Evaluation of non-response bias in a cohort study of World Trade Center terrorist attack survivors

Post-traumatic stress disorder and risk of first-time and repeated opioid-related hospitalizations among World Trade Center Health Registry enrollees

In 2021, and average of 220 deaths from opioid-related overdoses occurred daily in the US. Recent evidence suggests there is an association between post-traumatic stress disorder (PTSD) and increased opioid misuse, while little is known about opioid-related hospitalizations. This study used data from the World Trade Center Health Registry (WTCHR), a longitudinal cohort consisting of individuals directly exposed to the September 11th terrorist attacks with a high prevalence of resulting PTSD (3.8-29.6%). We linked WTCHR data to New York State hospitalization data to examine the question: do opioid-related hospitalizations (first time and repeated) differ by PTSD status. In a study sample of 37,968 adults, 145 experienced at least one episode of opioid-related hospitalization and 64 had repeated episodes during the study period. We found that in the 13-years post-9/11, individuals with PTSD had a significantly higher risk of a first-time opioid-related hospitalization (Hazard Ratio: 3.6, 95% CI: 2.7, 5.0) and repeated opioid-related hospitalizations (Hazard Ratio: 3.9, 95% CI: 2.7, 5.8) than those who did not have PTSD. Improved treatment of and increased screenings for PTSD may reduce the likelihood of opioid misuse in this population and consequently overdoses, hospitalizations, and healthcare costs.

Association of Rheumatoid Arthritis with Opioid Pain Medication Overuse among Persons Exposed to the 9/11 World Trade Center Disaster

We examined the association of post-9/11 rheumatoid arthritis (RA) diagnosis with opioid pain medication overuse among enrollees in the World Trade Center Health Registry (WTCHR). Opioid overuse was defined as the self-reported intake of prescribed opioids at a higher dosage or more often than directed in the last 12 months on one of the two most recent WTCHR surveys (2015-2016, 2020-2021). Post-9/11 RA was ascertained through self-reports and subsequently validated following medical record release by the enrollees' physicians or medical records review. We excluded those with self-reported RA that was not validated by their physicians and those who did not report being prescribed opioid pain medication in the last 12 months. Multivariable log-binomial regression was conducted to examine the relationship between post-9/11 RA diagnosis and opioid pain medication overuse, adjusting for sociodemographic characteristics and 9/11-related posttraumatic stress disorder (PTSD) symptoms. Of the 10,196 study enrollees, 46 had confirmed post-9/11 RA. The post-9/11 RA patients were mostly females (69.6% vs. 37.7%), less frequently non-Hispanic White (58.7% vs. 73.2%) individuals, and less often had attained a higher level of education (76.1% vs. 84.4%) compared to those without post-9/11 RA. Opioid pain medication overuse was significantly associated with a post-9/11 RA diagnosis (Adjusted Risk Ratio: 2.13, 95% CI: 1.44-3.17). More research is needed to better understand the use and management of prescribed opioids among WTC-exposed individuals with RA.

Trajectories of psychological distress among individuals exposed to the 9/11 World Trade Center disaster

BACKGROUND

Individuals present in lower Manhattan during the 9/11 World Trade Center (WTC) disaster suffered from significant physical and psychological trauma. Studies of longitudinal psychological distress among those exposed to trauma have been limited to relatively short durations of follow-up among smaller samples.

METHODS

The current study longitudinally assessed heterogeneity in trajectories of psychological distress among WTC Health Registry enrollees - a prospective cohort health study of responders, students, employees, passersby, and residents in the affected area (N = 30 839) - throughout a 15-year period following the WTC disaster. Rescue/recovery status and exposure to traumatic events of 9/11, as well as sociodemographic factors and health status, were assessed as risk factors for trajectories of psychological distress.

RESULTS

Five psychological distress trajectory groups were found: none-stable, low-stable, moderate-increasing, moderate-decreasing, and high-stable. Of the study sample, 78.2% were classified as belonging to the none-stable or low-stable groups. Female sex, being younger at the time of 9/11, lower education and income were associated with a higher probability of being in a greater distress trajectory group relative to the none-stable group. Greater exposure to traumatic events of 9/11 was associated with a higher probability of a greater distress trajectory, and community members (passerby, residents, and employees) were more likely to be in greater distress trajectory groups - especially in the moderate-increasing [odds ratios (OR) 2.31 (1.97-2.72)] and high-stable groups [OR 2.37 (1.81-3.09)] - compared to the none-stable group.

CONCLUSIONS

The current study illustrated the heterogeneity in psychological distress trajectories following the 9/11 WTC disaster, and identified potential avenues for intervention in future disasters.

Change in 9/11-related post-traumatic stress symptoms following cancer diagnosis

OBJECTIVE

Cancer can be a life-threatening stressor that may evoke pre-existing post-traumatic stress disorder (PTSD). We assessed change in 9/11-related PTSD symptoms following cancer diagnosis in a 9/11-exposed cohort, the World Trade Center Health Registry.

METHODS

We examined enrollees who had a first-time post-9/11 invasive cancer diagnosis and at least one pre- and two post-diagnosis 9/11-related PTSD assessments from enrolment through 2015. PTSD symptoms were measured using 17-item PTSD Checklist (PCL, range 17-85). Cancer was identified from New York State Cancer Registry and categorized as localized or advanced stage. We used piecewise spline linear mixed-effects models to examine rate of change in PCL scores from pre- to post-diagnosis periods, and whether the change differed by gender or stage, with time as fixed and random effects, adjusting for baseline age, race, and education.

RESULTS

9/11-related PTSD symptoms were slightly increasing in the pre-diagnosis period, while this trend reversed in the post-diagnosis period (β: -0.38; 95% CI: -0.60, -0.15). This trend was driven by male rescue/recovery workers (RRW), among whom significant decrease in rate of change in PCL scores was observed for those with advanced stage (slope change difference [95% CI]: -1.81 [-2.73, -0.90]). No significant difference in rate of change was observed among non-RRW. Among females, PCL scores tended to decrease slightly, with no significant difference in rate of change between pre- and post-diagnosis periods.

