PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-13 (13)
 

Clipboard (0)
None

Select a Filter Below

Journals
more »
Year of Publication
Document Types
1.  Validity of Ratings of Perceived Exertion in Patients with Type 2 Diabetes 
Purpose
To examine whether a subjective measure of moderate-intensity exercise (12-13 on Borg’s ratings of perceived exertion scale; RPE) corresponds to the target heart rate for moderate-intensity exercise (40-59% heart rate reserve; %HRR) and to determine the characteristics of those for whom RPE does not appropriately estimate exercise intensity.
Methods
3582 individuals with type 2 diabetes (age: 58.3±6.8 years; BMI: 35.9±5.9 kg/m2) underwent a maximal exercise test and minute-by-minute HR and RPE were recorded. Linear regression was used to determine the %HRR corresponding to an RPE of 12 and 13 for each individual.
Results
At an RPE of 12 or 13, 57% of participants fell within the target 40-59%HRR range, while 37% and 6% fell above and below this range, respectively. Participants with a %HRR ≥60% (above range) were more likely to be female (OR: 1.19; 95% CI: 1.01,1.40), African American (OR: 1.65; 95% CI: 1.35, 2.02) or Hispanic (OR: 1.57; 95% CI: 1.27, 1.95), have a higher BMI (OR: 1.03; 95% CI 1.01, 1.04) and HRmax (OR: 1.02; 95% CI: 1.01, 1.02), and lower fitness (OR: 0.90; 95% CI: 0.85, 0.94) and RPEmax (OR: 0.68; 95% CI: 0.63, 0.73), compared to those within the target 40-59%HRR range (p-values’<0.05).
Conclusions
RPE appropriately gauges exercise intensity in approximately half of overweight individuals with type 2 diabetes; however, more than one-third of participants were at an increased risk of exercising at a higher than prescribed intensity when using RPE. Future studies should continue to examine the characteristics of individuals for whom RPE appropriately estimates exercise intensity and for those whom it does not.
PMCID: PMC4255703  PMID: 25485308
ratings of perceived exertion; exercise; obesity; type 2 diabetes; exercise prescription; diabetes; obesity; ratings of perceived exertion
2.  Impact of Weight Loss on Ankle-Brachial Index and Inter-Artery Blood Pressures in Overweight and Obese Adults with Diabetes 
Obesity (Silver Spring, Md.)  2014;22(4):1032-1041.
Objective
To assess whether weight loss improves markers of peripheral artery disease and vascular stenosis.
Design and Methods
The Action for Health in Diabetes randomized clinical trial compared intensive lifestyle intervention (ILI) for weight loss to a control condition of diabetes support and education (DSE) in overweight or obese adults with type 2 diabetes. Annual ankle and brachial blood pressures over four years were used compute ankle-brachial indices (ABIs) and to assess inter-artery blood pressure differences in 5018 participants.
Results
ILI, compared to DSE, produced 7.8% (Year 1) to 3.6% (Year 4) greater weight losses. These did not affect prevalence of low (<0.90) ABI (3.60% in DSE versus 3.14% in ILI; p=0.20) or elevated (>1.40) ABI (7.52% in DSE versus 7.59% in ILI: p=0.90), but produced smaller mean (SE) maximum inter-artery systolic blood pressure differences among ankle sites [19.7 (0.2) mmHg for ILI versus 20.6 (0.2) mmHg for DSE (p<0.001)] and between arms [5.8 (0.1) mmHg for ILI versus 6.1 (0.1) mmHg for DSE (p=0.01)].
Conclusions
Four years of intensive behavioral weight loss intervention did not significantly alter prevalence of abnormal ABI, however it did reduce differences in systolic blood pressures among arterial sites.
doi:10.1002/oby.20658
PMCID: PMC3968218  PMID: 24174392
Peripheral artery disease; Weight loss; Diabetes
3.  Four-Year Change in Cardiorespiratory Fitness and Influence on Glycemic Control in Adults With Type 2 Diabetes in a Randomized Trial 
Diabetes Care  2013;36(5):1297-1303.
