Education has been robustly associated with cognitive reserve and dementia, but not with the rate... more Education has been robustly associated with cognitive reserve and dementia, but not with the rate of cognitive aging, resulting in some confusion about the mechanisms of cognitive aging. This study uses longitudinal data to differentiate between trajectories indicative of healthy versus pathological cognitive aging. Participants included 9,401 Health and Retirement Study respondents aged 55 and older who completed cognitive testing regularly over 17.3 years until most recently in 2012. Individual-specific random change-point modeling was used to identify age of incident pathological decline; acceleration is interpreted as indicating likely onset of pathological decline when it is significant and negative. These methods detect incident dementia diagnoses with specificity/sensitivity of 89.3%/44.3%, 5.6 years prior to diagnosis. Each year of education was associated with 0.09 (95% CI, 0.087-0.096; P<0.001) standard deviation higher baseline cognition and delayed onset of cognitive pathology (HR, 0.98; 95% CI, 0.96-0.99; P=0.006). Longitudinal random change-point modeling was able to reliably identify incident dementia. Accounting for incident cognitive pathology, we find that education predicts cognitive capability and delayed onset pathological declines.
ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health condi... more ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health conditions in the older adult population. If left untreated or uncontrolled, both may lead to more serious conditions such as heart disease, stroke, or heart attack. Additionally, a growing body of evidence suggests that individuals diagnosed with either HTN or DM are at increased risk for earlier or more dramatic declines than non-diagnosed peers across several cognitive domains (e.g., Arvanitakis et al., 2010; Kuo et al., 2005; van den Berg et al., 2009). Though HTN and DM often co-occur, their impacts on long-term cognitive functioning are typically considered independently. To the best of our knowledge, Hassing et al. (2004) is the only study to have compared impacts of HTN alone, DM alone and comorbid HTN and DM on cognitive level and rate of change. Findings suggested impacts of DM alone and comorbid HTN and DM on rate of cognitive change. However, this approach has not yet been extended to other datasets. Here, we present a multi-study replication and expansion of Hassing et al. to further our understanding of the roles that HTN and DM may play in age-related cognitive decline. Multilevel modeling was used to examine changes in cognitive scores across study occasions for participants diagnosed with HTN alone, DM alone, or comorbid HTN and DM in each independent longitudinal study. This discrete-group approach distinguishes these three groups for comparison to each other and non-cases. We report on the interactive effects of comorbid HTN and DM on cognitive trajectories relative to non-case, HTN-only and DM-only groups.
(1) To describe changes in objective measures of physical capability between ages 53 and 60-64 ye... more (1) To describe changes in objective measures of physical capability between ages 53 and 60-64 years; (2) to investigate the associations of behavioural risk factors (obesity, physical inactivity, smoking) and number of health conditions (range 0-4: hand osteoarthritis (OA); knee OA; severe respiratory symptoms; other disabling or life-threatening conditions (ie, cancer, cardiovascular disease, diabetes)) at age 53 years with these changes. Nationally representative prospective birth cohort study. England, Scotland and Wales. Up to 2093 men and women from the Medical Research Council National Survey of Health and Development, who have been followed-up since birth in 1946, and underwent physical capability assessments performed by nurses following standard protocols in 1999 and 2006-2010. Grip strength and chair rise speed were assessed at ages 53 and 60-64 years. Four categories of change in grip strength and chair rise speed were identified: decline, stable high, stable low, a reference group who maintained physical capability within a 'normal' range. Less healthy behavioural risk scores and an increase in the number of health conditions experienced were associated in a stepwise fashion with increased risk of decline in physical capability, and also of having low levels at baseline and remaining low. For example, the sex and mutually adjusted relative-risk ratios (95% CI) of being in the stable low versus reference category of chair rise speed were 1.58 (1.35-1.86) and 1.97 (1.57-2.47) per 1 unit change in behavioural risk score and health indicator count, respectively. These findings provide evidence of the associations of a range of modifiable factors with age-related changes in physical capability. They suggest the need to target multiple risk factors at least as early as mid-life when aiming to promote maintenance and prevent decline in physical capability in later life.
