Cassandra M. Germain

Impact of Obesity and Physical Activity on Functional Outcomes in the Elderly Data From NHANES 2005-2010

Objective: The objective of this study was to (a) to examine whether the association between obesity and physical functioning among older adults is moderated by physical activity (PA) and (b) to test whether this moderating effect varies by gender. Method: Data from adults (aged >60 years) who participated in the National Health and Nutrition Examination Surveys (2005-2010) were analyzed. Using multivariate logistic regression, we estimated the prevalence ratio (PR) of functional limitations and impairment in activities of daily living and instrumental activities of daily living, by body mass index and PA, while adjusting for age, educational level, and a comorbidity index. Results: The sample included 5,304 subjects (mean age = 70.4 years), and 50.5% were female. Overweight and obesity were associated with higher levels of functional limitations when compared with normal weight individuals regardless of the PA status (PR = 1.47, 95% confidence interval [CI] [1.17, 1.85], and PR = 2.71, 95% CI [2.00, 3.67], respectively) even after adjustment for confounders. Discussion: Overweight and obesity are associated with impairment in functional outcomes irrespective of PA.

Muscle Strength, Physical Activity, and Functional Limitations in Older Adults with Central Obesity

Background. Obesity and muscle weakness are independently associated with increased risk of physical and functional impairment in older adults. It is unknown whether physical activity (PA) and muscle strength combined provide added protection against functional impairment. This study examines the association between muscle strength, PA, and functional outcomes in older adults with central obesity. Methods. Prevalence and odds of physical (PL), ADL, and IADL limitation were calculated for 6,388 community dwelling adults aged ≥ 60 with central obesity. Individuals were stratified by sex-specific hand grip tertiles and PA. Logistic models were adjusted for age, education, comorbidities, and body-mass index and weighted. Results. Overall prevalence of PL and ADL and IADL limitations were progressively lower by grip category. Within grip categories, prevalence was lower for individuals who were active than those who were inactive. Adjusted models showed significantly lower odds of PL OR 0.42 [0.31, 0.56]; ADL OR 0.60 [0.43, 0.84], and IADL OR 0.46 [0.35, 0.61] for those in the highest grip strength category as compared to those in the lowest grip category. Conclusion. Improving grip strength in obese elders who are not able to engage in traditional exercise is important for reducing odds of physical and functional impairment.

A comparison of neuropsychological performance between US and Russia: Preparing for a global clinical trial

Understanding regional differences in cognitive performance is important for interpretation of data from large multinational clinical trials.

Community engagement in diverse populations for Alzheimer disease prevention trials.

The recruitment of asymptomatic volunteers has been identified as a critical factor that is delaying the development and validation of preventive therapies for Alzheimer disease (AD). Typical recruitment strategies involve the use of convenience samples or soliciting participation of older adults with a family history of AD from clinics and outreach efforts. However, high-risk groups, such as ethnic/racial minorities, are traditionally less likely to be recruited for AD prevention studies, thus limiting the ability to generalize findings for a significant proportion of the aging population. A community-engagement approach was used to create a registry of 2311 research-ready, healthy adult volunteers who reflect the ethnically diverse local community. Furthermore, the registry’s actual commitment to research was examined, through demonstrated participation rates in a clinical study. The approach had varying levels of success in establishing a large, diverse pool of individuals who are interested in participating in pharmacological prevention trials and meet the criteria for primary prevention research trials designed to delay the onset of AD. Our efforts suggest that entry criteria for the clinical trials need to be carefully considered to be inclusive of African Americans, and that sustained effort is needed to engage African Americans in pharmacological prevention approaches.

