This paper provides an assessment of the associations that weight loss patterns during the first year of an intensive lifestyle intervention have with four year maintenance and health outcomes. Two components described patterns of weight change during the first year of intervention: one reflected the typical pattern of weight loss over the 12 months, but distinguished those who lost larger amounts across the monthly intervals from those who lost less. The second component reflected the weight change trajectory, and distinguished a pattern of initial weight loss followed by regain versus a more sustained pattern of weight loss 2,438 individuals aged 45–76 years with type 2 diabetes mellitus, who enrolled in the weight loss intervention of a randomized clinical trial, were assigned scores according to how their weight losses reflected these patterns. Relationships these scores had with weight losses and health outcomes (glycosolated hemoglobin – HbA1c; systolic blood pressure, HDL-cholesterol, and triglycerides) over four years were described. Both individuals who had larger month-to-month weight losses in year 1 and whose weight loss was more sustained during the first year had better maintenance of weight loss over four years, independent of characteristics traditionally linked to weight loss success (p<0.001). While relationships with year 4 weight loss were stronger, the pattern of larger monthly weight loss during year 1 was also independently predictive of year 4 levels of HbA1c, HDL-cholesterol, and systolic blood pressure.
weight loss; type 2 diabetes mellitus; principal components analysis
While the gold standard method of cognitive assessment is a face-to-face administration, telephone-based assessments offer several advantages if they demonstrate reliability and validity.
Observational study; 110 participants randomly assigned to receive two administrations of the same cognitive test battery 6 months apart in one of four combinations (1st administration/2nd administration): telephone/telephone; telephone/face-to-face; face-to-face/telephone; or face-to-face/face-to-face.
Academic medical center
110 non-demented women between the ages of 65 and 90 years.
The battery included tests of attention, verbal learning and memory, verbal fluency, executive function, working memory and global cognitive functioning plus self-report measures of perceived memory problems, depressive symptoms, sleep disturbance and health-related quality of life. Test-retest reliability, concurrent validity, relative bias associated with telephone administration, and change scores were evaluated.
There were no statistically significant differences in scores on any of the cognitive tests or questionnaires between randomly assigned modes of administration at baseline indicating equivalence across modes. There was no significant bias for tests or questionnaires administered by telephone (ps>0.01). Nor was there a difference in mean change scores between administration modes except for the Category Fluency (p = 0.01) and the California Verbal Learning Test long delay-free recall (p < 0.01). Mean test-retest coefficients for the battery were not significantly different across groups though individual test-retest correlation coefficients were generally higher within mode than across mode.
Telephone administration of cognitive tests and questionnaires to older women is both reliable and valid. Use of telephone batteries can substantially reduce the economic cost and burden of cognitive assessments and increase enrollment, retention and data completeness thereby improving study validity.
cognition; assessment; telephone; validation; tests
Weight gain during young adulthood is common and is associated with increased cardiovascular risk. Preventing this weight gain from occurring may be critical to improving long-term health. Few studies have focused on weight gain prevention, and these studies have had limited success. SNAP (Study of Novel Approaches to Weight Gain Prevention) is an NIH-funded randomized clinical trial examining the efficacy of two novel self-regulation approaches to weight gain prevention in young adults compared to a minimal treatment control. The interventions focus on either small, consistent changes in eating and exercise behaviors, or larger, periodic changes to buffer against expected weight gains.
SNAP targets recruitment of six hundred young adults (18–35 years) with a body mass index between 21.0-30.0 kg/m2, who will be randomly assigned with equal probability to: (1) minimal intervention control; (2) self-regulation with Small Changes; or (3) self-regulation with Large Changes. Both interventions receive 8 weekly face-to-face group sessions, followed by 2 monthly sessions, with two 4-week refresher courses in each of subsequent years. Participants are instructed to report weight via web at least monthly thereafter, and receive monthly email feedback. Participants in Small Changes are taught to make small daily changes (~100 calorie changes) in how much or what they eat and to accumulate 2000 additional steps per day. Participants in Large Changes are taught to create a weight loss buffer of 5–10 pounds once per year to protect against anticipated weight gains. Both groups are encouraged to self-weigh daily and taught a self-regulation color zone system that specifies action depending on weight gain prevention success. Individualized treatment contact is offered to participants who report weight gains. Participants are assessed at baseline, 4 months, and then annually. The primary outcome is weight gain over an average of 3 years of follow-up; secondary outcomes include diet and physical activity behaviors, psychosocial measures, and cardiovascular disease risk factors.
