| 1. |
- Lövdén, Martin, et al.
(författare)
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The dimensionality of between-person differences in white matter microstructure in old age
- 2013
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Ingår i: Human Brain Mapping. - : Wiley. - 1065-9471 .- 1097-0193. ; 34:6, s. 1386-1398
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Tidskriftsartikel (refereegranskat)abstract
- Between-person differences in white matter microstructure may partly generalize across the brain and partly play out differently for distinct tracts. We used diffusion-tensor imaging and structural equation modeling to investigate this issue in a sample of 260 adults aged 60–87 years. Mean fractional anisotropy and mean diffusivity of seven white matter tracts in each hemisphere were quantified. Results showed good fit of a model positing that individual differences in white matter microstructure are structured according to tracts. A general factor, although accounting for variance in the measures, did not adequately represent the individual differences. This indicates the presence of a substantial amount of tract-specific individual differences in white matter microstructure. In addition, individual differences are to a varying degree shared between tracts, indicating that general factors also affect white matter microstructure. Age-related differences in white matter microstructure were present for all tracts. Correlations among tract factors did not generally increase as a function of age, suggesting that aging is not a process with homogenous effects on white matter microstructure across the brain. These findings highlight the need for future research to examine whether relations between white matter microstructure and diverse outcomes are specific or general. Hum Brain Mapp, 2012. © 2012 Wiley Periodicals, Inc.
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| 2. |
- Ferencz, Beata, et al.
(författare)
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The Benefits of Staying Active in Old Age : Physical Activity Counteracts the Negative Influence of PICALM, BIN1, and CLU Risk Alleles on Episodic Memory Functioning
- 2014
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Ingår i: Psychology and Aging. - : American Psychological Association (APA). - 0882-7974 .- 1939-1498. ; 29:2, s. 440-449
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Tidskriftsartikel (refereegranskat)abstract
- PICALM, BIN1, CLU, and APOE are top candidate genes for Alzheimer's disease, and they influence episodic memory performance in old age. Physical activity, however, has been shown to protect against age-related decline and counteract genetic influences on cognition. The aims of this study were to assess whether (a) a genetic risk constellation of PICALM, BIN1, and CLU polymorphisms influences cognitive performance in old age; and (b) if physical activity moderates this effect. Data from the SNAC-K population-based study were used, including 2,480 individuals (age range = 60 to 100 years) free of dementia at baseline and at 3- to 6-year follow-ups. Tasks assessing episodic memory, perceptual speed, knowledge, and verbal fluency were administered. Physical activity was measured using self-reports. Individuals who had engaged in frequent health-or fitness-enhancing activities within the past year were compared with those who were inactive. Genetic risk scores were computed based on an integration of risk alleles for PICALM (rs3851179 G allele, rs541458 T allele), BIN1 (rs744373 G allele), and CLU (rs11136000 T allele). High genetic risk was associated with reduced episodic memory performance, controlling for age, education, vascular risk factors, chronic diseases, activities of daily living, and APOE gene status. Critically, physical activity attenuated the effects of genetic risk on episodic memory. Our findings suggest that participants with high genetic risk who maintain a physically active lifestyle show selective benefits in episodic memory performance.
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| 3. |
- Grande, Giulia, et al.
(författare)
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Disability trajectories and mortality in older adults with different cognitive and physical profiles
- 2020
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Ingår i: Aging Clinical and Experimental Research. - : Springer Science and Business Media LLC. - 1594-0667 .- 1720-8319. ; 32:6, s. 1007-1016
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Tidskriftsartikel (refereegranskat)abstract
- Background Cognitive and physical deficits independently raise the risk for negative events in older adults. Less is known about whether their co-occurrence constitutes a distinct risk profile. This study quantifies the association between cognitive impairment, no dementia (CIND), slow walking speed (WS) and their combination and disability and mortality.Methods We examined 2546 dementia-free people aged >= 60 years, part of the Swedish National study on Aging and Care in Kungsholmen (SNAC-K) up to 12 years. The following four profiles were created: (1) healthy profile; (2) isolated CIND (scoring 1.5 SD below age-specific means on at least one cognitive domain); (3) isolated slow WS (< 0.8 m/s); (4) CIND+ slow WS. Disability was defined as the sum of impaired activities of daily living and trajectories of disability were derived from mixed-effect linear regression models. Piecewise proportional hazard models were used to estimate mortality rate [hazard ratios (HRs)]. Population attributable risks of death were calculated.Results Participants with both CIND and slow WS had the worst prognosis, especially in the short-term period. They experienced the steepest increase in disability and five times the mortality rate (HR 5.1; 95% CI 3.5-7.4) of participants free from these conditions. Similar but attenuated results were observed for longer follow-ups. Co-occurring CIND and slow WS accounted for 30% of short-term deaths.Conclusions Co-occurring cognitive and physical limitations constitute a distinct risk profile in older people, and account for a large proportion of short-term deaths. Assessing cognitive and physical function could enable early identification of people at high risk for adverse events.
