Bone Mineral Density During and After Lactation: A Comparison of African American and Caucasian Women.

During lactation, changes in maternal calcium metabolism are necessary to provide adequate calcium for newborn skeletal development. The calcium in milk is derived from the maternal skeleton through a process thought to be mediated by the actions of parathyroid hormone-related protein (PTHrP) in combination with decreased circulating estrogen concentrations. After weaning, bone lost during lactation is rapidly regained. Most studies of bone metabolism in lactating women have been performed in Caucasian subjects. There are well-documented differences between African American (AA) and Caucasian (C) bone metabolism, including higher bone mineral density (BMD), lower risk of fracture, lower 25-hydroxyvitamin D (25(OH) D), and higher PTH in AA compared to C. In this prospective paired cohort study, BMD and markers of bone turnover were compared in self-identified AA and C mothers during lactation and after weaning. BMD decreased in both AA and C women during lactation, with similar decreases at the lumbar spine (LS) and greater bone loss in the C group at the femoral neck (FN) and total hip (TH), demonstrating that AA are not resistant to PTHrP during lactation. BMD recovery compared to the 2 week postpartum baseline was observed 6 months after weaning, though the C group did not have complete recovery at the FN. Increases in markers of bone formation and resorption during lactation were similar in AA and C. C-terminal telopeptide (CTX) decreased to 30% below post-pregnancy baseline in both groups 6 months after weaning, while procollagen type 1 N-terminal (P1NP) returned to baseline in the AA group and fell to below baseline in the C group. Further investigation is required to determine impacts on long term bone health for women who do not fully recover BMD before a subsequent pregnancy.

Effectiveness of a behavioral lifestyle intervention on weight management and mobility improvement in older informal caregivers: a secondary data analysis.

BACKGROUND: Older informal caregivers are prone to sedentary behavior and obesity. With great caregiving burdens and frequent physical and mental distress, older informal caregivers may have low adherence and poor results in behavioral intervention for weight management. This study examined whether overweight or obese older informal caregivers could benefit from a behavioral weight management program as much as non-caregivers. METHODS: The Mobility and Vitality Lifestyle Program (MOVE UP) was a pre-post, community-based, 13-month lifestyle intervention study to help older adults improve physical function performance and lose weight. We identified a subset of informal caregivers (n = 29) and non-caregivers (n = 65) from the MOVE UP participants retrospectively. Changes in lower extremity function, weight, depressive symptoms, and self-efficacy from baseline were compared between caregivers and non-caregivers using paired t-tests and ANCOVA. RESULTS: Older informal caregivers had significantly lower session attendance rates than non-caregivers (67.7% vs 76.8%, P < 0.05), however, both informal caregivers and non-caregivers improved significantly in lower extremity function, weight loss, and self-efficacy in diet (Ps < 0.05). For each outcome, changes from baseline to the 13-month endpoint were the same among informal caregivers and non-caregivers. CONCLUSION: This study provides evidence that older informal caregivers can benefit from behavioral weight management interventions despite the challenge caregiving poses for effective self-care. Future behavioral intervention studies for older informal caregivers should adopt self-monitoring tools and extend the on-site delivery to home-based settings for higher adherence and greater flexibility. TRIAL REGISTRATION: Registered at clinicaltrials.gov (NCT02657239).

Association of fatigue, inflammation, and physical activity on gait speed: the Long Life Family Study.

BACKGROUND: Fatigue, inflammation, and physical activity (PA) are all independently associated with gait speed, but their directionality is not fully elucidated. AIMS: Evaluate the bidirectional associations amongst fatigue, inflammation, and PA on gait speed. METHODS: This cross sectional study included probands (n = 1280, aged 49-105) and offspring (n = 2772, aged 24-88) in the Long Life Family Study. We assessed gait speed, fatigue with the question "I could not get going", inflammation using fasting interleukin-6 (IL-6) and high sensitivity C-reactive protein (CRP), and self-reported PA as walking frequency in the past two weeks. The two generations were examined separately using linear mixed modeling. RESULTS: Lower fatigue, lower IL-6, and greater PA were all associated with faster gait speed in both generations (all p < 0.05); lower CRP was only associated with faster gait speed in the offspring. PA explained the association of fatigue and gait speed via a 16.1% (95% CI 9.7%, 26.7%) attenuation of the direct associations for the probands and 9.9% (95% CI 6.3%, 18.8%) in the offspring. In addition, IL-6 explained more of the association of fatigue and gait speed than the association between PA and gait speed, via a 14.9% (95% CI 9.2%, 23.4%) attenuation of the direct association in the offspring only. DISCUSSION: Results revealed a potential directionality from fatigue to IL-6 to PA that may lead to faster gait speed. Future work should examine these relationships longitudinally to establish temporality and causality. CONCLUSIONS: Our findings support a signal that lowering fatigue and inflammation and increasing physical activity may delay functional decline.