We investigated education and occupational influences as markers of cognitive reserve in relation... more We investigated education and occupational influences as markers of cognitive reserve in relation to cognitive performance and decline on multiple fluid and crystallized abilities in preclinical dementia. From the total sample of 702 participants stemming from the OCTOTwin Study (Sweden), aged 80+ at baseline in 1992–1993, only those who developed dementia during the study period (N = 127) were included in these analyses. Random effects models were used to examine the level of performance at the time of dementia diagnosis and the rates of decline prior to diagnosis. The results demonstrated that both fluid and crystallized abilities decline in preclinical stages, and that education and occupational class have independent moderating roles on the cognitive performance at the time of diagnosis, but not on the rates of decline.
Epidemiological studies in pre- and postmenopausal women and older men and women suggest that hig... more Epidemiological studies in pre- and postmenopausal women and older men and women suggest that higher fruit and vegetable intakes have a positive effect on bone health. Mechanisms have been attributed to the high alkali salt content of fruits and vegetables, which counteracts the effects of acid generating foods, such as meat and cereals. A higher dietary acid load has been
The importance of preventing and controlling hypertension (HTN) and diabetes mellitus (DM) to mit... more The importance of preventing and controlling hypertension (HTN) and diabetes mellitus (DM) to mitigate risks to physical health has long been understood by health care professionals. More recently, a growing body of evidence implicates HTN and DM in age-related cognitive decline and risk for dementia, though consensus has yet to be reached on whether older adults living with comorbid HTN and DM are at heightened risk for cognitive impairment. The present study sought to contribute to this topic through a coordinated analysis of 3 longitudinal studies of aging from England, Sweden, and the United States (total N = 12,513). Identical multilevel linear growth models were fit to each to estimate the impact of baseline disease status on initial level and change in verbal declarative memory performance. Overall, few associations between HTN, DM, and cognition were observed. Rate of decline was steeper for Swedish participants with independent HTN but attenuated for their American counterp...
ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health condi... more ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health conditions in the older adult population and both place diagnosed individuals at increased risk for earlier or more dramatic decline in several cognitive domains. Though HTN and DM often co-occur, their impacts on long-term cognitive functioning are typically considered independently. To the best of our knowledge, Hassing et al. (2004) is the only study to have compared impacts of HTN alone, DM alone and comorbid HTN and DM on cognitive level and rate of change in older adults. Here, we extend that approach to three independent longitudinal studies, using multilevel modeling to examine changes in cognitive scores across study occasions for participants diagnosed with comorbid HTN and DM relative to HTN-only and DM-only groups. Considering both conditions together is a critical next step to further our understanding of the roles that they may play in age-related cognitive decline.
outcomes such as mortality and low physical function. We hypothesised that the number of lifestyl... more outcomes such as mortality and low physical function. We hypothesised that the number of lifestyle risk factors (out of low physical activity, poor diet, obesity and smoking) may be associated with subsequent hospital admission among community-dwelling older people. Methods From 1998–2004, 2997 community-dwelling men and women (aged 59–73) who participated in the Hertfordshire Cohort Study (HCS) completed a baseline assessment. Physical activity was assessed using a questionnaire with a score ranging from 0–100; diet was assessed using a food frequency questionnaire and a prudent diet score, to indicate compliance with a healthy dietary pattern, was derived using principal component analysis. Smokers were regarded as individuals who were current smokers; obesity was defined as a BMI of 30.0 kg/m 2 or more; poor diet was defined as having a prudent diet score in the bottom quarter of the distribution and low physical activity was defined as having a physical activity score of 50 or less. Hospital Episode Statistics and mortality data up to 31/03/10 were linked with the HCS database. Survival analysis models and Poisson regression models were used to examine the association between the number of risk factors and the risk of the following types of hospital admission: any, elective, emergency, long stay (>7 days) and readmission within 30 days. Results There was a graded increase in the risk of all types of admission among men and women as the number of risk factors increased. For example, the unadjusted hazard ratios for emergency admission among men were: one risk factor vs none 1.11 [95% CI: 0.96,1.29], two vs none 1.25[95% CI: 1.04,1.49], three or four vs none 1.74[95% CI: 1.40,2.15]; and among women were: one vs none 1.15[95% CI: 0.96,1.38], two vs none 1.44[95% CI: 1.17,1.76], three or four vs none 1.96[95% CI: 1.36,2.81]. Associations for all types of admission remained significant after adjustment for age and number of systems medicated. Although, as in many cohort studies, a healthy participant effect is apparent in HCS, this is unlikely to have affected these results since this analysis was internal. Conclusion This study provides the first evidence that the number of lifestyle risk factors among community-dwelling men and women is associated with risk of subsequent hospital admission. As lifestyle risk factors often coexist and are more prevalent among lower socioeconomic groups, encouraging healthy lifestyles may have the potential to avert admission and reduce inequalities in health.
