Recruitment methods and yield rates for a multisite clinical trial exploring risk reduction for Alzheimer\u27s disease (rrAD)

INTRODUCTION: The risk reduction for Alzheimer\u27s disease (rrAD) trial was a multisite clinical trial to assess exercise and intensive vascular pharmacological treatment on cognitive function in community-dwelling older adults at increased risk for Alzheimer\u27s disease. METHODS: Eligibility, consent, and randomization rates across different referral sources were compared. Informal interviews conducted with each site\u27s project team were conducted upon study completion. RESULTS: Initially, 3290 individuals were screened, of whom 28% were eligible to consent, 805 consented to participate (87.2% of those eligible), and 513 (36.3% of those consented) were randomized. Emails sent from study site listservs/databases yielded the highest amount (20.9%) of screened individuals. Professional referrals from physicians yielded the greatest percentage of consented individuals (57.1%). Referrals from non-professional contacts (ie, friends, family; 75%) and mail/phone contact from a site (73.8%) had the highest yield of randomization. DISCUSSION: Professional referrals or email from listservs/registries were most effective for enrolling participants. The greatest yield of eligible/randomized participants came from non-professional and mail/phone contacts. Future trials should consider special efforts targeting these recruitment approaches. HIGHLIGHTS: Clinical trial recruitment is commonly cited as a significant barrier to advancing our understanding of cognitive health interventions.The most cited referral source was email, followed by interviews/editorials on the radio, television, local newspapers, newsletters, or magazine articles.The referral method that brought in the largest number of contacts was email but did not result in the greatest yield of consents or eligible participants.The sources that yielded the greatest likelihood of consent were professional referrals (ie, physician), social media, and mail/phone contact from study site.The greatest yield of eligible/randomized participants came from non-professional contacts and mail/phone contact from a site.Findings suggest that sites may need to focus on more selective referral sources, such as using contact mailing and phone lists, rather than more widely viewed recruitment sources, such as social media or TV/radio advertisements

Indirect and direct relations between aerobic fitness, physical activity, and academic achievement in elementary school students

BACKGROUND: There is evidence to suggest that increasing physical activity (PA) improves academic achievement (AA) in children and that aerobic fitness is associated with both cognitive function and AA. However, it is not known how these variables are interrelated and analyses with adequate control for socioeconomic variables are needed. It was hypothesized that PA would not directly affect AA but would have an indirect effect on AA through its effect on aerobic fitness. The purpose of this study was to test this hypothesized mediation using path analysis. METHODS: Cross-sectional data including AA, aerobic fitness, and daily PA assessed through accelerometry were collected from a large sample (N = 687) of 2nd and 3rd grade students. Demographic data were assessed via parent self-report. RESULTS: A total of 401 students wore the accelerometer for at least 10 hours on 3 days or more and were included in the final path analysis to evaluate potential relations among PA (predictor), aerobic fitness (mediator), and WIAT-III subtest standard scores (outcomes; i.e., reading, spelling, and mathematics). Findings showed a direct effect of PA on aerobic fitness (b = 0.009, p < 0.001) and an indirect effect (mediation) of PA via fitness on math achievement (b = 0.003, p < 0.01) after controlling for student’s grade, gender, body mass index, mother’s education level, and household income, as well as intraclass correlations among classes and schools. Neither PA nor aerobic fitness were correlated with WIAT-III reading or spelling scores. CONCLUSIONS: Mediation analysis indicated that PA exerted an influence on math achievement through its effects on aerobic fitness but was not associated with reading or spelling achievement scores

Pre–post intervention exploring cognitive function and relationships with weight loss, intervention adherence and dropout

Objective: To evaluate the association between baseline cognitive function, intervention dropout, adherence and 3-month weight loss (WL) when controlling for confounding demographic variables. Methods: 107 (Mage = 40.9 yrs.), BMI in the overweight and obese range (BMI = 35.6 kg/m2), men (N = 17) and women (N = 90) completed a 3-month WL intervention. Participants attended weekly behavioral sessions, comply with a reduced calorie diet, and complete 100 min of physical activity (PA)/wk. Cognitive function tasks at baseline included Flanker (attention), Stroop (executive control) and working memory, demographics, body weight and cardiovascular fitness were assessed at baseline. Session attendance, adherence to PA and diet were recorded weekly. Results: Baseline attention was positively correlated with age (p \u3c .05), education (p \u3c .05), attendance (p \u3c .05), diet (p \u3c .05) and PA (p \u3c .05). Baseline executive control (p \u3c .05) and working memory (p \u3c .05) were each associated with % WL. Baseline executive control (p \u3c .01) and working memory (p \u3c .001) were also each associated with education. ANOVA indicated that baseline attention (p \u3c .01) was associated with WL, specifically for comparing those who achieved 5–10% WL (p \u3c .01) and those who achieved greater than 10% WL (p \u3c .01) to those who dropped. Significance: Results suggest that stronger baseline attention is associated with completion of a 3-mo. WL intervention. Executive control and working memory are associated with amount of WL achieved. NCT registration: US NIH Clinical Trials, NCT0166471

