Sex-Specific Differences in Nutritional Status and Olfaction in Association with Cognitive Impairment Amongst Older Adults with Long COVID Syndrome

TL;DR

This study explores how sex-specific differences in nutrition and sense of smell relate to cognitive impairment in older adults with long COVID.

Contribution

The study identifies sex-specific associations between olfactory dysfunction and cognitive impairment in older adults with long COVID.

Findings

Cognitive impairment prevalence was lower in men compared to women.

Olfactory dysfunction was associated with cognitive impairment in women after multivariate analysis.

Nutritional factors were linked to cognitive impairment only in women.

Abstract

Background/Objectives: Long COVID has emerged as a significant public health concern, characterized by persistent symptoms following SARS-CoV-2 infection. Cognitive impairment is a common sequela, particularly among older adults (OAs). Although olfactory dysfunction and malnutrition have been previously associated with cognitive decline, it remains elusive to what extent sex-specific variations in these and additional factors will be pivotal to guiding targeted interventions in a sex-specific manner. To fill this gap in knowledge, we undertook a study with the purpose of investigating the contribution of sex-specific risk factors to the development of cognitive impairment (CI) in a cohort of OAs hospitalized with long COVID. Methods: We undertook a cross-sectional study among OAs hospitalized at a geriatric care unit. Olfactory function was assessed using the Sniffin’ Stick Test. Cognitive impairment was evaluated by the Mini-Mental State Examination, and nutritional status was assessed with the Mini Nutritional Assessment (MNA). Statistical analyses included linear regression. Results: A total of 45 patients with long COVID were included, of whom 51% were female. The prevalence of CI was lower in men compared to women. In the single variable analysis, nutritional factors were associated with CI only in women; importantly, the loss of olfactory function was associated with CI in the whole group and to CI in women after multivariate analysis. Conclusions: Olfactory dysfunction is a potential biomarker for cognitive impairment in OAs with long COVID in a sex-specific manner. In our study nutritional status and probable obesity could be additional factors associated with CI; nevertheless, this was not confirmed in our multivariate analysis; therefore, this hypothesis would need to be tested in larger studies.

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