To identify clinical measures that aid detection of impending severe mobility difficulty in older women.
Cross-sectional and longitudinal cohort study.
Urban community in Baltimore, Maryland.
One thousand two community-dwelling, moderate to severely disabled women aged 65 and older in the Women’s Health and Aging Study I.
Self-report and performance measures representing six domains necessary for mobility: central and peripheral nervous systems, muscles, bones and joints, perception, and energy. Severe mobility difficulty was defined as usual gait of 0.5 m/s or less, any reported difficulty walking across a small room, or dependence on a walking aid during a 4-m walking test.
Four hundred sixty-seven out of 984 (47%) had severe mobility difficulty at baseline, and 104/474 (22%) developed it within 12 months. Baseline mobility difficulty was correlated with poor vision, knee pain, feelings of helplessness, inability to stand with feet side by side for 10 seconds, difficulty keeping balance while dressing or walking, inability to rise from a chair five times, and cognitive impairment. Of these, knee pain (odds ratio (OR) = 1.74, 95% confidence interval (CI) = 1.05–2.89), helplessness (OR = 1.87, 95% CI = 1.10–3.24), poor vision (OR = 2.03, 95% CI = 1.06–3.89), inability to rise from a chair five times (OR = 2.50, 95% CI = 1.15–5.41), and cognitive impairment (OR = 4.75, 95% CI = 1.67–13.48) predicted incident severe mobility difficulty within 12 months, independent of age.
Five simple measures may aid identification of disabled older women at high risk of severe mobility difficulty. Further studies should determine generalizability to men and higher-functioning individuals.
aging; mobility difficulty; clinical assessment
In spite of evidence that physical activity has beneficial effects on health and age-related functional decline, there is a scarcity of detailed and accurate information on objectively measured daily activity and patterns of such activity in older adults.
Participants in the Baltimore Longitudinal Study of Aging (n = 611, 50% male, mean age 67, range 32–93) wore the Actiheart portable activity monitor for 7 days in the free-living environment. The association between activity and age was modeled using a continuous log-linear regression of activity counts on age with sex, body mass index, employment status, functional performance, and comorbid conditions as covariates.
In the fully adjusted model, continuous analyses demonstrated that overall physical activity counts were 1.3% lower for each year increase in age. Although there were no differences among morning levels of activity, there was significantly lower afternoon and evening activity in older individuals (p < .01). After adjusting for age, poor functional performance, nonworking status, and higher body mass index were independently associated with less physical activity (p < .001).
The use of accelerometers to characterize minute-by-minute intensity, cumulative physical activity counts, and daily activity patterns provides detailed data not gathered by traditional subjective methods, particularly at low levels of activity. The findings of a 1.3% decrease per year in activity from mid-to-late life, and the corresponding drop in afternoon and evening activity, provide new information that may be useful when targeting future interventions. Further, this methodology addresses essential gaps in understanding activity patterns and trends in more sedentary sectors of the population.
Epidemiology; Functional performance; Physical activity; Public health.
To examine associations between weight change, body composition, risk of mobility disability and mortality in older adults.
Prospective, longitudinal, population-based cohort.
The Health ABC Study.
Women (n=1044) and men (n=931) aged 70-79.
Weight,lean and fat mass from DXA measured annually over 5 years. Weight was defined as stable (n=664, referent group), loss (n=662), gain (n=321) or cycling (gain and loss, n=328) using change of 5% from year to year or from year 1 to 6. Mobility disability (two consecutive reports of difficulty walking one-quarter mile or climbing 10 steps) and mortality were determined for 8 years subsequent to the weight change period. Associations were analyzed with cox proportional hazards regression adjusted for covariates.
During follow-up, 313 women and 375 men developed mobility disability,322 women and 378 men were deceased. There was no risk of mobility disability or mortality with weight gain. Weight loss and weight cycling were associated with mobility disability in women:hazard ratio (HR)=1.88 (95% confidence interval (CI)=1.40-2.53),HR=1.59 (95% CI=1.11-2.29) and weight loss was associated in men:HR=1.30 (95% CI=1.01-1.69).Weight loss and weight cycling were associated with mortality risk in women:HR=1.47 (95% CI=1.07-2.01), HR=1.62 (95% CI=1.15-2.30) and in men:HR=1.41 (95% CI=1.09-1.83),HR=1.50 (95% CI=1.08-2.08). Adjustment for lean and fat mass and change in lean and fat mass from year 1 to 6 attenuated relationships between weight loss and mobility disability in men, and weight loss and mortality in men and women.