Sex, race and age differences in muscle strength and limitations in community dwelling older adults: Data from the Health and Retirement Survey (HRS)

BACKGROUND Aging-related muscle weakness is associated with increased risk of functional limitations and disability. This study examined the association between varying degrees of hand grip strength on functional ability in community-dwelling older adults. METHODS Cross-sectional analysis of 4289 men and 5860 women ≥60 from 2006 and 2008 waves of the population-based Health and Retirement Study (HRS) were stratified by sex-specific grip strength tertiles (low, mid, high). Prevalence and adjusted odds of physical limitations (PL), and ADL/IADL limitation were calculated by sex, race/ethnicity and age group (60-69, 70-79, 80+). Models were weighted, adjusted for age, sex, race/ethnicity, education, smoking status, BMI, comorbidities and participation in physical activity. RESULTS Prevalence of PL, ADL and IADL limitations were significantly lower among adults in the highest grip category as compared to those in the lowest grip category. Adjusted odds for PL OR 0.41[0.33,0.52]; ADL OR.51 [0.39,0.67], and IADL OR 0.47 [0.38-0.59] limitations were significantly lower among adults in the highest grip compared to the lowest grip category. However, notable differences were observed in the strength of these associations by gender, race and age group. CONCLUSION Demographic characteristics are important factors to consider for risk stratification and the development of effective grip strength training interventions for older adults.

Physical Activity Predicts Higher Physical Function in Older Adults: The Osteoarthritis Initiative

OBJECTIVES Physical activity reduces mobility impairments in elders. We examined the association of physical activity on risk of subjective and objective physical function in adults with and at risk for osteoarthritis (OA). METHODS Adults aged ≥ 60 years from the longitudinal Osteoarthritis Initiative, a prospective observational study of knee OA, were classified by sex-specific quartiles of Physical Activity Score for the Elderly scores. Using linear mixed models, we assessed 6-year data on self-reported health, gait speed, Late-Life Function and Disability Index (LLFDI) and chair stand. RESULTS Of 2252 subjects, mean age ranged from 66 to 70 years. Within each quartile, physical component (PCS) of the Short Form-12 and gait speed decreased from baseline to follow-up in both sexes (all P < .001), yet the overall changes across PASE quartiles between these 2 time points were no different (P = .40 and .69, males and females, respectively). Decline in PCS occurred in the younger age group, but rates of change between quartiles over time were no different in any outcomes in either sex. LLFDI scores declined in the 70+ age group. Adjusting for knee extensor strength reduced the strength of association. CONCLUSIONS Higher physical activity is associated with maintained physical function and is mediated by muscle strength, highlighting the importance of encouraging physical activity in older adults with and at risk for OA.

Physical Activity, Central Adiposity, and Functional Limitations in Community-dwelling Older Adults

Background and Purpose:Obesity and physical inactivity are independently associated with physical and functional limitations in older adults. The current study examines the impact of physical activity on odds of physical and functional limitations in older adults with central and general obesity. Methods:Data from 6279 community-dwelling adults aged 60 years or more from the Health and Retirement Study 2006 and 2008 waves were used to calculate prevalence and odds of physical and functional limitation among obese older adults with high waist circumference (waist circumference ≥88 cm in females and ≥102 cm in males) who were physically active versus inactive (engaging in moderate/vigorous activity less than once per week). Logistic regression models were adjusted for age, sex, race/ethnicity, education, smoking status, body mass index, and number of comorbidities. Results:Physical activity was associated with lower odds of physical and functional limitations among older adults with high waist circumference (odds ratio [OR], 0.59; confidence interval [CI], 0.52-0.68, for physical limitations; OR, 0.52; CI, 0.44-0.62, for activities of daily living; and OR, 0.44; CI, 0.39-0.50, for instrumental activities of daily living). Conclusions:Physical activity is associated with significantly lower odds of physical and functional limitations in obese older adults regardless of how obesity is classified. Additional research is needed to determine whether physical activity moderates long-term physical and functional limitations.

Prevalence of weakness and its relationship with limitations based on the Foundations for the National Institutes for Health project: data from the Health and Retirement Study.

