Associations between toxicity-weighted concentrations and dementia risk: Results from the Cardiovascular Health Cognition Study.

BACKGROUND: Air pollution is a modifiable risk factor for dementia. Yet, studies on specific sources of air pollution (i.e., toxic chemical emissions from industrial facilities) and dementia risk are scarce. We examined associations between toxicity-weighted concentrations of industrial pollution and dementia outcomes among a large, multi-site cohort of older adults. METHODS: Participants (n = 2770) were ≥ 65 years old (Mean = 75.3, SD = 5.1 years) from the Cardiovascular Health Cognition Study (1992-1999). Toxicity-weighted concentrations were estimated using the Risk Screening Environmental Indicator (RSEI) model which incorporates total reported chemical emissions with toxicity, fate, and transport models. Estimates were aggregated to participants' baseline census tract, averaged across 1988-1992, and log2-transformed. Dementia status was clinically adjudicated in 1998-1999 and categorized by subtype (Alzheimer's, vascular, mixed). We assessed whether RSEI-estimated toxicity-weighted concentrations were associated with 1) odds of prevalent dementia and 2) incident dementia risk by subtype. RESULTS: After adjusting for individual and census-tract level covariates, a doubling in toxicity-weighted concentrations was associated with 9 % higher odds of prevalent dementia (OR = 1.09, 95 % CI: 1.00, 1.19). In discrete-time survival models, each doubling in toxicity-weighted concentrations was associated with a 16 % greater hazard of vascular dementia (HR = 1.16, 95 % CI: 1.01, 1.34) but was not significantly associated with all-cause, Alzheimer's disease, or mixed dementia (p's > 0.05). DISCUSSION: Living in regions with higher toxicity-weighted concentrations was associated with higher odds of prevalent dementia and a higher risk of incident vascular dementia in this large, community-based cohort of older adults. These findings support the need for additional studies to examine whether toxic chemical emissions from industrial and federal facilities may be a modifiable target for dementia prevention.

Neighborhood Walkability Is Associated With Global Positioning System-Derived Community Mobility of Older Adults.

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 ±â€…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.

Association of Gait Quality With Daily-Life Mobility: An Actigraphy and Global Positioning System Based Analysis in Older Adults.

OBJECTIVE: Walking is a key component of daily-life mobility. We examined associations between laboratory-measured gait quality and daily-life mobility through Actigraphy and Global Positioning System (GPS). We also assessed the relationship between two modalities of daily-life mobility i.e., Actigraphy and GPS. METHODS: In community-dwelling older adults (N = 121, age = 77±5 years, 70% female, 90% white), we obtained gait quality from a 4-m instrumented walkway (gait speed, walk-ratio, variability) and accelerometry during 6-Minute Walk (adaptability, similarity, smoothness, power, and regularity). Physical activity measures of step-count and intensity were captured from an Actigraph. Time out-of-home, vehicular time, activity-space, and circularity were quantified using GPS. Partial Spearman correlations between laboratory gait quality and daily-life mobility were calculated. Linear regression was used to model step-count as a function of gait quality. ANCOVA and Tukey analysis compared GPS measures across activity groups [high, medium, low] based on step-count. Age, BMI, and sex were used as covariates. RESULTS: Greater gait speed, adaptability, smoothness, power, and lower regularity were associated with higher step-counts (0.20<|ρp| < 0.26, p < .05). Age(ß = -0.37), BMI(ß = -0.30), speed(ß = 0.14), adaptability(ß = 0.20), and power(ß = 0.18), explained 41.2% variance in step-count. Gait characteristics were not related to GPS measures. Participants with high (>4800 steps) compared to low activity (steps<3100) spent more time out-of-home (23 vs 15%), more vehicular travel (66 vs 38 minutes), and larger activity-space (5.18 vs 1.88 km2), all p < .05. CONCLUSIONS: Gait quality beyond speed contributes to physical activity. Physical activity and GPS-derived measures capture distinct aspects of daily-life mobility. Wearable-derived measures should be considered in gait and mobility-related interventions.