SNAP is unique in its focus on weight gain prevention in young adulthood. The trial will provide important information about whether either or both of these novel interventions are effective in preventing weight gain.
Weight gain prevention; Young adults; Obesity; Self-regulation; Self-weighing
Muscle weakness and obesity are two significant threats to mobility facing the increasing number of older adults. To date, there are no studies that have examined the association of strength and body mass index (BMI) on event rates on a widely used performance measure of major mobility disability.
This study was a secondary analysis of a randomized controlled trial in which sedentary functionally limited participants (70–89 years, Short Physical Performance Battery ≤ 9) who were able to complete a 400-m walk test at baseline were randomized to a physical activity or health education intervention and reassessed for major mobility disability every 6 months for up to 18 months. We evaluated whether baseline grip strength and BMI predicted failure to complete the 400-m walk test in 15 minutes or less (major mobility disability).
Among N = 406 participants with baseline measures, lower grip strength was associated with an increased risk for developing major mobility disability, with and without covariate adjustment (p < .01): The hazard ratio (95% confidence interval) for the lowest versus high sex-specific quartile of grip strength was 6.11 (2.24–16.66). We observed a U-shaped relationship between baseline BMI and the risk of developing major mobility disability, such that the risk for participants with a BMI of 25–29 kg/m2 was approximately half that of participants with BMI less than 25 or 30 kg/m2 or more (p = .04 in fully adjusted analyses).
Our data highlight the importance of muscle weakness, low BMI, and obesity as risk factors for major mobility disability in older adults. Being overweight may be protective for major mobility disability.
Physical disability; Physical activity; Older adults
Look AHEAD is a randomized trial determining whether intensive lifestyle intervention (ILI) aimed at long-term weight loss and increased physical fitness reduces cardiovascular morbidity and mortality in overweight and obese individuals with type 2 diabetes compared to control (diabetes support and education, DSE). We investigated the correlates of NT-proBNP, a biomarker associated with heart failure risk, in a subsample from 15 of 16 participating centers and tested the hypothesis that ILI decreased NT-proBNP levels. Baseline and one-year blood samples were assayed for NT-proBNP in a random sample of 1500 without, and all 628 with, self-reported baseline CVD (N=2128). Linear models were used to assess relationships that logtransformed NT-proBNP had with CVD risk factors at baseline and that 1-year changes in NT-proBNP had with intervention assignment. At baseline, the mean (SD) age, BMI, and hemoglobin A1c were 59.6 (6.8) years, 36.0 kg/m2 (5.8), and 7.2% (1.1), respectively. Baseline geometric mean NT-proBNP was not different by condition (ILI 53.3 vs DSE 51.5, p=0.45), was not associated with BMI, and was inversely associated with hemoglobin A1c. At 1 year, ILI participants achieved an average weight loss of 8.3% compared to 0.7% in DSE. At 1 year, NT-proBNP levels increased to a greater extent in the intervention arm (ILI +21.3% vs. DSE +14.2%, p=0.046). The increased NT-proBNP associated with ILI was correlated with changes in A1c, BMI, and body composition. In conclusion, among overweight and obese persons with diabetes, an intensive lifestyle intervention that reduced weight was associated with an increased NT-proBNP.
natriuretic peptides; diabetes mellitus; obesity
We sought to determine if type 2 diabetes mellitus (T2DM) was associated with accelerated decline in domain-specific measures of cognitive function and fine motor speed.
Women aged 65–80 years who were enrolled in a clinical trial of postmenopausal hormone therapy were grouped as having T2DM (n=179) or not (n=1984) and followed for an average of 5 years with annual standardized assessments of domain-specific cognitive function. Mean patterns of cognitive measures over time were contrasted between groups using general linear models and Wald tests, with varying levels of covariate adjustment. The influences of age at onset, use of oral medications, and use of insulin were also examined.
T2DM was associated with mean deficits of 0.2–0.4 standard deviations (SD) across follow-up in most cognitive domains. Consistent evidence that rates of decline were accelerated among women with T2DM was evident only for verbal knowledge and verbal memory (p<0.05). Decrements in fine motor speed, but no measure of cognitive function, were greater for women with earlier onset T2DM. Use of oral diabetes medications was associated with better relative cognitive function.
In these women, T2DM was associated with cognitive deficits in most domains. Relative deficits in verbal knowledge and verbal memory may continue to increase after deficits in other domains have stabilized. Relative deficits in fine motor speed may be greater among women with earlier onsets of T2DM. Use of insulin, which may reflect greater T2DM severity, was associated with relatively greater cognitive deficits.