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| 4. |
- Hooshmand, Babak, et al.
(författare)
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Association of Vitamin B-12, Folate, and Sulfur Amino Acids With Brain Magnetic Resonance Imaging Measures in Older Adults A Longitudinal Population-Based Study
- 2016
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Ingår i: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 73:6, s. 606-613
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Vitamin B-12, folate, and sulfur amino acids may be modifiable risk factors for structural brain changes that precede clinical dementia. OBJECTIVE To investigate the association of circulating levels of vitamin B-12, red blood cell folate, and sulfur amino acids with the rate of total brain volume loss and the change in white matter hyperintensity volume as measured by fluid-attenuated inversion recovery in older adults. DESIGN, SETTING, AND PARTICIPANTS The magnetic resonance imaging subsample of the Swedish National Study on Aging and Care in Kungsholmen, a population-based longitudinal study in Stockholm, Sweden, was conducted in 501 participants aged 60 years or older who were free of dementia at baseline. A total of 299 participants underwent repeated structural brain magnetic resonance imaging scans from September 17, 2001, to December 17, 2009. MAIN OUTCOMES AND MEASURES The rate of brain tissue volume loss and the progression of total white matter hyperintensity volume. RESULTS In the multi-adjusted linear mixed models, among 501 participants (300 women [59.9%]; mean [SD] age, 70.9 [9.1] years), higher baseline vitamin B-12 and holotranscobalamin levels were associated with a decreased rate of total brain volume loss during the study period: for each increase of 1 SD, beta (SE) was 0.048 (0.013) for vitamin B-12 (P < .001) and 0.040 (0.013) for holotranscobalamin (P = .002). Increased total homocysteine levels were associated with faster rates of total brain volume loss in the whole sample (beta [SE] per 1-SD increase, -0.035 [0.015]; P = .02) and with the progression of white matter hyperintensity among participants with systolic blood pressure greater than 140mmHg (beta [SE] per 1-SD increase, 0.000019 [0.00001]; P = .047). No longitudinal associations were found for red blood cell folate and other sulfur amino acids. CONCLUSIONS AND RELEVANCE This study suggests that both vitamin B-12 and total homocysteine concentrations may be related to accelerated aging of the brain. Randomized clinical trials are needed to determine the importance of vitamin B-12 supplementation on slowing brain aging in older adults.
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| 5. |
- Jonsson Laukka, Erika
(författare)
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Cognitive functioning during the transition from normal aging to dementia
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of this thesis was to address unresolved issues regarding cognitive functioning in preclinical dementia. Increasing the knowledge about the preclinical period of dementia might have important clinical implications. For example, it may facilitate early detection, and thereby increase the efficiency of available interventions. All five empirical studies were based on data from the Kungsholmen Project - a longitudinal population-based study targeting persons living in the Kungsholmen parish of Stockholm, Sweden, who were ¡Ý75 years on October 1, 1987. In Study I and II, we investigated potential preclinical cognitive deficits in vascular dementia (VaD). It is well established that Alzheimer's disease (AD), the most common dementia disorder, is preceded by a preclinical phase with cognitive deficits. However, few studies have targeted the preclinical period in VaD, despite the fact that persons with VaD constitute approximately one fourth of dementia cases. In Study I, both preclinical VaD and preclinical AD persons showed cognitive impairment relative to controls on tasks assessing episodic memory 3 years before diagnosis. Although the results indicated a somewhat more widespread cognitive impairment in preclinical AD, there were no differences between the two dementia groups on any of the cognitive measures examined. In Study II, we observed an association between global cognitive functioning and incident VaD 3, but not 6, years before diagnosis. The association remained after controlling for demographic factors and history of vascular disorders. In Study III and IV, we examined level and change in cognitive performance for preclinical dementia and impending death. We found that excluding persons with preclinical dementia from the impending death group resulted in markedly attenuated effects of mortality on cognitive performance. However, both impending death and preclinical dementia were associated with poorer cognitive performance at cross-section for all examined tasks. In Study III, the impending death persons showed no accelerated decline relative to the controls on a measure of global cognitive functioning, whereas the preclinical dementia persons declined twice as fast. Study IV focused on a smaller