MONDAY, July 20, 2026 (HealthDay News) -- Subjective olfactory impairment (SOI) is consistently associated with depression, according to a study published online July 9 in JAMA Otolaryngology-Head & Neck Surgery.Henry Bode, M.D., from the Karolinska Institute in Stockholm, and colleagues conducted a systematic literature review to quantify the association of objective olfactory impairment (OOI) and SOI with subjectively and/or objectively determined depression.Based on seven and 11 independent studies for the primary analyses of SOI and OOI, respectively, the researchers found SOI was associated with depression across the seven studies (odds ratio, 1.56; 95 percent confidence interval [CI], 1.19 to 2.05). Among studies with a low risk for bias, the association remained robust (odds ratio, 1.71; 95 percent CI, 1.18 to 2.46) across age groups and for subjective and objective depression. For OOI, there was an association with objective depression across the 11 studies (odds ratio, 1.26; 95 percent CI, 1.02 to 1.56) that was no longer significant after publication bias adjustment (odds ratio, 1.12; 95 percent CI, 0.87 to 1.44), but it remained robust in adults 65 years and older and individuals with anosmia."Our findings suggest that smell loss, particularly when subjectively reported, may co-occur with depression symptoms and reflect overlapping perceptual and affective processes; however, current evidence is not sufficient to support clinical recommendations," the authors write.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter