The journals of gerontology. Series A, Biological sciences and medical sciences最新文献

Excess adipose tissue may promote chronic systemic inflammation and oxidative stress, causing endothelial damage. Early evidence indicates that obesity may be associated with poorer cerebral perfusion. The purpose of this study was to examine the relationship between body composition and cerebral hemodynamics. A total of 248 middle-aged adults (50-58 years old; 55% women) underwent a ramp test on a cycle-ergometer until volitional exhaustion. Gas exchange was assessed on a breath-by-breath basis. Mean middle cerebral artery velocity (MCAv) was measured using transcranial Doppler, and pulsatility index (PI) calculated. Body composition was assessed by dual X-ray absorptiometry. Statistical analyses were performed using a compositional data approach including a three-compartment model for body composition (trunk fat mass, extremities fat mass, and fat-free mass). The unadjusted models for the whole sample showed that trunk fat mass relative to other compartments was negatively associated with MCAvrest, MCAvmax, and gain, and positively associated with PImax; extremities fat mass relative to other compartments was positively associated with MCAvrest and MCAvmax, and negatively associated with PImax; and fat-free mass relative to other compartments was positively associated with PImax. These associations were sex-dependent, remaining in the women's subgroup. However, after adjusting for confounders, these associations became non-significant, except for PImax in the whole sample and women's subgroup. These findings suggest a possible association between cerebral hemodynamics and body composition in middle-aged adults, highlighting sex-specific differences. Moreover, our results indicate that higher trunk fat mass relative to other compartments may negatively impact cerebral hemodynamics, reducing MCAv and increasing PImax.

Background: Single-country studies document varying time trends in memory function and impairment. Comparative analyses are limited.

Methods: We used self-respondent data on adults aged 50+ years in 13 countries from three surveys (USA: HRS, 1998-2018; England: ELSA, 2002-2018; 11 European countries: SHARE, 2004-2019). Memory is measured with tests of immediate and delayed word recall. Unweighted age- and gender-adjusted mixed effects regression models as well as models with adjustments for additional socio-demographic characteristics and health behaviors were examined. Heterogeneity in trends by gender, age group, and educational attainment were measured.

Results: The age-adjusted 10-year improvement in average test score is 0.04 standard deviations (SDs) (95% confidence interval (CI): 0.03, 0.05) in the USA, 0.17 SDs (95% CI: 0.15, 0.19) in England, and 0.24 SDs (95% CI: 0.23, 0.25) in SHARE countries. Trends are largely similar across gender, age groups, and educational attainment. Regional differences in trends remain after adjustment for potential mechanisms. Difference between the USA and other countries is particularly large under aged 75 years compared to over aged 75 years.

Conclusions: Pace of improvement in memory function varies strongly across countries. On average, the 11 European countries studied had the fastest improvement, followed by England. The trend in the USA indicates improvement, but at a much slower pace compared to that in England and other European countries. Uncovering the causes for the cross-country heterogeneity in time trends, and in particular the reasons for the comparatively poor performance of the USA, should be both a research and public health priority.

Background: The rapidly growing field of multimorbidity research demonstrates that changes in multimorbidity in mid- and late-life have far reaching effects on important person-centered outcomes, such as health-related quality of life. However, there are few organizing frameworks and comparatively little work weighing the merits and limitations of various quantitative methods applied to the longitudinal study of multimorbidity.

Methods: We identify and discuss methods aligned to specific research objectives with the goals of (i) establishing a common language for assessing longitudinal changes in multimorbidity, (ii) illuminating gaps in our knowledge regarding multimorbidity progression and critical periods of change, and (iii) informing research to identify groups that experience different rates and divergent etiological pathways of disease progression linked to deterioration in important health-related outcomes.

Results: We review practical issues in the measurement of multimorbidity, longitudinal analysis of health-related data, operationalizing change over time, and discuss methods that align with 4 general typologies for research objectives in the longitudinal study of multimorbidity: (i) examine individual change in multimorbidity, (ii) identify subgroups that follow similar trajectories of multimorbidity progression, (iii) understand when, how, and why individuals or groups shift to more advanced stages of multimorbidity, and (iv) examine the coprogression of multimorbidity with key health domains.