Although studies exploring relationships between obesity and cognitive impairment in the elderly are conflicting, literature suggests that overweight and obesity may be protective against cognitive impairment and dementia in older women. We examine the associations between changes in weight and waist circumference with global and domain-specific cognitive function in a large, well-defined cohort of 2283 older, post-menopausal women (age 65-79) prospectively followed through the Women's Health Initiative (WHI) Study of Cognitive Aging (WHISCA). We assessed the associations between changes in weight and waist circumference collected up to 5 years prior to WHISCA enrollment and mean levels of global and domain-specific cognitive performance across an average of 5.4 years of subsequent follow-up. There was a lack of associations between weight and cognition in women who remained stable or gained weight. The only significant relationships observed were in association with weight loss (p≤0.05), most likely signaling incipient disease. Moreover, cognition was not related to changes in waist circumference. Relationships were largely independent of initial BMI, self-reported caloric intake or dieting. The lack of associations between weight gain and cognition in women is consistent with the existent literature.
Late-life depressive symptoms (DS) increase the risk of incident mild cognitive impairment and probable dementia in the elderly. Our objectives were to examine the relationship between elevated DS and regional brain volumes including frontal lobe subregions, hippocampus and amygdala, and to determine whether elevated DS were associated with increased subclinical cerebrovascular disease in postmenopausal women.
DS were assessed an average of 8 years prior to structural brain MRI in 1372 women. The 8-item Burnam regression algorithm was used to define DS with a cut-point of 0.009. Adjusting for potential confounders, mean differences in total brain, frontal lobe subregions, hippocampus and amygdala volumes and total ischemic lesion volumes in the basal ganglia and the cerebral white and gray matter outside the basal ganglia were compared between women with and without DS.
Depressed women had lower baseline global cognition and were more likely to have prior hormone therapy history. After full adjustment, DS at baseline were associated with smaller superior and middle frontal gyral volumes. Hippocampal and amygdala volumes, and ischemic lesion volumes were similar in depressed and non-depressed women.
Depression was not assessed based on semi-structured interview, and we were unable to determine the temporal relationships between DS and frontal lobe volume differences due to the availability of only one MRI scan.
Elevated DS were associated with lower volumes in certain frontal lobe subregions but not in the medial temporal lobe structures. Our findings support the role of frontal lobe structures in late-life DS among women.
Late-life Depression; regional brain volumes; subclinical cerebrovascular disease; structural magnetic resonance imaging
Comparing findings from separate trials is necessary to choose among treatment options, however differences among study cohorts may impede these comparisons.
As a case study, to examine the overlap of study cohorts in two large randomized controlled clinical trials that assess interventions to reduce risk of major cardiovascular disease events in adults with type 2 diabetes in order to explore the feasibility of cross-trial comparisons
The Action for Health in Diabetes (Look AHEAD) and The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trials enrolled 5,145 and 10,251 adults with type 2 diabetes, respectively. Look AHEAD assesses the efficacy of an intensive lifestyle intervention designed to produce weight loss; ACCORD tests pharmacological therapies for control of glycemia, hyperlipidemia, and hypertension. Incidence of major cardiovascular disease events is the primary outcome for both trials. A sample was constructed to include participants from each trial who appeared to meet eligibility criteria and be appropriate candidates for the other trial’s interventions. Demographic characteristics, health status, and outcomes of members and non-members of this constructed sample were compared.
Nearly 80% of Look AHEAD participants were projected to be ineligible for ACCORD; ineligibility was primarily due to better glycemic control or no early history of cardiovascular disease. Approximately 30% of ACCORD participants were projected to be ineligible for Look AHEAD, often for reasons linked to poorer health. The characteristics of participants projected to be jointly eligible for both trials continued to reflect differences between trials according to factors likely linked to retention, adherence, and study outcomes.
Accurate ascertainment of cross-trial eligibility was hampered by differences between protocols.
Despite several similarities, the Look AHEAD and ACCORD cohorts represent distinct populations. Even within the subsets of participants who appear to be eligible and appropriate candidates for trials of both modes of intervention, differences remained. Direct comparisons of results from separate trials of lifestyle and pharmacologic interventions are compromised by marked differences in enrolled cohorts.
Randomized clinical trials; Cross-trial comparisons; Type 2 diabetes
As the number of older adults in the United States rises, maintaining functional independence among older Americans has emerged as a major clinical and public health priority. Older people who lose mobility are less likely to remain in the community; demonstrate higher rates of morbidity, mortality, and hospitalizations; and experience a poorer quality of life. Several studies have shown that regular physical activity improves functional limitations and intermediate functional outcomes, but definitive evidence showing that major mobility disability can be prevented is lacking. A Phase 3 randomized controlled trial is needed to fill this evidence gap.
