Sex-specific differences in nutritional status as risk factors for cognitive decline amongst older adults with Post-COVID Syndrome

Background/Objectives : Post-COVID syndrome (PCS) emerged as a significant public health concern, is characterized by persistent symptoms following SARS-CoV-2 infection. Cognitive impairment is a common sequela, particularly among older adults (OA). Although olfactory dysfunction and malnutrition have been previously associated to cognitive decline, it remains to be elusive to what extent sex-specific variations in these and additional factors will be pivotal to guide targeted interventions in a sex specific manner. This study seeks to identify clinical and biological correlates for cognitive decline in older adults, with emphasis in gender specificity. Methods : We underwent a cross-sectional study among older adults 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. Statistical analyses included linear regression. Results : A total of 45 patients with PCS were included. Cognitive impairment was observed in 66.7% of participants and was significantly associated with olfactory dysfunction, no direct association was found with nutritional status. However, on a multiple regression analysis, the nutritional status was significantly associated to cognitive decline. Conclusions : Olfactory dysfunction is a potential biomarker for cognitive impairment in older adults with PCS. In our study nutritional status emerged as a crucial factor associated to olfactory dysfunction and cognitive decline with a higher impact on women. Further research is needed to elucidate the underlying mechanisms related to a nutritional decline in older women with olfactory dysfunction and develop targeted interventions to mitigate cognitive decline in this vulnerable population, through improvement in nutrition and olfactory training.