Older adults who can identify smells while also retaining hearing, vision and touch, have half the risk of developing dementia, according to a new study.
Investigators followed nearly 1,800 participants in their 70s for up to 10 years. All participants were initially dementia-free, and about 18% were diagnosed during the study period.
The researchers linked even mild or moderate sensory impairment to increased risk. This suggests that people with diminished multi-sensory function could be targeted for early intervention, wrote first author Willa Brenowitz, Ph.D., from the University of California, San Francisco.
The sense of smell appears to be the most closely tied to dementia, found Brenowitz and colleagues. Participants whose smell declined by 10% were 19% more likely to be diagnosed with the condition. This compares with an increased risk of up to 3% for declines in vision, hearing and touch.
The results suggest that these sensory impairments could be due to the same disease factors that affect cognition, such as stroke, Brenowitz wrote. Another possibility is that some sensory impairments themselves contribute to cognitive decline. This decline could occur directly due to loss of function, or indirectly by causing social isolation, adverse mental health and physical function, she explained.
Full findings were published Monday in the journal Alzheimer’s and Dementia.