The Lifestyle Interventions and Independence for Elders (LIFE) Study is a Phase 3 multicenter randomized controlled trial designed to compare a supervised moderate-intensity physical activity program with a successful aging health education program in 1,600 sedentary older persons followed for an average of 2.7 years.
LIFE's primary outcome is major mobility disability, defined as the inability to walk 400 m. Secondary outcomes include cognitive function, serious fall injuries, persistent mobility disability, the combined outcome of major mobility disability or death, disability in activities of daily living, and cost-effectiveness.
Results of this study are expected to have important public health implications for the large and growing population of older sedentary men and women.
Disability; Physical activity; Exercise; Geriatrics; Physical function
To determine if body weight (BMI) is independently associated with cognitive function in postmenopausal women and the relationship between body fat distribution as estimated by waist-hip-ratio (WHR) and cognitive function.
Cross-sectional data analysis
Baseline data from the Women's Health Initiative (WHI) hormone trials.
8745 postmenopausal women aged 65–79 years, free of clinical evidence of dementia and completed baseline evaluation in the Women's Health Initiative (WHI) hormone trials.
Participants completed a Modified Mini-Mental State Examination (3MSE), health and lifestyle questionnaires, and standardized measurements of height, weight, body circumferences and blood pressure. Statistical analysis of associations between 3MSE scores, BMI and WHR after controlling for known confounders.
With the exception of smoking and exercise, vascular disease risk factors, including hypertension, waist measurement, heart disease and diabetes, were significantly associated with 3MSE score and were included as co-variables in subsequent analyses. BMI was inversely related to 3MSE scores, for every 1 unit increase in BMI, 3MSE decrease 0.988 (p=.0001) after adjusting for age, education and vascular disease risk factors. BMI had the most pronounced association with poorer cognitive functioning scores among women with smaller waist measurements. Among women with the highest WHR, cognitive scores increased with BMI.
Increasing BMI is associated with poorer cognitive function in women with smaller WHR. Higher WHR, estimating central fat mass, is associated with higher cognitive function in this cross-sectional study. Further research is needed to clarify the mechanism for this association.
obesity; cognition; dementia; waist-hip ratio; women
Conjugated equine estrogen (CEE) therapies when initiated among older women have been shown to produce small decrements in global cognitive function. We are interested whether these persist after cessation and extend to specific cognitive domains.
Randomized controlled clinical trial
Fourteen clinical centers of the Women's Health Initiative
2,304 women aged 65-80 years and free of probable dementia at enrollment
0.625 mg/day of CEE, with or without medroxyprogesterone acetate (MPA, 10 mg/day), and matching placebos
Annual administrations of a battery of cognitive tests during and following the trial
General linear models were used to compare on-trial and post-trial mean standardized test scores between treatment groups, with adjustment for baseline risk factors for cognitive impairment.
Assignment to CEE-based therapies was associated with small mean relative decrements in global and several domain-specific cognitive functions on-trial, which largely persisted through up to 4 years post-trial. The strongest statistical evidence was for global cognitive function: 0.07 standard deviation decrements both on-trial (p=0.007) and post-trial (p=0.01). Among domain specific scores, the mean relative decrements were slightly smaller, were less significant, and tended to be larger for CEE-alone therapy.
CEE-based therapies, when initiated after age 65 years, produce a small broad-based decrement in cognitive function that persists after their use is stopped. The differences in cognitive function however are small and would not be detectable or have clinical significance for an individual woman. Differences in effects among cognitive domains suggest that more than one mechanism may be involved.
Postmenopausal hormone therapy; Cognitive function; Women's health
The efficacy of non-pharmacological intervention approaches such as physical activity, strength, and cognitive training for improving brain health has not been established. Before definitive trials are mounted, important design questions on participation/adherence, training and interventions effects must be answered to more fully inform a full-scale trial.
SHARP-P was a single-blinded randomized controlled pilot trial of a 4-month physical activity training intervention (PA) and/or cognitive training intervention (CT) in a 2 × 2 factorial design with a health education control condition in 73 community-dwelling persons, aged 70-85 years, who were at risk for cognitive decline but did not have mild cognitive impairment.