Persistent polypharmacy and fall injury risk: the Health, Aging and Body Composition Study.

BACKGROUND: Older adults receive treatment for fall injuries in both inpatient and outpatient settings. The effect of persistent polypharmacy (i.e. using multiple medications over a long period) on fall injuries is understudied, particularly for outpatient injuries. We examined the association between persistent polypharmacy and treated fall injury risk from inpatient and outpatient settings in community-dwelling older adults. METHODS: The Health, Aging and Body Composition Study included 1764 community-dwelling adults (age 73.6 ± 2.9 years; 52% women; 38% black) with Medicare Fee-For-Service (FFS) claims at or within 6 months after 1998/99 clinic visit. Incident fall injuries (N = 545 in 4.6 ± 2.9 years) were defined as the initial claim with an ICD-9 fall E-code and non-fracture injury, or fracture code with/without a fall code from 1998/99 clinic visit to 12/31/08. Those without fall injury (N = 1219) were followed for 8.1 ± 2.6 years. Stepwise Cox models of fall injury risk with a time-varying variable for persistent polypharmacy (defined as ≥6 prescription medications at the two most recent consecutive clinic visits) were adjusted for demographics, lifestyle characteristics, chronic conditions, and functional ability. Sensitivity analyses explored if persistent polypharmacy both with and without fall risk increasing drugs (FRID) use were similarly associated with fall injury risk. RESULTS: Among 1764 participants, 636 (36%) had persistent polypharmacy over the follow-up period, and 1128 (64%) did not. Fall injury incidence was 38 per 1000 person-years. Persistent polypharmacy increased fall injury risk (hazard ratio [HR]: 1.31 [1.06, 1.63]) after adjusting for covariates. Persistent polypharmacy with FRID use was associated with a 48% increase in fall injury risk (95%CI: 1.10, 2.00) vs. those who had non-persistent polypharmacy without FRID use. Risks for persistent polypharmacy without FRID use (HR: 1.22 [0.93, 1.60]) and non-persistent polypharmacy with FRID use (HR: 1.08 [0.77, 1.51]) did not significantly increase compared to non-persistent polypharmacy without FRID use. CONCLUSIONS: Persistent polypharmacy, particularly combined with FRID use, was associated with increased risk for treated fall injuries from inpatient and outpatient settings. Clinicians may need to consider medication management for FRID and other fall prevention strategies in community-dwelling older adults with persistent polypharmacy to reduce fall injury risk.

Profiles of Accelerometry-Derived Physical Activity Are Related to Perceived Physical Fatigability in Older Adults.

Physical activity (PA) is associated with greater fatigability in older adults; little is known about magnitude, shape, timing and variability of the entire 24-h rest-activity rhythm (RAR) associated with fatigability. We identified which features of the 24-h RAR pattern were independently and jointly associated with greater perceived physical fatigability (Pittsburgh Fatigability Scale, PFS, 0-50) in older adults (n = 181, 71.3 ± 6.7 years). RARs were characterized using anti-logistic extended cosine models and 4-h intervals of PA means and standard deviations across days. A K-means clustering algorithm approach identified four profiles of RAR features: "Less Active/Robust", "Earlier Risers", "More Active/Robust" and "Later RAR". Quantile regression tested associations of each RAR feature/profile on median PFS adjusted for age, sex, race, body mass index and depression symptomatology. Later rise times (up mesor; ß = 1.38, p = 0.01) and timing of midpoint of activity (acrophase; ß = 1.29, p = 0.01) were associated with higher PFS scores. Lower PA between 4 a.m. and 8 a.m. was associated with higher PFS scores (ß = -4.50, p = 0.03). "Less Active/Robust" (ß = 6.14, p = 0.01) and "Later RAR" (ß = 3.53, p = 0.01) patterns were associated with higher PFS scores compared to "Earlier Risers". Greater physical fatigability in older adults was associated with dampened, more variable, and later RARs. This work can guide development of interventions aimed at modifying RARs to reduce fatigability in older adults.