Weight cycling and weight loss predict impendingmobility disability and mortality in old age, underscoring the prognostic importance of weight history.
Aging; obesity; physical function; body composition; muscle loss
Low literacy is common among the elderly and possibly more reflective of educational attainment than years of school completed. We examined the association between literacy and risk of likely dementia in older adults.
Participants were 2,458 black and white elders (aged 71–82) from the Health, Aging and Body Composition study, who completed the Rapid Estimate of Adult Literacy in Medicine and were followed for 8 years. Participants were free of dementia at baseline; incidence of likely dementia was defined by hospital records, prescription for dementia medication, or decline in Modified Mini-Mental State Examination score. We conducted Cox proportional hazard models to evaluate the association between literacy and incidence of likely dementia. Demographics, education, income, comorbidities, lifestyle variables, and apolipoprotein E (APOE) ε4 status were included in adjusted analyses.
Twenty-three percent of participants had limited literacy (<9th-grade level). Limited literacy, as opposed to adequate literacy (≥9th-grade level), was associated with greater incidence of likely dementia (25.5% vs17.0%; unadjusted hazard ratio [HR] = 1.75, 95% confidence interval 1.44–2.13); this association remained significant after adjustment. There was a trend for an interaction between literacy and APOE ε4 status (p = .07); the association between limited literacy and greater incidence of likely dementia was strong among ε4 noncarriers (unadjusted HR = 1.85) but nonsignificant among ε4 carriers (unadjusted HR = 1.25).
Limited literacy is an important risk factor for likely dementia, especially among APOE ε4-negative older adults, and may prove fruitful to target in interventions aimed at reducing dementia risk.
Cognitive aging; Risk factors; Epidemiology.
To evaluate race-related differences in depression onset and recovery in older persons, overall and by sex, and examine race-related differences in mortality according to depression.
Prospective cohort study.
General community in pre-designated zip code areas in Memphis, Tennessee, and Pittsburgh, Pennsylvania.
3,075 persons age 70-79 at baseline in the Health, Aging, and Body Composition study.
Depression was assessed at 8 time points over 10 years using the 10-item Center for Epidemiologic Studies – Depression (CES-D) scale; scores of <8 and ≥8 denoted nondepressed and depressed, respectively. We created variables for transitions across each 18-month time interval, namely, from nondepressed or depressed to nondepressed, depressed, or death, and determined the association between race and the average likelihood of these transitions over time.
A higher percentage of blacks than whites were depressed at nearly all time points. Adjusting for demographics, common chronic conditions, and body mass index, blacks had a higher likelihood of experiencing depression onset than whites (odds ratio, 1.22; 95% confidence interval, 1.03-1.43); among men, blacks were more likely to experience depression onset than whites (odds ratio, 1.44; 95% confidence interval, 1.24-2.89). Blacks also had a higher likelihood of transitioning from nondepressed to death (odds ratio, 1.79; 95% confidence interval, 1.30-2.46). Overall and in sex-stratified analyses, race was not associated with recovery from depression or with the transition from depression to death.
Our findings highlight race differences in depression in older persons and encourage further research on the course of depression in older blacks.
Aging; Depression; Depressive symptoms; Race differences; Epidemiology; Prospective studies
To examine the relationship between 25-hydroxyvitamin D (25(OH)D) levels and cognitive performance over time in older adults in the Health, Aging, and Body Composition (Health ABC) study.
Prospective cohort study
Community-dwelling participants in Pittsburgh, PA, and Memphis, TN
2,777 well-functioning adults aged 70–79 at baseline with serum 25(OH)D measured at the 12 month follow-up visit and cognitive function measured at baseline and 4-year follow-up visit.
Vitamin D status was categorized as 25(OH)D levels <20 ng/mL, 20 - <30 ng/mL, or ≥ 30ng/mL. Cognition was measured using the Modified Mini-Mental State Exam (3MS) and Digit Symbol Substitution Test (DSST). Linear regression models adjusting for multiple covariates, including age, education, sex, race, site, season, physical activity, and comorbidities were used in the analysis.