Conclusions: This work encourages a systematic approach to the quantitative study of change in multimorbidity and provides a valuable resource for researchers working to measure and minimize the deleterious effects of multimorbidity on aging populations.

Background: Neighborhood walkability may encourage greater out-of-home travel (ie, community mobility) to support independent functioning in later life. We examined associations between a novel walkability audit index and Global Positioning System (GPS)-derived community mobility in community-dwelling older adults. We compared associations with the validated Environmental Protection Agency (EPA) National Walkability Index and further examined moderation by clinical walking speed.

Methods: Participants were 146 older adults (Mean = 77.0 ± 6.5 years, 68% women) at baseline of a randomized trial to improve walking speed. A walkability index (range: 0-5; eg, land-use mix, crosswalks, and so on) was created using Google Street View audits within 1/8-mile of the home. Participants carried a GPS device for 5-7 days to derive objective measures of community mobility (eg, time spent out of home, accumulated distance from home).

Results: Each 1 SD (~1.3-point) greater walkability audit score was associated with a median 2.16% more time spent out of home (95% confidence interval [95% CI]: 0.30-4.03, p = .023), adjusting for individual demographics/health and neighborhood socioeconomic status. For slower walkers (4-m walking speed <1 m/s), each 1 SD greater audit score was also associated with a median 4.54 km greater accumulated distance from home (95% CI: 0.01-9.07, p (interaction) = .034). No significant associations were found for the EPA walkability index.

Conclusions: Walkability immediately outside the home was related to greater community mobility, especially for older adults with slower walking speeds. Results emphasize the need to consider the joint influence of local environment and individual functioning when addressing community mobility in older populations.

Background: Hearing loss is associated with restricted physical activity (PA) and impaired physical functioning, yet the relationship between severity of hearing impairment (HI) and novel PA measures in older adults with untreated HI is not well understood.

Methods: Analyses included 845 participants aged ≥70 years (mean = 76.6 years) with a better-hearing ear pure-tone average (PTA) ≥30 and <70 dB in the Aging and Cognitive Health Evaluation in Elders (ACHIEVE) study who wore an ActiGraph accelerometer for 7 days. Physical functioning measures included grip strength and the Short Physical Performance Battery (SPPB). Linear regression models estimated the association by HI level (moderate or greater [PTA ≥ 40 dB] vs mild [PTA < 40 dB]) and continuous hearing with total daily activity counts, active minutes/day, activity fragmentation, grip strength, and gait speed. Logistic regression models estimated odds ratios (ORs) and 95% confidence intervals (CIs) of poor performance on the SPPB (≤6) and its subtests (≤2). Mixed-effects models estimated differences by HI level in activity by time of day.

Results: Participants with moderate or greater HI had poorer physical functioning, particularly balance (OR = 2.17, 95% CI = 1.29-3.67), versus those with mild impairment. There was no association of HI level with activity quantities or fragmentation. For diurnal patterns of activity, participants with moderate or greater HI had fewer activity counts in the afternoon (12:00 pm -05:59 pm).

Conclusions: Older adults with worse hearing had shifted diurnal patterns and poorer balance performance. Exercise programs should be tailored to older adults with different levels of HI to maintain PA and physical functioning, particularly balance control.

Background: Cardiometabolic risk (CMR) is associated with cognitive health, but the association can be affected by broader social, economic, and medical contexts. The United States and China have very different developmental and epidemiological histories, and thus CMR among older people could be linked to cognitive function differently in the 2 countries.

Methods: Cross-sectional and longitudinal ordinary least squares regression models were estimated for each country using nationally representative samples of populations over age 50: 7 430/4 474 Americans and 6 108/3 655 Chinese in the cross-sectional/longitudinal samples.

