| 1. |
- Ekström, Ingrid, et al.
(författare)
-
Smell Loss Predicts Mortality Risk Regardless of Dementia Conversion
- 2017
-
Ingår i: Journal of The American Geriatrics Society. - : Wiley. - 0002-8614 .- 1532-5415. ; 65:6, s. 1238-1243
-
Tidskriftsartikel (refereegranskat)abstract
- ObjectivesTo determine whether dementia could explain the association between poor olfactory performance and mortality risk within a decade-long follow-up period.DesignProspective cohort study.SettingBetula Study, Umeå, Sweden.ParticipantsA population-based sample of adult participants without dementia at baseline aged 40 to 90 (N = 1,774).MeasurementsOlfactory performance using the Scandinavian Odor-Identification Test (SOIT) and self-reported olfactory function; several social, cognitive, and medical risk factors at baseline; and incident dementia during the following decade.ResultsWithin the 10-year follow-up, 411 of 1,774 (23.2%) participants had died. In a Cox model, the association between higher SOIT score and lower mortality was significant (hazard ratio (HR) = 0.74 per point interval, 95% confidence interval (CI) = 0.71-0.77, P < .001). The effect was attenuated, but remained significant, after controlling for age, sex, education, and health-related and cognitive variables (HR = 0.92, 95% CI = 0.87-0.97, P = .001). The association between SOIT score and mortality was retained after controlling for dementia conversion before death (HR = 0.92, 95% CI = 0.87-0.97, P = .001). Similar results were obtained for self-reported olfactory dysfunction.ConclusionPoor odor identification and poor self-reported olfactory function are associated with greater likelihood of future mortality. Dementia does not attenuate the association between olfactory loss and mortality, suggesting that olfactory loss might mark deteriorating health, irrespective of dementia.
|
|
| 2. |
- Larsson, Maria, et al.
(författare)
-
Loss of Olfactory Function Predicts Mortality Irrespective of Dementia Conversion : 10-year follow-up of an age-varied sample
- 2016
-
Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 41:9, s. e111-e288
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to examine the association between performance in odor identification and future mortality in a community cohort of adults aged between 40 and 90 years. We assessed olfactory performance with a 13-item-version of the Scandinavian Odor Identification Test (SOIT). The results showed that during follow-up (mean=9.4 years, standard deviation=2.23), 411 of 1774 (23.2%) participants died. In a Cox model, the association between higher SOIT score and mortality was highly significant (hazard ratio [HR]=0.74, per point interval, 95% confidence interval [CI]=0.71–0.77, p<0.001). The effect was attenuated, but remained significant after controlling for age, sex, education, and health and cognitive variables that were also associated with an increased risk of mortality (HR=0.92, 95% CI=0.87–0.97, p=0.001). Controlling for dementia conversion prior to death did not attenuate the association between SOIT score and mortality (HR=0.92, 95% CI=0.87–0.97, p=0.001). Similar results were obtained for olfactory sensitivity as assessed by self-report. Overall, the present findings show that poor odor identification performance is associated with an increased likelihood of future mortality in middle-aged and older adults, after controlling for social, cognitive, and medical risk factors. Most importantly, controlling for the development of dementia did not attenuate the association between odor identification and mortality, suggesting that olfactory decline might mark deteriorating health also irrespective of dementia.
|
|
| 3. |
- Olofsson, Jonas K., et al.
