Standing Blood Pressure and Risk of Falls, Syncope, Coronary Heart Disease, and Mortality

BACKGROUND

ACC/AHA guidelines caution against the use of antihypertensive therapy in the setting of low standing systolic BP (SBP) < 110 mm Hg due to unclear benefits.

METHODS

The Atherosclerosis Risk in Communities (ARIC) Study measured supine and standing SBP in adults aged 45-64 years between 1987 and 1989. We used Cox regression to evaluate the associations of low standing SBP (<110 mm Hg) with risk of falls, syncope, coronary heart disease (CHD), and mortality through December 31, 2019. Falls and syncope were ascertained by hospitalization and outpatient claims; CHD events were adjudicated. Associations were examined overall and in strata of hypertension stage, 10-year atherosclerotic cardiovascular disease (ASCVD) risk, age, and sex.

RESULTS

Among 12,467 adults followed a median of 24 years (mean age at enrollment 54.1 ± 5.8 years, 55% women, 26% Black adults), 3,000 (24%) had a standing SBP < 110 mm Hg. A standing SBP < 110 mm Hg compared to standing SBP ≥ 110 mm Hg was not significantly associated with falls or syncope, and was associated with a lower risk of CHD events and mortality with HRs of 1.02 (95% CI 0.94, 1.11), 1.02 (0.93, 1.11), 0.88 (0.80, 0.97), and 0.91 (0.86, 0.97), respectively. There were no clinically meaningful differences when stratified by hypertension stage, 10-year ASCVD risk, age, and sex.

CONCLUSIONS

In this community-based population, low standing SBP was common and not significantly associated with falls or syncope, but was associated with a lower risk of CHD and mortality. These findings do not support screening for low standing BP as a risk factor for adverse events.

Is an MRI-derived anatomical measure of dementia risk also a measure of brain aging?

Machine learning methods have been applied to estimate measures of brain aging from neuroimages. However, only rarely have these measures been examined in the context of biologic age. Here, we investigated associations of an MRI-based measure of dementia risk, the Alzheimer's disease pattern similarity (AD-PS) scores, with measures used to calculate biological age. Participants were those from visit 5 of the Atherosclerosis Risk in Communities Study with cognitive status adjudication, proteomic data, and AD-PS scores available. The AD-PS score estimation is based on previously reported machine learning methods. We evaluated associations of the AD-PS score with all-cause mortality. Sensitivity analyses using only cognitively normal (CN) individuals were performed treating CNS-related causes of death as competing risk. AD-PS score was examined in association with 32 proteins measured, using a Somalogic platform, previously reported to be associated with age. Finally, associations with a deficit accumulation index (DAI) based on a count of 38 health conditions were investigated. All analyses were adjusted for age, race, sex, education, smoking, hypertension, and diabetes. The AD-PS score was significantly associated with all-cause mortality and with levels of 9 of the 32 proteins. Growth/differentiation factor 15 (GDF-15) and pleiotrophin remained significant after accounting for multiple-testing and when restricting the analysis to CN participants. A linear regression model showed a significant association between DAI and AD-PS scores overall. While the AD-PS scores were created as a measure of dementia risk, our analyses suggest that they could also be capturing brain aging.

OLFACTORY IMPAIRMENT AND MICROSTRUCTURAL INTEGRITY OF THE BRAIN IN THE ARIC STUDY

We examined cross-sectional associations between microstructural integrity of the brain and olfaction in 1417 participants from the ARIC Study who completed MRI scans in 2011-2013 (mean age=76±2 years, 41% male). Microstructural integrity was measured by two diffusion tensor imaging measures, fractional anisotropy (FA, higher=better) and mean diffusivity (MD, higher=worse), and olfaction by a 12-item odor-identification test. In multivariable linear regression models, higher FA in several regions was associated with better olfaction, with the strongest association in the stria terminalis [β:0.333 (95%CI:0.188, 0.478) per standard deviation (SD) higher FA]. Higher MD was associated with lower olfaction in almost all regions, but associations were strongest for some temporal sub-regions [for example, hippocampus, β:-0.796 (95%CI: -0.942, -0.651) per SD higher MD]. Our findings suggest that neuronal microstructural integrity is an important predictor of olfaction; this may also have important implications in understanding early dementia neuropathology as olfaction is affected very early in dementia.