Sixty-eight percent of participants had 25(OH)D levels<30 ng/mL. Lower 25(OH)D levels were associated with lower baseline cognitive scores on the 3MS (adjusted means (95% CI): 89.9 (89.4–90.4), 90.8 (90.4–91.3), and 90.6 (90.2–91.1) for <20, 20-<30, and ≥30ng/mL, respectively; p trend =0.02) and the DSST (35.2 (34.5–36.0), 35.9 (35.2–36.6), and 37.0 (36.3–37.8), p trend =0.01). Participants with low 25(OH)D levels had greater declines in 3MS scores over 4 years than those with higher levels (LS mean change (95% CI): −1.0 (−1.5 to −0.6), −0.8 (−1.2 to −0.3), and −0.2 (−0.7 to 0.2) for <20, 20-<30, and ≥30ng/mL, respectively; p=0.05). There was no significant difference in DSST decline by 25(OH)D level.
Low 25(OH)D levels were associated with worse global cognitive function and greater decline over time as measured by the 3MS. Intervention trials are needed to determine if vitamin D supplementation can reduce cognitive decline.
Vitamin D; cognition; cognitive function; memory
To assess the associations among age, health status, and resting metabolic rate (RMR) in a large population of older adults.
Community-dwelling volunteers from the Baltimore Longitudinal Study of Aging (BLSA)
Four hundred twenty persons aged 40 – 96 (mean 68.2 ± 11.0) who underwent a comprehensive physical examination, cognitive assessment, resting metabolic rate testing, body composition assessment, and physical function testing during a three-day clinic visit.
Participants were assigned to “IDEAL” (Insight into the Determination of Exceptional Aging and Longevity) or “non-IDEAL” categories based on health status. IDEAL participants were defined by the absence of: physical and cognitive impairments, chronic conditions/comorbidities and blood profile alterations. A three-stage linear regression model was used to assess the relationship between RMR and age, using IDEAL classification as a predictor, adjusting for sex and body composition.
RMR averaged 1512.4 (± 442.9) kcal/day and was lower with advancing age (β = −8.55, p < 0.001). After adjusting for age, sex, and body composition RMR was 109.6 kcals/day lower in IDEAL than non-IDEAL participants (p < 0.005).
Individuals who are fully functional and free of major medical conditions have lower RMR than those affected by disease and functional impairments. These findings suggest that health status plays a role in energy utilization and regulation independent of age and body composition and that elevated RMR may be a global biomarker of poor health in older persons.
Aging; Resting Metabolic Rate; Comorbidities
Persistent and consistently observed racial disparities in physical functioning likely stem from racial differences in social resources and environmental conditions.
We examined the association between race and reported difficulty performing instrumental activities of daily living (IADL) in 347 African American (45.5%) and Whites aged 50 or above in the Exploring Health Disparities in Integrated Communities–Southwest Baltimore, Maryland Study (EHDIC-SWB).
Contrary to previous studies, African Americans had lower rates of disability (women: 25.6% vs. 44.6%, p = .006; men: 15.7% vs. 32.9%; p = .017) than Whites. After adjusting for sociodemographics, health behaviors, and comorbidities, African American women (odds ratio [OR] = 0.32, 95% confidence interval [CI] = [0.14, 0.70]) and African American men (OR = 0.34, 95% CI = [0.13, 0.90]) retained their functional advantage compared with White women and men, respectively.
These findings within an integrated, low-income urban sample support efforts to ameliorate health disparities by focusing on the social context in which people live.
disability; older adults; racial disparities; African Americans; EHDIC
The association between statin use and physical function is uncertain. The objective of this study was to examine the association between statin use and objectively assessed gait-speed decline in community-dwelling older adults.
Longitudinal cohort study.
Health, Aging, and Body Composition (Health ABC) study.
Two thousand five participants aged 70–79 years at baseline, with medication and gait speed data at years 1998–1999, 1999–2000, 2001–2002 and 2002–2003.
The independent variables were any statin use, their standardized daily doses (low, moderate, high) and lipophilicity. The primary outcome measure was gait speed decline ≥ 0.1 m/s in the following year of statin use. Multivariable generalized estimating equations were used, adjusting for demographic, health-related behaviors, health status and access to health care factors.
Statin use increased from 16.2% in 1998–1999 to 25.6% in 2002–2003. The overall proportions of those with gait speed decline ≥ 0.1 m/s increased from 22.2 to 23.9% between 1998–2003. Compared to non-users, any statin use was not associated with gait speed decline ≥ 0.1 m/s (adjusted odds ratio [AOR] = 0.90, 95% CI [0.77, 1.06]). Similar non-significant trends were also seen with the use of hydrophilic or lipophilic statins. Only low-dose statin users were found to have a 22% lower risk of gait speed decline (AOR = 0.78, 95% CI [0.61, 0.99]), which was mainly driven by the results from 1999–2000 follow-up.
