Using multivariate analytical methods we examined the demographic and WTC trauma-related variables that independently predicted reporting of physical symptoms. There was a dose-response relationship between physical symptoms and the personal level of exposure to WTC trauma. Primary victims were 48% more likely to report severe headaches or migraine relative to non-victims, and other victims were similar to non-victims in this regard (χ2 = 6.45, P = 0.0398). Also, women were 64% more likely to report severe headaches or migraine compared with men (χ2 = 8.06, P = 0.0045). Relative to non-victims, primary victims were 61% more likely to report cough whereas other victims were 40% more likely to report the same (χ2 = 6.70, P = 0.0351). Also, persons who experienced four or more significant life events were 44% more likely to report cough compared with those who had not experienced any significant life events after 9/11 (χ2 = 8.14, P = 0.0433).
The K6 instrument12 had a possible range of scores of 6 to 30. Workers who had a score that was ≥19 met the criteria for clinically significant psychological distress. Only 7% of all respondents endorsed symptoms that met the criteria for clinically significant psychological distress within the 4 weeks before the survey. The distribution of psychological distress was similar between those who worked SOC and those who worked NOC (7.08% vs 6.45%; P = 0.8213). Similarly, there were no significant differences in psychological distress based on degree of exposure to 9/11 trauma (primary victims, 7.98%; other victims, 4.71%; non-victims, 6.59%; P = 0.6082). Multivariate analysis demonstrated that the number of life-event stressors between 9/11 and the time of survey was an independent predictor of nonspecific psychological distress. The scores for nonspecific psychological distress was 48.5% higher for persons who reported four or more life events relative to those who had no significant life events (χ2 = 9.06, P = 0.0286).
The range of scores for the IES-R instrument was 0 to 88. Subjects with scores ≥24 met the criteria for clinically significant PTSD.14,24 The mean IES-R score for all respondents was 2.85. Although none of the subjects met the criteria for clinically significant PTSD, the level of exposure to WTC trauma was a significant predictor of total IES-R scores. Subjects who worked SOC tended to have higher mean scores on the hyperarousal sub-scale compared with those who worked NOC (0.89 vs 0.69; P = 0.0474). Multivariate analysis showed that IES-R scores were 26.4% higher for primary victims relative to non-victims. The scores for other victims were similar to that of non-victims (χ2 = 6.35, P = 0.0418). Similarly, primary victims were more likely to have higher mean scores on the intrusion and hyperarousal sub-scales relative to other and non-victims. (P = 0.0458 and P = 0.0033, respectively). Also, the total IES-R scores tended to increase with age. Relative to persons who were 39 years old or younger, IES-R scores were 63.1% higher in respondents who were ≥60 years old and 52.0% higher for those who were 40 to 59 years old (χ2 = 8.04, P = 0.0179).
New Onset Psychiatric Illnesses in the 2 Years After 9/11.
Overall, 9.0% of subjects reported that they had been diagnosed with a psychiatric illness such as depression, anxiety, or panic attacks between 9/11 and the time of the survey. Those who worked NOC were more likely to have been diagnosed with a psychiatric illness compared with those who worked SOC (16% vs 5%; P = 0.0008). Similarly, non-victims and other victims tended to report new onset psychiatric diagnoses relative to primary victims (13.1% vs 9.4% vs 6.9%) although these differences did not achieve statistical significance (P = 0.2241).
Work Productivity 2 Years After 9/11
The respondents were expected to work an average of 38 hours each week. Overall, respondents reported that they had worked on average 38 hours in the week before the survey. The mean number of total days absent including sick and non-sick days in the 28 days (4 weeks) before the survey was 4.15 (SD = 5.0) days. There were no statistically significant differences in the number of total days absent based on location of work or level of personal exposure to WTC trauma (Table 5).
As shown in Table 5, the mean number of sick days absent because of problems with physical or mental health in the 4 weeks before the survey was 1.83 (SD = 5.1) days for all the subjects. NOC workers had a slightly higher average number of sick days absent compared with SOC workers (2.2 days vs 1.6 days; P = 0.3036). Similarly, non-victims had a slightly higher average number of sick days absent compared with other victims and primary victims (2.2 days vs 1.8 days vs 3.2 days; P = 0.1317).
On-the-Job Productivity Losses.