Global Positioning System Indicators of Community Mobility and Future Health Outcomes Among Older Adults.

BACKGROUND: We examined the relationship between global positioning system (GPS) indicators of community mobility and incident hospitalizations, emergency department (ED) visits, and falls over 1-year in community-dwelling older adults. METHODS: We performed a secondary analysis of a randomized trial investigating a physical therapy intervention to improve mobility in older adults. One hundred and forty-eight participants (mean age: 76.9 ±â€…6.2 years; 65% female) carried a GPS device following the postintervention visit. Over 1-year, new hospitalizations, falls, and ED visits were reported. GPS indicators of community mobility included the median area and compactness of the standard deviation ellipse (SDE), the median percentage of time spent outside of home (TOH), and median maximum distance from home. Generalized linear models assessed the association between 1-year risk of outcomes and GPS measures adjusted for age, race, gender, body mass index, comorbidity burden, and fall history. RESULTS: The mean ±â€…standard deviation of the median SDE area was 4.4 ±â€…8.5 km2, median SDE compactness 0.7 ±â€…0.2, median percentage TOH 14.4 ±â€…12.0%, and median maximum distance from home was 38 ±â€…253 km. Each 5% increase in median percentage TOH was associated with a 24% lower risk of hospitalization (incident rate ratio = IRR = 0.76, 95%CI: 0.61-0.95; p = .01). The association persisted after covariate adjustment (IRR = 0.78, 95%CI: 0.63-0.98; p = .03). No significant associations appeared for any GPS indicators with incident falls or ED visits. CONCLUSIONS: Increased TOH was associated with a lower risk of incident hospitalization over 1 year among community-dwelling older adults. Restricted community mobility may be an indicator of activity limitations related to future health outcomes, but further study is warranted.

Effects of a Physical Therapist Intervention on GPS Indicators of Community Mobility in Older Adults: A Secondary Analysis of a Randomized Controlled Trial.

OBJECTIVE: The authors compared the effects of a standard strength and endurance intervention with a standard plus timing and coordination training intervention on community mobility measured using global positioning systems (GPS) among community-dwelling older adults in this secondary analysis of a randomized controlled trial. METHODS: Participants were randomized to a standard or a standard plus timing and coordination training program. Community mobility was measured using the Life Space Assessment (LSA) and GPS indicators of community mobility at baseline, as well as at 12 (immediately after the intervention), 24, and 36 weeks. Linear mixed models were used for analysis. RESULTS: There were 166 participants with GPS data at baseline, including 81 in the standard plus group and 85 in the standard group. The groups did not differ in participant characteristics or GPS measures at baseline. There were no significant within-group changes in GPS indicators of community mobility or LSA score over time, nor between-group differences of the same. CONCLUSION: There were no significant changes in community mobility with either intervention or between-intervention differences. These findings suggest that interventions targeting physical function alone may not be sufficient to improve community mobility or participation in older adults. Future research should focus on the development of multifaceted interventions targeted to improve real-world participation. IMPACT: The studied interventions did not significantly change community mobility measured using GPS-derived community mobility measures or self-report measures in older adults, suggesting that more comprehensive interventions may be needed to target improvements in community mobility.

OLDER ADULTS' SUBJECTIVE WELL-BEING EXPERIENCING THE EXERGAME "I AM DOLPHIN".

The objective of this study was to understand older adults' perceptions of the connections between an exergame intervention, "I Am Dolphin," and their subjective well-being. Researchers conducted three focus groups with 14 older adults who participated in the exergame feasibility study. The semi-structured focus groups were transcribed, coded, and analysed using deductive and inductive techniques. Three themes were constructed related to playing the exergame and participants' subjective well-being: 1) elevated mood (through scheduled activity, immersion, and socialization), 2) feelings of achievement (especially following frustration and competition), and 3) perceived cognitive or physical changes. These findings will help researchers better understand how exergames may relate to the well-being of older adults. Future investigators could use these findings to create and implement new exergame interventions.