Intervention attendance rates were higher in the CT and PACT groups: CT: 96%, PA: 76%, PACT: 90% (p=0.004), the interventions produced marked changes in cognitive and physical performance measures (p≤0.05), and retention rates exceeded 90%. There were no statistically significant differences in 4-month changes in composite scores of cognitive, executive, and episodic memory function among arms. Four-month improvements in the composite measure increased with age among participants assigned to physical activity training but decreased with age for other participants (intervention*age interaction p = 0.01). Depending on the choice of outcome, two-armed full-scale trials may require fewer than 1,000 participants (continuous outcome) or 2,000 participants (categorical outcome).
Good levels of participation, adherence, and retention appear to be achievable for participants through age 85 years. Care should be taken to ensure that an attention control condition does not attenuate intervention effects. Depending on the choice of outcome measures, the necessary sample sizes to conduct four-year trials appear to be feasible.
Clinicaltrials.gov Identifier: NCT00688155
Use of conjugated equine estrogens (CEE) has been linked to smaller regional brain volumes in women aged ≥65 years, however it is unknown whether this results in a broad-based characteristic pattern of effects. Structural MRI was used to assess regional volumes of normal tissue and ischemic lesions among 513 women who had been enrolled in a randomized clinical trial of CEE therapy for an average of 6.6 years, beginning at ages 65-80 years. A multivariate pattern analysis, based on a machine learning technique that combined Random Forest and logistic regression with L1 penalty, was applied to identify patterns among regional volumes associated with therapy and whether patterns discriminate between treatment groups. The multivariate pattern analysis detected smaller regional volumes of normal tissue within the limbic and temporal lobes among women that had been assigned to CEE therapy. Mean decrements ranged as high as 7% in the left entorhinal cortex and 5% in the left perirhinal cortex, which exceeded the effect sizes reported previously in frontal lobe and hippocampus. Overall accuracy of classification based on these patterns, however, was projected to be only 54.5%. Prescription of CEE therapy for an average of 6.6 years is associated with lower regional brain volumes, but it does not induce a characteristic spatial pattern of changes in brain volumes of sufficient magnitude to discriminate users and non-users.
Hormone therapy; MRI; Random Forest; WHIMS
We examined maximal graded exercise test (GXT) results in 5,783 overweight/obese men and women, aged 45–76 years, with type 2 diabetes, who were entering the Look AHEAD (Action for Health in Diabetes) study, to determine the prevalence and correlates of exercise-induced cardiac abnormalities.
RESEARCH DESIGN AND METHODS
Participants underwent symptom-limited maximal GXTs. Questionnaires and physical examinations were used to determine demographic, anthropometric, metabolic, and health status predictors of abnormal GXT results, which were defined as an ST segment depression ≥1.0 mm, ventricular arrhythmia, angina pectoris, poor postexercise heart rate recovery (<22 bpm reduction 2 min after exercise), or maximal exercise capacity less than 5.0 METs. Systolic blood pressure response to exercise was examined as a continuous variable, without a threshold to define abnormality.
Exercise-induced abnormalities were present in 1,303 (22.5%) participants, of which 693 (12.0%) consisted of impaired exercise capacity. ST segment depression occurred in 440 (7.6%), abnormal heart rate recovery in 206 (5.0%), angina in 63 (1.1%), and arrhythmia in 41 (0.7%). Of potential predictors, only greater age was associated with increased prevalence of all abnormalities. Other predictors were associated with some, but not all, abnormalities. Systolic blood pressure response decreased with greater age, duration of diabetes, and history of cardiovascular disease.
We found a high rate of abnormal GXT results despite careful screening for cardiovascular disease symptoms. In this cohort of overweight and obese individuals with type 2 diabetes, greater age most consistently predicted abnormal GXT. Long-term follow-up of these participants will show whether these abnormalities are clinically significant.
Cognitive function and physical performance are associated, but the common sequence of cognitive and physical decline remains unclear.
In the Women’s Health Initiative Memory Study (WHIMS) clinical trial, we examined associations at baseline and over a 6-year follow-up period between the Modified Mini-Mental State (3MS) Examination and three physical performance measures (PPMs): gait speed (meters/second), chair stands (number of stands in 15 seconds), and grip strength (kilograms). Using mixed models, we examined the baseline 3MS as predictor of change in PPM, change in the 3MS as predictor of change in PPM, and baseline PPM as predictors of 3MS change.
