The analytic sample included 10,074 male participants who completed 16,826 questionnaires between September 12, 2001, and September 11, 2005. Participants were predominantly white (93.8%), and on 9/11 had a mean age of 39.6 years (standard deviation ±7.5). The number of participants in each year of the cross-sectional analyses was 8,679 in year 1; 1,161 in year 2; 2,820 in year 3; and 4,166 in year 4. Of those taking questionnaires in year 1, 934 returned for a follow-up questionnaire in year 2, 2,319 returned in year 3, and 3,498 returned in year 4. In the overall sample, 16.0% (n=1,607) first arrived at WTC during the morning of 9/11 (Arrival Group 1), 64.5% (n=6,497) first arrived during the afternoon of 9/11 (Arrival Group 2), 11.7% (n=1,181) first arrived on 9/12 (Arrival Group 3), and 7.8% (n=789) first arrived between three and 14 days after 9/11 (Arrival Group 4). The median number of months of work at the WTC site was 4.4, and 32.4% of participants worked at the site for four months or longer. Of the 2,281 participants (22.6%) who retired by the end of the study, 1,402 (61.5%) retired with a disability, of which 58 were due to a psychological disability. shows these and other unadjusted demographic characteristics in relation to ever having elevated PTSD risk.
Characteristics of the firefighter population from the Fire Department of the City of New York (n=10,074) by ever having elevated PTSD risk, 2001–2005
Prevalence of PTSD
In the first year after 9/11 (from September 12, 2001, to September 11, 2002), 9.8% (n=851/8,679) of firefighters reported symptoms sufficient to meet our definition of elevated PTSD risk, reporting the threshold number of symptoms in each domain and a summary score of at least 9. Subsequently, the following percentages of firefighters met the criteria for elevated PTSD risk: 9.9%, 11.7%, and 10.6% for years 2, 3, and 4, respectively.
Elevated PTSD risk at any time during the study was associated with earlier arrival time (Arrival Group 1 vs. all others; OR=2.7; 95% CI 2.3, 3.0) () and with spending ≥4 months working at the WTC site (OR=2.0; 95% CI 1.8, 2.3; p<0.0001). Elevated PTSD risk was also associated with disability retirement at any time during the study (disability retirement vs. regular retirement or active status; OR=1.4; 95% CI 1.2, 1.6).
Prevalence rates of elevated PTSD risk based on time of arrival at the WTC site, by year (2001–2005) (n=10,074)a
In all years, symptoms in the DSM-IV-TR arousal domain remained the most common, reported by 45.9% to 53.3% of participants, depending on the follow-up year, followed by symptoms in the re-experiencing domain, reported by 32.6% to 39.3% of participants, depending on the follow-up year. Avoidance/numbing domain was the least reported symptom group, reported by only 16.8% to 20.3% of participants, depending on the follow-up year ().
Prevalence rates of each domain of the DSM-IV-TR® diagnostic criteria for PTSD— re-experiencing, avoidance/numbing, and arousal—by year (2001–2005) (n=10,074)a
In year 1, 15.5% of the cohort reported having increased difficulty functioning at home, and 9.1% reported increased difficulty functioning at work. These percentages remained fairly stable over time, with difficulty functioning at home consistently more common than difficulty functioning at work: 17.2% vs. 10.4% at year 2, 15.4% vs. 9.3% at year 3, and 14.0% vs. 8.6% at year 4 (p<0.0001, all years).
Difficulty functioning at home and separately, and difficulty functioning at work were associated with elevated PTSD risk during each time period. The same pattern also held true for each domain: arousal, re-experiencing, and avoidance/numbing ().
Associations in 10,074 firefighters from the Fire Department of the City of New York between reporting elevated PTSD risk, reporting each PTSD domain, and reporting difficulty functioning at home and at work, by year (2001–2005)
Work-related stressors were associated with ever having elevated PTSD risk. A total of 1,663 (16.5%) firefighters worked at a firehouse that experienced one or more 9/11-related deaths (range: 1–11; median = 3). For each additional death in a member's firehouse, there was a corresponding 10.0% increase in the odds of ever having elevated PTSD risk (OR=1.1; 95% CI 1.1, 1.2).
Supervisory responsibility was found to be an important stressor. Of those reporting supervisory responsibilities during the collapse (n=562), 80.2% were officers or line officers (n=101 and n=350, respectively), and 19.8% (n=111) were firefighters. We found a significantly greater proportion of elevated PTSD risk in firefighters (30.0%), who normally did not have supervisory responsibilities but assumed those responsibilities during the disaster, as compared with officers (17.0%) or line officers (16.0%), who already had training and supervisory experience (OR=2.4; 95% CI 1.5, 3.7).
Receiving any counseling services was associated with elevated PTSD risk. In year 1, those individuals with elevated PTSD risk were four times more likely to use counseling services (OR=4.0; 95% CI 3.4, 4.6). This association remained unchanged in years 2 through 4 (data not shown). Elevated PTSD risk was also associated with receiving emotional support from family, friends, or coworkers (OR=1.7; 95% CI 1.4, 2.1). Emotional support was not assessed after year 1, as that question was omitted from subsequent versions of the questionnaire.
Similar associations with elevated PTSD risk were found in all four years, with differences mainly due to smaller participant numbers in years 2 and 3. The association between elevated PTSD risk and WTC exposure (arrival group or duration of months spent working at WTC) was significant in year 4 as well as in year 1 ().
Adjusted odds ratios and 95% CIs in 10,074 firefighters from the Fire Department of the City of New York for covariates associated with elevated PTSD risk, by year (2001–2005)a
At year 1, in addition to WTC exposure, variables associated with elevated PTSD risk included receiving counseling services (OR=2.9; 95% CI 2.4, 3.5); reporting an increase in alcohol use (OR=2.8; 95% CI 2.3, 3.4); reporting a decrease in exercise because an individual did not feel like it (OR=2.3; 95% CI 1.9, 2.8); obtaining emotional support from family, friends, or coworkers (OR=1.5; 95% CI 1.1, 2.0); being awarded a disability retirement pension (OR=1.5; 95% CI 1.1, 2.2); and the number of deaths in the firehouse where a member was stationed on 9/11 (OR=1.1; 95% CI 1.0, 1.1).
At year 4, in addition to WTC exposure variables, significant correlates of elevated PTSD risk included receiving counseling services (OR=3.5; 95% CI 2.6, 4.3), reporting a decrease in exercise (OR=2.6; 95% CI 2.1, 3.4), reporting an increase in alcohol use (OR=2.2; 95% CI 1.7, 2.9), and reporting a religious affiliation (OR=1.8; 95% CI 1.4, 2.4). Disability retirement and the number of deaths in a member's firehouse were no longer statistically significant by year 4.