An Optimal Self-Report Physical Activity Measure for Older Adults: Does Physical Function Matter?

The authors compared two self-report measures of physical activity, the Physical Activity Scale for the Elderly (PASE) and the Community Healthy Activities Model Program for Seniors (CHAMPS), against the device-derived SenseWear Armband (SWA), to identify a recommended self-report tool to measure physical activity in older adults across physical function levels. A total of 65 community-dwelling older adults completed the PASE, CHAMPS, and seven full days of SWA wear. The authors measured physical function using the modified short physical performance battery (SPPB) and a usual-paced 6-m walk. Age- and sex-adjusted Spearman correlations showed that CHAMPS and SWA were correlated in higher functioning participants (SPPB: ρ = .33, p = .03; gait speed: ρ = .40, p = .006) and also correlated in lower functioning participants for SPPB (ρ = .70, p = .003) only. PASE and SWA were not significantly correlated across physical function. When an objective measure of physical activity is not practical, the CHAMPS questionnaire appears to capture physical activity for older adults across physical function levels.

Associations between novel jump test measures, grip strength, and physical performance: the Osteoporotic Fractures in Men (MrOS) Study.

BACKGROUND/AIMS: Weight-bearing jump tests measure lower extremity muscle power, velocity, and force, and may be more strongly related to physical performance than grip strength. However, these relationships are not well described in older adults. METHODS: Participants were 1242 older men (mean age 84 ± 4 years) in the Osteoporotic Fractures in Men (MrOS) Study. Jump peak power (Watts/kg body weight), force (Newton/kg body weight) at peak power, and velocity (m/s) at peak power were measured by jump tests on a force plate. Grip strength (kg/kg body weight) was assessed by hand-held dynamometry. Physical performance included 400 m walk time (s), 6 m usual gait speed (m/s), and 5-repeated chair stands speed (#/s). RESULTS: In adjusted Pearson correlations, power/kg and velocity moderately correlated with all performance measures (range r = 0.41-0.51; all p < 0.001), while correlations for force/kg and grip strength/kg were weaker (range r = 0.20-0.33; all p < 0.001). Grip strength/kg moderately correlated with power/kg (r = 0.44; p < 0.001) but not velocity or force/kg. In adjusted linear regression with standardized ßs, 1 SD lower power/kg was associated with worse: 400 m walk time (ß = 0.47), gait speed (ß = 0.42), and chair stands speed (ß = 0.43) (all p < 0.05). Associations with velocity were similar (400 m walk time: ß = 0.42; gait speed: ß = 0.38; chair stands speed: ß = 0.37; all p < 0.05). Force/kg and grip strength/kg were more weakly associated with performance (range ß = 0.18-0.28; all p < 0.05). CONCLUSIONS/DISCUSSION: Jump power and velocity had stronger associations with physical performance than jump force or grip strength. This suggests lower extremity power and velocity may be more strongly related to physical performance than lower extremity force or upper extremity strength in older men.

Three Year Functional Trajectories Among Old Age Survivors and Decedents: Dying Eliminates a Racial Disparity.

BACKGROUND: Long-term trajectories of disability comparing decedents and survivors and differences by race have not been assessed. OBJECTIVE: To examine self-reported difficulty in walking a quarter mile and the need for assistance with activities of daily living (ADL) beginning 3 years before death among decedents and age- and gender-matched survivors. DESIGN: A case-control sample drawn from the Health, Aging and Body Composition Study (Health ABC). Data were collected between 1997 and 2015. PARTICIPANTS: Of the 1991 participants who died by the end of the study, 1410 were interviewed for 3 years prior to death, including an interview 6 months before dying. Of these, 1379 decedents were successfully matched by age and gender with 1379 survivors and tracked over the same 3-year period. MAIN MEASURES: Self-reported difficulty walking a quarter mile and the ability to perform activities of daily living without assistance (bathing, dressing, transferring). KEY RESULTS: Decedents (mean age at death, 84) increased in mobility disability from 44.1% 3 years before death to 69.4% 6 months before death and in ADL disability from 32.9% to 58.4%. Among survivors, mobility disability increased from 31.4% to 40.7% and ADL disability from 17.4% to 31.4%. The proportion of decedents and survivors with mobility disability differed significantly in adjusted models at all assessment points (p < 0.0001). African-American survivors were significantly more disabled than White survivors at all points (p < 0.0001), but trajectories of disability among decedents did not differ by race in the last 18 months of life (p = 0.35). CONCLUSIONS: Trajectories of self-reported disability differ between survivors and decedents. Older adults who died were more disabled 3 years before death and also had a greater risk of increasing disability over each subsequent 6-month assessment. The gap in disability between African Americans and Whites was erased in the final 1 to 1.5 years before death.