CONCLUSIONS

We observed significant reduction in the rate of change in 9/11-related PTSD symptoms among male RRW. The underlying mechanism is unknown, necessitating future research.

Comparison of prevalence and exposure-disease associations using self-report and hospitalization data among enrollees of the world trade center health registry

BACKGROUND

Although many studies have investigated agreement between survey and hospitalization data for disease prevalence, it is unknown whether exposure-chronic disease associations vary based on data collection method. We investigated agreement between self-report and administrative data for the following: 1) disease prevalence, and 2) the accuracy of self-reported hospitalization in the last 12 months, and 3) the association of seven chronic diseases (rheumatoid arthritis, hypertension, heart attack, stroke, asthma, diabetes, hyperlipidemia) with four measures of 9/11 exposure.

METHODS

Enrollees of the World Trade Center Health Registry who resided in New York State were included (N = 18,206). Hospitalization data for chronic diseases were obtained from the New York State Planning and Research Cooperative System (SPARCS). Prevalence for each disease and concordance measures (kappa, sensitivity, specificity, positive agreement, and negative agreement) were calculated. In addition, the associations of the seven chronic diseases with the four measures of exposure were evaluated using logistic regression.

RESULTS

Self-report disease prevalence ranged from moderately high (40.5% for hyperlipidemia) to low (3.8% for heart attack). Self-report prevalence was at least twice that obtained from administrative data for all seven chronic diseases. Kappa ranged from 0.35 (stroke) to 0.04 (rheumatoid arthritis). Self-reported hospitalizations within the last 12 months showed little overlap with actual hospitalization data. Agreement for exposure-disease associations was good over the twenty-eight exposure-disease pairs studied.

CONCLUSIONS

Agreement was good for exposure-disease associations, modest for disease prevalence, and poor for self-reported hospitalizations. Neither self-report nor administrative data can be treated as the "gold standard." Which source to use depends on the availability and context of data, and the disease under study.

Association between post-traumatic stress disorder and alcohol-related hospitalizations among World Trade Center Health Registry enrollees

BACKGROUND

We examined both the impact of 9/11-related exposures and repeated assessments of post-traumatic stress disorder (PTSD) on the risk of alcohol-related hospitalizations (ARH) among individuals exposed to the World Trade Center (WTC) disaster.

METHODS

9/11-related exposures (witnessing traumatic events, physical injuries, or both) were measured at baseline and PTSD symptoms were assessed at four time points (2003-2016) using the PTSD Checklist-17 among 53,174 enrollees in the WTC Health Registry. ICD-9-CM and ICD-10-CM codes were used to identify ARHs (2003-2016) through linked administrative data. For the effect of 9/11-related exposures on ARH, Cox proportional-hazards regression estimated hazard ratios (HR) and 95 % confidence intervals (CI); for time-varying PTSD, extended Cox proportional-hazards regression was used. Models were adjusted fora priori confounders and stratified by enrollee group (uniformed rescue and recovery worker (RRW), non-uniformed RRW, and community members). Person-time was calculated from baseline or 9/12/2001 to the earliest of ARH, withdrawal, death, or end of follow-up (12/31/2016).

RESULTS

Across all 9/11-related exposures, community members and non-uniformed RRWs were at increased risk of ARHs; uniformed RRWs were not. In adjusted models, PTSD was associated with an increased risk of hospitalization across all groups [HR, (95 % CI): uniformed RRWs: 2.6, (1.9, 3.6); non-uniformed RRWs: 2.1, (1.7, 2.7); and community members: 2.6, (2.1, 3.2)].

CONCLUSIONS

Among certain enrollee groups, 9/11-related exposures are associated with an increased risk of ARH and that PTSD is strongly associated with ARHs among all enrollee groups. Findings may assist the clinical audience in improving screening and treatment.

Post-9/11 Mental Health Comorbidity Predicts Self-Reported Confusion or Memory Loss in World Trade Center Health Registry Enrollees

Numerous studies report elevated levels of chronic mental health conditions in those exposed to the World Trade Center attacks of 11 September 2001 (9/11), but few studies have examined the incidence of confusion or memory loss (CML) or its association with mental health in 9/11 attack survivors. We investigated the incidence of CML and its association with the number of post-9/11 mental health conditions (PTSD, depression, and anxiety) in 10,766 World Trade Center Health Registry (Registry) enrollees aged 35–64 at the time of the wave 4 survey (2015–2016) that completed all four-wave surveys and met the study inclusion criteria. We employed log-binomial regression to evaluate the associations between CML and the number of mental health conditions. A total of 20.2% of enrollees in the sample reported CML, and there was a dose-response relationship between CML and the number of mental health conditions (one condition: RR = 1.85, 95% CI (1.65, 2.09); two conditions: RR = 2.13, 95% CI (1.85, 2.45); three conditions: RR = 2.51, 95% CI (2.17, 2.91)). Survivors may be experiencing confusion or memory loss partly due to the mental health consequences of the 9/11 attacks. Clinicians treating patients with mental health conditions should be aware of potential cognitive impairment.

Injury Severity and Psychological Distress Sustained in the Aftermath of the Attacks of 11 September 2001 Predict Somatic Symptoms in World Trade Center Health Registry Enrollees Sixteen Years Later

The World Trade Center attacks of 11 September 2001 (9/11) have been associated with the subsequent development of chronic diseases. Few studies have investigated the burden of somatic symptoms on attack victims, or the association of such symptoms with exposure to the 9/11 attacks. World Trade Center Health Registry (Registry) enrollees who were present south of Chambers Street during or immediately after the 9/11 attacks and who provided consistent answers regarding injury sustained on 9/11 were followed prospectively for up to 16 years post-9/11/01. We employed linear regression to evaluate the associations between injury severity, psychological distress and somatic symptoms in 2322 persons who completed all four Registry surveys and a subsequent Health and Quality of Life survey. Twenty-one percent of subjects had a “very high” burden of somatic symptoms, greater than in populations not exposed to a disaster. Somatic symptoms exhibited a dose-response association separately with injury severity and psychological distress trajectories. Victims of the 9/11 attacks suffer from a substantial burden of somatic symptoms which are associated with physical and psychological consequences of exposure to the attacks. Physical and mental health professionals need to work together when treating those exposed to complex disasters such as 9/11.

Systemic Autoimmune Disease Among Adults Exposed to the September 11, 2001 Terrorist Attack

Objective

Autoimmune disease is an emerging condition among persons exposed to the September 11, 2001 attack on the World Trade Center (WTC). Components of the dust cloud resulting from the collapse of the WTC have been associated with development of a systemic autoimmune disease, as has posttraumatic stress disorder (PTSD). We undertook this study to determine whether dust exposure and PTSD were associated with an increased risk of systemic autoimmune disease in a 9/11‐exposed cohort.

Methods

Among 43,133 WTC Health Registry enrollees, 2,786 self‐reported having a post‐9/11 systemic autoimmune disease. We obtained informed consent to review medical records to validate systemic autoimmune disease diagnoses for 1,041 enrollees. Diagnoses of systemic autoimmune diseases were confirmed by classification criteria, rheumatologist diagnosis, or having been prescribed systemic autoimmune disease medication. Controls were enrollees who denied having an autoimmune disease diagnosis (n = 37,017). We used multivariable log‐binomial regression to examine the association between multiple 9/11 exposures and risk of post‐9/11 systemic autoimmune disease, stratifying by responders (rescue, recovery, and clean‐up workers) and community members (e.g., residents, area workers).

Results

We identified 118 persons with systemic autoimmune disease. Rheumatoid arthritis was most frequent (n = 71), followed by Sjӧgren's syndrome (n = 22), systemic lupus erythematosus (n = 20), myositis (n = 9), mixed connective tissue disease (n = 7), and scleroderma (n = 4). Among 9/11 responders, those with intense dust cloud exposure had almost twice the risk of systemic autoimmune disease (adjusted risk ratio 1.86 [95% confidence interval 1.02–3.40]). Community members with PTSD had a nearly 3‐fold increased risk of systemic autoimmune disease.

Conclusion

Intense dust cloud exposure among responders and PTSD among community members were associated with a statistically significant increased risk of new‐onset systemic autoimmune disease. Clinicians treating 9/11 survivors should be aware of the potential increased risk of systemic autoimmune disease in this population.

Non-participation and attrition in a longitudinal study of civilians exposed to the January 2015 terrorist attacks in Paris, France

BACKGROUND

Non-participation and attrition are rarely studied despite being important methodological issues when performing post-disaster studies. A longitudinal survey of civilians exposed to the January 2015 terrorist attacks in Paris, France, was conducted 6 (Wave 1) and 18 months (Wave 2) after the attacks. We described non-participation in Wave 1 and determined the factors associated with attrition in Wave 2.

METHODS

Multivariate logistic regression models were used to compare participants in both waves with those who participated in the first wave only. Analyses were performed taking the following factors into account: socio-demographic characteristics, exposure to terror, peri-traumatic reactions, psychological support, perceived social support, impact on work, social and family life, and mental health disorders. Characteristics of new participants in Wave 2 were compared with participants in both waves using a chi-square test.

RESULTS

Of the 390 persons who were eligible to participate in the survey, 190 participated in Wave 1 (participation rate: 49%). The most frequently reported reason for non-participation was to avoid being reminded of the painful event (32%, n = 34/105). In Wave 2, 67 were lost to follow-up, 141 people participated, of whom 123 participated in Wave 1 (re-participation rate: 65%) and 18 were new. Attrition in Wave 2 was associated with socio-demographic characteristics (age, French origin) and location during the attacks, but not with terror exposure or mental health disorders. Compared with those who participated in both waves, new participants declared less social and psychological support since the attacks.

CONCLUSIONS

Attrition at 6 months was not associated with exposure to terror or mental health disorders, which indicates that any bias in future analyses on IMPACTS on mental health outcomes will be limited. Our findings suggest the importance of adapting similar surveys for people of foreign origin and of improving strategies to avoid attrition of younger people, for example by using social media, peers, and the educational environment. The present study also revealed that a high level of exposure to terror and a lack of social and psychological support after a terrorist event could impede individuals' participation in similar surveys in the short term.

Association Between Posttraumatic Stress Disorder and Mortality Among Responders and Civilians Following the September 11, 2001, Disaster

IMPORTANCE

Posttraumatic stress disorder (PTSD) has been associated with increased mortality, primarily in studies of veterans. The World Trade Center Health Registry (Registry) provides a unique opportunity to study the association between PTSD and mortality among a population exposed to the World Trade Center attacks in New York, New York, on September 11, 2001 (9/11).

OBJECTIVES

To assess whether 9/11-related probable PTSD (PTSD) is associated with increased mortality risk, as well as whether this association differs when including repeated measures of PTSD over time vs a single baseline assessment.

DESIGN, SETTING, AND PARTICIPANTS

A longitudinal cohort study of 63 666 Registry enrollees (29 270 responders and 34 396 civilians) was conducted from September 5, 2003, to December 31, 2016, with PTSD assessments at baseline (wave 1: 2003-2004) and 3 follow-up time points (wave 2: 2006-2007, wave 3: 2011-2012, wave 4: 2015-2016). Data analyses were conducted from December 4, 2018, to May 20, 2019.

EXPOSURES

Posttraumatic stress disorder was defined using the 17-item PTSD Checklist-Specific (PCL-S) self-report measure (score ≥50) at each wave (waves 1-4). Baseline PTSD was defined using wave 1 PCL-S, and time-varying PTSD was defined using the PCL-S assessments from all 4 waves.

MAIN OUTCOMES AND MEASURES

Mortality outcomes were ascertained through National Death Index linkage from 2003 to 2016 and defined as all-cause, cardiovascular, and external-cause mortality.

