Gender-Related Differences in the Correlation between Odor Threshold, Discrimination, Identification, and Cognitive Reserve Index in Healthy Subjects

SIMPLE SUMMARY: Many studies indicated significant associations between olfactory function and cognitive abilities in healthy controls. However, the gender-related association between olfactory function and each specific cognitive domain of the Cognitive Reserve Index (CRI) questionnaire has so far not been evaluated. The aim of this study was to evaluate gender-related differences in the relationship between olfactory function and each specific cognitive domain of the CRI questionnaire, such as education, working activity, and leisure time in healthy subjects. Our data indicated significant gender-related associations between olfactory function and CRI score. In women, odor threshold, odor discrimination, and identification were associated with CRI-Leisure Time, while in men, only a significant association between odor threshold and CRI-Education was observed. ABSTRACT: Background: Many studies suggested that olfactory function could be associated with semantic memory, executive function, and verbal fluency. However, the gender-related association between olfactory function and the cognitive domain is not well investigated. The aim of this study was to estimate gender-related differences in the relationship between olfactory function and each specific cognitive domain of the Cognitive Reserve Index (CRI) questionnaire, such as education, working activity, and leisure time in healthy subjects. Methods: Two hundred and sixty-nine participants were recruited (158 women and 111 men), with a mean age of 48.1 ± 18.6 years. The CRI questionnaire and Sniffin’ Sticks test were used to evaluate the cognitive reserve and the olfactory function, respectively. Results: In all subjects, significant associations between the odor threshold versus CRI-Education, between the odor discrimina-tion and identification versus CRI-Working activity and CRI-Leisure Time, were found. In women, odor threshold, discrimination, and identification were associated with CRI-Leisure Time, while in men, only a significant association between odor threshold and CRI-Education was observed. Conclusions: Our data, showing significant gender-related associations between olfactory function and CRI scores, suggested the use of olfactory evaluation and cognitive reserve as an important screening tool for the early detection of mild cognitive impairment.