To relate dietary fat types to cognitive change in healthy community-based elders.
Among 6,183 older participants in the Women’s Health Study, we related intake of major fatty acids (FAs) (saturated [SFA], mono-unsaturated [MUFA], total poly-unsaturated [PUFA], trans-unsaturated) to late-life cognitive trajectory. Serial cognitive testing, conducted over 4 years, began 5 years post-dietary assessment. Primary outcomes were global cognition (averaging tests of general cognition, verbal memory and semantic fluency) and verbal memory (averaging tests of recall). We used analyses of response profiles and logistic regression to estimate multivariable-adjusted differences in cognitive trajectory and risk of worst cognitive change (worst 10%) by fat intake.
Higher SFA intake was associated with worse global cognitive (p-linear-trend=0.008) and verbal memory (p-linear-trend=0.01) trajectories. There was a higher risk of worst cognitive change, comparing highest vs. lowest SFA quintiles: the multivariable-adjusted odds ratio (OR) (95% confidence interval, CI) was 1.64 (1.04,2.58) for global cognition and 1.65 (1.04,2.61) for verbal memory. By contrast, higher MUFA intake was related to better global cognitive (p-linear-trend<0.001) and verbal memory (p-linear-trend=0.009) trajectories, and lower OR (95% CI) of worst cognitive change in global cognition (0.52 [0.31,0.88]) and verbal memory (0.56 [0.34,0.94]). Total fat, PUFA, and trans fat intakes were not associated with cognitive trajectory.
Higher SFA intake was associated with worse global cognitive and verbal memory trajectories, while higher MUFA intake was related to better trajectories. Thus, different consumption levels of the major specific fat types, rather than total fat intake itself, appeared to influence cognitive aging.
Individuals with vascular disease or risk factors have substantially higher rates of cognitive decline, yet little is known on means of maintaining cognition in this group.
We examined the relation between physical activity and cognitive decline in participants of the Women’s Antioxidant Cardiovascular Study (WACS), a cohort of women with prevalent vascular disease or ≥3 coronary risk factors. Recreational physical activity was assessed at baseline (1995–1996) and every two years thereafter. In 1998–2000, participants aged ≥65 years underwent a telephone cognitive battery including five tests of global cognition, verbal memory, and category fluency (n=2809). Tests were administered three additional times over 5.4 years. We used multivariable-adjusted generalized linear models for repeated measures to compare the annual rates of cognitive score changes across levels of total physical activity and on walking, as assessed at WACS baseline.
We found a significant trend (p-trend<0.001) of slower rates of cognitive decline with increasing energy expenditure. Compared to the bottom quintile of total physical activity, significant differences in rates of cognitive decline were observed from the fourth quintile (p=0.04 for fourth quintile, p<0.001 for fifth quintile) or the equivalent of daily 30-minute walks at a brisk pace. This difference was equivalent to the difference in cognitive decline observed for women who were younger by 5–7 years. Walking was also strongly related to slower rates of cognitive decline (p-trend=0.003).
Regular physical activity, including walking, was associated with better preservation of cognitive function in older women with vascular disease or risk factors.
Both type 2 diabetes and hyperinsulinemia have been related to diminished cognition. To address independent effects of increasing mid-life insulin secretion on late-life cognition, we prospectively examined the relation of plasma c-peptide levels to cognitive decline in a large sample of older women without diabetes or stroke.
Plasma c-peptide levels were measured in 1,187 “young-old” women (mean age=64 years) without diabetes in the Nurses’ Health Study. Cognitive decline was assessed approximately 10 years later. Three repeated cognitive batteries were administered over an average of 4.4 years using telephone-based tests of general cognition, verbal memory, category fluency, and attention. Primary outcomes were general cognition (measured by the Telephone interview for Cognitive Status [TICS], as well as a global score averaging all tests) and a verbal memory score averaging 4 tests of word-list and paragraph recall. Linear mixed effects models were used to compute associations between c-peptide levels and rates of cognitive decline.
Higher c-peptide levels were associated with faster decline in global cognition and verbal memory. Compared to those in the lowest c-peptide quartile, multivariable-adjusted mean differences (95% CI) in rates of decline for women in the highest quartile were −0.03 (−0.06, − 0.00) units/year for the global score, and −0.05 (−0.09, −0.02) units/year for verbal memory. Each one standard-deviation increase in c-peptide was associated with significantly faster decline on the TICS (p-trend=0.05), global score (p-trend=0.04) and verbal memory (p-trend=0.006).
