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Harbingers of Dementia—or Not?

Harbingers of Dementia—or Not?

  • Midlife hypertension and loss of sense of smell, but not personality changes, may precede the development of dementia in older patients, according to 3 new clinical studies.[1-3] Scroll through the slides for the latest findings and take-home messages.

  • 1. Midlife Hypertension Among Women Appears to Increase the Risk of Dementia Later in Life: Blood pressure was measured in 7238 people at an average age of 33, and again at an average age of 44. In their 40s, 22% of the group had hypertension, including 25% of men and 18% of women. During a later follow-up period, dementia developed in 532 study participants.

    Women who had hypertension in their 40s were 73% more likely to develop dementia than women who had stable, normal blood pressure during their 30s and 40s, even after adjustment for other factors that could affect the risk of dementia, such as smoking, diabetes, and BMI. There was no evidence that hypertension or changes in blood pressure increased dementia risk among men.[1]

  • Clinical Implications for Study 1: “High blood pressure in midlife is a known risk factor for dementia, but these results may help us better understand when this association starts, how changes in blood pressure affect the risk of dementia, and what the differences are between men and women,” said senior author Rachel A. Whitmer, PhD, of Kaiser Permanente Division of Research in Oakland, CA. “More research is needed to identify the possible sex-specific pathways through which the elevated blood pressure accelerates brain aging.”

  • 2. Older Adults With Normal Cognition Who Have Difficulty Identifying Odors Face a Higher Risk of Dementia: A study of 2906 men and women aged 57 to 85 years measured their objective odor identification ability at baseline using a validated 5-item test. Those who could not identify at least 4 out of 5 common odors were more than twice as likely as those with a normal sense of smell to develop dementia within 5 years.[2]

  • Clinical Implications for Study 2:  Assessing an individual’s risk of dementia using olfactory testing may provide an opportunity for early interventions for dementia. “These results show that the sense of smell is closely connected with brain function and health,” said senior author Jayant M. Pinto, MD, Professor of Surgery at the University of Chicago. “We think a decline in the ability to smell, specifically, but also sensory function more broadly, may be an important early sign, marking people at greater risk for dementia. We need to understand the underlying mechanisms, so we can understand neurodegenerative disease and hopefully develop new treatments and preventative interventions.”

  • 3. Preclinical Changes in Personality Do Not Necessarily Occur Before the Onset of Mild Cognitive Impairment or Dementia: A study of 2046 community-dwelling older adults examined personality and clinical assessments obtained between 1980 and 2016 from participants with no cognitive impairment at first assessment. They were followed up for as long as 36 years. Mild cognitive impairment was diagnosed in 104 participants (5.1%), and all-cause dementia was diagnosed in 255 (12.5%), including 194 (9.5%) with Alzheimer disease.

    Those who developed dementia scored higher on neuroticism and lower on conscientiousness and extraversion; however, there were no significant differences in change in personality between the non-impaired and the Alzheimer disease groups.[3]


  • Clinical Implications for Study 3: “We further found that personality remained stable even within the last few years before the onset of mild cognitive impairment,” said lead author Antonio Terracciano, Associate Professor at Florida State University College of Medicine. “Unlike previous research, this study examined multiple waves of self-rated personality data collected up to 36 years before participants developed any sign of dementia.” He noted personality changes remain an important consideration in the care of those who have already experienced the clinical onset of mild cognitive impairment or dementia.


    1. Gilsanz P, Mayeda ER, Glymour MM, et al. Female sex, early-onset hypertension, and risk of dementia. Neurology. 2017;89:1886-1893. doi: 10.1212/WNL.0000000000004602.

    2. Adams DR, Kern DW, Wroblewski KE, et al. Olfactory dysfunction predicts subsequent dementia in older U.S. adults. J Am Geriatr Soc. 2017 Sep 25. doi:10.1111/jgs.15048. [Epub ahead of print]

    3. Terracciano A, An Y, Sutin AR, et al. Personality change in the preclinical phase of Alzheimer disease. JAMA Psychiatry. 2017 Sep 20. doi:10.1001/jamapsychiatry.2017.2816. [Epub ahead of print]



Symptom of change in olfactory sense should lead to at least a differential diagnosis of dementia. Just because it is also 'normal' change in aging does not mean it could not precede dementia. It is at least associated, and should trigger further evaluation for dementia. Do not discount the loss of smelling sense.

Gabriele @

Changes in olfactory sense is not specific to dementia or considered a risk factor. Normal older adult changes includes a loss of smell---and is not specific to dementia. This is not an early sign of dementia, but may be part of normal aging of an older adult. I complete comprehensive geriatric assessments and I'm director of a Dementia Assessment Center. The use of smell comes up about every 3 to 4 years as an 'early' test for dementia. There is no specificity or reliability---as this is a change that may happen as we age. There have been 'home testing kits' developed and sold online to help 'people' complete their own 'home test' for dementia---it's a scam and until there is any definitive testing and research on the loss of smell as a finite early dementia symptom--this information should not be used. There will be a difficult time differentiating normal loss of smell from other causes of loss. Perhaps a massive research study would put this to rest once and for all---but I would look at the earliest cognitive deficits to test as early indicators, rather than a common normal aging change.

Nancy @

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