The possible range of scores for presenteeism questions adapted from the WHO HPQ was 5 to 25.16 The presenteeism questions were modified from the original because of concerns expressed by labor representatives about some of the questions in the WHO questionnaire. There are no established benchmarks for the adapted questionnaire. The mean presenteeism score for all the subjects was 9.44 (SD = 3.7). A median score of 9 was used as the criteria for presenteeism in the adapted questionnaire. Overall, 42.2% of subjects had presenteeism scores greater than 9, indicating lower quality of work within the 4 weeks (28 days) before the survey. There were no statistically significant differences in presenteeism scores based on location of work or level of exposure to 9/11 trauma (Table 6).
Self-Reported Changes in Overall Job Performance.
On average, all the respondents reported a slight decrease (−9%) in their overall job performance in the 4 weeks before the survey relative to their usual performance in the months before 9/11. Persons who had the highest levels of direct exposures tended to report slightly more decrements in job performance relative to those who had lower exposures to WTC trauma, although the differences did not achieve statistical significance. SOC workers reported a 10% decrease whereas NOC workers reported a 7% decrease in job performance 2 years after 9/11 (P = 0.27). Similarly, primary victims reported a 10% decrease, other victims reported a 9% decrease, whereas non-victims reported a 6% decrease in job performance (P = 0.17).
The Relationship Between Work Organizational Factors and Outcome Variables of Interest
We categorized perceived job stress into passive jobs, active jobs, low-strain jobs, and high-strain jobs using the psychological job demand and decision latitude model.25 Overall, 33.1% of the respondents had passive jobs, 25.2% had active jobs, 20.6% had low-strain jobs, and 21.1% had high-strain jobs. We also considered the effect of workplace social support on job stress and added a subcategory of isostrain, which consists of high strain in a setting of low social support.26 Overall, 17.1% of all respondents had isostrain jobs. Although there were no statistically significant differences based on work location or personal level of exposure to WTC trauma, the proportion of isostrain jobs was higher in NOC workers relative to SOC workers (21.4% vs 14.8%; P = 0.1094); and in non-victims relative to other victims and primary victims (21.9% vs 13.9% vs 16.1%; P = 0.3240) (Table 7). Given that isostrain is the highest level of perceived job stress, we used this as the indicator variable for job stress in multivariate analyses.
We categorized organizational culture into three main profiles (see OCI definitions in the Appendix) using the Organizational Culture Inventory.18 Overall, 34.4% of the respondents indicated that their workplace culture was Constructive, 42.5% reported a Passive/Defensive culture, whereas 23.1% reported an Aggressive/Defensive culture. For the purposes of multivariate analyses, we categorized organizational culture into two main variables: Constructive cultures and Defensive (Aggressive/Defensive and Passive/Defensive) cultures. Although there were no statistically significant differences based on work location or personal level of exposure to WTC trauma, the distribution of Defensive organizational cultures was slightly higher in NOC workers relative to SOC workers (82.2% vs 76.1%; P = 0.18). Also, 80.0% of non-victims, 85.7% of other victims, and 74.1% of primary victims reported Defensive organizational cultures at their respective worksites (P = 0.0886) (Table 8).
We also examined if organizational factors (perceived job stress and organizational culture) were independent predictors of any of the health or work productivity outcomes in a population of office workers who worked in Manhattan on 9/11, having controlled for covariates of interest. Workers who reported Defensive organizational cultures were 2.57 times more likely to report that they had isostrain jobs (high demand, low control, and low social support) compared with those who reported Constructive organizational cultures (χ2 = 6.05, P = 0.0139). Although organizational culture was not a significant predictor of psychological distress, it was a significant predictor of cough. Workers who reported Defensive organizational cultures were 34% more likely to report cough relative to those who reported a Constructive organizational culture (χ2 = 5.29, P = 0.0214). On-the-job productivity losses (presenteeism scores) were 15.3% higher for persons who worked in isostrain jobs relative to those with less stressful jobs (χ2 = 4.17, P = 0.0411).
