on incumbent firefighters, that an increased risk for poor sleep quality may continue along the life course despite retiring from the firefighter work environment.
Retired firefighters reported other doctor-diagnosed sleep disorders, including sleep apnea, insomnia, and restless legs syndrome. They also indicated sleep related issues such as snoring while sleeping; snorting, gasping or stop breathing while asleep; feeling unrested during the day, no matter total hours slept (50.5%); and taking sleeping pills/other medications to get sleep. These sleep related disorders were similar to those reported by incumbent firefighters in a study by Barger et al.4 They found that sleep-related attentional failures (i.e., asleep while driving and snoring) are highly prevalent in this group. Our study adds to the literature that retired firefighters continue to experience sleep disorders and issues on sleep quality into retirement, particularly among those retired firefighters at risk or PTSD. These findings of sleep initiation and quality in retired firefighters stands in contrast to those in a European cohort of public sector workers. Specifically, a 2017 study evaluating sleep difficulties in approximately 5,800 Finnish public sector workers (that includes first responders) found that retired workers slept approximately 20 minutes longer than before retirement and quality of sleep also improved.35 They documented that retired Finish workers experienced less early morning awakenings and less non-restorative sleep, compared to their last working years. Additional research is needed to understand how transitioning into retirement, changing shift-work patterns and removal out of the hazardous firefighter work environment impacts sleep quality and PTSD risk.
It is important to consider study limitations, specifically the use of self-reported health surveys, which could include the underreporting, overreporting, or withholding of information pertaining to personal poor sleep quality characteristics or psychiatric disorders. There are few studies available assessing correlation and agreement between self-reported versus actigraphy measured sleep duration and sleep latency in adults.36–39 Among available studies, it has been shown that participants may both overestimate and underestimate sleep latency and sleep duration when compared to actigraphy. Reporting of health information by firefighter could be influenced by an organizational culture of not reporting health conditions or health behaviors as to avoid re-assignment to administrative work or being pushed into early retirement. Participants in the AERIAL cohort predominately represent Florida firefighters which limits external generalizability to other firefighters around the country. Lastly, the PC-PTSD questionnaire is a screening tool classifying the risk of PTSD and not an official diagnosis of PTSD by a healthcare provider. Despite these limitations our study has several strengths to note. The AERIAL cohort is a dedicated prospective occupational cohort of retired firefighters that supports consistent and regular collection of health survey data of firefighters no longer tethered to a fire department. This cohort approach supports the longitudinal accuracy of data collection with regard to exposures, confounders, and endpoints. Hypothesis generation is another advantage with our cohort given we can investigate the temporal relationship between working as a firefighter and health conditions during retirement. The AERIAL cohort, to our knowledge, is the only ongoing U.S. study of retired firefighters that supports investigation into various health conditions that can be linked to occupational and non-occupational exposures.
CONCLUSION
Our analysis confirms our study hypothesis that risk for PTSD is associated with prolonged sleep latency among retired firefighters when compared to those without PTSD. Prolonged sleep latency is prevalent among retired career firefighters with and without PTSD. These findings have important implications for the study of sleep and mental health disorders in firefighters. Further research is needed to monitor the trajectory of delayed sleep onset latency and other sleep quality measures among trauma exposed incumbent firefighters with continuation into retirement. Occupational health and safety researchers should carefully evaluate the temporal association of sleep disorders and PTSD as to inform workplace interventions that could reduce the burden of sleep disorders in retirement.
Acknowledgements:
The authors would like to thank all the retired firefighters who took the time to participate in this research study. The authors would also like to thank Katerina M. Santiago, MPH for her support in collecting Advancing Epidemiology of Retired fIrefighters Aging Longitudinally (AERIAL) cohort data.
Funding:
This research work was supported by the State of Florida appropriation #2371B (Principal Investigator Kobetz) to the University of Miami (UM) Sylvester Comprehensive Cancer; and the National Cancer Institute of the National Institutes of Health under Award Number P30CA240139. The content is solely the responsibility of the authors and does not necessarily represent the official views of the Sylvester Comprehensive Cancer Center nor the National Institutes of Health.
Footnotes
Disclosures: The authors declare no potential conflicts of interest.
Institution and Ethics approval and informed consent: The study research protocol was reviewed and approved by the University Institutional Review Board (#20160896) at the University of Miami.
Disclaimers: The findings and conclusions in this paper are those of the authors and do not necessarily represent the views of the University of Miami, Miller School of Medicine, the National Institutes of Health and State of Florida.