These results suggest no detrimental effects of statin use on gait speed decline in community-dwelling older adults.
hydroxymethylglutaryl-CoA reductase inhibitors; statins; gait speed; physical function; aged
Knowledge of adipose composition in relation to mortality may help delineate inconsistent relationships between obesity and mortality in old age. We evaluated relationships between abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) density, mortality, biomarkers, and characteristics.
VAT and SAT density were determined from computed tomography scans in persons aged 65 and older, Health ABC (n = 2,735) and AGES-Reykjavik (n = 5,131), and 24 nonhuman primates (NHPs). Associations between adipose density and mortality (4–13 years follow-up) were assessed with Cox proportional hazards models. In NHPs, adipose density was related to serum markers and tissue characteristics.
Higher density adipose tissue was associated with mortality in both studies with adjustment for risk factors including adipose area, total fat, and body mass index. In women, hazard ratio and 95% CI for the densest quintile (Q5) versus least dense (Q1) for VAT density were 1.95 (1.36–2.80; Health ABC) and 1.88 (1.31–2.69; AGES-Reykjavik) and for SAT density, 1.76 (1.35–2.28; Health ABC) and 1.56 (1.15–2.11; AGES-Reykjavik). In men, VAT density was associated with mortality in Health ABC, 1.52 (1.12–2.08), whereas SAT density was associated with mortality in both Health ABC, 1.58 (1.21–2.07), and AGES-Reykjavik, 1.43 (1.07–1.91). Higher density adipose tissue was associated with smaller adipocytes in NHPs. There were no consistent associations with inflammation in any group. Higher density adipose tissue was associated with lower serum leptin in Health ABC and NHPs, lower leptin mRNA expression in NHPs, and higher serum adiponectin in Health ABC and NHPs.
VAT and SAT density provide a unique marker of mortality risk that does not appear to be inflammation related.
Obesity; Aging; Leptin; Adiponectin.
Older women have higher percent body fat, poorer physical function, lower strength, and higher rates of nonfatal chronic conditions than men. We sought to determine whether these differences explained physical performance differences between men and women.
Physical performance was assessed in the Health, Aging and Body Composition study in 2,863 men and women aged 70–79 with a composite 0–4 point score consisting of chair stands, standing balance including one-leg stand, and 6-m usual and narrow walk tests. Total body composition was measured by dual x-ray absorptiometry, thigh composition by computed tomography, and knee extensor strength by isokinetic dynamometer. Analysis of covariance estimated least square mean performance scores for men and women.
Men had higher performance scores than women (least square means: 2.33±0.02 vs 2.03±0.02, p < .0001), adjusted for race, study site, age, and height. Body composition measures (total body fat and thigh muscle area, muscle density, subcutaneous fat, and intermuscular fat) accounted for differences between men and women (least square means: 2.15±0.02 vs 2.17±0.02, p = .53). Higher strength in men partly explained the sex difference (least square means: 2.28±0.02 vs 2.12±0.02, p < .0001). Strength attenuated the association of thigh muscle mass with performance. Chronic health conditions did not explain the sex difference.
In a well-functioning cohort, poorer physical function in women compared with men can be explained predominantly by their higher fat mass, but also by other body composition differences. The higher proportion of body fat in women may put them at significant biomechanical disadvantage for greater disability in old age.
Body composition; Physical performance; Epidemiology.
Older adults commonly report disturbed sleep, and recent studies in humans and animals suggest links between sleep and Alzheimer disease biomarkers. Studies are needed that evaluate whether sleep variables are associated with neuroimaging evidence of β-amyloid deposition.
To determine the association between self-reported sleep parameters and β-amyloid deposition in community-dwelling older adults.
Baltimore Longitudinal Study of Aging, a prospective study of normative aging
70 adults (mean age = 76; range 53 - 91) in the BLSA neuroimaging study
Main Outcome Measure
β-amyloid burden, measured by [11C] Pittsburgh compound B (PiB) positron emission tomography (PET) distribution volume ratios (DVR)
After adjustment for potential confounders, reports of shorter sleep duration were associated with greater β-amyloid burden, measured by mean cortical DVR (cDVR; B = 0.08, 95% confidence interval (CI) 0.03, 0.14, p = 0.005) and precuneus DVR (B = 0.11, 95% CI 0.03, 0.18, p = 0.007). Reports of lower sleep quality were associated with greater β-amyloid burden measured by precuneus DVR (B = 0.08, 95% CI 0.01, 0.15, p = 0.025).