Among 1,793 women (mean age = 70.3 years, 89% white, and mean 3MS score = 95.1), PPM were weakly correlated with 3MS—gait speed: r = .06, p = .02; chair stands: r = .09, p < .001; and grip strength: r = .10, p < .001. Baseline 3MS score was associated with subsequent PPM decline after adjustment for demographics, comorbid conditions, medications, and lifestyle factors. For every SD (4.2 points) higher 3MS score, 0.04 SD (0.04 m/s) less gait speed and 0.05 SD (0.29 kg) less grip strength decline is expected over 6 years (p ≤ .01 both). Changes in 3MS and PPM were associated, particularly with chair stands and grip strength (p < .003 both). Baseline PPMs were not associated with subsequent 3MS change.
Baseline global cognitive function and change in global cognitive function were associated with physical performance change, but baseline physical performance was not associated with cognitive change in this cohort. These analyses support the hypothesis that cognitive decline on average precedes or co-occurs with physical performance decline.
Cognitive function; Physical performance; Cognition; Physical function
To compare the relative effects of conjugated equine estrogens (CEE), raloxifene, and tamoxifen therapies on cognition among women aged ≥65 years.
Annual Modified Mini-Mental State (3MS) examinations were used to assess global cognitive function in the two randomized placebo-controlled clinical trials of CEE therapies of the Women's Health Initiative Memory Study (WHIMS) and the Cognition in the Study of Tamoxifen and Raloxifene (CoSTAR). Analyses were limited to women who had 3MS testing at baseline and the first 3 years of follow-up and, because of potential ethnic-related differences between studies, to Caucasian women (WHIMS n = 6211, CoSTAR n = 250). Covariate adjustment was used to compare the postrandomization mean 3MS scores among the three active therapies with placebo therapy while controlling for differences between groups with respect to dementia risk factors.
At baseline, the average (SD) 3MS scores by group were 95.24 (4.28) for placebo, 95.19 (4.33) for CEE, 94.60 (4.76) for raloxifene, and 95.02 (4.03) for tamoxifen. Compared with placebo, each active therapy was associated with a small mean relative deficit in 3MS scores of ≤0.5 units, which was fairly consistent between women with and without prior hysterectomy. Relative deficits were slightly greater for tamoxifen (p = 0.001) and less marked for raloxifene (p = 0.06) and CEE (p = 0.02) therapies. Relative deficits appeared to be greater among women with lower baseline 3MS scores: p = 0.009 (tamoxifen), p = 0.08 (raloxifene), and p = 0.03 (CEE).
Although unmeasured differences between trials may have confounded analyses, these findings raise the possibility that both tamoxifen and raloxifene adversely affect cognitive function in older women; however, the magnitude of the effect is small, and the long-term consequences are unknown.
Although the Diabetes Prevention Program (DPP) developed a lifestyle weight loss intervention that has been demonstrated to prevent type 2 diabetes in high-risk individuals, it has yet to be widely adopted at the community level. The Healthy Living Partnership to Prevent Diabetes study (HELP PD) was designed to translate the DPP approach for use in community settings as a cost-effective intervention led by Community Health Workers (CHW's) and administered through a Diabetes Care Center (DCC). Approximately 300 overweight and obese (BMI 25-40 kg/m2) individuals with prediabetes (fasting blood glucose 95-124 mg/dl) were randomly assigned to either a lifestyle weight loss intervention (LW) or an enhanced usual care comparison condition (UC). The goal of LW is ≥7% weight loss achieved through increases in physical activity (180 min/wk) and decreases in caloric intake (approximately 1500 kcal/day). The intervention consists of CHW-led group-mediated cognitive behavioral meetings that occur weekly for 6 months and monthly thereafter for 18 months. UC consists of 2 individual meetings with a registered dietitian and a monthly newsletter. The primary outcome is change in fasting blood glucose. Secondary outcomes include cardiovascular risk factors, health-related quality of life, and social cognitive variables. Outcomes are masked and are collected every 6 months. The cost-effectiveness of the program will also be assessed. A community-based program that is administered through local DCC's and that harnesses the experience of community members (CHW's) may be a promising strategy for the widespread dissemination of interventions effective at preventing type 2 diabetes in high risk individuals.
translational research; randomized controlled trial; weight loss; prevention; type 2 diabetes; obesity
Both the prevalence and extent of brain magnetic resonance imaging (MRI) abnormalities are related to risk factors for dementia. Typically these associations have been explored separately, but an integrated modeling approach would allow the separate relationships to be consistently described and contrasted.
Region-specific measures of ischemic lesion volumes were obtained from standardized brain MRI from 1,403 women enrolled in the Women's Health Initiative hormone therapy trials. Mixed-effects mixed-distribution models were fitted to explore jointly the relationships that the region-specific prevalence of ischemic lesions and region-specific ischemic lesion volumes had with risk factors and scores from tests of cognitive function.