Partial meniscectomy is associated with increased risk of incident radiographic osteoarthritis and worsening cartilage damage in the following year.

OBJECTIVES: To assess whether partial meniscectomy is associated with increased risk of radiographic osteoarthritis (ROA) and worsening cartilage damage in the following year. METHODS: We studied 355 knees from the Osteoarthritis Initiative that developed ROA (Kellgren-Lawrence grade ≥ 2), which were matched with control knees. The MR images were assessed using the semi-quantitative MOAKS system. Conditional logistic regression was applied to estimate risk of incident ROA. Logistic regression was used to assess the risk of worsening cartilage damage in knees with partial meniscectomy that developed ROA. RESULTS: In the group with incident ROA, 4.4 % underwent partial meniscectomy during the year prior to the case-defining visit, compared with none of the knees that did not develop ROA. All (n = 31) knees that had partial meniscectomy and 58.9 % (n = 165) of the knees with prevalent meniscal damage developed ROA (OR = 2.51, 95 % CI [1.73, 3.64]). In knees that developed ROA, partial meniscectomy was associated with an increased risk of worsening cartilage damage (OR = 4.51, 95 % CI [1.53, 13.33]). CONCLUSIONS: The probability of having had partial meniscectomy was higher in knees that developed ROA. When looking only at knees that developed ROA, partial meniscectomy was associated with greater risk of worsening cartilage damage. KEY POINTS: • Partial meniscectomy is a controversial treatment option for degenerative meniscal tears. • Partial meniscectomy is strongly associated with incident osteoarthritis within 1 year. • Partial meniscectomy is associated with increased risk of worsening cartilage damage.

Community-Based Healthy Aging Interventions for Older Adults with Arthritis and Multimorbidity.

Examine the impact of programs led by community health workers on health and function in older adults with arthritis and other health conditions. We conducted a cluster-randomized trial of the Arthritis Foundation Exercise Program (AFEP) enhanced with the "10 Keys"™ to Healthy Aging compared with the AFEP program at 54 sites in 462 participants (mean age 73 years, 88 % women, 80 % white). Trained Community health workers delivered the 10-week programs. Outcomes assessed after 6 months included physical performance [Short Physical Performance Battery (SPPB)], Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, and preventive health behaviors. Both groups experienced improvements. Performance improved by 0.3 SPPB points in the AFEP/"10 Keys"™ group and 0.5 in AFEP alone; WOMAC scores declined by 3.0 and 3.9 points respectively. More participants had controlled hypertension at 6 months in both groups (60.1 % baseline to 76.7 % in AFEP/10 Keys and from 76.5 to 84.9 % in AFEP alone) and greater diabetes control (from 15.0 to 34.9 and 15.5 to 34.1 %, respectively). These community-based programs showed similar improvements in preventive health, mobility and arthritis outcomes.

Comparison of radiographic joint space width and magnetic resonance imaging for prediction of knee replacement: A longitudinal case-control study from the Osteoarthritis Initiative.

OBJECTIVE: To evaluate whether change in fixed-location measures of radiographic joint space width (JSW) and cartilage thickness by MRI predict knee replacement. METHODS: Knees replaced between 36 and 60 months' follow-up in the Osteoarthritis Initiative were each matched with one control by age, sex and radiographic status. Radiographic JSW was determined from fixed flexion radiographs and subregional femorotibial cartilage thickness from 3 T MRI. Changes between the annual visit before replacement (T0) and 2 years before T0 (T-2) were compared using conditional logistic regression. RESULTS: One hundred and nineteen knees from 102 participants (55.5 % women; age 64.2 ± 8.7 [mean ± SD] years) were studied. Fixed-location JSW change at 22.5 % from medial to lateral differed more between replaced and control knees (case-control [cc] OR = 1.57; 95 % CI: 1.23-2.01) than minimum medial JSW change (ccOR = 1.38; 95 % CI: 1.11-1.71). Medial femorotibial cartilage loss displayed discrimination similar to minimum JSW, and central tibial cartilage loss similar to fixed-location JSW. Location-independent thinning and thickening scores were elevated prior to knee replacement. CONCLUSIONS: Discrimination of structural progression between knee pre-placement cases versus controls was stronger for fixed-location than minimum radiographic JSW. MRI displayed similar discrimination to radiography and suggested greater simultaneous cartilage thickening and loss prior to knee replacement. KEY POINTS: • Fixed-location JSW predicts surgical knee replacement more strongly than minimum JSW. • MRI predicts knee replacement with similar accuracy to radiographic JSW. • MRI reveals greater cartilage thinning and thickening prior to knee replacement.

