The 4 item Concise Aging adults Smell Test (4CAST) to screen for olfactory-related comorbidities

Olfactory dysfunction (OD) is associated with numerous comorbidities, including cognitive decline and depression. Age-related OD is one of the most common causes of smell loss, but it is often underrecognized. In previous research the 4 item Concise Aging adults Smell Test (4CAST) accurately predicted psychophysical olfactory function in over 80% of older adults. This study examined the relationship of 4CAST to olfactory-related comorbidities.

A community-based cohort of adults over 50 years of age completed the 4CAST. Its association with olfactory-related comorbidities was assessed using: 1) National Institutes of Health Toolbox -Cognition Battery; 2) Questionnaire for Olfactory Disorders-Negative Statements (QOD-NS); 3) Patient Health Questionnaire 9 (PHQ9); 4) DeJong Giervald (DJG) social isolation scale; and 5) Mini-Nutritional Assessment (MNA).

Participants who failed the 4CAST had worse median scores for all measures of fluid cognition, QOD-NS, and PHQ9. Of participants who failed the 4CAST, 24-39% had cognition scores suggestive of possible cognitive impairment. Participant’s 4CAST results did not differ in crystallized cognition (Picture Vocabulary Test), total DJG and MNA scores.

The 4CAST is a quick screening instrument that may indicate psychophysical OD in older adults and identify olfactory-related comorbidities (i.e. cognitive decline, depression) that may merit further in-depth assessments.