RESULTS

Of 63 666 enrollees (38 883 men [61.1%]; mean [SD] age at 9/11, 40.4 [10.4] years), 6689 (10.8%) had PTSD at baseline (responders: 2702 [9.5%]; civilians: 3987 [12.0%]). Participants who were middle aged (2022 [12.5%]), female (3299 [13.8%]), non-Latino black (1295 [17.0%]), or Latino (1835 [22.2%]) were more likely to have PTSD. During follow-up, 2349 enrollees died (including 230 external-cause deaths and 487 cardiovascular deaths). Among all enrollees in time-varying analyses, PTSD was associated with all-cause, cardiovascular, and external-cause mortality, with adjusted hazard ratios (AHRs) of greater magnitude compared with analyses examining baseline PTSD. Among responders, time-varying PTSD was significantly associated with increased risk of all-cause (AHR, 1.91; 95% CI, 1.58-2.32), cardiovascular (AHR, 1.95; 95% CI, 1.25-3.04), and external-cause (AHR, 2.40; 95% CI, 1.47-3.91) mortality. Among civilians, time-varying PTSD was significantly associated with increased risk of all-cause (AHR, 1.54; 95% CI, 1.28-1.85), cardiovascular (AHR, 1.72; 95% CI, 1.15-2.58), and external-cause (AHR, 2.11; 95% CI, 1.06-4.19) mortality.

CONCLUSIONS AND RELEVANCE

The risk of mortality differed in examination of baseline PTSD vs repeated measures of PTSD over time, suggesting that longitudinal data should be used where possible. Comparable findings between responders and civilians suggest that 9/11-related PTSD is associated with an increased mortality risk.

Probable Posttraumatic Stress Disorder and Lower Respiratory Symptoms Among Rescue/Recovery Workers and Community Members After the 9/11 World Trade Center Attacks-A Longitudinal Mediation Analysis

OBJECTIVE

Posttraumatic stress disorder (PTSD) and lower respiratory symptoms (LRS) often coexist among survivors of the September 11, 2001 (9/11) World Trade Center (WTC) attacks. Research in police and nontraditional responders suggests that PTSD mediates the relationship between 9/11 physical exposures and LRS, but not vice versa. We replicated these findings in WTC rescue/recovery workers (R/R workers), extended them to exposed community members, and explored the interplay between both physical and psychological 9/11 exposures, probable PTSD, and LRS over a 10-year follow-up.

METHODS

Participants were 12,398 R/R workers and 12,745 community members assessed in three WTC Health Registry surveys (2003-2004, 2006-2007, and 2011-2012). LRS and 9/11 exposures were self-reported. Probable PTSD was defined as a PTSD Checklist score ≥44.

RESULTS

Probable PTSD predicted LRS (R/R workers: β = 0.88-0.98, p < .001; community members: β = 0.67-0.86, p < .001) and LRS predicted PTSD (R/R workers: β = 0.83-0.91, p < .001; community members: β = 0.68-0.75, p < .001) at follow-ups, adjusting for prior symptoms and covariates. In both R/R workers and community members, probable PTSD mediated the relationship between 9/11 physical exposures (dust cloud, long duration of work) and LRS (indirect effects, p = .001-.006), and LRS mediated the physical exposure-PTSD relationship (indirect effects, p = .001-.006). In R/R workers, probable PTSD mediated the psychological exposure (losing friends or loved ones, witnessing horrific events)-LRS relationship (indirect effect, p < .001), but LRS did not mediate the psychological exposure-PTSD relationship (indirect effect, p = .332). In community members, high 9/11 psychological exposure predicted both probable PTSD and LRS at follow-ups; probable PTSD mediated the psychological exposure-LRS relationship (indirect effect, p < .001), and LRS mediated the psychological exposure-PTSD relationship (indirect effect, p = .001).

CONCLUSIONS

Probable PTSD and LRS each mediated the other, with subtle differences between R/R workers and community members. A diagnosis of either should trigger assessment for the other; treatment should be carefully coordinated.

Risk of Stroke Among Survivors of the September 11, 2001, World Trade Center Disaster

OBJECTIVE

The aim of this study was to investigate the association between 9/11-related posttraumatic stress disorder (PTSD), dust cloud exposure, and subsequent development of stroke among 42,527 enrollees in the World Trade Center (WTC) Health Registry.

METHODS

Using four waves of longitudinal data from the WTC Health Registry surveys, we employed Cox proportional hazards regression models to assess the associations.

RESULTS

Incidence of stroke was higher among those with PTSD or intense dust cloud exposure than those without, and it was even higher for those who had experienced both. In fully adjusted models, participants with PTSD had an increased risk of developing stroke [adjusted hazards ratio (AHR) 1.69, 95% confidence interval (95% CI) 1.42 to 2.02], as did those with intense dust exposure (AHR 1.29, 95% CI 1.09 to 1.53).

CONCLUSION

We found that individuals with 9/11-related PTSD and/or intense dust exposure may have an increased risk of developing stroke.

Comparing life satisfaction and functioning 15 years after September 11, 2001 among survivors with and without injuries: a mixed-method study

PURPOSE

This study compares life satisfaction and limited activity days among 9/11 survivors with and without physical injuries using quantitative and qualitative approaches.

METHODS

The study population included World Trade Center Health Registry enrollees who reported being injured on 9/11 in 2003-2004 and a sample of non-injured enrollees who participated in a cross-sectional substudy. We used multivariable logistic regression to examine differences in life satisfaction and number of limited activity days in the last 30 days between those with and without injuries. The free-response section of the survey was analyzed qualitatively to compare themes of those with and without injuries.

RESULTS

The final sample consisted of 2821 adult enrollees. Compared to those who were not injured, those who were injured on 9/11 were more likely to report being unsatisfied with their life (adjusted odds ratio (AOR): 1.5, 95% confidence intervals (CI) 1.1-2.0) and have 14 or more limited activity days in the last 30 days (AOR: 1.4, 95% CI 1.0-1.9). Among those who were injured, being partially or completely prevented from working increased the odds of being unsatisfied with life and having 14 or more limited activity days. In qualitative analysis, the emotional trauma experienced from 9/11 was a major and common theme, regardless of injury status. Those with injuries were more likely to express anger/lack of recognition/appreciation, describe substance use/abuse, and have financial/health care access issues.

CONCLUSIONS

More than 15 years after 9/11, those who were injured continue to be impacted, reporting lower life satisfaction and more functional impairment.