Background: Education, a marker for cognitive reserve, is thought to be associated with lower ris... more Background: Education, a marker for cognitive reserve, is thought to be associated with lower risks of dementia, but less is known about its association with cognitive decline in preclinical stages of dementia. Methods: We examined the association between education and change in Mini-Mental State Examination (MMSE) in those who developed dementia diagnosis during the study period prior to the time of dementia diagnosis, in six international studies of ageing: Newcastle 85+, UK; The Three-City Study (3C) France; Leiden 85+ and Longitudinal Aging Study Amsterdam (LASA), Netherlands; Octogenarian Twins (OCTO-Twin), Sweden and Memory and Ageing Study (MAS), Australia. Using a coordinated analysis approach, we employed multilevel models to investigate the role of education on change in MMSE independently within each cohort, while controlling for common covariates such as age at baseline, sex, and time to dementia diagnosis from study entry within each cohort. Each individuals' cognitive scores were aligned according to distance (years) to dementia diagnosis. Findings: Higher levels of education (> 12 years) were associated with faster linear rates of decline in the MMSE scores from the study entry to the time of dementia diagnosis in three cohorts investigated LASA, OCTO-Twin, and MAS. However, in one cohort (Newcastle 85+), higher education was associated with a slower rate of decline in the preclinical stages of dementia (β= 0.93, 95% CI 0.09 to 1.77) compared to lower education, suggesting perhaps a difference in the educational system between the UK and the rest of Europe or Australia during the early 1990s. A random effects meta-analysis across data from all six studies indicated a non-significant steeper cognitive decline for those with higher education (β=-0.08, 95% CI-0.17 to 0.003). Conclusions: This coordinated approach analysis revealed no consistent protection for those with higher education in terms of lowering the rate of cognitive decline in the preclinical stages of dementia, which constitutes a major public health burden. This work supports only partially the cognitive reserve hypothesis, which suggests a delay in the clinical manifestation of dementia for those with higher education but a steeper decline once a certain threshold has been reached.
Education has been robustly associated with cognitive reserve and dementia, but not with the rate... more Education has been robustly associated with cognitive reserve and dementia, but not with the rate of cognitive aging, resulting in some confusion about the mechanisms of cognitive aging. This study uses longitudinal data to differentiate between trajectories indicative of healthy versus pathological cognitive aging. Participants included 9,401 Health and Retirement Study respondents aged 55 and older who completed cognitive testing regularly over 17.3 years until most recently in 2012. Individual-specific random change-point modeling was used to identify age of incident pathological decline; acceleration is interpreted as indicating likely onset of pathological decline when it is significant and negative. These methods detect incident dementia diagnoses with specificity/sensitivity of 89.3%/44.3%, 5.6 years prior to diagnosis. Each year of education was associated with 0.09 (95% CI, 0.087-0.096; P<0.001) standard deviation higher baseline cognition and delayed onset of cognitive ...