REFERENCES
- 1.Billings J, Focht W. Firefighter Shift Schedules Affect Sleep Quality. J Occup Environ Med. 2016;58(3):294–298. [DOI] [PubMed] [Google Scholar]
- 2.Carey MG, Al-Zaiti SS, Dean GE, Sessanna L, Finnell DS. Sleep problems, depression, substance use, social bonding, and quality of life in professional firefighters. J Occup Environ Med. 2011;53(8):928–933. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Lim D-K, Baek K-O, Chung I-S, Lee M-Y. Factors related to sleep disorders among male firefighters. Annals of occupational and environmental medicine. 2014;26(1):1–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Barger LK, Rajaratnam SM, Wang W, et al. Common sleep disorders increase risk of motor vehicle crashes and adverse health outcomes in firefighters. J Clin Sleep Med. 2015;11(3):233–240. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Barger LK, O’Brien CS, Rajaratnam SM, et al. Implementing a Sleep Health Education and Sleep Disorders Screening Program in Fire Departments: A Comparison of Methodology. J Occup Environ Med. 2016;58(6):601–609. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Stout JW, Beidel DC, Brush D, Bowers C. Sleep disturbance and cognitive functioning among firefighters. Journal of Health Psychology. 2021;26(12):2248–2259. [DOI] [PubMed] [Google Scholar]
- 7.Shi Y, Bender B, McGovern P, et al. Daytime sleepiness among Midwestern firefighters. Arch Environ Occup Health. 2021;76(7):433–440. [DOI] [PubMed] [Google Scholar]
- 8.Reid K Comparing performance on a simulated 12 hour shift rotation in young and older subjects. Occupational and Environmental Medicine. 2001;58(1):58–62. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Sagud M, Jaksic N, Vuksan-Cusa B, et al. Cardiovascular Disease Risk Factors in Patients with Posttraumatic Stress Disorder (PTSD): A Narrative Review. Psychiatr Danub. 2017;29(4):421–430. [DOI] [PubMed] [Google Scholar]
- 10.Gradus JL, Farkas DK, Svensson E, Ehrenstein V, Lash TL, Toft Sorensen H. Posttraumatic Stress Disorder and Gastrointestinal Disorders in the Danish Population. Epidemiology. 2017;28(3):354–360. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Milligan-Saville JS, Paterson HM, Harkness EL, et al. The Amplification of Common Somatic Symptoms by Posttraumatic Stress Disorder in Firefighters. J Trauma Stress. 2017;30(2):142–148. [DOI] [PubMed] [Google Scholar]
- 12.Vieweg WV, Julius DA, Bates J, et al. Posttraumatic stress disorder as a risk factor for obesity among male military veterans. Acta Psychiatr Scand. 2007;116(6):483–487. [DOI] [PubMed] [Google Scholar]
- 13.Germain A, Hall M, Krakow B, Katherine Shear M, Buysse DJ. A brief sleep scale for Posttraumatic Stress Disorder: Pittsburgh Sleep Quality Index Addendum for PTSD. J Anxiety Disord. 2005;19(2):233–244. [DOI] [PubMed] [Google Scholar]
- 14.U.S. Department of Veteran Affairs. Disaster Rescue and Response Workers. 2007; https://www.ptsd.va.gov/professional/treat/type/disaster_response_work.asp. Accessed March 16, 2022.