Results: In the United States, higher CMR is associated with worse cognitive function (b = -0.08, p < .016). Longitudinally, CMR increase is associated with worse cognitive function at a marginally significant level (b = -0.10, p = .055). No relationship between CMR level or change and cognitive function is observed in China. Higher education levels are linked to better cognitive function and slower cognitive decline in both countries. Unlike older Americans, relative to those with very low education levels, among older Chinese with the highest education level, a higher CMR links to better cognitive function (b = 0.63, p = .013) and slower cognitive decline (b = 0.35, p = .062); Nevertheless, a rapid increase in CMR is additionally harmful (b = -0.54, p = .050) for cognitive function and may lead to faster cognitive decline (b = -0.35, p = .079).

Conclusions: The significant relationship between CMR and cognitive function in the United States suggests the importance of monitoring and controlling CMR factors at older ages. The insignificant relationship in China may be explained by the high CMR among those with high education levels, highlighting the need for improving cardiometabolic health through education and promoting healthy lifestyles.

The inaugural Canadian Conferences on Translational Geroscience were held as 2 complementary sessions in October and November 2023. The conferences explored the profound interplay between the biology of aging, social determinants of health, the potential societal impact of geroscience, and the maintenance of health in aging individuals. Although topics such as cellular senescence, molecular and genetic determinants of aging, and prevention of chronic disease were addressed, the conferences went on to emphasize practical applications for enhancing older people's quality of life. This article summarizes the proceeding and underscores the synergy between clinical and fundamental studies. Future directions highlight national and global collaborations and the crucial integration of early-career investigators. This work charts a course for a national framework for continued innovation and advancement in translational geroscience in Canada.

Background: Dementia is expected to increase more rapidly in low- and middle-income countries (LMIC) than in high-income countries (HIC) in the coming decades. Nevertheless, research on dementia care remains limited for LMIC. This study aims to fill this gap by investigating care needs and care receipt in three LMIC: China, Mexico, and India.

Methods: Using harmonized data from the Gateway to Global Aging Data in China, Mexico, and India and focusing on individuals aged 65 and older with cognitive impairment (N = 15,118), we estimated the proportions of care needs related to difficulties with activities of daily living (ADL) and instrumental activities of daily living (IADL), and care receipt. We then used logistic regressions to examine the association between caregiver availability and informal care receipt.

Results: We observed relatively similar patterns in care need measures across countries and over time. In contrast, the association between caregiver availability and informal care receipt showed some cross-country variations. Generally, living with family members was associated with a higher probability of receiving informal care in China and India. However, for Mexico, this association was only evident for men. Additionally, we found that the magnitude of the association between caregiver availability and informal care receipt varied with the care recipient's gender.

Conclusions: While living with family members was generally associated with a higher likelihood of receiving informal care in China, Mexico, and India, there are differences in the association between caregiver availability and informal care receipt across countries and over time.

Background: Lower urinary tract symptoms (LUTS) in older men are associated with an increased risk of mobility limitations. Lower extremity muscle quality may represent a novel shared mechanism of both LUTS and mobility limitations.

Methods: We evaluated associations of thigh skeletal muscle measures (strength, area, and specific force) with total LUTS severity (American Urologic Association Symptom Index; AUASI) and voiding and storage subscores among 352 men aged ≥60 years enrolled in the Baltimore Longitudinal Study of Aging. Thigh muscle strength (Nm) was defined as maximum concentric 30°/s knee extensor torque, area (cm2), and specific force (Nm/cm2) defined as strength/area. Associations with AUASI score were estimated using multivariable linear regression and linear mixed models.

Results: Mean thigh muscle strength at baseline was 139.7Nm. In cross-sectional multivariable models, each 39Nm increment in thigh muscle strength and 0.28Nm/cm2 increment in specific force was associated with -1.17 point (95% CI: -1.93 to -.41) and -0.95 point (95% CI: -1.63 to -0.27) lower AUASI score, respectively. Similar associations were observed for voiding and storage subscores, although somewhat attenuated. In longitudinal analyses, baseline muscle measures were not associated with annual change in AUASI, and current changes in muscle measures and AUASI were unrelated.

Conclusions: Cross-sectionally, higher thigh muscle strength and specific force were associated with decreased LUTS severity in older men. However, we did not observe concurrent worsening LUTS severity with declining thigh muscle strength, area, or specific force in longitudinal analyses.