The magnitude of human and economic loss from the terrorist attacks on the WTC on 9/11 has been unparalleled in the United States since the Civil War.27 The majority of studies that have examined the psychological sequelae of the WTC disaster have tended to focus on NYC community adult residents27–33 and children34,35 or nation-wide surveys that assessed the stress reactions of Americans after 9/11.36–38 Although research has been done on post-disaster sequelae among workers who were directly involved in WTC rescue and recovery operations,4–7,39 and short-term health effects in office workers in close proximity to the WTC,8,9 fewer studies have examined the long-term health impact of the WTC disaster on office workers who were in proximity to the WTC disaster3 and long-term worker productivity.11 Specifically data are lacking on the organizational factors that predict post-disaster symptomatology or changes in worker productivity in response to different levels of worker exposures to WTC trauma.
In this study, we categorized office workers’ WTC-related exposures based on geographical location of the worksite and on personal levels of exposures to the traumatic event. By adopting the classification of victims of disasters by Taylor and Frazer,19 we were able to determine if there was a dose-response relationship between levels of exposures and reported symptoms after the WTC terrorist attacks. Our study demonstrated that relative to their counterparts with lower or indirect exposures, office workers who had the highest levels of exposure to WTC trauma (primary victims) or those whose worksites were located closest to the WTC (SOC) were significantly more likely to report cough or severe headaches or migraine 2 years after 9/11, and there was a dose-response relationship in the reports of cough based on personal levels of exposures to the WTC terrorist attacks.
We posit that the reported physical symptoms are related to exposures to irritant vapors, fumes, and particulates from the WTC debris and air pollutants. This is biologically plausible given that fires continued to smolder in ground zero for more than 3 months after 9/11, causing plumes of acrid smoke to pollute the air. Also, resuspended dusts were generated from debris removal and site recovery activities. Hence, the contamination of indoor air in office buildings in surrounding areas.40–42 The higher prevalence of cough or headache among highly exposed office workers in the present study is consistent with other studies that have reported respiratory or irritant symptoms among responders that were present in the cloud of dust when the buildings collapsed or those who worked at ground zero soon thereafter. For example, the phenomenon of “WTC cough” or “aerodigestive syndrome” because of mucous membrane irritation have been reported in WTC rescue and recovery workers,41,43 and some of these symptoms have persisted for more than 2 years after 9/11.6
Almost 80% of subjects reported either an Aggressive/Defensive or Passive/Defensive organizational culture in the workplace, and office workers who reported such negative organizational cultures were 34% more likely to report cough relative to those who reported a Constructive or positive organizational culture. This suggests that organizational variables may be independent predictors of symptoms in an office population 2 years post-disaster. It is uncertain whether this finding relates to subjects’ prior disaster exposure or is simply a product of the organizational culture itself. Does the perception of a negative work culture predispose to more health complaints even more so in aftermath of disaster exposure? The modifying effect of work culture on the reporting of physical symptoms in response to traumatic events in the work environment is an important area for further research.
Persons exposed to traumatic events can experience multiple symptoms with varying intensities including difficulty concentrating, memory loss, psychological distress, which may cause tardiness, absenteeism, and diminished work quality. For example, Dirkzwager et al.44 demonstrated a doubling of the average length of sickness absence among rescue workers who attended to a firework depot explosion in the Netherlands that resulted in 22 deaths and injured about 1000 people. There is little empirical data on work absence and productivity losses among office workers in the aftermath of a large-scale workplace disaster.
Data from the present study showed that the WTC terrorist attacks had minimal impact on absenteeism, on-the-job productivity losses, and changes in self-reported job performance in office workers 2 years after the event. Although there appeared to be a dose-response relationship in decreases in overall self-reported job performance based on levels of exposures to WTC trauma, the differences did not achieve statistical significance. Nevertheless, this study demonstrated that a Defensive organizational culture was an important predictor of perceived job stress. Specifically, persons who reported Defensive organizational cultures were more than twice as likely to report high job strain with low social support (ie, isostrain) relative to their counterparts who reported Constructive organizational cultures. Furthermore, persons who worked in isostrain jobs tended to have higher on-the-job productivity losses relative to their counterparts with less stressful jobs.