An Assessment of Long-Term Physical and Emotional Quality of Life of Persons Injured on 9/11/2001

Fifteen years after the disaster, the World Trade Center Health Registry (Registry) conducted The Health and Quality of Life Survey (HQoL) assessing physical and mental health status among those who reported sustaining an injury on 11 September 2001 compared with non-injured persons. Summary scores derived from the Short Form-12 served as study outcomes. United States (US) population estimates on the Physical Component Score (PCS-12) and Mental Component Score (MCS-12) were compared with scores from the HQoL and were stratified by Post-traumatic Stress Disorder (PTSD) and injury status. Linear regression models were used to estimate the association between both injury severity and PTSD and PCS-12 and MCS-12 scores. Level of injury severity and PTSD history significantly predicted poorer physical health (mean PCS-12). There was no significant difference between injury severity level and mental health (mean MCS-12). Controlling for other factors, having PTSD symptoms after 9/11 predicted a nearly 10-point difference in mean MCS-12 compared with never having PTSD. Injury severity and PTSD showed additive effects on physical and mental health status. Injury on 9/11 and a PTSD history were each associated with long-term decrements in physical health status. Injury did not predict long-term decrements in one's mental health status. Although it is unknown whether physical wounds of the injury healed, our results suggest that traumatic injuries appear to have a lasting negative effect on perceived physical functioning.

Conducting a study to assess the long-term impacts of injury after 9/11: participation, recall, and description

Background

The World Trade Center (WTC) attacks on September 11, 2001 (9/11) resulted in over 2700 fatalities and thousands injured. Injury on 9/11 has been identified as a risk factor for physical and mental health conditions, but the reasons for this are not well understood. In a population exposed to 9/11 and since followed, an in-depth study on the impacts of injury on 9/11 was conducted to identify factors that contribute to long-term functional issues. This report sought to examine factors influencing participation, participant recall of injury status over time, and determinants of injury severity.

Methods

Enrollees from the World Trade Center Health Registry who completed all surveys between 2003 and 2016 and initially reported being injured (N = 2699) as well as a sample of non-injured (N = 2598) were considered to be eligible for the Health and Quality of Life 15 Years after 9/11 (HQoL) Study. Predictors of study non-participation and inconsistent recall of injury over time (i.e., discrepant reports) were identified through fitting log binomial models.

Results

Participation rates were high overall (76.1%) and did not vary by initially reported injury status, although younger (vs. older), non-White (vs. White), and less educated (vs. more educated) enrollees were less likely to participate in the HQoL Study. Discrepant reporting of 9/11 injury status was much more common among enrollees who initially reported being injured on 9/11 (49.6%) compared with those who did not (7.3%). However, those who incurred more severe injuries on 9/11 were less likely to have discrepant reporting over time compared with those with more minor injuries (broken bone vs. sprain: risk ratio = 0.33, 95% Confidence Interval: 0.19, 0.57). Among those who consistently reported that they were injured on 9/11, most injuries occurred as a result of descending down stairs (31.5%) or by tripping and falling (19.9%); although being hit by a falling object was most often associated with high severity injuries (63.2%) compared with other modes of injury.

Conclusions

These findings highlight the methodological issues involved in conducting a study on the long-term impact of injury more than a decade after the initial incident and may be relevant to future investigators. Factors affecting participation rates, such as demographic characteristics, and those related to discrepant reporting over time, such as injury severity, may affect both the internal and external validity of studies examining the long-term impact of injury.

Pulmonary Fibrosis among World Trade Center Responders: Results from the WTC Health Registry Cohort

Dust created by the collapse of the World Trade Center (WTC) towers on 9/11 included metals and toxicants that have been linked to an increased risk of pulmonary fibrosis (PF) in the literature. Little has been reported on PF among WTC responders. This report used self-reported physician diagnosis of PF with an unknown sub-type to explore the association between levels of WTC dust exposure and PF. We included 19,300 WTC responders, enrolled in the WTC Health Registry in 2003–2004, who were followed for 11 years from 2004 to 2015. Exposure was defined primarily by intensity and duration of exposure to WTC dust/debris and work on the debris pile. Stratified Cox regression was used to assess the association. We observed 73 self-reported physician-diagnosed PF cases, with a PF incidence rate of 36.7/100,000 person-years. The adjusted hazard ratio (AHR) of PF was higher in those with a medium (AHR = 2.5, 95% CI = 1.1–5.8) and very high level of exposure (AHR = 4.5, 95% CI = 2.0–10.4), compared to those with low exposure. A test for exposure—response trend was statistically significant (P_trend = 0.004). Future research on WTC dust exposure and PF would benefit from using data from multiple WTC Health Program responder cohorts for increased statistical power and clinically confirmed cases.

Exposure to multiple disasters: The long-term effect of Hurricane Sandy (October 29, 2012) on NYC survivors of the September 11, 2001 World Trade Center attack

This study evaluated the impact of pre-Hurricane Sandy (Sandy) post-traumatic stress disorder (PTSD) trajectories on the relationship between Sandy exposures and post-Sandy 9/11-related PTSD among World Trade Center Health Registry (Registry) enrollees. The study population included 3,199 adult Registry enrollees who completed three surveys prior to Sandy in 2003-4, 2006-7, and 2011-12; a post-Hurricane Sandy survey (2013); and a follow-up survey in 2015-16. PTSD was assessed using the PTSD Checklist (PCL). Latent class growth analysis was used to identify groups of enrollees who shared a similar trajectory of change in PCL score in the time period prior to Sandy. We compared enrollees in each trajectory group to assess the impact of Sandy-related PTSD, Sandy exposures, and optimism on 9/11-related PTSD status post-Sandy (2015-16) using bivariate analyses and multivariable log-binomial regression. Sandy-related PTSD was the strongest predictor of subsequent 9/11-related PTSD. Lower optimism and higher Sandy exposure significantly predicted 9/11-related PTSD only in some trajectory groups. Hurricane Sandy may have exacerbated previously resolved symptoms of 9/11-related PTSD. This indicates a need after a disaster to assess and address mental health sequelae from previous traumatic exposures.