Higher levels of insulin secretion in those without diabetes may be related to decline in general cognition and verbal memory.
insulin; c-peptide; diabetes; cognitive decline; aging
Objective To determine whether low dose aspirin protects women aged 65 or more against cognitive decline.
Design Cohort study within both arms of the women's health study, a randomised, double blind, placebo controlled trial of low dose aspirin for the primary prevention of cardiovascular disease and cancer, 1992-5.
Setting Women's health study, 1998-2004.
Participants 6377 women aged 65 or more.
Interventions Low dose aspirin (100 mg on alternate days) or placebo for a mean of 9.6 years.
Main outcome measures Women had three cognitive assessments at two year intervals by telephone. The battery to assess cognition included five tests measuring general cognition, verbal memory, and category fluency. The primary prespecified outcome was a global score, averaging performance across all tests. The key secondary outcome was a verbal memory score, averaging performance on four measures of verbal memory.
Results At the initial assessment (mean 5.6 years after randomisation) cognitive performance in the aspirin group was similar to that of the placebo group (mean difference in global score −0.01, 95% confidence interval −0.04 to 0.02). Mean decline in the global score from the first to the final cognitive assessment was also similar in the aspirin compared with placebo groups (mean difference 0.01, −0.02 to 0.04). The risk of substantial decline (in the worst 10th centile of decline) was also comparable between the groups (relative risk 0.92, 0.77 to 1.10). Findings were similar for verbal memory; however, a 20% lower risk was observed for decline in category fluency with aspirin (relative risk 0.80, 0.67 to 0.97).
Conclusion Long term use of low dose aspirin does not provide overall benefits for cognition among generally healthy women aged 65 or more.
Type 2 diabetes has been associated with an increased risk of dementia. To assess possible independent effects of insulin, we investigated the relation of insulin levels to cognitive decline in nondiabetic women.
Fasting plasma insulin levels were measured in mid-life in 1,416 nondiabetic Nurses’ Health Study participants, who also completed cognitive testing that began 10 years later (current age: 70–75 years). Over 4 years, 3 assessments of general cognition, verbal memory, category fluency and attention were administered. Primary outcomes were the Telephone Interview for Cognitive Status (TICS) performance, the global score (average of all tests) and verbal memory (average of verbal recall tests). Linear mixed-effects models were used to calculate the association between insulin and cognitive decline.
Higher insulin levels were associated with a faster decline on the TICS and verbal memory. For analysis, batch-specific quartiles of insulin levels were constructed. Compared to the lowest quartile, adjusted differences in the annual rates of decline (with 95% CI values in parentheses) for the second, third and fourth quartiles were: TICS, −0.06 (−0.16, 0.03), −0.14 (−0.24, −0.04), and −0.09 (−0.19, 0.01) points (p trend = 0.04); verbal memory, −0.01 (−0.04, 0.02), −0.05 (−0.08, −0.02), and −0.02 (−0.05, 0.01) units (p trend = 0.02). These associations remained after multivariable adjustment.
Our study provides evidence for a potential role of higher fasting insulin levels in cognitive decline, possibly independent of diabetes.
Diabetes; Insulin, cognitive performance; Aging, cognitive decline; Dementia
Cognitive impairment is common in older adults with diabetes, yet it is unclear to what extent cognitive function is associated with health literacy. We hypothesized that cognitive function, independent of education, is associated with health literacy.
The sample included 537 African American, American Indian, and White men and women 60 years or older. Measures of cognitive function included the Mini-Mental State Examination (MMSE), Verbal Fluency, Brief Attention, and Digit Span Backward tests. Health literacy was assessed using the S-TOFHLA.
Cognitive function was associated with health literacy, independent of education and other important confounders. Every unit increase in the MMSE, Digit Span Backward, Verbal Fluency or Brief Attention was associated with a 20% (p<.001), 34% (p<.001), 5% (p<.01), and 16% (p<.01) increase in the odds of having adequate health literacy, respectively.