Among community-dwelling older adults, reports of shorter sleep duration and lower sleep quality are associated with greater β-amyloid burden. Further studies with objective sleep measures are needed to determine whether sleep disturbance causes or accelerates Alzheimer disease.
Information about the about the prevalence and correlates of self-reported medication nonadherence using multiple measures in older adults with chronic cardiovascular conditions is needed.
To examine the prevalence and correlates of self-reported medication nonadherence among community-dwelling elders with chronic cardiovascular conditions.
Participants (n=897) included members from the Health, Aging and Body Composition study with coronary heart disease, diabetes mellitus, and/or hypertension at year 10. Self-reported nonadherence was measured by the 4-item Morisky Medication Adherence Scale (MMAS-4) and 2-item cost-related nonadherence (CRN-2) scale at year 11. Factors (demographic, health status, and access to care) were examined for association with the MMAS-4 and then for association with the CRN-2 scale.
Nonadherence per the MMAS-4 and CRN-2 scale was reported by 40.7% and 7.7% of participants, respectively, with little overlap (3.7%). Multivariable logistic regression analyses found that black race was significantly associated with nonadherence per the MMAS-4 (p=0.002) and the CRN-2 scale (p=0.005). Other correlates of nonadherence per the MMAS-4 (with independent associations) included having cancer (p=0.04), a history of falls (p=0.02), sleep disturbances (p=0.04) and having a hospitalization in the previous 6 months (p=0.005). Conversely, being unmarried (p=0.049), having worse self-reported health (p=0.04) and needs being poorly met by income (p=0.02) showed significant independent associations with nonadherence per the CRN-2 scale.
Self-reported medication nonadherence was common in older adults with chronic cardiovascular conditions and only one factor – race – was associated with both types. The research implication of this finding is that it highlights the need to measure both types of self-reported nonadherence in older adults. Moreover, the administration of these quick measures in the clinical setting should help identify specific actions such as patient education or greater use of generic medications or pill boxes that may address barriers to medication nonadherence.
medication adherence; chronic disease; aged
To determine whether anemia is associated with incident dementia in older adults.
We studied 2,552 older adults (mean age 76.1 years; 38.9% black; 51.8% female) participating in the Health, Aging, and Body Composition study and free of dementia at baseline. We defined anemia using WHO criteria (hemoglobin concentration <13 g/dL for men and <12 g/dL for women). Dementia diagnosis was determined by dementia medication use, hospital records, or a change in Modified Mini-Mental State (3MS) score of more than 1.5 SD from mean. Discrete time Cox proportional hazard regression models were used to examine the hazard for developing dementia associated with anemia.
Of 2,552 participants, 392 (15.4%) older adults had anemia at baseline. Over 11 years of follow-up, 455 (17.8%) participants developed dementia. In the unadjusted model, those with baseline anemia had an increased risk of dementia (23% vs 17%, hazard ratio = 1.64; 95% confidence interval 1.30, 2.07) compared to those without anemia. The association remained significant after adjusting for demographics, APOE ε4, baseline 3MS score, comorbidities, and renal function. Additional adjustment for other anemia measures (mean corpuscular volume, red cell distribution width), erythropoietin, and C-reactive protein did not appreciably change the results. There was no interaction by sex and race on risk of developing dementia.
Among older adults, anemia is associated with an increased risk of developing dementia. Findings suggest that further study of anemia as a risk factor for dementia and a target for intervention for cognitive health is warranted.
The relationship between low socioeconomic status (SES) and depressive symptoms is well described, also in older persons. Although studies have found associations between low SES and unhealthy lifestyle factors and between unhealthy lifestyle factors and depressive symptoms, not much is known about unhealthy lifestyles as a potential explanation of socioeconomic differences in depressive symptoms in older persons.
To study the independent pathways between SES (education, income, perceived income, and financial assets), lifestyle factors (smoking, alcohol use, body mass index, and physical activity), and incident depressive symptoms (CES-D 10 and reported use of antidepressant medication), we used 9 years of follow-up data (1997–2007) from 2,694 American black and white participants aged 70–79 from the Health, Aging, and Body Composition (Health ABC) study. At baseline, 12.1% of the study population showed prevalent depressive symptoms, use of antidepressant medication, or treatment of depression in the five years prior to baseline. These persons were excluded from the analyses.