RELATIONSHIPS OF CEREBRAL PERFUSION WITH GAIT SPEED ACROSS AGE AND SYSTOLIC BLOOD PRESSURE LEVELS

We hypothesized that poorer cerebral perfusion could impair mobility, particularly at lower systolic blood pressure (SBP). Cerebral perfusion was measured via arterial spin-labelled (ASL)-MRI in community-dwelling adults of the Mayo Clinic Study of Aging. Usual-pace gait speed was assessed over 5.6 meters on an electronic mat. Linear regression models estimated cross-sectional gait speed associations with ASL and modifying effects of age and SBP, adjusting for sex and body mass index. Results report differences in gait speed (meter/second) per standard deviation (SD) lower ASL or SBP (mean=139.1 mmHg, SD=19.7 mmHg). Among 479 participants (aged 31-94 years; mean age 67.6 years; 44% women; mean gait speed 1.17m/s), relationships of ASL with gait speed varied by age and SBP (ASL-x-age interaction: p<.007; ASL-x-SBP interaction: p<.007). At age 65, 75 or 85 years and a SBP of 120mmHg, each SD lower ASL was associated with a 0.04 m/s (0.01,0.07), 0.07 m/s (0.04,0.10), and 0.09 m/s (0.05,0.13) slower gait speed at respective ages. At age 65, 75 or 85 years with low ASL (1 SD below the mean), each SD lower SBP was associated with 0.06 (0.02,0.09) m/s, 0.03 (0.01,0.06) m/s or .01 (-0.02,0.04) m/s slower gait speed, respectively. With high ASL (mean ASL+1SD), lower SBP trended towards faster gait at older age, e.g. estimated gait speed was 0.04 m/s (0.00,0.09) faster for each SD lower SBP at age 85years. Poorer cerebral perfusion may contribute to slower gait, particularly with lower SBP. The interrelations of cerebral perfusion, SBP, and age with mobility merit further study.

FINDING YOURSELF: PERSONALIZED MEDICINE, DATA SCIENCE, AND INTERACTIVE VISUALIZATIONS

Personalized medicine is care that is tailored to an individual patient. In contrast, randomized trials are designed to report evidence of benefits and harms “on average”. The average trial participant though, is often healthier than older patients seen in clinical practice. A variety of methods have been proposed which offer improvements to traditional (but questionable) practices of one-subgroup-at-a-time examinations of treatment effect heterogeneity, but translating evidence from these advancements has received less attention. Data Science initiatives have allowed broader data sharing, data harmonization and data synthesizing approaches, as well as an enormous maturing of interactive visualization techniques. Motivated by the SPRINT study and using advanced approaches of marginalized standardization and the Predictive Approaches to Treatment effect Heterogeneity (PATH) statement, we show how researchers, regulators, clinicians and patients can "find themselves" on the treatment effect continuum and be better informed of potential individualized evidence through interactive visualizations.

NOVEL INTERVENTIONS AND TARGETS FOR THE PREVENTION OF DEMENTIA AND FRAILTY: 2021 EDITOR’S CHOICE ARTICLES FROM JGMS

This symposium will present four 2021 “Editor’s Choice” articles from the Journal of Gerontology Medical Sciences that focus on novel interventions and targets for the prevention of dementia and frailty. Jeffrey Scherrer and colleagues, in their article “Lower Risk for Dementia Following Adult Tetanus, Diphtheria, and Pertussis (Tdap) Vaccination,” examine the links between adult vaccinations and decreased dementia risk. Katharine Brewster, Justin Golub (presenter), and colleagues, in “Age-Related Hearing Loss, Late-Life Depression, and Risk for Incident Dementia in Older Adults,” investigate hearing loss and depression as independent risk factors for eventual conversion to dementia. By understanding these potentially reversible mechanisms for dementia, targets for early interventions could be identified. “Association Between Long-Term Aspirin Use and Frailty in Men: The Physicians’ Health Study,” written by Ariela Orkaby and colleagues, examines the association between long-term aspirin use and frailty, furthering our understanding of the benefits of anti-inflammatory medications even in older adults. Kristen George and coauthors, in their article, “Impact of Cardiovascular Risk Factors in Adolescence, Young Adulthood, and Midlife on Late-Life Cognition: Study of Healthy Aging in African Americans,” examine how cardiovascular risk factors early in life may affect late life cognition in Black Americans. Beverly Gwen Windham, the discussant, will highlight commonalities and lessons learned from these studies.