These results suggest that cognitive function is associated with health literacy in older adults with diabetes. Because poor cognitive function may undermine health literacy, efforts to target older adults on improving health literacy should consider cognitive function as a risk factor.
cognition; health literacy; diabetes
Objective To examine the association of type 2 diabetes with baseline cognitive function and cognitive decline over two years of follow up, focusing on women living in the community and on the effects of treatments for diabetes.
Design Nurses' health study in the United States. Two cognitive interviews were carried out by telephone during 1995-2003.
Participants 18 999 women aged 70-81 years who had been registered nurses completed the baseline interview; to date, 16 596 participants have completed follow up interviews after two years.
Main outcome measures Cognitive assessments included telephone interview of cognitive status, immediate and delayed recalls of the East Boston memory test, test of verbal fluency, delayed recall of 10 word list, and digit span backwards. Global scores were calculated by averaging the results of all tests with z scores.
Results After multivariate adjustment, women with type 2 diabetes performed worse on all cognitive tests than women without diabetes at baseline. For example, women with diabetes were at 25-35% increased odds of poor baseline score (defined as bottom 10% of the distribution) compared with women without diabetes on the telephone interview of cognitive status and the global composite score (odds ratios 1.34, 95% confidence interval 1.14 to 1.57, and 1.26, 1.06 to 1.51, respectively). Odds of poor cognition were particularly high for women who had had diabetes for a long time (1.52, 1.15 to 1.99, and 1.49, 1.11 to 2.00, respectively, for ≥ 15 years' duration). In contrast, women with diabetes who were on oral hypoglycaemic agents performed similarly to women without diabetes (1.06 and 0.99), while women not using any medication had the greatest odds of poor performance (1.71, 1.28 to 2.281, and 1.45, 1.04 to 2.02) compared with women without diabetes. There was also a modest increase in odds of poor cognition among women using insulin treatment. All findings were similar when cognitive decline was examined over time.
Conclusions Women with type 2 diabetes had increased odds of poor cognitive function and substantial cognitive decline. Use of oral hypoglycaemic therapy, however, may ameliorate risk.
Associations between postmenopausal hormone therapy (HT) and cognitive decline may depend on apolipoprotein E (APOE) status or timing of initiation.
We included 16,514 Nurses’ Health Study participants aged 70–81 years who were followed since 1976 and completed up to three telephone cognitive assessments (2 years apart), between 1995 and 2006. The tests assessed general cognition (Telephone Interview of Cognitive Status (TICS)), verbal memory, and category fluency. We used longitudinal analyses to estimate differences in cognitive decline across hormone groups. APOE genotype was available in 3697 participants.
Compared with never users, past or current HT users showed modest but statistically significant worse rates of decline in the TICS: the multivariable-adjusted difference in annual rate of decline in the TICS among current estrogen only users versus never users was −0.04 (95% CI = −0.07, −0.004); for current estrogen+progestin users, the mean difference was −0.05 (95% CI = −0.10, −0.002). These differences were equivalent to those observed in women who are 1–2 years apart in age. We observed no protective associations with early timing of hormone initiation. We found suggestive interactions with APOE e4 status (e.g., on TICS, p-interaction = 0.10), where the fastest rate of decline was observed among APOE e4 carriers who were current HT users.
Regardless of timing of initiation, HT may be associated with worse rates of decline in general cognition, especially among those with an APOE e4 allele.
In 1 previous study, it was shown that neighborhood socioeconomic disadvantage is associated with cognitive decline among Latinos. No studies have explored whether and to what extent individual-level socioeconomic factors account for the relation between neighborhood disadvantage and cognitive decline. The purpose of the present study was to assess the influence of neighborhood socioeconomic position (SEP) on cognitive decline and examine how individual-level SEP factors (educational level, annual income, and occupation) influenced neighborhood associations over the course of 10 years. Participants (n = 1,789) were community-dwelling older Mexican Americans from the Sacramento Area Latino Study on Aging. Neighborhood SEP was derived by linking the participant's individual data to the 2000 decennial census. The authors assessed cognitive function with the Modified Mini-Mental State Examination. Analyses used 3-level hierarchical linear mixed models of time within individuals within neighborhoods. After adjustment for individual-level sociodemographic characteristics, higher neighborhood SEP was significantly associated with cognitive function (β = −0.033; P < 0.05) and rates of decline (β = −0.0009; P < 0.10). After adjustment for individual educational level, neighborhood SEP remained associated with baseline cognition but not with rates of decline. Differences in individual educational levels explained most of the intra- and interneighborhood variance. These results suggest that the effect of neighborhood SEP on cognitive decline among Latinos is primarily accounted for by education.
aging; cognition; education; Mexican Americans; residence characteristics
Objective To evaluate the association between migraine and cognitive decline among women.
