Exposure to Cadmium, Lead, and Tobacco Smoke linked to olfactory impairment: JAMA

According to recent research, it has ben found out that modifiable environmental exposures may contribute to olfactory impairment that occurs with aging, as published in the JAMA Otolaryngology- Head and Neck Surgery.

Olfactory impairment is common in older adults. Identification of modifiable risk factors for olfactory impairment at midlife has the potential to reduce the burden of olfactory impairment at older ages.

Hence, Carla R. Schubert and colleagues from the Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison carried out the present study with the objective to determine the 10-year cumulative incidence of olfactory impairment and evaluate potentially modifiable risk factors for impairment including exposure to cadmium, lead, and tobacco smoke.

Data from the Beaver Dam Offspring Study, a longitudinal cohort study of sensory health and aging in a general population, were available from examinations at baseline (2005-2008), 5 years (2010-2013), and 10 (2015-2017) years.

The authors included a total of 2312 participants without olfactory impairment at baseline and with olfaction data available at the 5- and/or 10-year examination. Olfactory impairment was measured by the San Diego Odor Identification Test.

Cox discrete-time proportional hazards analyses were used to model associations between baseline covariates, including blood cadmium and lead levels and tobacco smoke exposure, and the 10-year cumulative incidence of olfactory impairment.

The following findings were highlighted-

4. Of the 2312 participants, 1269 (54.9%) were women; mean age was 49 years (range, 22-84 years) at baseline.
5. The 10-year cumulative incidence of olfactory impairment was 4.6% (95% CI, 3.7%-5.6%) and increased with age.
6. Because of high collinearity, cadmium and tobacco smoke exposure were modeled separately.
7. In a multivariable adjusted model, higher blood cadmium level (hazard ratio [HR], 1.70; 95% CI, 1.05-2.74) was associated with the 10-year cumulative incidence of olfactory impairment.
8. Substituting tobacco smoke exposure for cadmium in the model, high exposure to tobacco smoke as a current smoker (HR, 2.94; 95% CI, 1.63-5.29, smoker vs no exposure) or from environmental tobacco smoke (HR, 2.65; 95% CI, 1.24-5.63, high vs no exposure) was also associated with an increased risk for developing olfactory impairment.
9. Blood lead levels were not associated with olfactory impairment.

Therefore, the authors concluded that "modifiable environmental exposures may contribute to olfactory impairment that occurs with aging. Identification of modifiable risk factors for olfactory impairment may lead to prevention strategies that have the potential to reduce the burden of olfactory impairment at older ages."