Endurance and gait speed relationships with mild cognitive impairment and dementia

INTRODUCTION

Slower mobility is associated with mild cognitive impairment (MCI) and dementia. We examined the interaction of endurance with gait speed on prevalent MCI and dementia.

METHODS

Cross-sectional multinomial regression in the ARIC cohort (n = 2844 participants; 71 to 94 years; 44% men; 18% Black persons) with cognitive status (normal/MCI/dementia), 4 m gait speed, and endurance (2 minute walk [2MW]).

RESULTS

Faster gait speed (up to but not above 1 m/s) and better 2MW were separately associated with lower dementia risk. Good performance in both (2MW = 200 m, gait speed = 1.2 m/s) was associated with 99% lower dementia (Relative Prevalence Ratio [RPR] = 0.01 [95% CI: 0.0 to 0.06]) and 73% lower MCI, RPR = 0.27 (0.15 to 0.48) compared to poor performance in both (2MW = 100 m, gait speed = 0.8 m/s). Models incorporating a gait speed-by-2MW interaction term outperformed gait speed-only models (P < .001).

DISCUSSION

Gait speed relationships with dementia diminish at faster gait speeds. Combining endurance with gait speed may yield more sensitive markers of MCI and dementia than gait speed alone.

Association Between Thyroid Dysfunction and Incident Dementia in the Atherosclerosis Risk in Communities Neurocognitive Study

Background:

Abnormal thyroid hormone levels (high or low) and autoimmunity from autoimmune thyroid disease (AITD) may increase dementia risk.

Methods:

We examined the associations of thyroid dysfunction or possible AITD in 1990 - 1992 with dementia through 2017 in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. Thyroid dysfunction (subclinical and overt hypo- or hyperthyroidism and euthyroidism) was categorized from serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) cut-points and AITD from anti-thyroid peroxidase (anti-TPO) antibody positivity. Dementia was identified primarily based on cognitive test performance, neuropsychological examinations and clinician review of suspected cases. Additional cases of dementia were ascertained through telephone interviews or relevant hospital and death certificate codes. Cox regression with multivariable adjustment was used for analysis.

Results:

After exclusions for missing data, 12,481 participants were included in the analysis (mean index exam age 57 ± 5.7 (44% male, 25% black)), and 2,235 incident dementia cases were identified. AITD was not significantly associated with dementia. Subclinical hypothyroidism was associated with a lower risk of dementia (hazard ratio (HR) (95% confidence interval (CI)): 0.74 (0.60 - 0.92)), while overt hyperthyroidism was associated with a higher risk of dementia (HR (95% CI): 1.40 (1.02 - 1.92)) compared to euthyroid participants. Participants with serum FT4 concentrations above the 95th percentile were at an increased risk of dementia compared to those in the middle 90% of FT4 (HR (95% CI): 1.23 (1.02 - 1.48)).

Conclusions:

Subclinical hypothyroidism was associated with reduced risk of dementia, whereas overt hyperthyroidism, particularly very elevated FT4, was associated with increased risk of dementia. The association between subclinical hypothyroidism and reduced risk of dementia cannot be explained, but may have been an artifact due to change. By extrapolation, effective treatment of overt hyperthyroidism may modestly reduce dementia risk in older adults.

Carotid Intima-Media Thickness and Silent Brain Infarctions in a Biracial Cohort: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Both hypertensive and atherosclerotic processes contribute to common carotid artery intima-media thickness (CCA-IMT). Elevated CCA-IMT may be indicative of subclinical cerebrovascular disease; however, its role in the absence of concomitant carotid artery plaque is uncertain, and few studies have examined associations in Black populations.

MATERIALS AND METHODS

At cohort visit 3 (1993-1995) a subset of stroke-free participants (641 Blacks and 702 Whites, mean age 63) from the Atherosclerosis Risk in Communities (ARIC) study was imaged by brain MRI and carotid ultrasound. A CCA-IMT >0.9 mm was considered elevated. Asymptomatic brain lesions ≥3 mm were considered silent brain infarctions (SBI). Subcortical SBI measuring 3 to <20 mm were considered lacunes. Associations between elevated CCA-IMT and SBI were analyzed with Poisson regression.