Background/Objectives:The objectives of this study were to determine the prevalence of muscle weakness using the two 2014 Foundation for the National Institutes of Health (FNIH) Sarcopenia Project criteria and its relationship with physical limitations, basic activities of daily living (ADL) and instrumental ADL.Subjects/Methods:We performed a cross-sectional analysis of community-dwelling adults from the Health and Retirement Study 2006–2008 and identified a subsample of 5092 adults aged ⩾60 years with grip strength (GS) data. Self-reported physical limitations, basic ADL and instrumental ADL were assessed. Criteria for GS (men<26 kg; women <16 kg) and GS adjusted for body mass index (GS/BMI; men <1.0; women <0.56) were applied to the sample. We determined the prevalence of muscle weakness in each sex. Multivariable logistic regression was used to calculate the association of physical limitations, basic ADL and instrument ADL with weakness definitions in each sex.Results:Mean age was 72.1 years (54.9% female). Mean GS was 38.3 and 22.9 kg and mean BMI was 29 kg/m2, respectively, in men and women. Weakness prevalence using GS and GS:BMI definitions were 7.8 and 15.2 (P<0.001), respectively, in men and 11.4 and 13.3% (P=0.04) in women. Overall prevalence of physical limitations, basic ADL limitations and instrumental ADL limitations was 52.9, 28.1 and 35.9%, respectively. In those with weakness, prevalence of physical limitations, basic ADL and instrumental ADL was 78.5, 42.3 and 65.3%, respectively, using the GS definition, and 79.7, 40.7 and 58.8%, respectively, using the GS/BMI definition. GS and the GS/BMI definitions of weakness were strongly associated with physical limitations (odds ratio (OR) 2.19 (95% confidence interval (CI): (1.67–2.87)) and 2.52 (2.01–3.17)), basic ADL (OR 1.59 (1.22–2.07) and 1.66 (1.32–2.07)) and instrumental ADLs (OR 1.98 (1.28–2.54) and 1.78 (1.44–2.20)).Conclusions:The new FNIH guidelines for weakness are associated with higher prevalence of physical limitations, basic ADL impairments and instrumental ADL impairments as compared with individuals without weakness.

Effect of APOE and CD33 on Cognitive Decline

Objective An Alzheimer’s disease (AD) diagnosis is preceded by a long period of cognitive decline. We previously demonstrated increased risk of decline among individuals possessing one or more APOE ε4 alleles together with a family history of AD. The objective of this study is to investigate the possibility that such an increased risk might be due to AD risk genes with small effects in combination with APOE. Methods Participants in the Health and Retirement Study (HRS) over the age of 65, who contributed DNA, and had two or more evaluations with an abbreviated version of the modified Telephone Interview for Cognitive Status (TICS-m) were eligible for the study (n = 7451). A genetic risk score (g-score) was derived using AD risk genes’ meta-analyses data, assigning risk according to the number of risk alleles and summed over all the risk genes. Trajectories of cognitive function were modeled in four groups of Caucasian participants with and without one or more APOE ε4 alleles and either a high or low g-score: APOE ε4-/low g-score; APOE ε4-/high g-score; APOE ε4+/low g-score; and APOE ε4+/high g-score. Post hoc analyses evaluated interactions between individual genes and APOE. Results Individuals in the APOE ε4+/high g-score group exhibited the greatest cognitive decline over time (p<.0001). This risk appeared to be greater than the sum of the effects of either high g-score or APOE ε4 alone. When gene interactions were individually tested with APOE, a statistically significant interaction with CD33 was discovered (p = 0.04) although the interaction was no longer significant when adjusted for multiple comparisons. Conclusions Individuals with multiple AD risk genes in addition to having one or more APOE ε4 alleles are at greater risk of cognitive decline than individuals with either APOE ε4 or a high genetic risk score. Among those with one or more APOE ε4 alleles, having one or more copies of the CD33 C (risk) allele may further increase the risk of cognitive decline.

Challenges in international clinical trials to delay early symptomatic Alzheimer's disease

odds ranging from 2.4 to 4.99. The pooled adjusted risk ratio was 2.91 (95% confidence interval: 1.51 5.61). Risk estimates were presented in the context of a key confounder-cerebral infarcts-which are more common in those with T2DM and might contribute to the manifestation of clinical AD. We provide evidence from clinico-neuropathologic studies that demonstrates the following: First, those with dementia at postmortem are more likely to have both AD-type and cerebrovascular pathologies. Second, cerebral infarcts are more common than AD-type pathology in those with T2DM and dementia. Finally, cerebral infarcts reduce the number of AD lesions required for the manifestation of clinical dementia, but they do not appear to interact synergistically with AD-type pathology. Conclusions: Therefore, the increased risk of clinically diagnosed AD seems to be mediated through cerebrovascular pathology.