Over a period of 9 years time, 860 participants (31.9%) developed depressive symptoms. Adjusted hazard ratios for incident depressive symptoms were higher in participants from lower SES groups compared to the highest SES group. The strongest relationships were found for black men. Although unhealthy lifestyle factors were consistently associated with low SES, they were weakly related to incident depressive symptoms. Lifestyle factors did not significantly reduce hazard ratios for depressive symptoms by SES.
In generally healthy persons aged 70–79 years lifestyle factors do not explain the relationship between SES and depressive symptoms. (250)
Health ABC study; Socioeconomic status; Lifestyle factors; Depressive symptoms; Elderly; United States
Hypoglycemia commonly occurs in patients with diabetes mellitus (DM) and may negatively influence cognitive performance. Cognitive impairment in turn can compromise DM management and lead to hypoglycemia.
To prospectively evaluate the association between hypoglycemia and dementia in a biracial cohort of older adults with DM.
DESIGN AND SETTING
Prospective population-based study.
We studied 783 older adults with DM (mean age, 74.0 years; 47.0% of black race/ethnicity; and 47.6% female) who were participating in the prospective population-based Health, Aging, and Body Composition Study beginning in 1997 and who had baseline Modified Mini-Mental State Examination scores of 80 or higher.
MAIN OUTCOME MEASURES
Dementia diagnosis was determined during the follow-up period from hospital records indicating an admission associated with dementia or the use of prescribed dementia medications. Hypoglycemic events were determined during the follow-up period by hospital records.
During the 12-year follow-up period, 61 participants (7.8%) had a reported hypoglycemic event, and 148 (18.9%) developed dementia. Those who experienced a hypoglycemic event had a 2-fold increased risk for developing dementia compared with those who did not have a hypoglycemic event (34.4% vs 17.6%, P < .001; multivariate-adjusted hazard ratio, 2.1; 95% CI, 1.0–4.4). Similarly, older adults with DM who developed dementia had a greater risk for having a subsequent hypoglycemic event compared with participants who did not develop dementia (14.2% vs 6.3%, P < .001; multivariate-adjusted hazard ratio, 3.1; 95% CI, 1.5–6.6). Further adjustment for stroke, hypertension, myocardial infarction, and cognitive change scores produced similar results.
CONCLUSION AND RELEVANCE
Among older adults with DM, there seems to be a bidirectional association between hypoglycemia and dementia.
Metabolic syndrome (MetS) and functional limitation have been linked, but whether and how specific components of MetS and associated factors, such as inflammation, drive this relationship is unknown.
Data are from 2,822 men and women, aged 70–79 years, participating in the Health, Aging, and Body Composition (Health ABC) study and followed for 5 years. Presence of MetS at baseline was defined according to the National Cholesterol Education Program Adult Treatment Panel III guidelines. Interleukin-6, C-reactive protein, and body fat mass were measured at baseline. Measures of physical performance, including 400-m walk time, 20-m walking speed, and the Health ABC physical performance battery (PPB) were obtained at baseline and examination years 2, 4, and 6.
A total of 1,036 (37%) individuals met criteria for MetS. MetS was associated with poorer physical performance at baseline. Effect estimates between MetS and gait speed, and components of the Health ABC PPB (standing balance and repeated sit-to-stand performance) were modestly attenuated after adjustment for inflammation. All associations were attenuated to nonsignificance after adding total body fat mass to the model. Longitudinal analyses yielded similar results. Individual MetS component analysis revealed that abdominal obesity explained the largest fraction of the variation in physical performance.
Although inflammatory biomarkers partially accounted for the relationship between MetS and aspects of physical performance, overall findings implicate adiposity as the primary factor explaining poorer physical performance in older adults with MetS.
Metabolic syndrome; Physical function; Inflammation; Obesity.
Previous studies have suggested that hearing loss, which is highly prevalent but undertreated in older adults, may be associated with gait and physical functioning. Determining if hearing loss is independently associated with gait speed is critical toward understanding whether hearing rehabilitative interventions could help mitigate declines in physical functioning in older adults.
We analyzed cross-sectional data from the 1999–2002 cycles of the National Health and Nutritional Examination Survey during which participants 50–69 years (n = 1180) underwent hearing and gait speed assessments. Hearing was defined by a pure tone average of hearing thresholds at 0.5–4 kHz tones in the better-hearing ear. Gait speed was obtained in a timed 20-foot (6.1 meter) walk. Linear and logistic regression models were used to examine the association between hearing loss and gait speed while adjusting for demographic and cardiovascular risk factors. Analyses incorporated sampling weights to yield results generalizable to the U.S. population.