International journal of geriatric psychiatry, Jan 15, 2015
Cognitive performance shows a marked deterioration in close proximity to death, as postulated by ... more Cognitive performance shows a marked deterioration in close proximity to death, as postulated by the terminal decline hypothesis. The effect of education on the rate of terminal decline in the oldest people (i.e. persons 85+ years) has been controversial and not entirely understood. In the current study, we investigated the rate of decline prior to death with a special focus on the role of education and socioeconomic position, in two European longitudinal studies of ageing: the Origins of Variance in the Old-Old: Octogenarian Twins (OCTO-Twin) and the Newcastle 85+ study. A process-based approach was used in which individuals' cognitive scores were aligned according to distance to death. In a coordinated analysis, multilevel models were employed to examine associations between different markers of cognitive reserve (education and socioeconomic position) and terminal decline using the mini-mental state examination (MMSE), controlling for age at baseline, sex, dementia incidence a...
criteria for mild cognitive impairment (MCI) capture an intermediate cognitive state between norm... more criteria for mild cognitive impairment (MCI) capture an intermediate cognitive state between normal ageing and dementia, associated with increased dementia risk. Whether criteria for MCI are applicable in the context of stroke and can be used to predict dementia in stroke cases is not known. to determine the prevalence of MCI in individuals with stroke and identify predictors of 2-year incident dementia in stroke cases. individuals were from the Medical Research Council Cognitive Function and Ageing Study. MCI prevalence in individuals with stroke was determined. Logistic regression, with receiver operating characteristic curve analysis, was used to identify variables associated with risk of dementia in stroke cases including MCI criteria, demographic, health and lifestyle variables. of 2,640 individuals seen at the first assessment, 199 reported stroke with no dementia. In individuals with stroke, criteria for MCI are not appropriate, with less than 1% of stroke cases being classified as having MCI. However, in individuals with stroke two components of the MCI definition, subjective memory complaint and cognitive function (memory and praxis scores) predicted 2-year incident dementia (area under the curve = 0.85, 95% CI: 0.77-0.94, n = 113). criteria for MCI do not appear to capture risk of dementia in the context of stroke in the population. In stroke cases, subjective and objective cognitive performance predicts dementia and these variables could possibly be incorporated into dementia risk models for stroke cases. Identifying individuals with stroke at greatest risk of dementia has important implications for treatment and intervention.
Education has been robustly associated with cognitive reserve and dementia, but not with the rate... more Education has been robustly associated with cognitive reserve and dementia, but not with the rate of cognitive aging, resulting in some confusion about the mechanisms of cognitive aging. This study uses longitudinal data to differentiate between trajectories indicative of healthy versus pathological cognitive aging. Participants included 9,401 Health and Retirement Study respondents aged 55 and older who completed cognitive testing regularly over 17.3 years until most recently in 2012. Individual-specific random change-point modeling was used to identify age of incident pathological decline; acceleration is interpreted as indicating likely onset of pathological decline when it is significant and negative. These methods detect incident dementia diagnoses with specificity/sensitivity of 89.3%/44.3%, 5.6 years prior to diagnosis. Each year of education was associated with 0.09 (95% CI, 0.087-0.096; P&amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) standard deviation higher baseline cognition and delayed onset of cognitive pathology (HR, 0.98; 95% CI, 0.96-0.99; P=0.006). Longitudinal random change-point modeling was able to reliably identify incident dementia. Accounting for incident cognitive pathology, we find that education predicts cognitive capability and delayed onset pathological declines.
ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health condi... more ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health conditions in the older adult population. If left untreated or uncontrolled, both may lead to more serious conditions such as heart disease, stroke, or heart attack. Additionally, a growing body of evidence suggests that individuals diagnosed with either HTN or DM are at increased risk for earlier or more dramatic declines than non-diagnosed peers across several cognitive domains (e.g., Arvanitakis et al., 2010; Kuo et al., 2005; van den Berg et al., 2009). Though HTN and DM often co-occur, their impacts on long-term cognitive functioning are typically considered independently. To the best of our knowledge, Hassing et al. (2004) is the only study to have compared impacts of HTN alone, DM alone and comorbid HTN and DM on cognitive level and rate of change. Findings suggested impacts of DM alone and comorbid HTN and DM on rate of cognitive change. However, this approach has not yet been extended to other datasets. Here, we present a multi-study replication and expansion of Hassing et al. to further our understanding of the roles that HTN and DM may play in age-related cognitive decline. Multilevel modeling was used to examine changes in cognitive scores across study occasions for participants diagnosed with HTN alone, DM alone, or comorbid HTN and DM in each independent longitudinal study. This discrete-group approach distinguishes these three groups for comparison to each other and non-cases. We report on the interactive effects of comorbid HTN and DM on cognitive trajectories relative to non-case, HTN-only and DM-only groups.