sample that had completed a cognitive test battery. In contrast to Study III, we observed significant terminal-decline effects for select cognitive tasks even after controlling for preclinical dementia. These effects were only observed for tasks in which the controls showed no significant decline. In Study V, we examined the influence of preclinical dementia and impending death on the crosssectional relationship between age and cognitive performance. We found that removal of the preclinical dementia and impending death groups from the original sample affected the crosssectional age-cognition relationships relatively little. In sum, cognitive deficits constitute an early sign of VaD as well as of AD, with the pattern of preclinical cognitive impairment being similar for the two disorders. We also found that a considerable proportion of the impending-death effect is accounted for by preclinical dementia. Further, accelerated cognitive decline is most often a sign of impending dementia, although accelerated decline may be observed in the years preceding death for tasks showing little agerelated cognitive change. Finally, removal of persons in a preclinical phase of dementia or in close proximity to death affects the cross-sectional age-cognition relationship in an elderly sample relatively little, suggesting that the biological aging process exerts negative influences on cognitive functioning beyond those resulting from dementia and mortality.
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| 6. |
- Laukka, Erika J., et al.
(författare)
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Associations between White Matter Microstructure and Cognitive Performance in Old and Very Old Age
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:11
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Tidskriftsartikel (refereegranskat)abstract
- Increasing age is associated with deficits in a wide range of cognitive domains as well as with structural brain changes. Recent studies using diffusion tensor imaging (DTI) have shown that microstructural integrity of white matter is associated with cognitive performance in elderly persons, especially on tests that rely on perceptual speed. We used structural equation modeling to investigate associations between white matter microstructure and cognitive functions in a population-based sample of elderly persons (age >= 60 years), free of dementia, stroke, and neurological disorders (n = 253). Participants underwent a magnetic resonance imaging scan, from which mean fractional anisotropy (FA) and mean diffusivity (MD) of seven white matter tracts were quantified. Cognitive functioning was analyzed according to performance in five task domains (perceptual speed, episodic memory, semantic memory, letter fluency, and category fluency). After controlling for age, FA and MD were exclusively related to perceptual speed. When further stratifying the sample into two age groups, the associations were reliable in the old-old (>= 78 years) only. This relationship between white matter microstructure and perceptual speed remained significant after excluding persons in a preclinical dementia phase. The observed pattern of results suggests that microstructural white matter integrity may be especially important to perceptual speed among very old adults.
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| 7. |
- Olofsson, Jonas K., et al.
(författare)
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Interaction Between Odor Identification Deficit and APOE4 Predicts 6-Year Cognitive Decline in Elderly Individuals
- 2020
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Ingår i: Behavior Genetics. - : Springer Science and Business Media LLC. - 0001-8244 .- 1573-3297. ; 50:1, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- Olfactory identification impairment might indicate future cognitive decline in elderly individuals. An unresolved question is to what extent this effect is dependent on the ApoE-epsilon 4, a genotype associated with risk of Alzheimer's Disease (AD). Given the current concern about reproducibility in empirical research, we assessed this issue in a large sample (n = 1637) of older adults (60 - 96 years) from the population-based longitudinal Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). A hierarchical regression analysis was carried out to determine if a low score on an odor identification test, and the presence of ApoE-epsilon 4, would predict the magnitude of a prospective 6-year change in the Mini-Mental State Examination (MMSE) after controlling for demographic, health-related, and cognitive variables. We found that overall, lower odor identification performance was predictive of cognitive decline, and, as hypothesized, we found that the effect was most pronounced among ApoE-epsilon 4 carriers. Our results from this high-powered sample suggest that in elderly carriers of the ApoE-epsilon 4 allele, odor identification impairment provides an indication of future cognitive decline, which has relevance for the prognosis of AD.
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| 8. |
- Thorvaldsson, Valgeir, 1976, et al.