Although the magnitude of the WTC terrorist attacks was much larger than the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City, data from this study and other researchers27,31 indicate that the long-term psychological sequelae from the WTC disaster is relatively low when compared with the psychological impact of the bombing disaster on Oklahoma City survivors and residents. For example, approximately 45% of the survivors (primary victims) of the Oklahoma City bombing had a post-disaster psychiatric disorder approximately 6 months after the event.2 There was also a doubling in the reported rates of perceived stress and psychological distress among adult residents of the Oklahoma City metropolitan areas and these psychological effects persisted for more than 1 year after the bombing.45
The prevalence of clinically significant psychological distress 2 years after the WTC terrorist attacks was relatively low among office workers in this study. Only 7% of the respondents endorsed symptoms of nonspecific psychological distress, and multivariate analysis showed that this was likely related to personal life-event stressors and not because of WTC trauma. Even among those subjects that had the highest level of exposure to the 9/11 trauma (primary victims), the prevalence of psychological distress was approximately 8%. This relatively low level of post-disaster psychological sequelae has been observed in another study of NYC residents where the investigators found that PTSD prevalence declined from 7.5% 1 month after 9/11 to 0.6% 6 months after 9/11.31
The reasons for the differential psychological impact of the terrorist attacks in Oklahoma City versus NYC are unknown. A possible explanation for the lower prevalence of long-term psychological sequelae post-9/11 is that NYC is a more fast-paced, high-stress environment overall relative to Oklahoma City. Also, NYC has had prior terrorism exposure with the bombing of the WTC in the early 1990s. In addition, there was tremendous national and international outpouring of psychosocial or financial support for NYC victims after 9/11. As such NYC residents and workers may have been better able to cope and were less likely to have long-term psychological distress compared with their counterparts in Oklahoma City. The reason(s) for the differential impacts of disasters or traumatic events on psychological symptoms in diverse communities is an important area for future research.
An unexpected finding in this study is the significantly higher rates of reporting of new onset psychiatric illnesses such as depression, anxiety disorder, and panic attacks in the 2 years after 9/11 among persons that were not directly exposed to WTC trauma (NOC workers) relative to persons with more direct exposures (SOC workers). We hypothesize that relative to NOC workers who comprised largely of non-victims, those that were directly exposed (SOC workers, primary victims) were more likely to have had access to or utilized WTC-related psychological or counseling programs made available by employer or community organizations. As such, the higher rates of reported psychiatric illnesses in persons considered less exposed may in fact be a delayed reaction from indirect exposures to the large-scale disaster that that traumatized the entire nation and was not recognized in workers that were located further away from the WTC attacks.
An important study limitation is that the study was conducted 2 years after 9/11. As such, persons who were the most adversely impacted by WTC trauma and were no longer hired at the worksites at the time of the survey are not represented in the study population. Hence, this study is only representative of the “survivor” population, and likely underestimates the true prevalence of symptoms and productivity losses in the exposed population. On the other hand, those workers who volunteered to participate may have had higher exposures, or experienced health effects post-9/11 and as such may be over represented in the study population. Also, as with any survey research, all data reported are based on subjects’ self-report, as such objective measures of work productivity variables that can only be obtained from employer records were not available to these investigators.
Although our study population was racially and socioeconomically diverse, and a wide variety of industries or professions were well represented in the study population, another limitation of this study is that the population is comprised of public sector and union workers. As such the results cannot be generalized to private sector workers as there are likely organizational culture differences between public versus private sector workers. For example, more than half of our study population had worked for the same employer for at least 10 years. This is not likely representative of the private sector workers who may have shorter average work tenures with the same employer, hence a more mobile workforce. In addition, the sample size of this pilot study is relatively small. A much larger study that includes private sector workers would be required to be able to generalize the research findings to all office workers.
In conclusion, the majority of office workers in this study reported that they were in good or excellent health 2 years after 9/11. Those workers that had the highest exposures to the WTC attacks were more likely to report headaches or cough relative to their less exposed counterparts. A perception of Defensive organizational cultures was highly prevalent in the study population. Office workers who reported Defensive organizational cultures were more likely to report cough and perceived job stress compared with those who reported Constructive organizational cultures. Job stress was an independent predictor of on-the-job productivity losses. The modifying effect of organizational culture on workers’ health and productivity in response to traumatic events in the work environment is an important area for further research.
This research was supported in part by the Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health (NIOSH) Grant 5 R21 OH007713-02, and the NIEHS sponsored UMDNJ Center for Environmental Exposures and Disease, Grant NIEHS P30ES005022.
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