Odor identification ability and self-reported upper respiratory symptoms in workers at the post-9/11 World Trade Center site

Following the World Trade Center (WTC) collapse on September 11, 2001, more than 40,000 people were exposed to a complex mixture of inhalable nanoparticles and toxic chemicals. While many developed chronic respiratory symptoms, to what degree olfaction was compromised is unclear. A previous WTC Medical Monitoring and Treatment Program study found that olfactory and nasal trigeminal thresholds were altered by the toxic exposure, but not scores on a 20-odor smell identification test. Objectives: To employ a well-validated 40-item smell identification test to definitively establish whether the ability to identify odors is compromised in a cohort of WTC-exposed individuals and, if so, whether the degree of compromise is associated with self-reported severity of rhinitic symptoms. Methods: The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 99 WTC-exposed persons and 99 matched normal controls. The Sino-Nasal Outcomes Test (SNOT-20) was administered to the 99 WTC-exposed persons and compared to the UPSIT scores. Results: The mean (SD) UPSIT scores were lower in the WTC-exposed group than in age-, sex-, and smoking history-matched controls [respective scores: 30.05 (5.08) vs 35.94 (3.76); p = 0.003], an effect present in a subgroup of 19 subjects additionally matched on occupation (p < 0.001). Fifteen percent of the exposed subjects had severe microsmia, but only 3% anosmia. SNOT-20 scores were unrelated to UPSIT scores (r = 0.20; p = 0.11). Conclusion: Exposure to WTC air pollution was associated with a decrement in the ability to identify odors, implying that such exposure had a greater influence on smell function than previously realized.