OBJECTIVE
To examine an intensive lifestyle intervention (ILI) compared with diabetes support and education (DSE) on 4-year change in fitness and physical activity (PA), and to examine the effect of change in fitness and PA, adjusting for potential confounders, on glycemic control in the Look AHEAD Trial.
RESEARCH DESIGN AND METHODS
Subjects were overweight/obese adults with type 2 diabetes mellitus (T2DM) with available fitness data at 4 years (n = 3,942).This clinical trial randomized subjects to DSE or ILI. DSE subjects received standard care plus information related to diet, PA, and social support three times per year. ILI subjects received weekly intervention contact for 6 months, which was reduced over the 4-year period, and were prescribed diet and PA. Measures included weight, fitness, PA, and HbA1c.
RESULTS
The difference in percent fitness change between ILI and DSE at 4 years was significant after adjustment for baseline fitness and change in weight (3.70 vs. 0.94%; P < 0.01). At 4 years, PA increased by 348 (1,562) kcal/week in ILI vs. 105 (1,309) kcal/week in DSE (P < 0.01). Fitness change at 4 years was inversely related to change in HbA1c after adjustment for clinical site, treatment, baseline HbA1c, prescribed diabetes medication, baseline fitness, and weight change (P < 0.01). Change in PA was not related to change in HbA1c.
CONCLUSIONS
A 4-year ILI increased fitness and PA in overweight/obese individuals with T2DM. Change in fitness was associated with improvements in glycemic control, which provides support for interventions to improve fitness in adults with T2DM.
doi:10.2337/dc12-0712
PMCID: PMC3631819  PMID: 23223405
4.  Four-Year Analysis of Cardiovascular Disease Risk Factors, Depression Symptoms, and Antidepressant Medicine Use in the Look AHEAD (Action for Health in Diabetes) Clinical Trial of Weight Loss in Diabetes 
Diabetes Care  2013;36(5):1088-1094.
OBJECTIVE
To study the association of depressive symptoms or antidepressant medicine (ADM) use with subsequent cardiovascular disease (CVD) risk factor status in the Look AHEAD (Action for Health in Diabetes) trial of weight loss in type 2 diabetes.
RESEARCH DESIGN AND METHODS
Participants (n = 5,145; age [mean ± SD] 58.7 ± 6.8 years; BMI 35.8 ± 5.8 kg/m2) in two study arms (intensive lifestyle [ILI], diabetes support and education [DSE]) completed the Beck Depression Inventory (BDI), reported ADM use, and were assessed for CVD risk factors at baseline and annually for 4 years. Risk factor–positive status was defined as current smoking, obesity, HbA1c >7.0% or insulin use, and blood pressure or cholesterol not at levels recommended by expert consensus panel or medicine to achieve recommended levels. Generalized estimating equations assessed within-study arm relationships of elevated BDI score (≥11) or ADM use with subsequent year CVD risk status, controlled for demographic variables, CVD history, diabetes duration, and prior CVD risk status.
RESULTS
Prior year elevated BDI was associated with subsequent CVD risk factor–positive status for the DSE arm (A1C [odds ratio 1.30 (95% CI 1.09–1.56)]; total cholesterol [0.80 (0.65–1.00)]; i.e., protective from high total cholesterol) and the ILI arm (HDL [1.40 (1.12–1.75)], triglyceride [1.28 (1.00–1.64)]). Prior year ADM use predicted subsequent elevated CVD risk status for the DSE arm (HDL [1.24 (1.03–1.50)], total cholesterol [1.28 (1.05–1.57)], current smoking [1.73 (1.04–2.88)]) and for the ILI arm (A1C [1.25 (1.08–1.46)], HDL [1.32 (1.11–1.58)], triglycerides [1.75 (1.43–2.14)], systolic blood pressure [1.39 (1.11–1.74)], and obesity [1.46 (1.22–2.18)]).
