Associations of combined smoking and drinking with subjective and objective olfactory dysfunction: A secondary dataset analysis of NHANES 2013-2014.

INTRODUCTION: The association between smoking, alcohol consumption, and olfactory dysfunction (OD) remains inconclusive, and few studies have simultaneously examined their relationships with both subjective and objective OD in large population-based samples. This study aimed to investigate the associations of different smoking and drinking statuses with subjective and objective OD among US adults aged ≥40 years. METHODS: This secondary dataset analysis of NHANES 2013-2014 included 3376 adults aged ≥40 years who completed the chemosensory questionnaire, smoking and alcohol use questionnaires, and the odor identification test. Subjective OD was based on self-reported olfactory impairments from the NHANES chemosensory questionnaire, and objective OD was assessed using an 8-item odor identification test (score 0-5 indicating impairment). Smoking status was classified based on smoking index, serum cotinine, and time to first cigarette; heavy drinking was defined based on daily drinking habits during any period in life. Multivariable logistic regression models adjusted for demographic factors and OD-related risk factors. RESULTS: The prevalence of subjective and objective OD was 20.3% and 18.3%, respectively. For subjective OD, significantly elevated adjusted odds were observed for chronic smoker (AOR=1.47; 95% CI: 1.12-1.93), chronic active smoker (AOR=1.55; 95% CI: 1.16-2.08), high dependent active smoker (AOR=1.69; 95% CI: 1.19-2.40), chronic smoker-heavy drinker (AOR=1.72; 95%CI: 1.14-2.60), and active smoker-heavy drinker (AOR=1.90; 95% CI: 1.25-2.88). For objective OD, significantly higher adjusted odds were found for chronic smoker (AOR=1.64; 95% CI: 1.26-2.12), chronic active smoker (AOR=1.59; 95% CI: 1.10-2.32), high dependent smoker-heavy drinker (AOR=2.69; 95% CI: 1.36-5.34), and chronic smoker-heavy drinker (AOR=1.67; 95% CI: 1.12-2.50). CONCLUSIONS: Chronic smoking and heavy drinking, particularly in combination, are significantly associated with both subjective and objective OD in US adults aged ≥40 years. These findings suggest that smoking and heavy alcohol use may represent modifiable risk factors for olfactory impairment. Further longitudinal studies are warranted to confirm these associations and explore underlying mechanisms.