Publications by authors named "Letitia H Perdue"
Whether initiation of statins could increase survival free of dementia and disability in adults aged ≥75 years is unknown. PREVENTABLE, a double-blind, placebo-controlled randomized pragmatic clinical trial, will compare high-intensity statin therapy (atorvastatin 40 mg) with placebo in 20,000 community-dwelling adults aged ≥75 years without cardiovascular disease, disability, or dementia at baseline. Exclusion criteria include statin use in the prior year or for >5 years and inability to take a statin.
View Article and Find Full Text PDFBackground Excess visceral adiposity is associated with increased risk of cardiometabolic disorders. Short-term well-controlled clinical trials suggest that regular avocado consumption favorably affects body weight, visceral adiposity, and satiety. Methods and Results The HAT Trial (Habitual Diet and Avocado Trial) was a multicenter, randomized, controlled parallel-arm trial designed to test whether consuming 1 large avocado per day for 6 months in a diverse group of free-living individuals (N=1008) with an elevated waist circumference compared with a habitual diet would decrease visceral adiposity as measured by magnetic resonance imaging.
View Article and Find Full Text PDFObjective: This study aimed to determine the impact of weight gain prevention interventions on changes in cardiovascular risk factors over 6 years.
Methods: The Study of Novel Approaches to Weight Gain Prevention (SNAP) randomized 599 participants (ages 18-35; 46% with BMI 21-25; 54% with BMI 25-30) to Large Changes (produce buffer by losing 5-10 pounds initially), Small Changes (daily small changes in intake and activity) or Control and followed 355 participants with ongoing intervention and assessments through 6 years.
Results: There were no significant differences among interventions for changes in weight or cardiovascular disease (CVD) risk factors from baseline to 6 years.
Objective: This study aimed to characterize young adults who experienced significant weight gains (> 10%) over 3 years in a weight gain prevention program.
Methods: Secondary data analysis from the Study of Novel Approaches to Weight Gain Prevention (SNAP), a randomized trial comparing two self-regulation interventions and a control arm in young adults (18-35 years; BMI 21-30.9 kg/m ), was used.
Objective: The study objective was to determine whether two self-regulation interventions that reduced 3-year weight gain in young adults remain effective at 6 years.
Methods: A randomized trial was conducted in two academic settings in 599 young adults, aged 18 to 35 years, with normal weight or overweight; 504 (84%) reconsented for a 6-year extension (Study of Novel Approaches to Weight Gain Prevention-Extended [SNAP-E]) with ongoing intervention and assessments. Weight gain over 6 years was compared for all assigned to Control, Large Changes (LC; lose 5-10 pounds initially), and Small Changes (SC; make small daily changes in intake and activity).
Importance: Weight gain occurs commonly in young adults and has adverse effects on health.
Objective: To compare 2 self-regulation interventions vs control in reducing weight gain in young adults over a mean follow-up of 3 years.
Design, Setting, And Participants: Randomized clinical trial in 2 academic settings of 599 participants aged 18 to 35 years with body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) of 21.
Background: The Systolic Blood Pressure Intervention Trial is a multicenter, randomized clinical trial of 9361 participants with hypertension who are ≥50 years old. The trial is designed to evaluate the effect of intensive systolic blood pressure control (systolic blood pressure goal <120 mm Hg) compared to standard control (systolic blood pressure goal <140 mm Hg) on cardiovascular events using commonly prescribed antihypertensive medications and lifestyle modification.
Objective: To describe the recruitment strategies and lessons learned during recruitment of the Systolic Blood Pressure Intervention Trial cohort and five targeted participant subgroups: pre-existing cardiovascular disease, pre-existing chronic kidney disease, age ≥75 years, women, and minorities.
Purpose: To report additional ocular outcomes of intensive treatment of hyperglycemia, blood pressure, and dyslipidemia in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study.
Design: Double 2×2 factorial, multicenter, randomized clinical trials in people with type 2 diabetes who had cardiovascular disease or cardiovascular risk factors. In the glycemia trial, targets of intensive and standard treatment were: hemoglobin A1c <6.
Purpose: To compare evaluation by clinical examination with image grading at a reading center for the classification of diabetic retinopathy and diabetic macular edema.
Methods: Action to Control Cardiovascular Risk in Diabetes (ACCORD) and Family Investigations of Nephropathy in Diabetes (FIND) had similar methods of clinical and fundus photograph evaluation. For analysis purposes, the photographic grading scales were condensed to correspond to the clinical scales, and agreement between clinicians and reading center classification were compared.