Design Prospective cohort study.
Setting Women’s Health Study, United States.
Participants 6349 women aged 65 or older enrolled in the Women’s Health Study who provided information about migraine status at baseline and participated in cognitive testing during follow-up. Participants were classified into four groups: no history of migraine, migraine with aura, migraine without aura, and past history of migraine (reports of migraine history but no migraine in the year prior to baseline).
Main outcome measures Cognitive testing was carried out at two year intervals up to three times using the telephone interview for cognitive status, immediate and delayed recall trials of the east Boston memory test, delayed recall trial of the telephone interview for cognitive status 10 word list, and a category fluency test. All tests were combined into a global cognitive score, and tests assessing verbal memory were combined to create a verbal memory score.
Results Of the 6349 women, 853 (13.4%) reported any migraine; of these, 195 (22.9%) reported migraine with aura, 248 (29.1%) migraine without aura, and 410 (48.1%) a past history of migraine. Compared with women with no history of migraine, those who experienced migraine with or without aura or had a past history of migraine did not have significantly different rates of cognitive decline in any of the cognitive scores: values for the rate of change of the global cognitive score between baseline and the last observation ranged from −0.01 (SE 0.04) for past history of migraine to 0.08 (SE 0.04) for migraine with aura when compared with women without any history of migraine. Women who experienced migraine were also not at increased risk of substantial cognitive decline (worst 10% of the distribution of decline). When compared with women without a history of migraine, the relative risks for the global score ranged from 0.77 (95% confidence interval 0.46 to 1.28) for women with migraine without aura to 1.17 (0.84 to 1.63) for women with a past history of migraine.
Conclusion In this prospective cohort of women, migraine status was not associated with faster rates of cognitive decline.
Cardiovascular disease and vascular risk factors increase rates of cognitive impairment, but very little is known regarding prevention in this high-risk group. The heart-healthy Mediterranean-type dietary pattern may beneficially influence both vascular and cognitive outcomes.
We examined the association between Mediterranean-style diet and cognitive decline in women with prevalent vascular disease or ≥3 coronary risk factors.
Design / Participants / Setting
Prospective cohort study among 2504 women participants of the Women’s Antioxidant Cardiovascular Study (WACS), a cohort of female health professionals Adherence to the Mediterranean diet was determined at WACS baseline (1995–1996) using a zero-to-nine-point scale with higher scores indicating higher adherence. In 1998–2000, participants aged ≥ 65 years underwent a telephone cognitive battery including five tests of global cognition, verbal memory, and category fluency. Tests were administered three additional times over 5.4 years.
Statistical analyses performed
We used multivariable-adjusted generalized linear models for repeated measures to compare the annual rates of cognitive score changes across tertiles of Mediterranean diet score, as assessed at WACS baseline.
In both basic- and multivariable-adjusted models, Mediterranean diet was not related to cognitive decline. No effect modification was detected by age, education, depression, cardiovascular disease severity at WACS baseline, or level of cognition at initial assessment.
In women at higher risk of cognitive decline due to vascular disease or risk factors, adherence to the Mediterranean diet was not associated with subsequent 5-year cognitive change.
cognitive decline; vascular disease; hypertension; Mediterranean diet; longitudinal study
Although education is consistently related to better cognitive performance, findings on the relationship between education and age-associated cognitive change have been conflicting. Using measures of multiple cognitive domains from four waves of the Asset and Health Dynamics of the Oldest Old study, a representative sample of Americans aged 70 years and older, the authors performed growth curve modeling to examine the relationships between education, initial cognitive score, and the rate of decline in cognitive function. More years of education were linked to better initial performance on each of the cognitive tests, and higher levels of education were linked to slower decline in mental status. However, more education was unrelated to the rate of decline in working memory, and education was associated with somewhat faster cognitive decline on measures of verbal memory. These findings highlight the role of early-life experiences not only in long-term cognitive performance but also in old-age cognitive trajectories.