Sensorimotor Peripheral Nerve Function and the Longitudinal Relationship With Endurance Walking in the Health, Aging and Body Composition Study.

OBJECTIVES: To determine whether lower extremity sensorimotor peripheral nerve deficits are associated with reduced walking endurance in older adults. DESIGN: Prospective cohort study with 6 years of follow-up. SETTING: Two university research clinics. PARTICIPANTS: Community-dwelling older adults enrolled in the Health, Aging and Body Composition Study from the 2000-2001 annual clinical examination (N=2393; mean age ± SD, 76.5±2.9y; 48.2% men; 38.2% black) and a subset with longitudinal data (n=1178). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants underwent peripheral nerve function examination in 2000-2001, including peroneal motor nerve conduction amplitude and velocity, vibration perception threshold, and monofilament testing. Symptoms of lower extremity peripheral neuropathy included numbness or tingling and sudden stabbing, burning, pain, or aches in the feet or legs. The Long Distance Corridor Walk (LDCW) (400 m) was administered in 2000-2001 and every 2 years afterward for 6 years to assess endurance walking performance over time. RESULTS: In separate, fully adjusted linear mixed models, poor vibration threshold (>130 µm), 10-g and 1.4-g monofilament insensitivity were each associated with a slower 400-m walk completion time (16.0 s, 14.4s, and 6.9 s slower, respectively; P<.05 for each). Poor motor amplitude (<1 mV), poor vibration perception threshold, and 10-g monofilament insensitivity were related to greater slowing per year (4.7, 4.2, and 3.8 additional seconds per year, respectively; P<.05), although poor motor amplitude was not associated with initial completion time. CONCLUSIONS: Poorer sensorimotor peripheral nerve function is related to slower endurance walking and greater slowing longitudinally. Interventions to reduce the burden of sensorimotor peripheral nerve function impairments should be considered to help older adults maintain walking endurance-a critical component for remaining independent in the community.

Sensorimotor Peripheral Nerve Function and Physical Activity in Older Men.

We determined whether sensorimotor peripheral nerve (PN) function was associated with physical activity (PA) in older men. The Osteoporotic Fractures in Men Study Pittsburgh, PA, site (n = 328, age 78.8 ± 4.7 years) conducted PN testing, including: peroneal motor and sural sensory nerve conduction (latencies, amplitudes: CMAP and SNAP for motor and sensory amplitude, respectively), 1.4g/10g monofilament (dorsum of the great toe), and neuropathy symptoms. ANOVA and multivariate linear regression modeled PN associations with PA (Physical Activity Scale for the Elderly [PASE] and SenseWear Armband). After multivariable adjustment, better motor latency was associated with higher PASE scores (160.5 ± 4.8 vs. 135.6 ± 6.7, p < .01). Those without versus with neuropathy symptoms had higher PASE scores (157.6 ± 5.3 vs. 132.9 ± 7.1, p < .01). Better versus worse SNAP was associated with slightly more daily vigorous activity (9.5 ± 0.8 vs. 7.3 ± 0.7, p = .05). Other PN measures were not associated with PA. Certain PN measures were associated with lower PA, suggesting a potential pathway for disability.

Association of Aging-Related Endophenotypes With Mortality in 2 Cohort Studies: the Long Life Family Study and the Health, Aging and Body Composition Study.