Background: Although observational evidence has suggested that the measurement of coronary artery calcium (CAC) may improve risk stratification for cardiovascular events and thus help guide the use of lipid-lowering therapy, this contention has not been evaluated within the context of a randomized trial. The Value of Imaging in Enhancing the Wellness of Your Heart (VIEW) trial is proposed as a randomized study in participants at low intermediate risk of future coronary heart disease (CHD) events to evaluate whether CAC testing leads to improved patient outcomes.
Purpose: To describe the challenges encountered in designing a prototypical screening trial and to examine the impact of uncertainty on power.
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Purpose: Three network laboratories measured antibodies to islet autoantigens. Antibodies to glutamic acid decarboxylase (GAD65 [GADA]) and the intracellular portion of protein tyrosine phosphatase (IA-2(ic) [IA-2A]) were measured by similar, but not identical, methods in samples from participants in the Type 1 Diabetes Genetics Consortium (T1DGC).
Methods: All laboratories used radiobinding assays to detect antibodies to in vitro transcribed and translated antigen, but with different local standards, calibrated against the World Health Organization (WHO) reference reagent.
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Purpose: This article describes several ethical, legal, and social issues typical of international genetics biobanking, as encountered in the Type 1 Diabetes Genetics Consortium (T1DGC).
Methods: By studying the examples set and lessons learned from other international biobanking studies and by devoting considerable time and resources to identifying, addressing, and continually monitoring ethical and regulatory concerns, T1DGC was able to minimize the problems reported by some earlier studies.
Conclusions: Several important conclusions can be drawn based on the experience in this study: (1) Basic international standards for research ethics review and informed consent are broadly consistent across developed countries.
Background: When collecting phenotypic data in clinics across the globe, the Type 1 Diabetes Genetics Consortium (T1DGC) used several techniques that ensured consistency, completeness, and accuracy of the data.
Purpose: The aim of this article is to describe the procedures used for collection, entry, processing, and management of the phenotypic data in this international study.
Methods: The T1DGC ensured the collection of high quality data using the following procedures throughout the entire study period.
Background And Purpose: The Type 1 Diabetes Genetics Consortium (T1DGC) is an international project whose primary aims are to: (a) discover genes that modify type 1 diabetes risk; and (b) expand upon the existing genetic resources for type 1 diabetes research. The initial goal was to collect 2500 affected sibling pair (ASP) families worldwide.
Methods: T1DGC was organized into four regional networks (Asia-Pacific, Europe, North America, and the United Kingdom) and a Coordinating Center.
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Purpose: To yield large amounts of DNA for many genotype analyses and to provide a renewable source of DNA, the Type 1 Diabetes Genetics Consortium (T1DGC) harvested DNA and peripheral blood mononuclear cells (PBMCs) from individuals with type 1 diabetes and their family members in several regions of the world.
Methods: DNA repositories were established in Asia-Pacific, Europe, North America, and the United Kingdom. To address region-specific needs, different methods and sample processing techniques were used among the laboratories to extract and to quantify DNA and to establish Epstein-Barr virus transformed cell lines.
Background: Although human leukocyte antigen (HLA) DQ and DR loci appear to confer the strongest genetic risk for type 1 diabetes, more detailed information is required for other loci within the HLA region to understand causality and stratify additional risk factors. The Type 1 Diabetes Genetics Consortium (T1DGC) study design included high-resolution genotyping of HLA-A, B, C, DRB1, DQ, and DP loci in all affected sibling pair and trio families, and cases and controls, recruited from four networks worldwide, for analysis with clinical phenotypes and immunological markers.
Purpose: In this article, we present the operational strategy of training, classification, reporting, and quality control of HLA genotyping in four laboratories on three continents over nearly 5 years.
Background: We investigated whether intensive glycemic control, combination therapy for dyslipidemia, and intensive blood-pressure control would limit the progression of diabetic retinopathy in persons with type 2 diabetes. Previous data suggest that these systemic factors may be important in the development and progression of diabetic retinopathy.
Methods: In a randomized trial, we enrolled 10,251 participants with type 2 diabetes who were at high risk for cardiovascular disease to receive either intensive or standard treatment for glycemia (target glycated hemoglobin level, <6.
Objective: To assess the cross-sectional association of thiazolidinediones with diabetic macular edema (DME).
Methods: The cross-sectional association of DME and visual acuity with thiazolidinediones was examined by means of baseline fundus photographs and visual acuity measurements from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Visual acuity was assessed in 9690 participants in the ACCORD trial, and 3473 of these participants had fundus photographs that were centrally read in a standardized fashion by masked graders to assess DME and retinopathy from October 23, 2003, to March 10, 2006.