education; socioeconomic status; cognition; memory; growth curve modeling
The authors used data from 6 waves of the Health and Retirement Study to evaluate changes in the prevalence of cognitive impairment among adults 70 years of age or older from 1993 to 2004. Having sampling weights for each wave enabled the authors to create merged waves that represented cross-sections of the community-dwelling older population for that year. Logistic regression analyses with year as the predictor were used to estimate trends and determine the contribution of sociodemographic and health status variables to decreasing trends in the prevalence of cognitive impairment over time (score ≤8 on a modified Telephone Interview Cognitive Screen). Results showed an annual decline in the prevalence of cognitive impairment of 3.4% after adjustment for age, gender, and prior test exposure (odds ratio (OR) = 0.966, 95% confidence interval (CI): 0.941, 0.992). The addition of socioeconomic variables to the model attenuated the trend by 72.1%. The annual percentage of decline in impairment was larger for blacks (OR = 0.943, 95% CI: 0.914, 0.973) and Hispanics (OR = 0.954, 95% CI: 0.912, 0.997) than for whites (OR = 0.971, 95% CI: 0.936, 1.006), although the differences were not statistically significant. Linear probability models used in secondary analyses showed larger percentage-point declines for blacks and Hispanics. Improvements in educational level contributed to declines in cognitive impairment among older adults—particularly blacks and Hispanics—in the United States.
African Americans; aged; aged, 80 and over; cognition disorders; health status disparities; Hispanic Americans; prevalence; socioeconomic factors
To estimate the effect of education and income on incident heart failure (HF) hospitalization among post-menopausal women.
Investigations of socioeconomic status (SES) have focused on outcomes after HF diagnosis, not associations with incident HF. We used data from the Women’s Health Initiative Hormone Trials to examine the association between SES levels and incident HF hospitalization.
We included 26,160 healthy, post-menopausal women. Education and income were self-reported. ANOVA, Chi-square tests, and proportional hazards models were used for statistical analysis, with adjustment for demographics, co-morbid conditions, behavioral factors, and hormone and dietary modification assignments.
Women with household incomes <$20,000/year had higher HF hospitalization incidence (57.3/10,000 person-years) than women with household incomes >$50,000/year (16.7/10,000 person-years; p<0.01). Women with less than a high school education had higher HF hospitalization incidence (51.2/10,000 person-years) than college graduates and above (25.5/10,000 person-years; p<0.01). In multivariable analyses, women with the lowest income levels had 56% higher risk (HR 1.56, 95% CI 1.19 to 2.04) than the highest income women; women with the least amount of education had 21% higher risk for incident HF hospitalization (HR 1.21, 95% CI 0.90 to 1.62) than the most educated women.
Lower income is associated with an increased incidence of HF hospitalization among healthy, post-menopausal women, whereas multivariable adjustment attenuated the association of education with incident HF.
heart failure; socioeconomic status; women
Understanding preclinical transitions to impairment in cognitive abilities associated with risks for functional difficulty and dementia. This study characterized in the Women's Health and Aging Study (WHAS) II 9-year declines and transitions to impairment across domains of cognition.
The WHAS II is an observational study of initially high-functioning, community-dwelling women aged 70–80 years at baseline. Random-effects models jointly compared rates of decline, and discrete-time Cox models estimated hierarchies of incident clinical impairment on measures of psychomotor speed and executive function (EF) using the Trail Making Test and in immediate and delayed verbal recall using the Hopkins Verbal Learning Test. Patterns of transition were related to incidence of global cognitive impairment on the Mini-Mental State Exam (MMSE).
Mean decline and impairment occurred first in EF and preceded declines in memory by about 3 years. Thereafter, memory decline was equivalent to that for EF. Over 9 years, 49% developed domain-specific impairments. Risk of incident EF impairment occurred in 37% of the sample and was often the first impairment observed (23.7%), at triple the rate for psychomotor speed (p < .01). Risk of immediate and delayed recall impairments was nearly double that for psychomotor speed (p values <.01). Incident impairment in EF and delayed recall was associated with greater risk for MMSE impairment.
Executive dysfunction developed first among nearly one quarter of older women and was associated with elevated risk for global cognitive impairment. Because EF declines preceded memory declines and are important to efficient storage and retrieval EF represents an important target for interventions to prevent declines in memory and MMSE both of which are associated with progression to dementia.