RESULTS

Elevated CCA-IMT was identified in 168 participants (16% of Blacks, 10% of Whites), and SBI were observed in 156 (15% of Blacks, 8% of Whites). Elevated CCA-IMT was strongly related to anterior circulation SBI, posterior circulation SBI, and lacunes. After adjustments, elevated CCA-IMT remained associated with greater number of lacunes in Blacks ([prevalence ratio, PR] = 1.60; 95% confidence interval [CI]: 1.02-2.51), but not Whites (PR = 0.85; 95% CI: 0.35-2.04); P value for interaction = 0.12. Among Black participants without concomitant carotid plaque, elevated CCA-IMT was associated with twice the number of lacunes (PR = 2.00; 95% CI: 1.05-3.82).

CONCLUSIONS

In older Black adults, elevated CCA-IMT is independently associated with lipohyalinosis of the cerebral small vessels, irrespective of concomitant carotid plaque and vascular risk factors.

Prevalence and correlates of depressive symptoms in older adults across the glycaemic spectrum: the Atherosclerosis Risk in Communities (ARIC) study

AIMS

To document the prevalence of current depressive symptoms and history of depression across the glycaemic spectrum in older adults, and examine if measures of health status and healthcare satisfaction, access and utilization explain differences in the prevalence of current depressive symptoms by diabetes status.

METHODS

We conducted a cross-sectional study of 6226 participants aged 67-90 years who attended the 2011-2013 visit of the Atherosclerosis Risk in Communities (ARIC) study. Diabetes was based on self-report, medication use and HbA_1c . Current depressive symptoms were defined using the Center for Epidemiologic Studies Depression 11-item questionnaire, and history of depression was assessed via self-report. We examined obesity, history of cardiovascular disease, hypertension, kidney disease, cognitive function, and self-reported health compared with others. Prevalence and prevalence ratios were estimated using age-, race-, and sex-adjusted Poisson regression.

RESULTS

The prevalence of current depressive symptoms was 5.4% in people without diabetes and 11.0% in people with diabetes (prevalence ratio 2.04, 95% CI 1.60, 2.48); the prevalence of history of depression was 11% in people without diabetes and 17.7% in people with diabetes (prevalence ratio 1.61, 95% CI 1.28,1.95). Strong correlates of current depressive symptoms were history of depression (prevalence ratio 3.86, 95% CI 3.05, 4.90) and reporting poor health compared with others (prevalence ratio 3.88, 95% CI 2.93, 5.15). No variables had significantly different associations with depressive symptoms across glycaemic categories (P for interaction >0.10).

CONCLUSIONS

In older adults, current depressive symptoms were twice as prevalent in people with diabetes compared with those without. Measures of health status and healthcare did not explain differences in depressive symptoms between people with and without diabetes.

Cardiovascular Dysfunction and Frailty Among Older Adults in the Community: The ARIC Study

Background

The contribution of cardiovascular dysfunction to frailty in older adults is uncertain. This study aimed to define the relationship between frailty and cardiovascular structure and function, and determine whether these associations are independent of coexisting abnormalities in other organ systems.

Methods

We studied 3,991 older adults (mean age 75.6±5.0 years; 59% female) from the Atherosclerosis Risk in Communities (ARIC) Study in whom the following six organ systems were uniformly assessed: cardiac (by echocardiography), vascular (by ankle-brachial-index and pulse-wave-velocity), pulmonary (by spirometry), renal (by estimated glomerular filtration rate), hematologic (by hemoglobin), and adipose (by body mass index and bioimpedance). Frailty was defined by the presence of ≥3 of the following: low strength, low energy, slowed motor performance, low physical activity, or unintentional weight loss.

Results

Two hundred eleven (5.3%) participants were frail. In multivariable analyses adjusted for demographics, diabetes, hypertension, and measures of other organ system function, frailty was independently and additively associated with left ventricular hypertrophy (odds ratio [OR] = 1.72; 95% confidence interval [CI] = 1.30-2.40), reduced global longitudinal strain (reflecting systolic function; OR = 1.68; 95% CI = 1.16-2.44), and greater left atrial volume index (reflecting diastolic function; OR = 1.60; 95% CI = 1.13-2.27), which together demonstrated the greatest association with frailty (OR = 2.10; 95% CI = 1.57-2.82) of the systems studied. Lower magnitude associations were observed for vascular and pulmonary abnormalities, anemia, and impaired renal function. Cardiovascular abnormalities remained associated with frailty after excluding participants with prevalent cardiovascular disease.

Conclusions

Abnormalities of cardiac structure and function are independently associated with frailty, and together show the greatest association with frailty among the organ systems studied.

