Olfactory loss and aging: connections with health and well-being

Abstract

Age related olfactory dysfunction, or presbyosmia, is a common sensory impairment in aging adults. People in this demographic group with comorbid conditions or exposure to viral, traumatic, or environmental insults remain at the greatest risk for impairment. Several methods for assessing olfaction exist, but they are only available in special settings and require consideration of age, sex, ancestry, and cognition. Perhaps most importantly, olfactory dysfunction has been suggested as an early sign of Alzheimer’s and Parkinson’s disease and therefore may serve as a tool in the diagnosis and prognosis of these neurodegenerative conditions. Outside of this context, olfactory loss also impacts nutrition, safety, and social relationships, and even predicts mortality itself. This review covers the detection and manifestations of olfactory decline in aging individuals and the myriad ways in which olfactory impairment is connected to their health and well-being.

Effect of Physical Activity on Olfactory Acuity: A Systematic Review

“…In addition, there are also relations between loss of smell and social isolation [11][12][13], reduced cognitive functions [11,[14][15][16][17][18], fragile mental health [11,19], and nutritional problems [10,11]. Adequate energy intake is crucial to execute daily tasks with full autonomy or to perform a more intense activity, such as sports or other forms of exercise [11,20]. Also, food consumption is directly connected to environmental stimuli such as the appearance of the food, its smell and the social context [21].…”

“…This deterioration of the sense of smell can affect diet differently in each person. For example, there may be a decrease in the feeling of hunger, a lower quality energy intake, or even a lower protein consumption which could increase the loss of autonomy [10,11]. In addition, there are also relations between loss of smell and social isolation [11][12][13], reduced cognitive functions [11,[14][15][16][17][18], fragile mental health [11,19], and nutritional problems [10,11].…”

“…For example, there may be a decrease in the feeling of hunger, a lower quality energy intake, or even a lower protein consumption which could increase the loss of autonomy [10,11]. In addition, there are also relations between loss of smell and social isolation [11][12][13], reduced cognitive functions [11,[14][15][16][17][18], fragile mental health [11,19], and nutritional problems [10,11]. Adequate energy intake is crucial to execute daily tasks with full autonomy or to perform a more intense activity, such as sports or other forms of exercise [11,20].…”

Olfactory identification, cognition, depressive symptoms, and 5-year mortality in patients with subjective cognitive decline, mild cognitive impairment, and Alzheimer’s disease

“…Presbyosmia, or gradual degeneration of the sense of smell, is a common symptom of aging [2,3]. More than half of all individuals aged 80 or above are affected by it [4] due to accumulative environmental effects on the olfactory nerve [2], the only cranial nerve exposed to external surroundings [5]. In the elderly population, olfactory impairment is associated with increased mortality [5][6][7][8][9][10][11].…”

“…2 explains variance percentage, representing the sum of squares of squared factor loadings of each row of an NTBV-15 (short version) subtest. Eigenvalue λ, on the other hand, represents the sum of squares of each factor's column and comprises values > 1.…”