Cognitive decline; Executive dysfunction; Memory; Cognitive impairment; Mild cognitive impairment
To examine the association between hormone therapy (HT) and cognitive performance or dementia, focusing on the duration and type of treatment used, as well as the timing of initiation of HT in relation to the menopause.
Women 65 years and older were recruited in France as part of the Three City Study. At baseline and 2 and 4 year follow-up, women were administered a short cognitive test battery and a clinical diagnosis of dementia was made. Detailed information was also gathered relating to current and past HT use. Analysis was adjusted for a number of socio-demographic, behavioural, physical and mental health variables, as well as Apolipoprotein ε4 (Apoe-ε4).
Among 3130 naturally postmenopausal women, current HT users performed significantly better than never users on verbal fluency, working memory and psychomotor speed. These associations varied according to the type of treatment and a longer duration of HT appeared to be more beneficial. However, initiation of HT close to the menopause was not associated with better cognition. HT did not significantly reduce dementia risk over 4 years but current treatment diminished the negative effect associated with Apoe-ε4.
Current HT was associated with better performance in certain cognitive domains but these associations are dependent on the duration and type of treatment used. We found no evidence that HT needs to be initiated close to the menopause to have a beneficial effect on cognitive function in later life. Current HT may decrease the risk of dementia associated with the Apoe-ε4 allele.
Aged; Aged, 80 and over; Apolipoproteins E; genetics; Cognition Disorders; drug therapy; etiology; genetics; Cohort Studies; Dementia; complications; genetics; Estrogen Replacement Therapy; methods; Female; Humans; Logistic Models; Neuropsychological Tests; Retrospective Studies
To test the hypothesis that frequent participation in cognitive activities can moderate the effects of limited education on cognitive functioning.
A national study of adult development and aging, Midlife in the United States (MIDUS), with assessments conducted at the second wave of measurement in 2004-2006.
Assessments were made over the telephone (cognitive measures) and in a mail questionnaire (demographic variables, measures of cognitive and physical activity, and self-rated health).
A total of 3343 men and women between the ages of 32 and 84 with a mean age of 55.99.
The dependent variables were Episodic Memory (Immediate and Delayed Word List Recall) and Executive Functioning (Category Fluency, Backward Digit Span, Backward Counting Speed, Reasoning, and Attention Switching Speed). The independent variables were years of education and frequency of cognitive activity (reading, writing, doing word games or puzzles, and attending lectures). The covariates were age, sex, self-rated health, income, and frequency of physical activity.
The two cognitive measures were regressed on education, cognitive activity frequency, and their interaction, while controlling for the covariates. Education and cognitive activity were significantly correlated with both cognitive abilities. The interaction of education and cognitive activity was significant for episodic memory, but not for executive functioning.
Those with lower education had lower cognitive functioning, but this was qualified by level of cognitive activity. For those with lower education, engaging frequently in cognitive activities showed significant compensatory benefits for episodic memory, which has promise for reducing social disparities in cognitive aging.
cognitive activity; education; memory; executive function; cognitive aging
The purpose of this article is to examine knowledge and health beliefs associated with cervical cancer screening among Korean American women. A telephone survey was conducted with 189 Korean American women in the Chicago area. Age, marital status, income, knowledge of early detection method for cervical cancer, and perceived beliefs about benefits of and barriers to receiving Pap tests were all related to outcomes of ever having a Pap test and having had one in the preceding 3 years. Variables uniquely related to ever having a Pap test were education, employment status, fluency in English, and proportion of life spent in the United States. Variables uniquely related to having had the test during the preceding 3 years were having a usual source of care and regular checkups. Different intervention components are suggested for the groups of Korean American women who have never had a Pap smear and for those who have not had one in the preceding 3 years, in addition to common intervention strategies that aim to increase knowledge and perceived benefit and to decrease perceived barriers to receiving Pap tests.
cervical cancer; screening behaviors; health behavior; symptom focus; Korean Americans; Pap smear; knowledge; beliefs
Objectives. Evidence shows education positively impacts cognitive ability. However, researchers have given little attention to the potential impact of adult education on cognitive ability, still malleable in midlife. The primary study aim was to examine whether there were continuing effects of education over the life course on midlife cognitive ability.
Methods. This study used data from the Medical Research Council National Survey of Health and Development, also known as the British 1946 birth cohort, and multivariate regression to estimate the continuing effects of adult education on multiple measures of midlife cognitive ability.