Orthostatic Hypotension in Middle-Age and Risk of Falls

BACKGROUND

One-third of older adults fall each year. Orthostatic hypotension (OH) has been hypothesized as an important risk factor for falls, but findings from prior studies have been inconsistent.

METHODS

We conducted a prospective study of the association between baseline OH (1987-1989) and risk of falls in the Atherosclerosis Risk in Communities (ARIC) Study. Falls were ascertained during follow-up via ICD-9 hospital discharge codes or Centers for Medicare & Medicaid Services claims data. OH was defined as a drop in systolic blood pressure (SBP) ≥20mm Hg or diastolic blood pressure (DBP) ≥10mm Hg within 2 minutes of moving from the supine to standing position. Changes in SBP or DBP during OH assessments were also examined as continuous variables.

RESULTS

During a median follow-up of 23 years, there were 2,384 falls among 12,661 participants (mean age 54 years, 55% women, 26% black). OH was associated with risk of falls even after adjustment for demographic characteristics and other risk factors (hazard ratio (HR): 1.30; 95% confidence interval (CI): 1.10, 1.54; P = 0.002). Postural change in DBP was more significantly associated with risk of falls (HR 1.09 per -5mm Hg change in DBP; 95% CI: 1.05, 1.13; P < 0.001) than postural change in SBP (HR 1.03 per -5mm Hg change in SBP; 95% CI: 1.01, 1.05; P = 0.002).

CONCLUSIONS

In a community-based, middle-aged population, OH, and in particular, postural change in DBP, were independent risk factors for falls over 2 decades of follow-up. Future studies are needed to examine OH thresholds associated with increased risk of falls.

Diabetes, hyperglycemia, and the burden of functional disability among older adults in a community-based study

BACKGROUND

There is a need for continued surveillance of diabetes-related functional disability. In the present study, we examined associations between diabetes, hyperglycemia, and the burden of functional disability in a community-based population.

METHODS

A cross-sectional analysis was conducted of 5035 participants who attended Visit 5 (2011-13) of the Atherosclerosis Risk in Communities study. Functional disability was dichotomously defined by any self-reported difficulty performing 12 tasks essential to independent living grouped into four functional domains. Associations of diagnosed diabetes (via self-report) and undiagnosed diabetes and prediabetes (via HbA1c) with functional disability were evaluated using Poisson regression.

RESULTS

Participants had a mean age of 75 years, 42 % were male, 22 % were Black, and 31 % had diagnosed diabetes. Those with diagnosed diabetes had a significantly greater burden of functional disability than those without diabetes, even after adjustment for demographics, health behaviors, and comorbidities: prevalence ratios (95 % confidence intervals) were 1.24 (1.15, 1.34) for lower extremity mobility, 1.14 (1.07, 1.21) for general physical activities, 1.33 (1.16, 1.52) for instrumental activities of daily living (ADL), and 1.46 (1.24, 1.73) for ADL (all P < 0.05). The associations of undiagnosed diabetes and prediabetes with disability were not statistically significant (all P > 0.05).

CONCLUSIONS

Among older adults, the burden of functional disability associated with diabetes was not entirely explained by known risk factors, including comorbidities. Hyperglycemia below the threshold for the diagnosis of diabetes was not associated with disability. Research into effective strategies for the prevention of functional disability among older adults with diabetes is needed.

Physical Function, Hyperuricemia, and Gout in Older Adults

OBJECTIVE

Gout prevalence is high in older adults and those affected are at risk of physical disability, yet it is unclear whether they have worse physical function.

METHODS

We studied gout, hyperuricemia, and physical function in 5,819 older adults (age ≥65 years) attending the 2011-2013 Atherosclerosis Risk in Communities Study visit, a prospective US population-based cohort. Differences in lower extremity function (Short Physical Performance Battery [SPPB] and 4-meter walking speed) and upper extremity function (grip strength) by gout status and by hyperuricemia prevalence were estimated in adjusted ordinal logistic regression (SPPB) and linear regression (walking speed and grip strength) models. Lower scores or times signify worse function. The prevalence of poor physical performance (first quartile) by gout and hyperuricemia was estimated using adjusted modified Poisson regression.