CONCLUSIONS
Aggressive monitoring of CVD risk in diabetic patients with depressive symptoms or who are treated with ADM may be warranted.
doi:10.2337/dc12-1871
PMCID: PMC3631821  PMID: 23359362
5.  Intraindividual Variability in Domain-Specific Cognition and Risk of Mild Cognitive Impairment and Dementia 
Intraindividual variability among cognitive domains may predict dementia independently of interindividual differences in cognition. A multidomain cognitive battery was administered to 2305 older adult women (mean age 74 years) enrolled in an ancillary study of the Women's Health Initiative. Women were evaluated annually for probable dementia and mild cognitive impairment (MCI) for an average of 5.3 years using a standardized protocol. Proportional hazards regression showed that lower baseline domain-specific cognitive scores significantly predicted MCI (N = 74), probable dementia (N = 45), and MCI or probable dementia combined (N = 101) and that verbal and figural memory predicted each outcome independently of all other cognitive domains. The baseline intraindividual standard deviation across test scores (IAV Cognitive Domains) significantly predicted probable dementia and this effect was attenuated by interindividual differences in verbal episodic memory. Slope increases in IAV Cognitive Domains across measurement occasions (IAV Time) explained additional risk for MCI and MCI or probable dementia, beyond that accounted for by interindividual differences in multiple cognitive measures, but risk for probable dementia was attenuated by mean decreases in verbal episodic memory slope. These findings demonstrate that within-person variability across cognitive domains both at baseline and longitudinally independently accounts for risk of cognitive impairment and dementia in support of the predictive utility of within-person variability.
doi:10.1155/2013/495793
PMCID: PMC3881440  PMID: 24454359
6.  Telephone interview for cognitive status (TICS) screening for clinical trials of physical activity and cognitive training: the seniors health and activity research program pilot (SHARP-P) study† 
International journal of geriatric psychiatry  2011;26(2):10.1002/gps.2503.
Objective:
To examine the performance of the Telephone Interview for Cognitive Status (TICS) for identifying participants appropriate for trials of physical activity and cognitive training interventions.
Methods:
Volunteers (N = 343), ages 70–85 years, who were being recruited for a pilot clinical trial on approaches to prevent cognitive decline, were administered TICS and required to score ≥31 prior to an invitation to attend clinic-based assessments. The frequencies of contraindications for physical activity and cognitive training interventions were tallied for individuals grouped by TICS scores. Relationships between TICS scores and other measures of cognitive function were described by scatterplots and correlation coefficients.
Results:
Eligibility criteria to identify candidates who were appropriate candidates for the trial interventions excluded 51.7% of the volunteers with TICS<31. TICS scores above this range were not strongly related to cognition or attendance at screening visits, however overall enrollment yields were approximately half for participants with TICS = 31 versus TICS = 41, and increased in a graded fashion throughout the range of scores.
Conclusions:
Use of TICS to define eligibility criteria in trials of physical activity and cognitive training interventions may not be worthwhile in that many individuals with low scores would already be eliminated by intervention-specific criteria and the relationship of TICS with clinic-based tests of cognitive function among appropriate candidates for these interventions may be weak. TICS may be most useful in these trials to identify candidates for oversampling in order to obtain a balanced cohort of participants at risk for cognitive decline.
doi:10.1002/gps.2503
PMCID: PMC3832189  PMID: 21229597
clinical trial design; cognitive interventions; eligibility criteria
7.  Lifestyle Intervention Improves Heart Rate Recovery from Exercise in Adults with Type 2 Diabetes: Results from the Look AHEAD Study 
Journal of Obesity  2012;2012:309196.
The primary aims of this paper were (1) to evaluate the influence of intensive lifestyle weight loss and exercise intervention (ILI) compared with diabetes support and education (DSE) upon Heart Rate Recovery (HRR) from graded exercise testing (GXT) and (2) to determine the independent and combined effects of weight loss and fitness changes upon HRR. In 4503 participants (45–76 years) who completed 1 year of intervention, HRR was measured after a submaximal GXT to compare the influence of (ILI) with (DSE) upon HRR. Participants assigned to ILI lost an average 8.6% of their initial weight versus 0.7% in DSE group (P < 0.001) while mean fitness increased in ILI by 20.9% versus 5.8% in DSE (P < 0.001). At Year 1, all exercise and HRR variables in ILI improved (P < 0.0001) versus DSE: heart rate (HR) at rest was lower (72.8 ± 11.4 versus 77.7 ± 11.7 b/min), HR range was greater (57.7 ± 12.1 versus 53.1 ± 12.4 b/min), HR at 2 minutes was lower (89.3 ± 21.8 versus 93.0 ± 12.1 b/min), and HRR was greater (41.25 ± 22.0 versus 37.8 ± 12.5 b/min). Weight loss and fitness gain produced significant separate and independent improvements in HRR.
