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

Asthma, classical conditioning, and the autonomic nervous system - a hypothesis for why children wheeze

Paediatric asthma is an increasing global healthcare problem for which current treatments are not always effective. This review explores how abnormal triggering of the autonomic diving reflex might be important in explaining research findings and the real-world experience of asthma. It hypothesises that the way in which stress during pregnancy is associated with childhood asthma could be through effects on the developing nervous system. This results in increased parasympathetic responsiveness and specifically, excessive triggering of the diving reflex in response to wetting and cooling of the face and nose as occurs with upper airway infections and allergic rhinitis. In aquatic mammals the reflex importantly includes the contraction of airway smooth muscle to minimise lung volume and prevent nitrogen narcosis from diving at depth. Misfiring of this reflex in humans could result in the pathological airway narrowing that occurs in asthma. The diving reflex, and possibly also smooth muscle, is a vestigial remnant of our aquatic past. The hypothesis further suggests that classically conditioned reflex responses to neutral cues and contexts that were present at the same time as the stimuli that initially caused symptoms, become of themselves ongoing triggers of recurrent wheeze. Symptoms occurring in this way, irrespective of the presence of allergens and ongoing airway sensitisation, explain why allergen avoidance is poorly effective in alleviating wheeze and why asthma is made worse by stress. Interventions to suppress the diving reflex and to prevent reflex conditioned wheezing could result in more effective asthma management.

Impact of a Large Fire and Subsequent Pollution Control Failure at a Coke Works on Acute Asthma Exacerbations in Nearby Adult Residents

Clairton, Pennsylvania, is home to the largest coke works facility in the United States (US). On 24 December 2018, a large fire occurred at this facility and damaged pollution control equipment. Although repairs were not completed for several months, production continued at pre-fire capacity and daily emissions increased by 24 to 35 times, with multiple exceedances of monitored levels of outdoor air pollution (OAP). The aim of this study was to objectively evaluate the impact of this industrial incident and resultant OAP exceedances on asthma morbidity. We assessed pre-fire and post-fire rate ratios (RR) of outpatient and emergency department (ED) visits for asthma exacerbations among nearby adult residents. Pre-fire versus post-fire RRs increased for both visit types: RR = 1.82 (95% CI: 1.30, 2.53; p < 0.001) and 1.84 (95% CI: 1.05, 3.22; p = 0.032) for outpatient and ED visits, respectively. Additionally, total visit rates increased on days with OAP exceedances: RR = 2.47 (95% CI: 1.52, 4.01; p < 0.0001), 1.58 (95% CI: 1.00, 2.48; p = 0.048) and 1.79 (95% CI: 1.27, 2.54; p = 0.001) for PM_2.5, SO₂, and H₂S exceedance days, respectively. These results show a near doubling of acute visits for asthma exacerbations in nearby adult residents during this industrial incident and underscore the need for prompt remediation and public notification of OAP exceedances to prevent adverse health impacts.

Dietary phenotype and advanced glycation end-products predict WTC-obstructive airways disease: a longitudinal observational study

Background

Diet is a modifier of metabolic syndrome which in turn is associated with World Trade Center obstructive airways disease (WTC-OAD). We have designed this study to (1) assess the dietary phenotype (food types, physical activity, and dietary habits) of the Fire Department of New York (FDNY) WTC-Health Program (WTC-HP) cohort and (2) quantify the association of dietary quality and its advanced glycation end product (AGE) content with the development of WTC-OAD.

Methods

WTC-OAD, defined as developing WTC-Lung Injury (WTC-LI; FEV₁ < LLN) and/or airway hyperreactivity (AHR; positive methacholine and/or positive bronchodilator response). Rapid Eating and Activity Assessment for Participants-Short Version (REAP-S) deployed on 3/1/2018 in the WTC-HP annual monitoring assessment. Clinical and REAP-S data of consented subjects was extracted (7/17/2019). Diet quality [low-(15–19), moderate-(20–29), and high-(30–39)] and AGE content per REAP-S questionnaire were assessed for association with WTC-OAD. Regression models adjusted for smoking, hyperglycemia, hypertension, age on 9/11, WTC-exposure, BMI, and job description.

Results

N = 9508 completed the annual questionnaire, while N = 4015 completed REAP-S and had spirometry. WTC-OAD developed in N = 921, while N = 3094 never developed WTC-OAD. Low- and moderate-dietary quality, eating more (processed meats, fried foods, sugary drinks), fewer (vegetables, whole-grains),and having a diet abundant in AGEs were significantly associated with WTC-OAD. Smoking was not a significant risk factor of WTC-OAD.

Conclusions

REAP-S was successfully implemented in the FDNY WTC-HP monitoring questionnaire and produced valuable dietary phenotyping. Our observational study has identified low dietary quality and AGE abundant dietary habits as risk factors for pulmonary disease in the context of WTC-exposure. Dietary phenotyping, not only focuses our metabolomic/biomarker profiling but also further informs future dietary interventions that may positively impact particulate matter associated lung disease.

Comorbid posttraumatic stress disorder and major depressive disorder are associated with asthma morbidity among World Trade Center workers

BACKGROUND

World Trade Center (WTC) rescue and recovery workers have a high burden of asthma, comorbid posttraumatic stress disorder (PTSD), and major depressive disorder (MDD). PTSD is associated with worse asthma outcomes.

OBJECTIVE

In this study, we evaluated whether the relationship between PTSD and asthma morbidity is modified by the presence of MDD.

METHODS

We used data from a cohort of WTC workers with asthma. Asthma control (asthma control questionnaire), resource utilization, and quality of life (asthma quality of life questionnaire) were evaluated. We used regression analyses to evaluate the adjusted association of PTSD and MDD with asthma control, resource utilization, and quality of life.

RESULTS

Of the study cohort of 293 WTC workers with asthma, 19% had PTSD alone, 2% had MDD alone, and 12% had PTSD and MDD. Adjusted mean differences (95% confidence interval) in asthma control questionnaire scores were 1.32 (0.85-1.80) for WTC workers with PTSD and MDD, 0.44 (0.03-0.84) for those with PTSD alone, and 0.50 (-0.38 to 1.38) for workers with MDD alone compared with those without MDD or PTSD. WTC workers with PTSD and MDD, PTSD alone, and MDD alone had mean (95% confidence interval) adjusted differences in asthma quality of life questionnaire scores of -1.67 (-2.22 to -1.12), -0.56 (-2.23 to -1.12), and -1.21 (-2.23 to -0.18), respectively, compared with workers without MDD or PTSD. Similar patterns were observed for acute resource utilization.

CONCLUSION

PTSD and MDD seem to have a synergistic effect that worsens asthma control and quality of life. Efforts to improve asthma outcomes in this population should address the negative impacts of these common mental health conditions.