(författare)
-
Long-term episodic memory decline is associated with olfactory deficits only in carriers of ApoE-є4
- 2016
-
Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 85, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- The ɛ4 allele of the Apolipoprotein E gene is a genetic risk factor for late-onset dementia of the Alzheimers' type (DAT), which is characterized by loss of both episodic memoryand olfactory functions. Little is known about the possible role of ɛ4 in the association between ongoing episodic memory decline and olfactory deficits in the general population, but such information is relevant in determining the relevance of olfaction as a marker of DAT risk. The present study was based on a large, population-based sample (n=1087, aged 45–90 years, of which 324 were ɛ4-carriers). Episodic memory change rates were established using data collected every 5 years for a 10–20 year interval leading up to an olfactory assessment using the Scandinavian Odor Identification Test at the last wave of data collection. Participants were classified according to whether or not their episodic memory ability declined more rapidly than the age-typical norm (by >1SD). Our main result is that only in ɛ4-carriers was episodic memory decline associated with odor identification impairment. In individuals without ɛ4, odor identification was unrelated to episodic memory decline status. Follow-up analyses indicated that this moderation by ɛ4 was due to the olfactory nature of the identification test, and that the effect was not caused by 63 individuals with dementia. Our results suggest that the ɛ4 determines the functional association between ongoing episodic memory decline and olfaction. These findings are consistent with the notion that ɛ4-carriers with DAT, compared to non-carriers, display a cortical atrophy pattern that is more focused on mediotemporal lobe regions supporting olfactory and episodic memory functions. Olfactory and memory assessments might provide complementary information on mediotemporal atrophy prior to clinical dementia onset, but the ɛ4 should be considered when using olfactory assessment as an early-stage indicator.
|
|
| 4. |
- Ekström, Ingrid, 1988-, et al.
(författare)
-
Subjective Olfactory Loss in Older Adults Concurs with Long-Term Odor Identification Decline
- 2019
-
Ingår i: Chemical Senses. - Oxford : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 44:2, s. 105-112
-
Tidskriftsartikel (refereegranskat)abstract
- Olfactory impairments may provide early indications of future health outcomes in older adults. Thus, an important question concerns whether these impairments can be self-assessed. Previous findings of cross-sectional studies indicate low correlations between self-reported olfactory function and objective olfactory performance. On the other hand, subjective olfactory impairments predict future dementia and mortality in longitudinal settings. No previous study has assessed the relationship between subjectively and objectively measured decline in olfaction over time. Based on data for 903 older adults derived from the Betula Study, a Swedish population-based prospective study, we tested whether rate-of-change in odor identification could be predicted from subjective olfactory decline over a time span of 10 years during which subjective and objective odor functions were assessed on 2 or 3 test occasions. Indeed, we found that participants who experienced subjective olfactory decline over the study period also had significantly steeper rates of decline in odor identification, even after adjusting for demographic, cognitive, and genetic factors that previously have been associated with performance in odor identification. This association was, however, not present in a subsample with baseline cognitive impairment. We interpret these results as evidence that when asked about whether they have an olfactory impairment or not, older persons are assessing intraindividual olfactory changes, rather than interindividual differences. Our results indicate that subjective olfactory loss reflects objective olfactory decline in cognitively intact older adults. This association might be harnessed to predict health outcomes and highlights the need to develop effective olfactory self-assessments.
|
|
| 5. |
- Josefsson, Maria, et al.
(författare)
-
APOE-epsilon 4 effects on longitudinal decline in olfactory and non-olfactory cognitive abilities in middle-aged and old adults
- 2017
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Characterizing aging-related decline trajectories in mental abilities, and relationships of the epsilon 4 allele of the Apolipoprotein gene, helps to identify individuals at high risk for dementia. However, longitudinal changes in olfactory and non-olfactory cognitive abilities have not been investigated in relation to the epsilon 4 allele. In the present study, participants from a large population-based study (657 middle-aged and 556 old) were tested over 10 years on their performance on an odor identification task and three non-olfactory cognitive tasks; MMSE, episodic memory, and semantic memory. Our key finding is that in middle-aged participants, odor identification declined twice as fast for epsilon 4/4 homozygotes, compared to non-carriers. However, in old participants, the epsilon 4/4 homozygotes showed an impaired odor identification ability, but they declined at a similar rate as the non-carriers. Furthermore, in old participants all assessments displayed aging-related declines, but exaggerated declines in epsilon 4-carriers were found only in MMSE and episodic memory assessments. In sum, we present evidence that odor identification ability starts to decline already in middle-aged, and that carriers of epsilon 4/4, who are at highest risk of developing dementia, decline twice as fast. Our results may have implications for use of odor identification assessment in detection of early-stage dementia.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Olofsson, Jonas K., et al.