Results. Educational attainment completed by early adulthood was associated with all measures of cognitive ability in late midlife. The continued effect of education was apparent in the associations between adult education and higher verbal ability, verbal memory, and verbal fluency in late midlife. We found no association between adult education and mental speed and concentration.
Discussion. Associations between adult education and midlife cognitive ability indicate wider benefits of education to health that may be important for social integration, well-being, and the delay of cognitive decline in later life.
This study aimed to examine the association between diabetes and hyperglycaemia—assessed by HbA1c—and change in cognitive function in persons with and without diabetes.
This was a prospective cohort study of 8,442 non-diabetic and 516 diabetic participants in the Atherosclerosis Risk in Communities (ARIC) study. We examined the association of baseline categories of HbA1c with 6 year change in three measures of cognition: the digit symbol substitution test (DSST); the delayed word recall test (DWRT); and the word fluency test (WFT). Our primary outcomes were the quintiles with the greatest annual cognitive decline for each test. Logistic regression models were adjusted for demographic (age, sex, race, field centre, education, income), lifestyle (smoking, drinking) and metabolic (adiposity, blood pressure, cholesterol) factors.
The mean age was 56 years. Women accounted for 56% of the study population and 21% of the study population were black. The mean HbA1c was 5.7% overall: 8.5% in persons with and 5.5% in persons without diabetes. In adjusted logistic regression models, diagnosed diabetes was associated with cognitive decline on the DSST (OR 1.42, 95% CI 1.14–1.75, p=0.002), but HbA1c was not a significant independent predictor of cognitive decline when stratifying by diabetes diagnosis (diabetes, p trend=0.320; no diabetes, p trend=0.566). Trends were not significant for the DWRT or WFT in either the presence or the absence of diabetes.
Hyperglycaemia, as measured by HbA1c, did not add predictive power beyond diabetes status for 6 year cognitive decline in this middle-aged population. Additional work is needed to identify the non-glycaemic factors by which diabetes may contribute to cognitive decline.
Cognition; Diabetes; Epidemiology; Haemoglobin A1c
Dietary fat intake may influence the rate of cognitive change among those at high risk due to vascular disease or risk factors.
Women’s Antioxidant Cardiovascular Study began in 1995-96 as a randomized trial of antioxidants and B vitamin supplementation for secondary prevention in women with cardiovascular disease or ≥ 3 coronary risk factors. From 1998-99, eligible participants aged ≥ 65 years were administered a telephone cognitive battery including five tests of general cognition, memory and category fluency (n=2 551). Tests were administered four times over 5.4 years. The primary outcome was a global composite score averaging z-scores of all tests. Multivariable generalized linear models for repeated measures were used to evaluate the difference in cognitive decline rates across tertiles of total fat and various types of fat.
Total fat intake or different types of fat were not related to cognitive decline. However, older age significantly modified the association: among the oldest participants, higher intakes of mono- and poly-unsaturated fat were inversely related to cognitive decline (p-interaction: 0.06 and 0.04, respectively), and the rate differences between the highest and lowest tertiles were cognitively equivalent to the rate differences observed with being 4-6 years younger.
In women at high risk of cognitive decline due to vascular disease or risk factors, dietary fat intake was not associated with 5-year cognitive change. However, a possible protective relation of unsaturated fats with cognitive decline in the oldest women warrants further study.
cognition; epidemiology; fats; risk factors; women; cardiovascular disease
While the gold standard method of cognitive assessment is a face-to-face administration, telephone-based assessments offer several advantages if they demonstrate reliability and validity.
Observational study; 110 participants randomly assigned to receive two administrations of the same cognitive test battery 6 months apart in one of four combinations (1st administration/2nd administration): telephone/telephone; telephone/face-to-face; face-to-face/telephone; or face-to-face/face-to-face.
Academic medical center
110 non-demented women between the ages of 65 and 90 years.
The battery included tests of attention, verbal learning and memory, verbal fluency, executive function, working memory and global cognitive functioning plus self-report measures of perceived memory problems, depressive symptoms, sleep disturbance and health-related quality of life. Test-retest reliability, concurrent validity, relative bias associated with telephone administration, and change scores were evaluated.