Characterizing Mental Health Treatment Utilization among Individuals Exposed to the 2001 World Trade Center Terrorist Attacks 14⁻15 Years Post-Disaster

Following the World Trade Center (WTC) attacks in New York City (NYC) on 11 September 2001 (9/11), thousands in NYC experienced significant stress reactions and disorders, presenting an immediate need for counseling and treatment. While other studies documented post-9/11 mental health treatment utilization, none have data more than two years post-disaster. We used data from 35,629 enrollees of the WTC Health Registry, a longitudinal cohort study of those exposed to the WTC attacks, to examine predictors of counseling after 9/11, the types of practitioners seen, and the perceived helpfulness of therapy up to 15 years post-disaster. Among enrollees, 37.7% reported receiving counseling at some time after 9/11. Predictors of seeking counseling included race/ethnicity, age at 9/11, education level, exposure to the WTC attacks, other traumatic experiences, mental health symptomology, and pre-9/11 counseling. Whites and Hispanics, those who were children on 9/11, and those with high levels of exposure to the WTC attacks sought counseling soonest after 9/11. Among those who sought counseling, Blacks, Asians, and those with lower education and income were less likely to see mental health specialists and more likely to see general practitioners or religious advisors. Finally, among those who sought recent counseling, women, Blacks, those aged ≥65 years, and those with very high WTC exposures were more likely to rate their recent counseling as very helpful. This study used data up to 15 years post-disaster to document mental health treatment utilization patterns, trends, and disparities that have implications for future preparedness plans and needs assessments.

PTSD and comorbid depression: Social support and self-efficacy in World Trade Center tower survivors 14-15 years after 9/11

OBJECTIVE

Following the World Trade Center (WTC) terrorist attack in New York City, prevalence rates of posttraumatic stress disorder (PTSD) and depression remain elevated. Although social support and self-efficacy have been associated with PTSD, little is known about their differential effect on PTSD and depressive comorbidity.

METHOD

WTC tower survivors (n = 1,304) were assessed at Wave 1 (2003-2004), Wave 2 (2006-2007), Wave 3 (2011-2012), and Wave 4 (2015-2016).

RESULTS

At Wave 4, 13.0% of participants had probable PTSD, a decrease from 16.5% at Wave 1. In addition, 4.1% (54) were identified as having PTSD alone, 6.8% (89) had depression alone, and 8.9% (116) had comorbid PTSD and depression. Of those with PTSD, 68.2% also had comorbid depression. WTC tower survivors with PTSD and comorbid depression reported greater PTSD symptom severity and were more likely to have had greater exposure to the events of 9/11 (adjusted odds ratio [aOR] = 1.14) and lower self-efficacy (aOR = 0.85) than those with depression alone. Less perceived social support predicted only depression and not PTSD, whereas less perceived self-efficacy equally predicted having PTSD or depression (aOR = 0.76).

CONCLUSIONS

Findings indicate that self-efficacy may be more important to the severity and chronicity of PTSD symptoms than social support. Multivariate comparisons suggest that PTSD with comorbid depression is a presentation of trauma-dependent psychopathologies, as opposed to depression alone following trauma, which was independent of trauma exposure and may be secondary to the traumatic event and posttraumatic response. Implications for assessment and treatment are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Prevalence of and factors associated with mammography and prostate-specific antigen screening among World Trade Center Health Registry enrollees, 2015-2016

To compare the prevalence of mammography and prostate-specific antigen (PSA) testing in 9/11-exposed persons with the prevalence among the US population, and examine the association between 9/11 exposures and these screening tests using data from the World Trade Center Health Registry (WTCHR) cohort. We studied 8190 female and 13,440 male enrollees aged ≥40 years at survey completion (2015–2016), who had a medical visit during the preceding year, had no self-reported breast or prostate cancer, and did not have screening for non-routine purposes. We computed age-specific prevalence of mammography (among women) and PSA testing (among men), and compared to the general population using 2015 National Health Interview Survey data (NHIS). We also computed the adjusted prevalence ratio (PR) and 95% confidence interval (95% CI) to examine the relationship between 9/11 exposures and screening uptakes using modified Poisson regression. Our enrollees had higher prevalences of mammogram and PSA testing than the US general population. 9/11 exposure was not associated with mammography uptake. Proximity to the WTC at the time of the attacks was associated with PSA testing in the age 60–74 group (PR = 1.06; 95% CI = 1.00–1.12). Among rescue/recovery workers and volunteers (RRW), being a firefighter was associated with higher PSA testing than other RRW across all age groups (40–49: PR = 1.45, 95% CI 1.16–1.81; 50–59: PR = 1.33, 95% CI 1.22–1.44; 60–74: PR = 1.14, 95% CI 1.06–1.23). Screening activities should be considered when studying cancer incidence and mortality in 9/11 exposed populations.

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Prevalence of breast and prostate cancer screening was higher than the U.S. population.

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World Trade Center exposure was not associated with breast cancer screening.

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Firefighters had higher PSA testing than other type of rescue and recovery workers.

Asthma among World Trade Center First Responders: A Qualitative Synthesis and Bias Assessment

The World Trade Center (WTC) disaster exposed the responders to several hazards. Three cohorts i.e., the Fire Department of New York (FDNY), the General Responder Cohort (GRC), and the WTC Health Registry (WTCHR) surveyed the exposed responder population. We searched Pubmed and Web of Science for literature on a well-published association between the WTC exposures and asthma, focusing on new-onset self-reported physician-diagnosed asthma. The resulting five articles were qualitatively assessed for potential biases. These papers were independently reviewed by the co-authors, and conclusions were derived after discussions. While, the cohorts had well-defined eligibility criteria, they lacked information about the entire exposed population. We conclude that selection and surveillance biases may have occurred in the GRC and WTCHR cohorts, but were likely to have been minimal in the FDNY cohort. Health care benefits available to responders may have increased the reporting of both exposure and outcome in the former, and decreased outcome reporting in the FDNY cohort. Irrespective of the biases, the studies showed similar findings, confirming the association between WTC exposure and self-reported physician-diagnosed asthma among responders. This suggests that health data gathered under great duress and for purposes other than epidemiology can yield sound conclusions. Potential biases can, however, be minimized by having validated survey instruments and worker registries in place before events occur.

