Responders or workers who breathed in a toxic mix of airborne chemicals, smoke, and dust in the wake of the September 11, 2001, World Trade Center disaster experienced a reduced ability to detect odors and irritants more than two years after they were exposed, says research published in the May 18 online issue of the journal Environmental Health Perspectives.
The research, which was funded by the NIDCD, was conducted by scientists with the Monell Chemical Senses Center in Philadelphia, along with other collaborators.
"The nose performs many sensory functions that are critical for human health and safety," said lead author Pamela Dalton, Ph.D., in Monell's press release. "The sensory system that detects irritants is the first line of defense to protect the lungs against airborne toxic chemicals. The loss of the ability of the nose to respond to a strong irritant means that the reflexes that protect the lungs from toxic exposures will not be triggered." According to other studies, thousands of individuals exposed to the World Trade Center site immediately following the disaster have developed chronic respiratory conditions.
The nose's ability to detect odors and irritants makes use of two highly sensitive and discriminating systems. Our sense of smell relies on olfactory receptors high in the nasal cavity that, upon attaching to specific odor molecules, will send signals to the brain, which are translated as a particular smell. Our chemical irritant warning system relies on the trigeminal nerve, a nerve in the head that, when activated by a harmful chemical, causes your eyes to water and your nose to burn or sting. Under normal conditions, exposure to a chemical irritant will cause a person to reflexively sneeze and cough, protecting the lungs from damage. A person with reduced sensitivity, however, will be less likely to have this reaction.
Beginning in September 2003, the researchers examined 102 paid and volunteer World Trade Center responders who were on site at the time of and following the disaster and compared them to people of similar ages, genders, and job titles who weren't exposed. Ninety-seven percent of the World Trade Center group were near the lower Manhattan site during the week following the buildings' collapse, when the pollutants were likely at their highest.
The researchers found that 22 percent of the workers were below the normal range in their ability to discriminate odors while nearly 75 percent showed a decreased ability to detect irritants. What's more, workers who were exposed to the dust cloud at the moment the buildings collapsed experienced the most damage in their ability to detect irritants, with individuals virtually unable to detect the test irritant n-butanol, a chemical that is used in the manufacture of many substances, including some drugs, plastics, and solvents.
The researchers next plan to screen a larger number of individuals who were exposed to the World Trade Center site in hopes of determining how extensive this health issue might be in 9/11 responders; they also plan to re-evaluate individuals who participated in the initial study to assess whether the problem persists, worsens, or recovers over time.
Read the article "Chemosensory Loss: Functional Consequences of the World Trade Center Disaster" in the journal Environmental Health Perspectives, or read the abstract in Pub Med.
Source:
The above article is reprinted from materials provided by the National Institute on Deafness and Other Communication Disorders (NIDCD)
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