(författare)
-
Odor Identification Deficit as a Predictor of Five-Year Global Cognitive Change : Interactive Effects with Age and ApoE-ε4
- 2009
-
Ingår i: Behavior Genetics. - : Springer Netherlands. - 0001-8244 .- 1573-3297. ; 39:5, s. 496-503
-
Tidskriftsartikel (refereegranskat)abstract
- Olfactory impairments are present in common neurodegenerative disorders and predict conversion to dementia in non-demented individuals with cognitive impairment. In cognitively intact elderly, evidence is sparse regarding the role of olfactory deficits in predicting cognitive impairment. The present study investigated predictors of 5-year prospective decline in the Mini-Mental State Examination (MMSE) in a large (n = 501), population-based sample of elderly (65–90 years) individuals. All participants were genotyped for the ApoE gene, assessed for health factors, and were non-demented at the baseline assessment. After partialling out the influences of demographic and health-factors at baseline and dementia at follow-up, poor odor identification ability in combination with older age and the ApoE-ε4 allele predicted larger prospective global cognitive decline. This effect could not be produced by a vocabulary test. In sum, the findings suggest that an olfactory deficit can dissociate between benign and malign global cognitive development in non-demented, very old ε4-carriers, who are at high risk of developing dementia.
|
|
| 9. |
- Olofsson, Jonas K, 1965-, et al.
(författare)
-
Odor identification impairment in carriers of ApoE-ε4 is independent of clinical dementia
- 2010
-
Ingår i: Neurobiology of Aging. - : Elsevier. - 0197-4580 .- 1558-1497. ; 31:4, s. 567-577
-
Tidskriftsartikel (refereegranskat)abstract
- The ApoE gene is expressed in olfactory brain structures and is believed to play a role in neuronal regenerative processes as well as in development of Alzheimer's disease (AD), the most common form of dementia. The ε4 allele has been reported to be associated with compromised odor identification ability in the elderly, and this deficit has been interpreted as a sign of pre-diagnostic AD. However, because it has not been demonstrated that the relationship between the ε4 allele and odor identification is mediated by dementia, it is possible that the ε4 allele may have an effect on odor identification over and above any effects of dementia. The present study investigated effects of ApoE-status on odor identification in a large, population-based sample (n = 1236) of adults (45–80 years), who were assessed for dementia at time of testing and 5 years later. The results showed that the ε4 allele was associated with an odor identification deficit among elderly participants (75–80). Critically, this effect remained after current and pre-diagnostic dementia, vocabulary, global cognitive status and health variables were partialled out. The present results suggest that the ApoE gene plays a role in olfactory functioning that is independent of dementia conversion within 5 years.
|
|
| 10. |
- Olofsson, Jonas K., et al.
(författare)
-
Olfaction and Aging : A Review of the Current State of Research and Future Directions
- 2021
-
Ingår i: i-Perception. - : SAGE Publications. - 2041-6695. ; 12:3, s. 1-24
-
Forskningsöversikt (refereegranskat)abstract
- Olfaction, the sense of smell, is characterized by a notable age-dependency such that aging individuals are more likely to have poor olfactory abilities. These impairments are considered to be mostly irreversible and as having potentially profound effects on quality of life and food behavior, as well as constituting warning signs of mortality, cognitive dysfunction, and dementia. Here, we review the current state of research on aging and olfaction, focusing on five topics which we regard to be of particular relevance for the field: nutrition and health, cognition and dementia, mortality, environment and genetics, and training-based enhancement. Under each of these headlines, we provide a state-of-the-art overview and discuss gaps in our knowledge which might be filled by further research. Understanding how olfactory abilities are diminished in aging, and how they may be alleviated or recovered, involves a set of challenging tasks for researchers in the years to come.
|
|