RESULTS

Ten percent of participants reported a history of gout and 21% had hyperuricemia. There was no difference in grip strength by history of gout (P = 0.77). Participants with gout performed worse on the SPPB test; they had 0.77 times (95% confidence interval [95% CI] 0.65, 0.90, P = 0.001) the prevalence odds of a 1-unit increase in SPPB score and were 1.18 times (95% CI 1.07, 1.32, P = 0.002) more likely to have poor SPPB performance. Participants with a history of gout had slower walking speed (mean difference -0.03; 95% CI -0.05, -0.01, P < 0.001) and were 1.19 times (95% CI 1.06, 1.34, P = 0.003) more likely to have poor walking speed. Similarly, SPPB score and walking speed, but not grip strength, were worse in participants with hyperuricemia.

CONCLUSION

Older adults with gout and hyperuricemia are more likely to have worse lower extremity, but not upper extremity, function.

Association Strength of Three Adiposity Measures with Autonomic Nervous System Function in Apparently Healthy Employees

OBJECTIVES

To investigate the association of different measures of central (abdominal) and overall adiposity with autonomic nervous system (ANS) function, indexed by heart rate variability (HRV), in apparently healthy human adults.

DESIGN AND MEASUREMENTS

Cross-sectional data of 8,538 participants (20% female, age: 41 ± 11 years, body mass index (BMI): 24 ± 4 kg/m2, waist circumference (WC): 91 ± 12 cm, waist-to-height ratio (WHtR): 0.45 ± 0.08) were available for analysis.

RESULTS

All measures of adiposity were inversely correlated with vagally-mediated HRV indexed by RMSSD (all p<0.001). Strongest associations were found with WC and RMSSD (r = -0.29). Associations were stronger in males (WC r = -0.32) than in females (WC r = -0.23). Partial correlations revealed the same pattern for RMSSD (WC all pcc = -0.12 p<0.001; WC male pcc = -0.14 p<0.001; WC female pcc = -0.06 p<0.05). Correlation strength of BMI and WHtR with RMSSD were similar and significantly weaker compared to WC (p < .001) in unadjusted analysis. Overall, nonparametric Kendall's τb led to the same conclusions.

CONCLUSION

The present data supports previous findings, that HRV is related to measures of adiposity in healthy individuals. In line with previous research, we found that WC is more strongly related to measures of HRV, indicating that WC best captures adiposity related risk.

Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53949)

General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health- and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N=53,949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P=3.93 × 10(-9), MIR2113; rs17522122, P=2.55 × 10(-8), AKAP6; rs10119, P=5.67 × 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P=1 × 10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N=6617) and the Health and Retirement Study (N=5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e.=5%) and 28% (s.e.=7%), respectively. Using polygenic prediction analysis, ~1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N=5487; P=1.5 × 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

Device-guided slow-breathing effects on end-tidal CO(2) and heart-rate variability

Previous studies have reported that regular practice of a device-guided slow-breathing (DGB) exercise decreases resting blood pressure (BP) in hypertensive patients. The performance of DGB is associated with acute decreases in sympathetic vascular tone, and it has been suggested that the decreases in resting BP produced by regular practice of DGB over periods of weeks are due to chronic decreases in sympathetic nervous system activity. However, the kidneys respond to sympathetically mediated changes in BP by readjusting blood volume levels within a few days. Thus, the mechanism by which DGB could produce long-term BP changes remains to be clarified. Previous research with laboratory animals and human subjects has shown that slow, shallow breathing that increases pCO(2) potentiates BP sensitivity to high sodium intake. These findings raise the possibility that deeper breathing during DGB that decreases BP might involve opposite changes in pCO(2). The present study tested the hypothesis that performance of DGB acutely decreases a marker of pCO(2), end-tidal CO(2) (PetCO(2)). Breathing rate, tidal volume, and PetCO(2) were monitored before, during, and after a 15-min session of DGB by patients with elevated BP. BP, heart rate, and heart-rate variability (HRV) were also measured under these conditions. A control group was also studied before, during, and after a 15-min session of spontaneous breathing (SB). The DGB group, but not the SB group, showed progressive and substantial increases in tidal volume and low-frequency HRV and decreases in PetCO(2) and systolic BP. The PetCO(2) effects persisted into the posttask, rest period. The findings are consistent with the hypothesis that habitual changes in breathing patterns of the kind observed during DGB could potentiate an antihypertensive adaptation via effects on pCO(2) and its role in cardiovascular homeostasis.