In a model adjusted for demographic and cardiovascular risk factors, a 25 dB hearing loss was associated with slower gait speed (−0.05 m/s per 25 dB HL [95% CI: −0.09 – −0.02]) and a nearly two-fold increased odds of having a gait speed < 1.0 m/s (OR 2.0, 95% CI: 1.2 –3.3). The reduction in gait speed associated with a 25 dB hearing loss was equivalent to that associated with an age difference of nearly 12 years.
Greater hearing loss is independently associated with slower gait speed. Further studies investigating the mechanistic basis of this association and whether hearing rehabilitative interventions could affect gait and physical functioning are needed.
Although gait speed slows with age, the rate of slowing varies greatly. To date, little is known about the trajectories of gait speed, their correlates, and their risk for mortality in older adults.
Gait speed during a 20-m walk was measured for a period of 8 years in initially well-functioning men and women aged 70–79 years participating in the Health, Aging and Body Composition study. We described the trajectories of gait speed and examined their correlates using a group-based mixture model. Also risk associated with different gait speed trajectories on all-cause mortality was estimated using a Cox-proportional hazard model.
Of 2,364 participants (mean age, 73.5±2.9 years; 52% women), we identified three gait speed trajectories: slow (n = 637), moderate (n = 1,209), and fast decline (n = 518). Those with fast decline slowed 0.030 m/s per year or 2.4% per year from baseline to the last follow-up visit. Women, blacks, and participants who were obese, had limited knee extensor strength, and had low physical activity were more likely to have fast decline than their counterparts. Participants with fast decline in gait speed had a 90% greater risk of mortality than those with slow decline.
Despite being well-functioning at baseline, a quarter of older adults experienced fast decline in gait speed, which was associated with an increased risk of mortality.
Gait speed; Older adults; Mortality.
Brain-derived neurotrophic factor (BDNF) plays a role in the maintenance and function of neurons. Although persons with Alzheimer’s disease have lower cortical levels of BDNF, evidence regarding the association between circulating BDNF and cognitive function is conflicting. We sought to determine the correlates of BDNF level and whether BDNF level was prospectively associated with cognitive decline in healthy older adults. We measured serum BDNF near baseline in 912 individuals. Cognitive status was assessed repeatedly with the modified Mini-Mental Status Examination and the Digit Symbol Substitution test over the next 10 years. We evaluated the association between BDNF and cognitive decline with longitudinal models. We also assessed the association between BDNF level and demographics, comorbidities and health behaviors. We found an association between serum BDNF and several characteristics that are also associated with dementia (race and depression), suggesting that future studies should control for these potential confounders. We did not find evidence of a longitudinal association between serum BDNF and subsequent cognitive test trajectories in older adults, although we did identify a potential trend toward a cross-sectional association. Our results suggest that serum BDNF may have limited utility as a biomarker of prospective cognitive decline.
To better understand the association between diabetes and cognitive impairment, we evaluated macro- and microstructural brain MRI measures for the total brain and regions of interest (ROIs) in a group of community-dwelling elders with and without diabetes.
RESEARCH DESIGN AND METHODS
MRI measures were obtained on 308 elders (mean age 83.3 years; n = 85 with diabetes) from the Health ABC Healthy Brain Substudy. We performed a series of linear regressions and used standardized β values to estimate the cross-sectional association between diabetes and macrostructural (gray matter volume [GMV] and white matter hyperintensities [WMHs]) and microstructural (mean diffusivity [MD] and fractional anisotropy [FA]) measures for the total brain and ROIs. Models were adjusted for age, race, and sex; GMV values for ROIs were also adjusted for total brain volume (TBV).
In multivariate-adjusted models, diabetes was associated with lower total GMV (P = 0.0006), GMV in the putamen (P = 0.02 for left and right), and TBV (P = 0.04) and greater cerebral atrophy (P = 0.02). There was no association with WMHs. On microstructural measures, diabetes was associated with reduced FA for total white matter (P = 0.006) and greater MD for the hippocampus (P = 0.006 left; P = 0.01 right), dorsolateral prefrontal cortex (P = 0.0007, left; P = 0.002, right), left posterior cingulate (P = 0.02), and right putamen (P = 0.02). Further adjustment for stroke, hypertension, and myocardial infarction produced similar results.
In this cross-sectional study, elders with diabetes compared with those without had greater brain atrophy and early signs of neurodegeneration. Further studies are needed to determine whether these structural changes associated with diabetes predict risk of cognitive decline.