The Midwest Exercise Trial for the Prevention of Weight Regain: MET POWeR

Weight reduction in overweight and obese individual’s results in physiological and behavioral changes that make the prevention of weight regain more difficult than either initial weight loss or the prevention of weight gain. Exercise is recommended for the prevention of weight regain by both governmental agencies and professional organizations. To date, the effectiveness of exercise recommendations for the prevention of weight regain has not been evaluated in a properly designed, adequately powered trial. Therefore, we will conduct a randomized trial to evaluate the effectiveness of 3 levels of exercise on the prevention of weight regain, in initially overweight and obese sedentary men and women. Participants will complete a 3 month weight loss intervention of decreased energy intake (EI) and increased exercise (100 minutes/week). Participants achieving clinically significant weight loss (≥ 5% of initial weight), will then be randomly assigned to 12 months of verified exercise at 3 levels (150, 225 or 300 minutes/week). This study will evaluate: 1) the effectiveness of 3 levels of exercise on the prevention of weight regain over 12 months subsequent to clinically significant weight loss (≥ 5%); 2) gender differences in weight regain in response to 3 levels of exercise; and 3) potential compensatory changes in daily physical activity (PA) and EI on weight regain in response to 3 levels of exercise. Results of this investigation will provide information to develop evidenced based recommendations for the level of exercise associated with the prevention of weight regain

Voxel-Based Morphometry Reveals Brain Gray Matter Volume Changes in Successful Dieters

Objective: To compare regional brain volume predictors of percent weight loss (WL) in dieters with obesity (DwO) and in the same participants categorized as “successful” (≥7% WL) or “unsuccessful” dieters

Measuring enjoyment of physical activity in older adults: invariance of the physical activity enjoyment scale (paces) across groups and time

The purpose of this study was to validate the Physical Activity Enjoyment Scale (PACES) in a sample of older adults. Participants within two different exercise groups were assessed at two time points, 6 months apart. Group and longitudinal invariance was established for a novel, 8-item version of the PACES. The shortened, psychometrically sound measure provides researchers and practitioners an expedited and reliable instrument for assessing the enjoyment of physical activity

Rationale and Methods for a Multicenter Clinical Trial Assessing Exercise and Intensive Vascular Risk Reduction in Preventing Dementia (rrAD Study)

Alzheimer\u27s Disease (AD) is an age-related disease with modifiable risk factors such as hypertension, hypercholesterolemia, obesity, and physical inactivity influencing the onset and progression. There is however, no direct evidence that reducing these risk factors prevents or slows AD. The Risk Reduction for Alzheimer\u27s Disease (rrAD) trial is designed to study the independent and combined effects of intensive pharmacological control of blood pressure and cholesterol and exercise training on neurocognitive function. Six hundred and forty cognitively normal older adults age 60 to 85 years with hypertension and increased risk for dementia will be enrolled. Participants are randomized into one of four intervention group for two years: usual care, Intensive Reduction of Vascular Risk factors (IRVR) with blood pressure and cholesterol reduction, exercise training (EX), and IRVR+EX. Neurocognitive function is measured at baseline, 6, 12, 18, and 24 months; brain MRIs are obtained at baseline and 24 months. We hypothesize that both IRVR and EX will improve global cognitive function, while IRVR+EX will provide a greater benefit than either IRVR or EX alone. We also hypothesize that IRVR and EX will slow brain atrophy, improve brain structural and functional connectivity, and improve brain perfusion. Finally, we will explore the mechanisms by which study interventions impact neurocognition and brain. If rrAD interventions are shown to be safe, practical, and successful, our study will have a significant impact on reducing the risks of AD in older adults. NCT Registration: NCT02913664

Beyond vascularization: aerobic fitness is associated with N-acetylaspartate and working memory

Aerobic exercise is a promising form of prevention for cognitive decline; however, little is known about the molecular mechanisms by which exercise and fitness impacts the human brain. Several studies have postulated that increased regional brain volume and function are associated with aerobic fitness because of increased vascularization rather than increased neural tissue per se. We tested this position by examining the relationship between cardiorespiratory fitness and N-acetylaspartate (NAA) levels in the right frontal cortex using magnetic resonance spectroscopy. NAA is a nervous system specific metabolite found predominantly in cell bodies of neurons. We reasoned that if aerobic fitness was predominantly influencing the vasculature of the brain, then NAA levels should not vary as a function of aerobic fitness. However, if aerobic fitness influences the number or viability of neurons, then higher aerobic fitness levels might be associated with greater concentrations of NAA. We examined NAA levels, aerobic fitness, and cognitive performance in 137 older adults without cognitive impairment. Consistent with the latter hypothesis, we found that higher aerobic fitness levels offset an age-related decline in NAA. Furthermore, NAA mediated an association between fitness and backward digit span performance, suggesting that neuronal viability as measured by NAA is important in understanding fitness-related cognitive enhancement. Since NAA is found exclusively in neural tissue, our results indicate that the effect of fitness on the human brain extends beyond vascularization; aerobic fitness is associated with neuronal viability in the frontal cortex of older adults