- 15.Gulliver SB, Zimering RT, Knight J, et al. A prospective study of firefighters’ PTSD and depression symptoms: The first 3 years of service. Psychological trauma: theory, research, practice, and policy. 2021;13(1):44. [DOI] [PubMed] [Google Scholar]
- 16.Stanley IH, Hom MA, Hagan CR, Joiner TE. Career prevalence and correlates of suicidal thoughts and behaviors among firefighters. J Affect Disord. 2015;187:163–171. [DOI] [PubMed] [Google Scholar]
- 17.Corneil W, Beaton R,Murphy S, Johnson C, Pike K Exposure to traumatic incidents and prevalence of posttraumatic stress symptomatology in urban firefighters in two countries. Journal of Occupational Health Psychology. 1999;4(2):131–141. [DOI] [PubMed] [Google Scholar]
- 18.Weber FC, Norra C, Wetter TC. Sleep Disturbances and Suicidality in Posttraumatic Stress Disorder: An Overview of the Literature. Front Psychiatry. 2020;11:167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Schaefer Solle N, Caban-Martinez AJ, Levy RA, et al. Perceptions of health and cancer risk among newly recruited firefighters in South Florida. Am J Ind Med. 2018;61(1):77–84. [DOI] [PubMed] [Google Scholar]
- 20.Williams SG, Collen J, Orr N, Holley AB, Lettieri CJ. Sleep disorders in combat-related PTSD. Sleep Breath. 2015;19(1):175–182. [DOI] [PubMed] [Google Scholar]
- 21.Colvonen PJ, Ellison J, Haller M, Norman SB. Examining Insomnia and PTSD Over Time in Veterans in Residential Treatment for Substance Use Disorders and PTSD. Behav Sleep Med 2019;17(4):524–535. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Pigeon WR, Campbell CE, Possemato K, Ouimette P. Longitudinal relationships of insomnia, nightmares, and PTSD severity in recent combat veterans. J Psychosom Res. 2013;75(6):546–550. [DOI] [PubMed] [Google Scholar]
- 23.Chiu S, Webber MP, Zeig-Owens R, et al. Performance characteristics of the PTSD Checklist in retired firefighters exposed to the World Trade Center disaster. Annals of clinical psychiatry : official journal of the American Academy of Clinical Psychiatrists. 2011;23(2):95–104. [PubMed] [Google Scholar]
- 24.Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. A metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377–381. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Harris PA, Taylor R, Minor BL, et al. The REDCap consortium: Building an international community of software platform partners. J Biomed Inform. 2019;95:103208. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Langford DJ, Theodore BR, Balsiger D, et al. Number and type of post-traumatic stress disorder symptom domains are associated with patient-reported outcomes in patients with chronic pain. 2018;19(5):506–514. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Shrivastava D, Jung S, Saadat M, Sirohi R, Crewson K. How to interpret the results of a sleep study. J Community Hosp Intern Med Perspect. 2014;4(5):24983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 28.Littner MR, Kushida C, Wise M, et al. Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test. Sleep. 2005;28(1):113–121. [DOI] [PubMed] [Google Scholar]
- 29.de Boer M, Nijdam MJ, Jongedijk RA, et al. The spectral fingerprint of sleep problems in post-traumatic stress disorder. Sleep. 2020;43(4). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Colvonen PJ, Straus LD, Stepnowsky C, McCarthy MJ, Goldstein LA, Norman SB. Recent Advancements in Treating Sleep Disorders in Co-Occurring PTSD. Curr Psychiatry Rep. 2018;20(7):48. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Harvey SB, Milligan-Saville JS, Paterson HM, et al. The mental health of fire-fighters: An examination of the impact of repeated trauma exposure. Aust N Z J Psychiatry. 2016;50(7):649–658. [DOI] [PubMed] [Google Scholar]
- 32.Katsavouni F, Bebetsos E, Malliou P, Beneka A. The relationship between burnout, PTSD symptoms and injuries in firefighters. Occup Med (Lond). 2016;66(1):32–37. [DOI] [PubMed] [Google Scholar]
- 33.Skeffington PM, Rees CS, Mazzucchelli TG, Kane RT. The Primary Prevention of PTSD in Firefighters: Preliminary Results of an RCT with 12-Month Follow-Up. PLoS One. 2016;11(7):e0155873. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Mignot E, Lin L, Finn L, et al. Correlates of sleep-onset REM periods during the Multiple Sleep Latency Test in community adults. Brain. 2006;129(6):1609–1623. [DOI] [PubMed] [Google Scholar]
- 35.Myllyntausta S, Salo P, Kronholm E, et al. Changes in Sleep Difficulties During the Transition to Statutory Retirement. Sleep. 2018;41(1). [DOI] [PubMed] [Google Scholar]
- 36.Lauderdale DS, Knutson KL, Yan LL, Liu K, Rathouz PJJE. Sleep duration: how well do self-reports reflect objective measures? The CARDIA Sleep Study. 2008;19(6):838. [Google Scholar]
- 37.Girschik J, Fritschi L, Heyworth J, Waters FJJoe. Validation of self-reported sleep against actigraphy. 2012;22(5):462–468. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Cederberg KL, Mathison BG, Schuetz ML, Motl RWJJoCSM. Discrepancies between self-reported and device-measured sleep parameters in adults with multiple sclerosis. 2022;18(2):415–421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39.Billings JMJJocsm. Firefighter sleep: a pilot study of the agreement between actigraphy and self-reported sleep measures. 2022;18(1):109–117. [DOI] [PMC free article] [PubMed] [Google Scholar]