Nitrogen dioxide pollution exposure is associated with olfactory dysfunction in older U.S. adults

Area of Science:

• Environmental Health
• Gerontology
• Otorhinolaryngology

Background:

• Olfactory dysfunction significantly impacts quality of life, physical and social functioning, and mortality.
• Nitrogen dioxide (NO2) is a common air pollutant linked to respiratory illnesses.
• The olfactory nerve's direct exposure to airborne pollutants necessitates investigating NO2's role in smell impairment.

Purpose of the Study:

• To investigate the association between exposure to nitrogen dioxide (NO2) and olfactory dysfunction.
• To determine if NO2 pollution contributes to impaired smell in older adults.

Main Methods:

• Utilized data from the National Social Life, Health, and Aging Project (NSHAP), a representative sample of U.S. adults aged 57-85.
• Assessed olfactory function using a validated odor identification test.
• Quantified NO2 exposure using EPA's Aerometric Information Retrieval System (AIRS) data closest to participants' residences, analyzed via multivariate logistic regression.

Main Results:

• 22.6% of older U.S. adults exhibited impaired olfactory function.
• An interquartile range (IQR) increase in NO2 exposure was associated with a 35% increase in the odds of olfactory dysfunction (OR, 1.35; 95% CI, 1.07 to 1.72).
• The association remained significant after adjusting for demographic, lifestyle, and health factors.

Conclusions:

• This study provides the first evidence linking NO2 exposure to olfactory dysfunction in older U.S. adults.
• NO2 exposure emerges as a significant environmental factor contributing to smell impairment.
• Findings suggest a broader role for NO2 in nasal health and disease.