(1) To describe changes in objective measures of physical capability between ages 53 and 60-64 ye... more (1) To describe changes in objective measures of physical capability between ages 53 and 60-64 years; (2) to investigate the associations of behavioural risk factors (obesity, physical inactivity, smoking) and number of health conditions (range 0-4: hand osteoarthritis (OA); knee OA; severe respiratory symptoms; other disabling or life-threatening conditions (ie, cancer, cardiovascular disease, diabetes)) at age 53 years with these changes. Nationally representative prospective birth cohort study. England, Scotland and Wales. Up to 2093 men and women from the Medical Research Council National Survey of Health and Development, who have been followed-up since birth in 1946, and underwent physical capability assessments performed by nurses following standard protocols in 1999 and 2006-2010. Grip strength and chair rise speed were assessed at ages 53 and 60-64 years. Four categories of change in grip strength and chair rise speed were identified: decline, stable high, stable low, a reference group who maintained physical capability within a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;normal&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; range. Less healthy behavioural risk scores and an increase in the number of health conditions experienced were associated in a stepwise fashion with increased risk of decline in physical capability, and also of having low levels at baseline and remaining low. For example, the sex and mutually adjusted relative-risk ratios (95% CI) of being in the stable low versus reference category of chair rise speed were 1.58 (1.35-1.86) and 1.97 (1.57-2.47) per 1 unit change in behavioural risk score and health indicator count, respectively. These findings provide evidence of the associations of a range of modifiable factors with age-related changes in physical capability. They suggest the need to target multiple risk factors at least as early as mid-life when aiming to promote maintenance and prevent decline in physical capability in later life.
We investigated education and occupational influences as markers of cognitive reserve in relation... more We investigated education and occupational influences as markers of cognitive reserve in relation to cognitive performance and decline on multiple fluid and crystallized abilities in preclinical dementia. From the total sample of 702 participants stemming from the OCTOTwin Study (Sweden), aged 80+ at baseline in 1992–1993, only those who developed dementia during the study period (N = 127) were included in these analyses. Random effects models were used to examine the level of performance at the time of dementia diagnosis and the rates of decline prior to diagnosis. The results demonstrated that both fluid and crystallized abilities decline in preclinical stages, and that education and occupational class have independent moderating roles on the cognitive performance at the time of diagnosis, but not on the rates of decline.
Epidemiological studies in pre- and postmenopausal women and older men and women suggest that hig... more Epidemiological studies in pre- and postmenopausal women and older men and women suggest that higher fruit and vegetable intakes have a positive effect on bone health. Mechanisms have been attributed to the high alkali salt content of fruits and vegetables, which counteracts the effects of acid generating foods, such as meat and cereals. A higher dietary acid load has been
The importance of preventing and controlling hypertension (HTN) and diabetes mellitus (DM) to mit... more The importance of preventing and controlling hypertension (HTN) and diabetes mellitus (DM) to mitigate risks to physical health has long been understood by health care professionals. More recently, a growing body of evidence implicates HTN and DM in age-related cognitive decline and risk for dementia, though consensus has yet to be reached on whether older adults living with comorbid HTN and DM are at heightened risk for cognitive impairment. The present study sought to contribute to this topic through a coordinated analysis of 3 longitudinal studies of aging from England, Sweden, and the United States (total N = 12,513). Identical multilevel linear growth models were fit to each to estimate the impact of baseline disease status on initial level and change in verbal declarative memory performance. Overall, few associations between HTN, DM, and cognition were observed. Rate of decline was steeper for Swedish participants with independent HTN but attenuated for their American counterp...
ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health condi... more ABSTRACT Hypertension (HTN) and diabetes mellitus (DM) are two of the most prevalent health conditions in the older adult population and both place diagnosed individuals at increased risk for earlier or more dramatic decline in several cognitive domains. Though HTN and DM often co-occur, their impacts on long-term cognitive functioning are typically considered independently. To the best of our knowledge, Hassing et al. (2004) is the only study to have compared impacts of HTN alone, DM alone and comorbid HTN and DM on cognitive level and rate of change in older adults. Here, we extend that approach to three independent longitudinal studies, using multilevel modeling to examine changes in cognitive scores across study occasions for participants diagnosed with comorbid HTN and DM relative to HTN-only and DM-only groups. Considering both conditions together is a critical next step to further our understanding of the roles that they may play in age-related cognitive decline.
outcomes such as mortality and low physical function. We hypothesised that the number of lifestyl... more outcomes such as mortality and low physical function. We hypothesised that the number of lifestyle risk factors (out of low physical activity, poor diet, obesity and smoking) may be associated with subsequent hospital admission among community-dwelling older people. Methods From 1998–2004, 2997 community-dwelling men and women (aged 59–73) who participated in the Hertfordshire Cohort Study (HCS) completed a baseline assessment. Physical activity was assessed using a questionnaire with a score ranging from 0–100; diet was assessed using a food frequency questionnaire and a prudent diet score, to indicate compliance with a healthy dietary pattern, was derived using principal component analysis. Smokers were regarded as individuals who were current smokers; obesity was defined as a BMI of 30.0 kg/m 2 or more; poor diet was defined as having a prudent diet score in the bottom quarter of the distribution and low physical activity was defined as having a physical activity score of 50 or less. Hospital Episode Statistics and mortality data up to 31/03/10 were linked with the HCS database. Survival analysis models and Poisson regression models were used to examine the association between the number of risk factors and the risk of the following types of hospital admission: any, elective, emergency, long stay (&gt;7 days) and readmission within 30 days. Results There was a graded increase in the risk of all types of admission among men and women as the number of risk factors increased. For example, the unadjusted hazard ratios for emergency admission among men were: one risk factor vs none 1.11 [95% CI: 0.96,1.29], two vs none 1.25[95% CI: 1.04,1.49], three or four vs none 1.74[95% CI: 1.40,2.15]; and among women were: one vs none 1.15[95% CI: 0.96,1.38], two vs none 1.44[95% CI: 1.17,1.76], three or four vs none 1.96[95% CI: 1.36,2.81]. Associations for all types of admission remained significant after adjustment for age and number of systems medicated. Although, as in many cohort studies, a healthy participant effect is apparent in HCS, this is unlikely to have affected these results since this analysis was internal. Conclusion This study provides the first evidence that the number of lifestyle risk factors among community-dwelling men and women is associated with risk of subsequent hospital admission. As lifestyle risk factors often coexist and are more prevalent among lower socioeconomic groups, encouraging healthy lifestyles may have the potential to avert admission and reduce inequalities in health.
Background: Education, a marker for cognitive reserve, is thought to be associated with lower ris... more Background: Education, a marker for cognitive reserve, is thought to be associated with lower risks of dementia, but less is known about its association with cognitive decline in preclinical stages of dementia. Methods: We examined the association between education and change in Mini-Mental State Examination (MMSE) in those who developed dementia diagnosis during the study period prior to the time of dementia diagnosis, in six international studies of ageing: Newcastle 85+, UK; The Three-City Study (3C) France; Leiden 85+ and Longitudinal Aging Study Amsterdam (LASA), Netherlands; Octogenarian Twins (OCTO-Twin), Sweden and Memory and Ageing Study (MAS), Australia. Using a coordinated analysis approach, we employed multilevel models to investigate the role of education on change in MMSE independently within each cohort, while controlling for common covariates such as age at baseline, sex, and time to dementia diagnosis from study entry within each cohort. Each individuals' cognitive scores were aligned according to distance (years) to dementia diagnosis. Findings: Higher levels of education (> 12 years) were associated with faster linear rates of decline in the MMSE scores from the study entry to the time of dementia diagnosis in three cohorts investigated LASA, OCTO-Twin, and MAS. However, in one cohort (Newcastle 85+), higher education was associated with a slower rate of decline in the preclinical stages of dementia (β= 0.93, 95% CI 0.09 to 1.77) compared to lower education, suggesting perhaps a difference in the educational system between the UK and the rest of Europe or Australia during the early 1990s. A random effects meta-analysis across data from all six studies indicated a non-significant steeper cognitive decline for those with higher education (β=-0.08, 95% CI-0.17 to 0.003). Conclusions: This coordinated approach analysis revealed no consistent protection for those with higher education in terms of lowering the rate of cognitive decline in the preclinical stages of dementia, which constitutes a major public health burden. This work supports only partially the cognitive reserve hypothesis, which suggests a delay in the clinical manifestation of dementia for those with higher education but a steeper decline once a certain threshold has been reached.