Regular slow-breathing exercise effects on blood pressure and breathing patterns at rest

Previous studies reported that a device-guided slow-breathing (DGB) exercise decreases resting blood pressure (BP) in hypertensive patients. This study investigated the effects of daily practice of DGB on (a) 24-h BP and breathing patterns in the natural environment, as well as (b) BP and breathing pattern during clinic rest. Altogether, 40 participants with pre-hypertension or stage 1 hypertension were trained to decrease breathing rate through DGB or to passively attend to breathing (control, CTL) during daily 15-min sessions. The participants practiced their breathing exercise at home for 4 weeks. The DGB (but not the CTL) intervention decreased clinic resting BP, mid-day ambulatory systolic BP (in women only) and resting breathing rate, and increased resting tidal volume. However, 24-h BP level was not changed by DGB or CTL interventions, nor was overnight breathing pattern. These findings are consistent with the conclusion that a short-term, autonomic mechanism mediated the observed changes in resting BP, but provided no evidence that regular DGB affected factors involved in long-term BP regulation. Additional research will be needed to determine whether 24-h BP can be lowered by a more prolonged intervention.

Physical and cognitive performance and burden of anticholinergics, sedatives, and ACE inhibitors in older women

Polypharmacy, common in older people, confers both risk of adverse outcomes and benefits. We assessed the relationship of commonly prescribed medications with anticholinergic and sedative effects to physical and cognitive performance in older individuals. The study population comprised 932 moderately to severely disabled community-resident women aged 65 years or older who were participants in the Women's Health and Aging Study I. A scale based on pharmacodynamic principles was developed and utilized as a measure of drug burden. This was related to measures of physical and cognitive function. After adjusting for demographics and comorbidities, anticholinergic drug burden was independently associated with greater difficulty in four physical function domains with adjusted odds ratios (95% confidence interval (CI)) of 4.9 (2.0-12.0) for balance difficulty; 3.2 (1.5-6.9) for mobility difficulty; 3.6 (1.6-8.0) for slow gait; 4.2 (2.0-8.7) for chair stands difficulty; 2.4 (1.1-5.3) for weak grip strength; 2.7 (1.3-5.4) for upper extremity limitations; 3.4 (1.7-6.9) for difficulty in activities of daily living; and 2.4 (95% CI, 1.1-5.1) for poor performance on the Mini-Mental State Examination. Sedative burden was associated only with impaired grip strength (3.3 (1.5-7.3)) and mobility difficulty (2.4 (1.1-5.3)). The burden of multiple drugs can be quantified by incorporating the recommended dose regimen and the actual dose and frequency of drug taken. Anticholinergic drug burden is strongly associated with limitations in physical and cognitive function. Sedative burden is associated with impaired functioning in more limited domains. The risk associated with exposure of vulnerable older women to drugs with anticholinergic properties, and to a lesser extent those with sedative properties, implies that such drugs should not be used in this patient group without compelling clinical indication.

Impaired Vision and the Ability to Take Medications

OBJECTIVES

To assess relationships between vision (contrast sensitivity, stereopsis, visual acuity) and a performance-based measure of ability to implement new medications.

DESIGN

Cross-sectional analysis; prospective cohort study.

SETTING

Community-based.

PARTICIPANTS

Three hundred thirty-five participants aged 73 to 82 in Year 3 of the Women's Health and Aging Study II, a representative sample of the two-thirds least-disabled community-dwelling women.

MEASUREMENTS

Hopkins Medication Schedule Pillbox Ratio, a joint measure of accuracy and time, and a performance-based measure of ability to implement a prescription. Participants received written and verbal instructions for taking two medications and were directed to place pills in a pillbox accordingly. Vision assessments: contrast sensitivity (Pelli-Robson letter sensitivity chart), stereopsis (Randot Circles), and visual acuity (Early Treatment Diabetic Retinopathy Study eye chart).

RESULTS

Forty-four percent (148/335) of women incorrectly placed one or both medications. Each vision measure was positively associated with Pillbox Ratio scores and varied with cognition and time to completion. Better visual acuity, contrast sensitivity, and stereopsis were each associated with better performance in women with poor cognition who filled the pillbox quickly. Additionally, better visual acuity was associated with better performance in participants with good cognition who filled the pillbox slowly; better stereopsis was associated with better performance in participants with poor cognition who filled the pillbox slowly and whose stereoacuity was below normal.

CONCLUSION

Visual acuity, contrast sensitivity, and stereopsis should be considered potential risk factors for impaired ability to implement a medication regimen in older adults. Future research should investigate the role of vision, including contrast sensitivity and stereopsis, on performance of other instrumental activities of daily living.