Women with greater probabilities (prevalence) of having ischemic lesions in brain regions also tended to have larger volumes (extent) of ischemic lesions within the affected regions (p < 0.001). Across the 5 regions included in analyses (frontal, limbic, occipital, parietal and temporal), prevalence and extent varied (p < 0.001). Each was increased among women who were older, had hypertension or who had previously been classified as cognitively impaired (p < 0.01). Additionally, extent was significantly increased among women with a history of smoking (p = 0.02). Cognitive function tests were more strongly related to the extent than prevalence of ischemic lesions and relationships varied among cognitive domains (p < 0.001).
Mixed-effects mixed-distribution models provide a coherent basis for examining relationships involving the prevalence and extent of ischemic brain lesions. Across the cohort and regions we examined, relationships with risk factors and cognitive function appeared to be stronger for extent than for prevalence.
Statistical methods; Brain magnetic resonance imaging; Cognition; Women's health
In this work we use a large scale regularization approach based on penalized logistic regression to automatically classify structural MRI images (sMRI) according to cognitive status. Its performance is illustrated using sMRI data from the Alzheimer Disease Neuroimaging Initiative (ADNI) clinical database. We downloaded sMRI data from 98 subjects (49 cognitive normal and 49 patients) matched by age and sex from the ADNI website. Images were segmented and normalized using SPM8 and ANTS software packages. Classification was performed using GLMNET library implementation of penalized logistic regression based on coordinate-wise descent optimization techniques. To avoid optimistic estimates classification accuracy, sensitivity, and specificity were determined based on a combination of three-way split of the data with nested 10-fold cross-validations. One of the main features of this approach is that classification is performed based on large scale regularization. The methodology presented here was highly accurate, sensitive, and specific when automatically classifying sMRI images of cognitive normal subjects and Alzheimer disease (AD) patients. Higher levels of accuracy, sensitivity, and specificity were achieved for gray matter (GM) volume maps (85.7, 82.9, and 90%, respectively) compared to white matter volume maps (81.1, 80.6, and 82.5%, respectively). We found that GM and white matter tissues carry useful information for discriminating patients from cognitive normal subjects using sMRI brain data. Although we have demonstrated the efficacy of this voxel-wise classification method in discriminating cognitive normal subjects from AD patients, in principle it could be applied to any clinical population.
high dimensional; large scale regularization; logistic regression; GLMNET; ADNI; curse of dimensionality; elastic net
Postmenopausal conjugated equine estrogens (CEE) therapies increase the risk of cognitive impairment in women aged 65 years or older and are associated with smaller regional brain volumes; however, the link between these two phenomena has not been established.
Standardized magnetic resonance imaging was performed on 1,403 women, 1–4 years after they had participated in randomized placebo-controlled clinical trials of CEE-based therapies. Women included in this report were aged 65–80 years and free of dementia and mild cognitive impairment (MCI) when originally enrolled in the trials, which lasted an average of 4–6 years and were conducted at 14 academic U.S. medical centers. The associations that regional brain volumes and ischemic lesion volumes had with the development of cognitive impairment (i.e., dementia or MCI) were contrasted between treatment groups using analyses of covariance.
Fifty-three women developed MCI or probable dementia during follow-up. Among women who had been prescribed CEE-based therapies, cognitive impairment was associated with relatively smaller hippocampal (p = .0002) and total brain volumes (p = .03). Qualitatively, these associations appeared to be independent of their level of pretreatment cognitive function. Among women who had been prescribed placebo, these relationships were not evident; instead, cognitive impairment was associated with greater ischemic lesion volume in the frontal lobe (p = .007) and overall (p = .02).
A mechanism by which CEE-based postmenopausal hormone therapy induces cognitive impairment appears to be through increased brain atrophy.
Hormone therapy; Magnetic resonance imaging; Women's health
To demonstrate how principal components analysis can be used to describe patterns of weight changes in response to an intensive lifestyle intervention
Principal components analysis was applied to monthly percent weight changes measured on 2,485 individuals enrolled in the lifestyle arm of the Action for Health in Diabetes (Look AHEAD) clinical trial. These individuals were 45–75 years of age, with Type 2 diabetes and body mass indices >25 kg/m2. Associations between baseline characteristics and weight loss patterns were described using analyses of variance.