Longitudinal determinants of depression among World Trade Center Health Registry enrollees, 14-15 years after the 9/11 attacks

BACKGROUND

Exposure to the September 11, 2001 (9/11) terrorist attacks has been found to be associated with posttraumatic stress disorder (PTSD) and comorbid PTSD and depression up to 10-11 years post-disaster. However, little is known about the longitudinal predictors of mental health conditions over time.

METHODS

We examined longitudinal determinants of depression within strata of PTSD among 21,258 enrollees of the World Trade Center Health Registry who completed four questionnaires over 14 years of follow-up (Wave 1 in 2003-04; Wave 2 in 2005-06; Wave 3 in 2011-12; and Wave 4 in 2015-16). PTSD status was measured using the PTSD checklist on all four waves and defined as a score of ≥ 44; depression was assessed using the 8-item Patient Health Questionnaire at Waves 3 and 4 and defined as a score of ≥ 10.

RESULTS

Across Waves 3 and 4, 18.6% experienced depression, and it was more common among those who ever had PTSD (56.1%) compared with those who had not (5.6%). Across PTSD strata, predictors of depression included low income, unemployment, low social integration and support, post-9/11 traumatic life events, and chronic physical illness. These factors also decreased the likelihood of recovering from depression.

LIMITATIONS

Depression symptoms were not measured at Waves 1 and 2; data was self-reported.

CONCLUSIONS

These findings highlight the substantial burden of depression in a trauma-exposed population 14-15 years post-disaster, especially among those with PTSD. Similar life stressors predicted the course of depression among those with and without PTSD which may inform public health and clinical interventions.

Comorbidity amplifies the effects of post-9/11 posttraumatic stress disorder trajectories on health-related quality of life

PURPOSE

The present study aims to examine the impact of physical and mental health comorbidities on the association between post-9/11 posttraumatic stress disorder (PTSD) trajectories over 10 years and health-related quality of life (HRQOL) among 9/11-exposed persons.

METHODS

30,002 responding adult World Trade Center Health Registry enrollees reporting no pre-9/11 PTSD were studied. PTSD trajectories (chronic, delayed, remitted, no PTSD) were defined based on a 17-item PTSD Checklist-Specific to 9/11 across three waves of survey data. Three indicators of poor HRQOL were defined based on CDC HRQOL-4 measures. We computed age-adjusted prevalence of physical and mental health comorbidity (depression/anxiety) by PTSD trajectory and used modified Poisson regression to assess the effect of PTSD trajectory on poor HRQOL prevalence, accounting for comorbidity.

RESULTS

Age-adjusted prevalence of overall comorbid conditions was 95.8 and 61.4% among the chronic and no-PTSD groups, respectively. Associations between 9/11-related PTSD trajectories and poor HRQOL were significant and became greater when comorbidity was included. Adjusted prevalence ratios were elevated for fair/poor health status (APR 7.3, 95% CI 6.5, 8.2), ≥ 14 unhealthy days (4.7; 95% CI 4.4, 5.1), and ≥ 14 activity limitation days during the last 30 days (9.6; 95% CI 8.1, 11.4) in the chronic PTSD group with physical and mental health comorbidity compared to those without PTSD and comorbidity; similar associations were observed for delayed PTSD.

CONCLUSIONS

Ten years post-9/11 physical and mental health comorbidities have a substantial impact on the PTSD trajectories and HRQOL association. The need for early identification and treatment of PTSD and comorbidity should be emphasized to potentially improve HRQOL.

Persistent Post-9/11 Hearing Problems Among World Trade Center Health Registry Rescue and Recovery Workers, 2001 to 2007

OBJECTIVE

To examine the association between 9/11-related exposures and self-reported hearing problems among 16,579 rescue/recovery workers in the World Trade Center (WTC) Health Registry.

METHODS

Using Registry Waves 1 (2003 to 2004) and 2 (2006 to 2007), we modeled the association between two metrics of 9/11-related exposures and hearing difficulties.

RESULTS

The prevalence of incident, persistent hearing problems was 4.4%. In a fully adjusted model, workers with higher environmental hazards scores were twice as likely (interquartile range OR 2.1; 95% confidence interval [CI] 1.8, 2.5) to report hearing problems. Based on the same fully adjusted model, workers unable to hear in the dust cloud were 2.3 (95% CI 1.8, 3.0) times more likely to report hearing problems as compared with workers not in the dust cloud.

CONCLUSIONS

We observed a consistent association between WTC-related exposures and self-reported hearing problems among rescue/recovery workers.

Injury, intense dust exposure, and chronic disease among survivors of the World Trade Center terrorist attacks of September 11, 2001

Background

The World Trade Center attack of September 11, 2001 in New York City (9/11) exposed thousands of people to intense concentrations of hazardous materials that have resulted in reports of increased levels of asthma, heart disease, diabetes, and other chronic diseases along with psychological illnesses such as post-traumatic stress disorder (PTSD). Few studies have discriminated between health consequences of immediate (short-term or acute) intense exposures versus chronic residential or workplace exposures.

Methods

We used proportional hazards methods to determine adjusted hazard ratios (AHRs) for associations between several components of acute exposures (e.g., injury, immersion in the dust cloud) and four chronic disease outcomes: asthma, other non-neoplastic lung diseases, cardiovascular disease, and diabetes, in 8701 persons free of those conditions prior to exposure and who were physically present during or immediately after the World Trade Center attacks. Participants were followed prospectively up to 11 years post-9/11.

Results

Heart disease exhibited a dose-response association with sustaining injury (1 injury type: AHR =2.0, 95% CI (Confidence Interval) 1.1–3.6; 2 injury types: AHR = 3.1, 95% CI 1.2–7.9; 3 or more injury types: AHR = 6.8, 95% CI 2.0–22.6), while asthma and other lung diseases were both significantly associated with dust cloud exposure (AHR = 1.3, 95% CI 1.0–1.6). Diabetes was not associated with any of the predictors assessed in this study.