There were no statistically significant differences in scores on any of the cognitive tests or questionnaires between randomly assigned modes of administration at baseline indicating equivalence across modes. There was no significant bias for tests or questionnaires administered by telephone (ps>0.01). Nor was there a difference in mean change scores between administration modes except for the Category Fluency (p = 0.01) and the California Verbal Learning Test long delay-free recall (p < 0.01). Mean test-retest coefficients for the battery were not significantly different across groups though individual test-retest correlation coefficients were generally higher within mode than across mode.
Telephone administration of cognitive tests and questionnaires to older women is both reliable and valid. Use of telephone batteries can substantially reduce the economic cost and burden of cognitive assessments and increase enrollment, retention and data completeness thereby improving study validity.
cognition; assessment; telephone; validation; tests
Cognitive reserve is associated with a lower risk of dementia but the extent to which it shapes cognitive aging trajectories remains unclear. Our objective is to examine the impact of three markers of reserve from different points in the lifecourse on cognitive function and decline in late adulthood.
Data are from 5234 men and 2220 women, mean age 56 years (standard deviation=6) at baseline, from the Whitehall II cohort study. Memory, reasoning, vocabulary, phonemic and semantic fluency were assessed three times over 10 years. Linear mixed models were used to assess the association between markers of reserve (height, education, and occupation) and cognitive decline, using the 5 cognitive tests and a global cognitive score composed of these tests.
All three reserve measures were associated with baseline cognitive function, with strongest associations with occupation and the weakest with height. All cognitive functions except vocabulary declined over the 10 year follow-up period. On the global cognitive test, there was greater decline in the high occupation group (−0.27; 95% confidence interval (CI): −0.28, −0.26) compared to the intermediate (−0.23; 95% CI: −0.25, −0.22) and low groups (−0.21; 95% CI: −0.24, −0.19); p=0.001. The decline in reserve groups defined by education (p=0.82) and height (p=0.55) was similar.
Cognitive performance over the adult lifecourse was remarkably higher in the high reserve groups. However, rate of cognitive decline did not differ between reserve groups except occupation where there was some evidence of greater decline in the high occupation group.
The value of self-reported memory complaints for identifying or predicting future cognitive decline or dementia is controversial, but observations from a third party, or “informant”, may prove more useful. The relationship between Informant and Self ratings of cognitive status and neuropsychological test scores was examined in a cohort of 384 non-demented, community-dwelling women, aged sixty and older, participating in a single-site Women’s Health Initiative ancillary study. Each participant and her respective informant separately completed the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE)1. Participants also underwent neuropsychological testing and responded to questionnaires on depression and functioning in complex activities of daily living. All neuropsychological test scores were significantly correlated (p-values <.05 to <.01) with Informant IQCODE ratings while Self ratings overestimated cognitive functioning in some domains. Furthermore, the Self and Informant ratings were both positively correlated with depression and negatively correlated with participants’ activity level. Therefore, Informant judgments of functional abilities are robust predictors of cognitive status in high functioning non-demented women. These results suggest that informants may be sensitive to changes that are not clinically significant but that may represent an incipient trend for decline.
Normal Aging; IQCODE; Informant-rating; Self-rating; Cognitive impairment; Screening
The effect of breastfeeding on cognitive abilities is examined in the offspring of highly educated women and compared to the effects in women with low or middle educational attainment. All offspring consisted of 12-year old mono- or dizygotic twins and this made it possible to study the effect of breastfeeding on mean cognition scores as well as the moderating effects of breastfeeding on the heritability of variation in cognition. Information on breastfeeding and cognitive ability was available for 6,569 children. Breastfeeding status was prospectively assessed in the first years after birth of the children. Maternal education is positively associated with performance on a standardized test for cognitive ability in offspring. A significant effect of breastfeeding on cognition was also observed. The effect was similar for offspring with mothers with a high, middle, and low educational level. Breast-fed children of highly educated mothers score on average 7.6 point higher on a standardized test of cognitive abilities (CITO test; range 500–550; effects size = .936) than formula-fed children of mothers with a low education. Individual differences in cognition scores are largely accounted for by additive genetic factors (80%) and breastfeeding does not modify the effect of genetic factors in any of the three strata of maternal education. Heritability was slightly lower in children with a mother with a middle-level education.
Breastfeeding; Cognition; Maternal education; G×E