One method by which to identify fundamental biological processes that may contribute to age-related disease and disability, instead of disease-specific processes, is to construct endophenotypes comprising linear combinations of physiological measures. Applying factor analyses methods to phenotypic data (2006-2009) on 28 traits representing 5 domains (cognitive, cardiovascular, metabolic, physical, and pulmonary) from 4,472 US and Danish individuals in 574 pedigrees from the Long Life Family Study (United States and Denmark), we constructed endophenotypes and assessed their relationship with mortality. The most dominant endophenotype primarily reflected the physical activity and pulmonary domains, was heritable, was significantly associated with mortality, and attenuated the association of age with mortality by 24.1%. Using data (1997-1998) on 1,794 Health, Aging and Body Composition Study participants from Memphis, Tennessee, and Pittsburgh, Pennsylvania, we obtained strikingly similar endophenotypes and relationships to mortality. We also reproduced the endophenotype constructs, especially the dominant physical activity and pulmonary endophenotype, within demographic subpopulations of these 2 cohorts. Thus, this endophenotype construct may represent an underlying phenotype related to aging. Additional genetic studies of this endophenotype may help identify genetic variants or networks that contribute to the aging process.

Can structural joint damage measured with MR imaging be used to predict knee replacement in the following year?

PURPOSE: To assess whether magnetic resonance (MR) imaging-based cross-sectional measures of structural joint damage can be used to predict knee replacement during the following year. MATERIALS AND METHODS: Participants were drawn from the Osteoarthritis Initiative, a longitudinal observational study that includes 4796 participants who have knee osteoarthritis or are at risk. The HIPAA-compliant protocol was approved by the institutional review boards of all participating centers, and written informed consent was obtained from all participants. During the 5 years of follow-up, 199 knees underwent knee replacement and were matched with 199 control knees that did not undergo knee replacement. Knees were matched according to radiographic disease stage and patient sex and age. All knees that underwent knee replacement and had MR images available from the year before surgery were included. MR images were assessed for cartilage damage, bone marrow lesions, meniscal damage, meniscal extrusion, synovitis, and effusion prior to reported knee replacement. Conditional logistic regression was applied to assess the risk of knee replacement. Analyses were performed on a compartmental and knee level. RESULTS: Participants had a mean age ± standard deviation of 64.2 years ± 8.4 (range, 47-82 years) and were predominantly women (232 of 398 participants, 58.3%). Risk for knee replacement was significantly increased for knees that exhibited two or more subregions with severe cartilage loss (odds ratio [OR], 16.5; 95% confidence interval [CI]: 3.96, 68.76), more than two subregions with bone marrow lesions (OR, 4.00; 95% CI: 1.75, 9.16), medial meniscal maceration (OR, 1.84; 95% CI: 1.13, 2.99), effusion (OR, 4.75; 95% CI: 2.55, 8.85), or synovitis (OR, 2.17; 95% CI: 1.33, 3.56), but not extrusion (OR, 1.00; 95% CI: 0.60,1.67), when compared with knees that did not exhibit these features as the reference standard. CONCLUSION: Apart from meniscal extrusion, all features of tissue abnormalities at MR imaging were related to clinical prognosis and could be used to predict knee replacement in the following year.

Impact of protecting ligands on surface structure and antibacterial activity of silver nanoparticles.

Silver nanoparticles (Ag NPs) have attracted much attention in the past decade because of their unique physicochemical properties and notable antibacterial activities. In particular, thiol-protected Ag NPs have come to the forefront of metal nanoparticle studies, as they have been shown to possess high stability and interesting structure-property relationships. However, a clear correlation between thiol-protecting ligands, the resulting Ag NP surface structure, and their antibacterial properties has yet to be determined. Here, a multielement (Ag and S), multi-edge (Ag K-edge, Ag L3-edge, S K-edge) X-ray absorption spectroscopy (XAS) methodology was used to identify the structure and composition of Ag NPs protected with cysteine. XAS characterization was carried out on similar-sized Ag NPs protected with poly(vinylpyrrolidone) (PVP), in order to provide a valid comparison of the ligand effect on surface structure. The PVP-Ag NPs showed a metallic Ag surface and composition, consistent with metal NPs protected by weak protecting ligands. On the other hand, the Cys-Ag NPs exhibited a distinct surface shell of silver sulfide, which is remarkably different than previously studied Cys-Ag NPs. The minimum inhibitory concentration (MIC) of both types of Ag NPs against Gram-positive (+) and Gram-negative (-) bacteria were tested, including Staphylococcus aureus (+), Escherichia coli (-), and Pseudomonas aeruginosa (-). It was found that the MICs of the Cys-Ag NPs were significantly lower than the PVP-Ag NPs for each bacteria, implicating the influence of the sulfidized surface structure. Overall, this work shows the effect of ligand on the surface structure of Ag NPs, as well as the importance of surface structure in controlling antibacterial activity.