Conclusion

In this study we demonstrated that the acute exposures of injury and dust cloud that were sustained on 9/11/2001 had significant associations with later heart and respiratory diseases. Continued monitoring of 9/11 exposed persons’ health by medical providers is warranted for the foreseeable future.

On the impact of nonresponse in logistic regression: application to the 45 and Up study

Background

In longitudinal studies, nonresponse to follow-up surveys poses a major threat to validity, interpretability and generalisation of results. The problem of nonresponse is further complicated by the possibility that nonresponse may depend on the outcome of interest. We identified sociodemographic, general health and wellbeing characteristics associated with nonresponse to the follow-up questionnaire and assessed the extent and effect of nonresponse on statistical inference in a large-scale population cohort study.

Methods

We obtained the data from the baseline and first wave of the follow-up survey of the 45 and Up Study. Of those who were invited to participate in the follow-up survey, 65.2% responded. Logistic regression model was used to identify baseline characteristics associated with follow-up response. A Bayesian selection model approach with sensitivity analysis was implemented to model nonignorable nonresponse.

Results

Characteristics associated with a higher likelihood of responding to the follow-up survey include female gender, age categories 55–74, high educational qualification, married/de facto, worked part or partially or fully retired and higher household income. Parameter estimates and conclusions are generally consistent across different assumptions on the missing data mechanism. However, we observed some sensitivity for variables that are strong predictors for both the outcome and nonresponse.

Conclusions

Results indicated in the context of the binary outcome under study, nonresponse did not result in substantial bias and did not alter the interpretation of results in general. Conclusions were still largely robust under nonignorable missing data mechanism. Use of a Bayesian selection model is recommended as a useful strategy for assessing potential sensitivity of results to missing data.

Electronic supplementary material

The online version of this article (doi:10.1186/s12874-017-0355-z) contains supplementary material, which is available to authorized users.

Quantitative bias analysis in an asthma study of rescue-recovery workers and volunteers from the 9/11 World Trade Center attacks

PURPOSE

When learning bias analysis, epidemiologists are taught to quantitatively adjust for multiple biases by correcting study results in the reverse order of the error sequence. To understand the error sequence for a particular study, one must carefully examine the health study's epidemiologic data-generating process. In this article, we describe the unique data-generating process of a man-made disaster epidemiologic study.

METHODS

We described the data-generating process and conducted a bias analysis for a study associating September 11, 2001 dust cloud exposure and self-reported newly physician-diagnosed asthma among rescue-recovery workers and volunteers. We adjusted an odds ratio (OR) estimate for the combined effect of missing data, outcome misclassification, and nonparticipation.

RESULTS

Under our assumptions about systematic error, the ORs adjusted for all three biases ranged from 1.33 to 3.84. Most of the adjusted estimates were greater than the observed OR of 1.77 and were outside the 95% confidence limits (1.55, 2.01).

CONCLUSIONS

Man-made disasters present some situations that are not observed in other areas of epidemiology. Future epidemiologic studies of disasters could benefit from a proactive approach that focuses on the technical aspect of data collection and gathers information on bias parameters to provide more meaningful interpretations of results.

Asthma among Staten Island fresh kills landfill and barge workers following the September 11, 2001 World Trade Center terrorist attacks

BACKGROUND

Although airborne respiratory irritants at the World Trade Center (WTC) site have been associated with asthma among WTC Ground Zero workers, little is known about asthma associated with work at the Staten Island landfill or barges.

METHODS

To evaluate the risk of asthma first diagnosed among Staten Island landfill and barge workers, we conducted a survey and multivariable logistic regression analysis regarding the association between Staten Island landfill and barge-related work exposures and the onset of post-9/11 asthma.

RESULTS

Asthma newly diagnosed between September 11, 2001 and December 31, 2004 was reported by 100/1,836 (5.4%) enrollees. Jobs involving sifting, digging, welding, and steel cutting, enrollees with high landfill/barge exposure index scores or who were police and sanitation workers, and enrollees with probable posttraumatic stress disorder all had increased odds ratios for new-onset asthma.

CONCLUSIONS

Post-9/11 asthma cumulative incidence among Staten Island landfill/barge workers was similar to that of other WTC disaster rescue and recovery workers. Am. J. Ind. Med. 59:795-804, 2016. © 2016 Wiley Periodicals, Inc.

Risk factors for and consequences of persistent lower respiratory symptoms among World Trade Center Health Registrants 10 years after the disaster

OBJECTIVES

The prevalence of persistent lower respiratory symptoms (LRS) among rescue/recovery workers, local area workers, residents and passers-by in the World Trade Center Health Registry (WTCHR) was analysed to identify associated factors and to measure its effect on quality of life (QoL) 10 years after 9/11/2001.

METHODS

This cross-sectional study included 18 913 adults who completed 3 WTCHR surveys (2003-2004 (Wave 1 (W1)), 2006-2007 (Wave 2 (W2)) and 2011-2012 (Wave 3 (W3)). LRS were defined as self-reported cough, wheeze, dyspnoea or inhaler use in the 30 days before survey. The prevalence of three LRS outcomes: LRS at W1; LRS at W1 and W2; and LRS at W1, W2 and W3 (persistent LRS) was compared with no LRS on WTC exposure and probable mental health conditions determined by standard screening tests. Diminished physical and mental health QoL measures were examined as potential LRS outcomes, using multivariable logistic and Poisson regression.

RESULTS

Of the 4 outcomes, persistent LRS was reported by 14.7%. Adjusted ORs for disaster exposure, probable post-traumatic stress disorder (PTSD) at W2, lacking college education and obesity were incrementally higher moving from LRS at W1, LRS at W1 and W2 to persistent LRS. Half of those with persistent LRS were comorbid for probable PTSD, depression or generalised anxiety disorder. Enrollees with persistent LRS were 3 times more likely to report poor physical health and ∼ 50% more likely to report poor mental health than the no LRS group.

CONCLUSIONS

LRS, accompanied by mental health conditions and decreased QoL, have persisted for at least 10 years after 9/11/2001. Affected adults require continuing surveillance and treatment.