Studies suggest that physically active people have reduced risk of incident cognitive impairment in late life. However, these studies are limited by reliance on subjective self-reports of physical activity, which only moderately correlate to objective measures and often exclude activity not readily quantifiable by frequency and duration. The objective of this study was to investigate the relationship between activity energy expenditure (AEE), an objective measure of total activity, and incidence of cognitive impairment.
We calculated AEE as 90% of total energy expenditure (assessed over two weeks using doubly-labeled water) minus resting metabolic rate (measured using indirect calorimetry) in 197 men and women (mean 74.8 years) who were free of mobility and cognitive impairments at study baseline (1998–2000). Cognitive function was assessed at baseline and 2 or 5 years later using the Modified Mini-Mental State Examination (3MS). Cognitive impairment was defined as a decline of >1.0 SD (9 points) between baseline and follow-up.
After adjustment for baseline 3MS, demographics, fat free mass, sleep duration, self-reported health, and diabetes, older adults in the highest sex-specific tertile of AEE had lower odds of incident cognitive impairment than those in the lowest tertile (OR, 95% CI 0.09, 0.01–0.79). There was also a significant dose response between AEE and incidence of cognitive impairment (p-for-trend over tertiles=0.05).
These findings indicate that greater activity energy expenditure may be protective against cognitive impairment in a dose-response manner. The significance of overall activity in contrast to vigorous or light activity should be determined.
Periodontal disease has been associated with poorer cross-sectional cognitive function and is correlated with adverse vascular outcomes, but has received little prospective investigation in relation to cognitive decline.
Analysis of a prospective cohort study.
The Health, Aging and Body Composition (Health ABC) Study
Participants and measurements
We examined the prospective association between a range of oral health parameters and cognitive function using data on 1053 participants who were administered the Modified Mini-Mental State Examination (3MS) at year 1 (baseline) and year 3, and had participated in a comprehensive periodontal examination at year 2. We investigated 3MS decline from year 3 to 5 in 947 (89.9%) participants. Covariates included age, sex, education, race, cardiovascular disease/risk and depressive symptoms.
Most indicators of adverse oral health at year 2 were associated with cognitive impairment based on averaged 3MS scores <80 for years 1 and 3, but these associations were substantially confounded by education and race. Higher gingival index, a measure of gingival inflammation, at year 2 remained independently associated with this definition of cognitive impairment and, in fully adjusted analyses, was also an independent predictor of a 5+ point cognitive decline from years 3 to 5.
Periodontitis may be a risk factor for cognitive decline. Gingivitis is reversible and periodontitis to some degree is preventable and controllable when manifest. Therefore, further research is needed to clarify potential underlying mechanisms and oral health interventions that potentially might ameliorate cognitive decline.
cognitive decline; cognitive impairment; periodontitis; periodontal diseases; gingivitis
Older adults with depression have an increased risk of developing dementia. Low plasma beta-amyloid 42 (Aβ42) and Aβ42/Aβ40 have emerged as promising biomarkers of dementia. The association between depression and plasma Aβ is unclear.
In this longitudinal study of 988 community-dwelling elders from the Health Aging and Body Composition study, depression was assessed with the Center for Epidemiologic Studies-Depression Scale 10-item version. We determined the association between Aβ42 and Aβ42/Aβ40 tertile and depression at baseline and over 9 years. We also stratified the models to determine if apolipoprotein E e4 allele status modified the associations.
Mean baseline age was 74.0 ± 3.0 years, 51 (5.2%) participants had depression, 545 (55.2%) were women, 531 (53.7%) were black, and 286 (30.7%) had one or more apolipoprotein E e4 allele. At baseline, there was no association between Aβ42/Aβ40 or Aβ42 and depression. Over 9 years, 220 (23.5%) participants developed depression. In adjusted Cox proportional hazards models, among those with one or more e4 allele, low Aβ42/Aβ40 was associated with an increased risk of developing depression over time (low 10.8% vs high 3.2%, hazard ratio = 2.38, 95% confidence interval: 1.15–4.92). Among those with no e4 allele, there was no association between Aβ42/Aβ40 and risk of depression over time (13.3% vs 17.5%, hazard ratio = 0.80, 95% confidence interval: 0.52–1.23; p value for interaction = .003).
The association between low plasma Aβ42/Aβ40 and increased risk of incident depression among those with one or more apolipoprotein E e4 allele implies a synergistic relationship similar to that found with dementia. Future work should investigate the interrelationships among plasma Aβ42/Aβ40, depression, and dementia.
Depression; Epidemiology; Plasma beta amyloid