Three components collectively accounted for 97.0% of total intra-subject variance: a gradually decelerating weight loss (88.8%), early versus late weight loss (6.6%), and a mid-year trough (1.6%). In agreement with previous reports, each of the baseline characteristics we examined had statistically significant relationships with weight loss patterns. As examples, males tended to have a steeper trajectory of percent weight loss and to lose weight more quickly than women. Individuals with higher HbA1c tended to have a flatter trajectory of percent weight loss and to have mid-year troughs in weight loss compared to those with lower HbA1c.
Principal components analysis provided a coherent description of characteristic patterns of weight changes and is a useful vehicle for identifying their correlates and potentially for predicting weight control outcomes.
Principal components analysis; intervention studies; weight loss
To determine the prevalence and risk factors for urinary incontinence among different racial/ethnic groups of overweight and obese women with type 2 diabetes.
RESEARCH DESIGN AND METHODS
Cross-sectional analysis of baseline data from the Action for Health in Diabetes (Look AHEAD) study, a randomized clinical trial with 2,994 overweight/obese women with type 2 diabetes.
Weekly incontinence (27%) was reported more often than other diabetes-associated complications, including retinopathy (7.5%), microalbuminuria (2.2%), and neuropathy (1.5%). The prevalence of weekly incontinence was highest among non-Hispanic whites (32%) and lowest among African Americans (18%), and Asians (12%) (P < 0.001). Asian and African American women had lower odds of weekly incontinence compared with non-Hispanic whites (75 and 55% lower, respectively; P < 0.001). Women with a BMI of ≥35 kg/m2 had a higher odds of overall and stress incontinence (55–85% higher; P < 0.03) compared with that for nonobese women. Risk factors for overall incontinence, as well as for stress and urgency incontinence, included prior hysterectomy (40–80% increased risk; P < 0.01) and urinary tract infection in the prior year (55–90% increased risk; P < 0.001).
Among overweight and obese women with type 2 diabetes, urinary incontinence is highly prevalent and far exceeds the prevalence of other diabetes complications. Racial/ethnic differences in incontinence prevalence are similar to those in women without diabetes, affecting non-Hispanic whites more than Asians and African Americans. Increasing obesity (BMI ≥35 kg/m2) was the strongest modifiable risk factor for overall incontinence and stress incontinence in this diverse cohort.
Cognitive impairment is an important contributor to disability. Limited clinical trial evidence exists regarding the impact of physical exercise on cognitive function (CF). We report results of a pilot study to provide estimates of the relative impact of physical activity (PA) on 1-year changes in cognitive outcomes and to characterize relationships between changes in mobility disability and changes in cognition in older adults at increased risk for disability.
Sedentary persons (102) at increased risk for disability (aged 70–89 years) were randomized to moderate-intensity PA or health education. Participants were administered the Digit Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), modified Stroop test, and Modified Mini-Mental State Examination at baseline and 1 year.
Group differences were not significant but improvements in cognitive scores were associated with improvements in physical function. Specifically, the DSST significantly correlated with change in the Short Physical Performance Battery score (r = .38, p = .0002), in chair stand score (r = .26, p = .012), in balance score (r = .21, p = .046), and in 400-m gait speed (r = .15, p = .147). Change recall on the RAVLT and in the Stroop test was also positively correlated with changes in chair stand and balance, respectively.
These results provide further support for the benefits of exercise on CF in older adults. An adequately powered clinical trial of PA involving older adults at increased risk for cognitive disability is needed to expand the indications for prescribing exercise for prevention of decline in brain function.
Exercise; Cognition; Aging; Prevention; LIFE study
It is well recognized that physical activity (PA) is important for older adults; yet, clinicians remain pessimistic about the ability of older adults with compromised function to adhere to long-term treatment and to maintain behavior change once treatment has been terminated.
We examined the functional status of older adults at a field center (Wake Forest University) 2 years after completing 12 months of treatment in the Lifestyle Interventions and Independence for Elders Pilot study. At baseline, participants were randomized to either a PA or a successful aging (SA) control group. Outcome measures included an interview assessment of PA, the Short Physical Performance Battery (SPPB), and performance on a 400-m self-paced walking test.
Two years after the formal intervention had ended, participants who were originally in the PA group continued to engage in more minutes of moderate PA and tended to have better SPPB and walking speed than those in the SA group (effect sizes [ES]: SPPB = 0.40, walking speed = 0.37). Seven (12.7%) participants in the PA group failed the 400-m walk at the 36-month follow-up assessment, whereas this number was 11 (21.6%) in the SA group.
Older adults who have compromised physical function are able to sustain some of the benefits derived from participating in structured PA 2 years after supervised treatment has been terminated.
Aging; Disability; Mobility; SPPB; 400-m walk