Body Mass Index and Cognition: Associations Across Mid- to Late Life and Gender Differences.

BACKGROUND: Higher mid-life body mass index (BMI) is associated with lower late-life cognition. Associations between later-life BMI and cognition are less consistent; evidence suggests reverse causation may play a role. We aimed to characterize associations between BMI and cognition across a wide age range during mid- to late life (55-85 years) and examine whether associations vary by gender. METHODS: We used data from the Health and Retirement Study (HRS) (N = 39,153) to examine the association between BMI and 3 cognitive outcomes: cognitive level, cognitive decline, and cognitive impairment. We used a series of linear regression, mixed effects regression, and logistic regression models, adjusting for potential confounders. RESULTS: Higher BMI before age 65 (midlife) was associated with lower cognitive performance, faster rates of cognitive decline, and higher odds of cognitive impairment in late life. Averaging across analyses assessing associations between BMI measured before age 60 and late-life cognition, a 5-unit higher level of BMI was associated with a 0.26 point lower cognitive score. Beyond age 65, associations flipped, and higher BMI was associated with better late-life cognitive outcomes. Associations in both directions were stronger in women. Excluding those with BMI loss attenuated findings among women in older ages, supporting the reverse causation hypothesis. CONCLUSIONS: In this sample, age 65 represented a critical turning point between mid- and late life for the association between BMI and cognition, which has important implications for recruitment strategies for studies focused on risk factors for late-life cognitive outcomes. Evidence of gender differences raises the need to further investigate plausible mechanisms.

Older Adults and Three-Dimensional Exergaming: Motivators and Barriers to Participation and Retention.

Background: Cognitive and physical activity are important for daily functioning. However, limited research exists on the motivators and barriers associated with older adults participating and adhering to exergame studies that promote physical and cognitive activity. Our objective was to examine older adults' motivators and barriers to joining and completing a three-dimensional exergame study. Methods: Fourteen older adults who participated in the exergame study contributed to one of three focus group discussions. Inductive and deductive methods were used to analyze the qualitative data. Results: Motivators for joining were generativity, peer referrals, self-improvement, and curiosity. Accomplishment, immersion, and exercise were motivators for retention. Participants also cited the structured schedule and adaptive difficulty features as motivators for retention. Barriers to participation included frustration due to lack of level advancement and fatigue/pain during gameplay. Some (n = 3) reported camera tracking issues as a barrier. Unanticipated gender-based trends arose when examining perceptions of the study team's role and motivators for retention. Conclusion: These findings will inform future research strategies for participant recruitment, enrollment, and retention, in addition to providing insights into the design of motivating, enjoyable, and sustainable exergames for older adults.

Exploring the Relationship Between Engagement in Enriching Early-Life Activities During Adolescence and Cognition in Later-Life: Results From the Health and Retirement Study.

The cognitive benefits associated with mid- to late-life engagement have been demonstrated in several studies. However, the link between engagement in enriching early-life activities (EELAs) during adolescence and later-life cognition has been relatively unexplored in major epidemiological studies. We examined the EELA-cognition relationship in a nationally representative sample of adults aged 50+. A subset of Health and Retirement Study respondents (n=3482) completed cognitive tests and returned a retrospective early-life activity inventory. Linear regression models analyzed the EELA-cognition relationship, and multiple imputation addressed missingness. Each additional EELA was associated with a 0.36 point higher cognitive score (95% CI: 0.24, 0.47). This relationship remained significant after adjusting for potential confounders (B=0.16; 95% CI: [0.06, 0.26]). EELA engagement was associated with better later-life cognitive performance. This study is understood to be the first to examine the EELA-cognition relationship using a large, nationally representative dataset. The findings highlight the importance of early-life engagement during an important developmental period (e.g., adolescence).