(författare)
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Onset and rate of cognitive change before dementia diagnosis: findings from two Swedish population-based longitudinal studies
- 2011
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Ingår i: Journal of the International Neuropsychological Society. - 1469-7661 .- 1355-6177. ; 17:1, s. 154-62
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Tidskriftsartikel (refereegranskat)abstract
- We used data from two population-based longitudinal studies to estimate time of onset and rate of accelerated decline across cognitive domains before dementia diagnosis. The H70 includes an age-homogeneous sample (127 cases and 255 non-cases) initially assessed at age 70 with 12 follow-ups over 30 years. The Kungsholmen Project (KP) includes an age-heterogeneous sample (279 cases and 562 non-cases), with an average age of 82 years at initial assessment, and 4 follow-ups spanning 13 years. We fit mixed linear models to the data and determined placement of change points by a profile likelihood method. Results demonstrated onset of accelerated decline for fluid (speed, memory) versus crystallized (verbal, clock reading) abilities occurring approximately 10 and 5 years before diagnosis, respectively. Although decline before change points was greater for fluid abilities, acceleration was more pronounced for crystallized abilities after the change points. This suggests that onset and rate of acceleration vary systematically along the fluid-crystallized ability continuum. There is early onset in fluid abilities, but these changes are difficult to detect due to substantial age-related decline. Onset occurred later and acceleration was greater in crystallized abilities, suggesting that those markers may provide more valid identification of cases in later stages of the prodromal phase.
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| 9. |
- Tian, Qu, et al.
(författare)
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Association of Dual Decline in Memory and Gait Speed With Risk for Dementia Among Adults Older Than 60 Years A Multicohort Individual-Level Meta-analysis
- 2020
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Ingår i: JAMA Network Open. - : American Medical Association (AMA). - 2574-3805. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- Question Is a decline in both memory and gait speed with aging associated with a higher risk of dementia than no decline or a decline in memory or gait only in older adults? Findings In this meta-analysis of 6 studies including 8699 participants from the United States and Europe, a decline in both memory and gait was associated with 6.28 times higher risk of developing dementia than no decline. Meaning Older adults without dementia with parallel declines in memory and gait are associated with high risk of developing dementia and may be a group to target for prevention. This meta-analysis assesses whether parallel declines in memory and gait speed among older adults, compared with those who experience no decline or decline in either memory or gait speed only, are associated with risk of developing dementia. Importance Dual decline in both memory and gait speed may characterize a group of older individuals at high risk for future dementia. Objective To assess the risk of dementia in older persons who experience parallel declines in memory and gait speed compared with those who experience no decline or decline in either memory or gait speed only. Design, Setting, and Participants A multicohort meta-analysis was performed of 6 prospective cohort studies conducted between 1997 and 2018 in the United States and Europe. Participants were 60 years or older, had an initial gait speed of more than 0.6 m/s (ie, free of overt dismobility), with repeated measures of memory and gait speed before dementia diagnosis during a mean follow-up of 6.6 to 14.5 years. Within each study, participants were divided into 4 groups: memory decline only, gait speed decline only, dual decline, or no decline (hereafter referred to as usual agers). Gait decline was defined as a loss of 0.05 m/s or more per year; memory decline was defined as being in the cohort-specific lowest tertile of annualized change. Main Outcomes and Measures Risk of incident dementia according to group membership was examined by Cox proportional hazards regression with usual agers as the reference, adjusted for baseline age, sex, race/ethnicity, educational level, study site, and baseline gait speed and memory. Results Across the 6 studies of 8699 participants, mean age ranged between 70 and 74 years and mean gait speed ranged between 1.05 and 1.26 m/s. Incident dementia ranged from 5 to 21 per 1000 person-years. Compared with usual agers, participants with only memory decline had 2.2 to 4.6 times higher risk for developing dementia (pooled hazard ratio, 3.45 [95% CI, 2.45-4.86]). Those with only gait decline had 2.1 to 3.6 times higher risk (pooled hazard ratio, 2.24 [95% CI, 1.62-3.09]). Those with dual decline had 5.2 to 11.7 times the risk (pooled hazard ratio, 6.28 [95% CI, 4.56-8.64]). Conclusions and Relevance In this study, dual decline of memory and gait speed was associated with increased risk of developing dementia among older individuals, which might be a potentially valuable group for preventive or therapeutic interventions. Why dual decline is associated with an elevated risk of dementia and whether these individuals progress to dementia through specific mechanisms should be investigated by future studies.
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