Education has been robustly associated with cognitive reserve and dementia, but not with the rate... more Education has been robustly associated with cognitive reserve and dementia, but not with the rate of cognitive aging, resulting in some confusion about the mechanisms of cognitive aging. This study uses longitudinal data to differentiate between trajectories indicative of healthy versus pathological cognitive aging. Participants included 9,401 Health and Retirement Study respondents aged 55 and older who completed cognitive testing regularly over 17.3 years until most recently in 2012. Individual-specific random change-point modeling was used to identify age of incident pathological decline; acceleration is interpreted as indicating likely onset of pathological decline when it is significant and negative. These methods detect incident dementia diagnoses with specificity/sensitivity of 89.3%/44.3%, 5.6 years prior to diagnosis. Each year of education was associated with 0.09 (95% CI, 0.087-0.096; P<0.001) standard deviation higher baseline cognition and delayed onset of cognitive ...
International journal of geriatric psychiatry, Jan 15, 2015
Cognitive performance shows a marked deterioration in close proximity to death, as postulated by ... more Cognitive performance shows a marked deterioration in close proximity to death, as postulated by the terminal decline hypothesis. The effect of education on the rate of terminal decline in the oldest people (i.e. persons 85+ years) has been controversial and not entirely understood. In the current study, we investigated the rate of decline prior to death with a special focus on the role of education and socioeconomic position, in two European longitudinal studies of ageing: the Origins of Variance in the Old-Old: Octogenarian Twins (OCTO-Twin) and the Newcastle 85+ study. A process-based approach was used in which individuals' cognitive scores were aligned according to distance to death. In a coordinated analysis, multilevel models were employed to examine associations between different markers of cognitive reserve (education and socioeconomic position) and terminal decline using the mini-mental state examination (MMSE), controlling for age at baseline, sex, dementia incidence a...
criteria for mild cognitive impairment (MCI) capture an intermediate cognitive state between norm... more criteria for mild cognitive impairment (MCI) capture an intermediate cognitive state between normal ageing and dementia, associated with increased dementia risk. Whether criteria for MCI are applicable in the context of stroke and can be used to predict dementia in stroke cases is not known. to determine the prevalence of MCI in individuals with stroke and identify predictors of 2-year incident dementia in stroke cases. individuals were from the Medical Research Council Cognitive Function and Ageing Study. MCI prevalence in individuals with stroke was determined. Logistic regression, with receiver operating characteristic curve analysis, was used to identify variables associated with risk of dementia in stroke cases including MCI criteria, demographic, health and lifestyle variables. of 2,640 individuals seen at the first assessment, 199 reported stroke with no dementia. In individuals with stroke, criteria for MCI are not appropriate, with less than 1% of stroke cases being classified as having MCI. However, in individuals with stroke two components of the MCI definition, subjective memory complaint and cognitive function (memory and praxis scores) predicted 2-year incident dementia (area under the curve = 0.85, 95% CI: 0.77-0.94, n = 113). criteria for MCI do not appear to capture risk of dementia in the context of stroke in the population. In stroke cases, subjective and objective cognitive performance predicts dementia and these variables could possibly be incorporated into dementia risk models for stroke cases. Identifying individuals with stroke at greatest risk of dementia has important implications for treatment and intervention.
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