# Exploring mechanisms of obstructive sleep apnea (OSA) in WTC responders

> **NIH ALLCDC U01** · ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI · 2020 · $496,523

## Abstract

Obstructive sleep apnea (OSA) occurs in 5-20% of the adult population. The pathophysiology of OSA is
multifactorial and includes impaired upper airway anatomy, low arousal threshold, respiratory control instability,
and/or altered neuro-muscular control of upper airway muscles. A validated method has been pioneered by
Wellman and Sands to calculate the relative contribution of each of these components from diagnostic
polysomnography and this approach may define pathophysiologic phenotypes of the syndrome. We and others
have shown that WTC dust-exposed subjects have a high prevalence of conditions such as chronic
rhinosinustis, gastroesophageal reflux disease, post-traumatic stress disorder and obesity that increase risk for
OSA. Our goal is to define how these comorbid conditions might act via individual pathophysiologic
mechanisms defined as a “phenotype of OSA.” Our current data in over 600 WTC responders shows an
extraordinary prevalence of OSA of 75 %. We have also found an association between new or worsening
chronic rhinosinusitis (CRS) symptoms since 9/11 and OSA that is significant even after controlling for known
risk factors for OSA such as age, gender and BMI. This association is not explained by increased nasal
resistance in those with CRS, suggesting other mechanisms could impact upper airway function in CRS
including neuropathy, fibrosis and reduced upper airway sensitivity that impairs mechanoreflexes to negative
pressure. We propose that an impaired afferent limb of upper airway reflexes impairs the ability to perceive
and/or process upper airway loading and contributes to failure of upper airway stiffening. Furthermore, the high
prevalence of OSA even in subjects without CRS highlights the need to identify the mechanisms of OSA in
these subjects. The aims of this proposal are to 1. Examine the mechanism by which CRS increases the risk
for OSA. Building on our previous findings of increased prevalence of OSA in subjects with CRS symptoms, we
will examine the role of sensory function (2-point discrimination and vibration sensitivity threshold) in the upper
airway in four groups of 50 subjects each with and without OSA and with and without CRS. 2. Examine the
relationship of the mechanistic OSA phenotype components to CRS in WTC responders. In 100 subjects
diagnosed with OSA (50 with CRS and 50 without CRS) we will test if upper airway muscle compensation is
lower in subjects with CRS. 3. Examine differences in the distribution of OSA pathophysiologic phenotypes
between WTC responders and matched patients from a sleep clinic population without exposure to WTC dust.
In 100 subjects in each group we will test the hypothesis that WTC subjects have a greater proportion of
subjects with a) mild UA collapsibility b) low arousal threshold and c) low muscle compensation compared to
non-WTC subjects. This proposal will provide insight into the pathophysiologic mechanisms and mechanistic
components of OSA in WTC Responders, which could help i...

## Key facts

- **NIH application ID:** 9934057
- **Project number:** 5U01OH011481-03
- **Recipient organization:** ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
- **Principal Investigator:** INDU A AYAPPA
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** ALLCDC
- **Fiscal year:** 2020
- **Award amount:** $496,523
- **Award type:** 5
- **Project period:** 2018-07-01 → 2021-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9934057

## Citation

> US National Institutes of Health, RePORTER application 9934057, Exploring mechanisms of obstructive sleep apnea (OSA) in WTC responders (5U01OH011481-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9934057. Licensed CC0.

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