Using GPS Technologies to Examine Community Mobility in Older Adults.

BACKGROUND: Objective measures of community mobility are advantageous for capturing movement outside the home. Compared with subjective, self-reported techniques, global positioning system (GPS) technologies leverage passive, real-time location data to reduce recall bias and increase measurement precision. We developed methods to quantify community mobility among community-dwelling older adults and assessed how GPS-derived indicators relate to clinical measures of physical and cognitive performance. METHODS: Participants (n = 149; M ± standard deviation [SD] = 77.1 ± 6.5 years) from the program to improve mobility in aging (PRIMA) study, a physical therapy intervention to improve walking ability, carried a GPS device for 7 days. Community mobility was characterized by assessing activity space, shape, duration, and distance. Associations between GPS-derived indicators and cognition and physical function were evaluated using Spearman correlations. RESULTS: In adjusted models, a larger activity space, greater duration (eg, time out-of-home), and greater distance traveled from home were correlated with better 6-Minute Walk Test performance (ρ = 0.17-0.23, p's < .05). A more circular activity shape was related to poorer performance on the Trail Making Test, Part A (ρ = 0.18, p < .05). More time out-of-home and a larger activity space were correlated with faster times on the Trail Making Test, Part B (ρ = -0.18 to -0.24, p's < .05). Community mobility measures were not associated with global cognition, skilled walking, or usual gait speed. CONCLUSION: GPS-derived community mobility indicators capture real-world activity among older adults and were correlated with clinical measures of executive function and walking endurance. These findings will guide the design of future interventions to promote community mobility.

Exergames and Depressive Symptoms in Older Adults: A Systematic Review.

To synthesize and critique studies that examined the impact of exergames on depressive symptoms in older adults. Articles were retrieved from the databases CINAHL, Embase, PsychINFO, and Medline. Studies were included in the review if they involved a physical activity/videogame intervention and measured outcomes of depressive symptoms in older adults. The search generated 957 articles for consideration, which were narrowed to 17 articles after applying exclusion criteria. In studies that required depressive symptoms as an inclusion criterion, there was an improvement in depressive symptoms in older adults following the exergame intervention. In studies that did not require depressive symptoms as an inclusion criterion, researchers found mixed results. Future older adult exergame research should measure depression as a primary outcome, utilize control groups with random sampling, consist of larger sample sizes, and include people with disabilities.

Development and validation of improved PM2.5 models for public health applications using remotely sensed aerosol and meteorological data.

In this study, Moderate Resolution Imaging Spectrometer (MODIS) satellite measurements of aerosol optical depth (AOD) from different retrieval algorithms have been correlated with ground measurements of fine particulate matter less than 2.5 µm (PM2.5). Several MODIS AOD products from different satellites (Aqua vs. Terra), retrieval algorithms (Dark Target vs. Deep Blue), collections (5.1 vs. 6), and spatial resolutions (10 km vs. 3 km) for cities in the Western, Midwestern, and Southeastern USA have been evaluated. We developed and validated PM2.5 prediction models using remotely sensed AOD data. These models were further improved by incorporating meteorological variables (temperature, relative humidity, precipitation, wind gust, and wind direction) from the North American Land Data Assimilation System Phase 2 (NLDAS-2). Adding these meteorological data significantly improved the simulation quality of all the PM2.5 models, especially in the Western USA. Temperature, relative humidity, and wind gust were significant meteorological variables throughout the year in the Western USA. Wind speed was the most significant meteorological variable for the cold season while for the warm season, temperature was the most prominent one in the Midwestern and Southeastern USA. Using this satellite-derived PM2.5 data can improve the spatial coverage, especially in areas where PM2.5 ground monitors are lacking, and studying the connections between PM2.5 and public health concerns including respiratory and cardiovascular diseases in the USA can be further advanced.