Circadian rest-activity rhythms predict future increases in depressive symptoms among community-dwelling older men.

OBJECTIVE: Circadian rest-activity rhythms (CARs) have been cross-sectionally associated with depressive symptoms, although no longitudinal research has examined whether CARs are a risk factor for developing depressive symptoms. METHODS: We examined associations of CARs (measured with actigraphy over a mean of 4.8 days) with depressive symptoms (measured with the Geriatric Depression Scale) among 2,892 community-dwelling older men (mean age: 76.2 ± 5.5 years) from the MrOS Sleep Study who were without cognitive impairment. Among 2,124 men with minimal (0-2) symptoms at baseline, we assessed associations between CAR parameters and increases to mild (3-5) or clinically significant (≥6) symptoms after an average of 1.2 (±0.32) years. RESULTS: Cross-sectional associations between rhythm height parameters were independent of chronic diseases, lifestyle, sleep, and self-reported physical activity covariates. For example, men in the lowest mesor quartile had twice the adjusted odds (adjusted odds ratio [AOR]: 2.04, 95% confidence interval [CI]: 1.36-3.04, p = 0.0005) of having prevalent clinically significant symptoms (compared to minimal). Longitudinally, low CAR robustness (being in the lowest quartile of the pseudo-F statistic) was independently associated with increasing odds of developing symptoms (i.e., AOR for having clinically significant depressive symptoms at follow-up = 2.58, 95% CI: 1.11-5.99, p = 0.03). CONCLUSION: CAR disturbances are indicative of depressive symptomology. Low CAR robustness may independently contribute to the risk of worsening depression symptomology.

Assessing the quality of a non-randomized pragmatic trial for primary prevention of falls among older adults.

Current approaches to falls prevention mostly rely on secondary and tertiary prevention and target individuals at high risk of falls. An alternative is primary prevention, in which all seniors are screened, referred as appropriate, and educated regarding falls risk. Little information is available on research designs that allow investigation of this approach in the setting of aging services delivery, where randomization may not be possible. Healthy Steps for Older Adults, a statewide program of the Pennsylvania (PA) Department of Aging, involves a combination of education about falls and screening for balance problems, with referral to personal physicians and home safety assessments. We developed a non-randomized statewide trial, Falls Free PA, to assess its effectiveness in reducing falls incidence over 12 months. We recruited 814 seniors who completed the program (503 first-time participants, 311 people repeating the program) and 1,020 who did not participate in the program, from the same sites. We assessed the quality of this non-randomized design by examining recruitment, follow-up across study groups, and comparability at baseline. Of older adults approached in senior centers, 90.5 % (n = 2,219) signed informed consent, and 1,834 (82.4 %) completed baseline assessments and were eligible for follow-up. Attrition in the three groups over 12 months was low and non-differential (<10 % for withdrawal and <2 % for other loss to follow-up). Median follow-up, which involved standardized monthly assessment of falls, was 10 months in all study groups. At baseline, the groups did not differ in measures of health or falls risk factors. Comparable status at baseline, recruitment from common sites, and similar experience with retention suggest that the non-randomized design will be effective for assessment of this approach to primary prevention of falls.

Primary prevention of falls: effectiveness of a statewide program.

OBJECTIVES: We examined a population-wide program, Pennsylvania's Healthy Steps for Older Adults (HSOA), designed to reduce the incidence of falls among older adults. Older adults completing HSOA are screened and educated regarding fall risk, and those identified as being at high risk are referred to primary care providers and home safety resources. METHODS: From 2010 to 2011, older adults who completed HSOA at various senior center sites (n = 814) and a comparison group of older adults from the same sites who did not complete the program (n = 1019) were recruited and followed monthly. Although participants were not randomly allocated to study conditions, the 2 groups did not differ in fall risk at baseline or attrition. We used a telephone interactive voice response system to ascertain the number of falls that occurred each month. RESULTS: In multivariate models, adjusted fall incidence rate ratios (IRRs) were lower in the HSOA group than in the comparison group for both total (IRR = 0.83; 95% confidence interval [CI] = 0.72, 0.96) and activity-adjusted (IRR = 0.81; 95% CI = 0.70, 0.93) months of follow-up. CONCLUSIONS: Use of existing aging services in primary prevention of falls is feasible, resulting in a 17% reduction in our sample in the rate of falls over the follow-up period.