doi:10.1155/2012/309196
PMCID: PMC3512322  PMID: 23227314
8.  Weight Change and Cognitive Function: Findings from the Women's Health Initiative Study of Cognitive Aging 
Obesity (Silver Spring, Md.)  2011;19(8):1595-1600.
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.
doi:10.1038/oby.2011.23
PMCID: PMC3175491  PMID: 21394095
9.  Designing clinical trials for assessing the effects of cognitive training and physical activity interventions on cognitive outcomes: The Seniors Health and Activity Research Program Pilot (SHARP-P) Study, a randomized controlled trial 
BMC Geriatrics  2011;11:27.
Background
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.
Methods
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.
Results
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).
Conclusions
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.
Trial Registration
Clinicaltrials.gov Identifier: NCT00688155
doi:10.1186/1471-2318-11-27
PMCID: PMC3126708  PMID: 21615936
10.  Application of machine learning methods to describe the effects of conjugated equine estrogens therapy on region-specific brain volumes 
Magnetic resonance imaging  2011;29(4):546-553.
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.
doi:10.1016/j.mri.2010.12.001
PMCID: PMC3079024  PMID: 21292420
Hormone therapy; MRI; Random Forest; WHIMS
11.  Relative Effects of Tamoxifen, Raloxifene, and Conjugated Equine Estrogens on Cognition 
Journal of Women's Health  2010;19(3):371-379.
Abstract
Objective
To compare the relative effects of conjugated equine estrogens (CEE), raloxifene, and tamoxifen therapies on cognition among women aged ≥65 years.
Methods
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.
Results
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).
Conclusions
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.
doi:10.1089/jwh.2009.1605
PMCID: PMC2867626  PMID: 20136553
12.  A Uniform Approach to Modeling Risk Factor Relationships for Ischemic Lesion Prevalence and Extent: The Women's Health Initiative Magnetic Resonance Imaging Study 
Neuroepidemiology  2009;34(1):55-62.
Background
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.
Methods
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.
Results
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).
Conclusions
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.
doi:10.1159/000260071
PMCID: PMC2818378  PMID: 19940514
Statistical methods; Brain magnetic resonance imaging; Cognition; Women's health
13.  Relationship of Hypertension, Blood Pressure, and Blood Pressure Control With White Matter Abnormalities in the Women’s Health Initiative Memory Study (WHIMS)—MRI Trial 
This paper evaluates the relationship of blood pressure (BP) levels at Women’s Health Initiative (WHI) baseline, treatment of hypertension, and white matter abnormalities among women in conjugated equine estrogen (CEE) and medroxyprogesterone acetate and CEE-alone arms. The WHI Memory Study—Magnetic Resonance Imaging (WHIMS-MRI) trial scanned 1424 participants. BP levels at baseline were significantly positively related to abnormal white matter lesion (WML) volumes. Participants treated for hypertension but who had BP ≥140/90 mm Hg had the greatest amount of WML volumes. Women with untreated BP ≥140/90 mm Hg had intermediate WML volumes. Abnormal WML volumes were related to hypertension in most areas of the brain and were greater in the frontal lobe than in the occipital, parietal, or temporal lobes. Level of BP at baseline was strongly related to amount of WML volumes. The results of the study reinforce the relationship of hypertension and BP control and white matter abnormalities in the brain. The evidence to date supports tight control of BP levels, especially beginning at younger and middle age as a possible and perhaps only way to prevent dementia.
doi:10.1111/j.1751-7176.2009.00234.x
PMCID: PMC2864933  PMID: 20433539

Results 1-13 (13)