Overview of Public Access Data Sets - Intervention and Post-Intervention Phases

Data from the Look AHEAD trial, Action for Health in Diabetes, include Intervention Phase results with new data from Ancillary Study and Post-Intervention Phase results. These can be accessed through application to the National Institute of Diabetes and Digestive and Kidney Diseases; NIDDK Central Repository: https://repository.niddk.nih.gov/studies/look-ahead/. . Look AHEAD Principal Investigators may access the full data archive directly from the Look AHEAD site after login.

The Intervention Phase involves baseline and follow-up data from two randomized groups: Diabetes Support and Education, or Intensive Lifestyle Intervention. The trial enrollment began in 2001 with follow-up continuing through September 14, 2012, when the intensive intervention was stopped. The recommendation from the National Institutes of Health (NIH) directed that the Intensive Lifestyle Intervention be concluded, with an intent to continue studying the benefits and risks of the intervention. Data collection continued in 2012 and 2013, with a protocol directed Continuation Study starting in 2013. In this archive, Post-intervention Phase data are included through 2015. Data collection on the cohort continues through 2020 on post-intervention participants. Additional updates are planned as data become available.

The trial cohort began with 5145 participants. Consented and randomized participants, only, are included in this archive; those participants participating from Native American sites are excluded, per consent limitations, resulting in a cohort of 4901. Data collected during the Intervention Phase covers an approximately 10-year period. Study outcome data are included, describing time to first event within the Intervention Phase: primary, secondary, and other cardiovascular events. The adjudication process for determining all study outcomes (Mortality, Cardiovascular Events, Cancer, and Fractures) is in process; these data are also planned for future updates.

An Ancillary study: Cognitive and Physical Functioning, involving new data collection, was initiated during Year 8 of the Intervention Phase on a subset of participants. Follow-up or initial assessments in a second ancillary study, also on a subset of participants, was completed in approximately Year 10. Specific aims for the Continuation Study in the Post-Intervention Phase focused on cognitive and physical functioning, resulting in a third round of follow-up or initial assessments on participants. As such, one to three sets of battery assessments have been administered to participants. Approximately 20% of the data were collected during the Intervention Phase. NIH Toolbox Cognition Domain measurements were collected once on a subset of participants, all during Post-Intervention. Cognitive battery assessments are available on 3717 participants (5123 assessments) and NIH Toolbox data on 1004 participants. Mobility disability, measured and adjudicated from initial physical function assessments, are available for 3620 participants.

The Post-Intervention Phase covers a three-year period of data collection after the intervention was stopped, including many of the same measurements and questionnaires collected during intervention. There was a one-year period of data collection that continued following the Intervention Phase, prior to the initiation of the Continuation Study. 4365 participants participated in the Post-Intervention Phase; 4201 consented to the Continuation Study for either phone contact or clinic visits with 3659 making a clinic visit.

Descriptions of available data are provided in pdf files and organized as follows:

  1. Overview
  2. Available Data
    1. Key Data
    2. Intervention Phase Results
    3. Cognitive Function Results
    4. Physical Function Results
    5. Post-Intervention Results

The Overview offers a brief orientation to the Look AHEAD study and outlines data available in the archive. Available Data provides Contents Listings of Variables, Summary Statistics, and Data Collection Forms. Illustrations of forms include the data entry screen shot which displays variable names in context with value definitions; these are concatenated with the data collection form used at the clinical centers.

Under “Key Data” are descriptions of essential variables that can be mapped to all data sets and primary outcome data. Intervention and Post-Intervention Results include: “Measures”, descriptions of data relating to physical measurements, study assessments, or electronically captured data; and, “Questionnaires”, descriptions of data relating to most data collections forms. Cognitive and Physical Function Results combine Ancillary Study and Post-Intervention Results.

Data sets largely provide recurring data for each participant starting with screening, covering randomization, and biannual visits during Intervention or yearly visits during Post-Intervention; see data availability for scheduled follow-up, as each measurement or questionnaire differs in follow-up pattern. Data collection forms were modified as needed during the operation of the trial. The final versions of forms are presented in this archive.

Guidelines followed for data preparation in this release comply with the regulations of the Health Insurance Portability and Accountability Act (HIPAA), eliminating all variables including personal identifying information. Further de-identification of participants is obtained by exchanging original study identifiers with randomly assigned identifiers. All dates have been exchanged with variables expressed in relation to days according to randomization.

Public Data
           complete_data_description.zip
       1-Overview
                 Look AHEAD Public Access Data - Overview - 1. Introduction.pdf
                 Look AHEAD Public Access Data - Overview - 2. Synopsis.pdf
                 Look AHEAD Public Access Data - Overview - 3a. Intervention Examination & Follow-up Timeline.pdf
                 Look AHEAD Public Access Data - Overview - 3b. Post-Intervention Examination & Follow-up Timeline.pdf
                 Look AHEAD Public Access Data - Overview - 4. Data Availability.pdf
       2-Available Data
             A. Key Data
                   Key Data Contents
                             Contents.LA2_BaselineVariables.pdf
                             Contents.LA3_ActivityStatus.pdf
                             Contents.LA4_Outcomes1.pdf
                             Contents.LA_Key.pdf
                             Contents.PI_ActivityStatus.pdf
                   Key Data Summary Statistics
                             Summary Statistics.LA2_BaselineVariables.pdf
                             Summary Statistics.LA3_ActivityStatus.pdf
                             Summary Statistics.LA4_Outcomes1.pdf
                             Summary Statistics.LA_Key.pdf
                             Summary Statistics.PI_ActivityStatus.pdf
             B. Intervention Results
                   Intervention Measures Data Collection Forms
                             DXA_Questionnaire.pdf
                             PhysicalMeasures_ABI_Waist.pdf
                             PhysicalMeasures_BP_BMI.pdf
                   Intervention Measures Data Set Contents
                             Contents.Accelerometry0.pdf
                             Contents.Accelerometry1.pdf
                             Contents.DXA.pdf
                             Contents.DXA_Questionnaire.pdf
                             Contents.EducationAssessment.pdf
                             Contents.InterventionAssessment.pdf
                             Contents.LaboratoryMeasures.pdf
                             Contents.PhysicalMeasures_ABI_Waist.pdf
                             Contents.PhysicalMeasures_BP_BMI.pdf
                             Contents.StressTest_MaximalGXT.pdf
                             Contents.StressTest_SubmaxGXT.pdf
                   Intervention Measures Data Set Summary Statistics
                             Summary Statistics.Accelerometry0.pdf
                             Summary Statistics.Accelerometry1.pdf
                             Summary Statistics.DXA.pdf
                             Summary Statistics.DXA_Questionnaire.pdf
                             Summary Statistics.EducationAssessment.pdf
                             Summary Statistics.InterventionAssessment.pdf
                             Summary Statistics.LaboratoryMeasures.pdf
                             Summary Statistics.PhysicalMeasures_ABI_Waist.pdf
                             Summary Statistics.PhysicalMeasures_BP_BMI.pdf
                             Summary Statistics.StressTest_MaximalGXT.pdf
                             Summary Statistics.StressTest_SubmaxGXT.pdf
                   Intervention Questionnaire Data Collection Forms
                             Costs_ResourceUse.pdf
                             HealthBehaviors_Alcohol.pdf
                             HealthBehaviors_DietRaw.pdf
                             HealthBehaviors_EatingPatterns.pdf
                             HealthBehaviors_ExerciseHabits.pdf
                             HealthBehaviors_Tobacco.pdf
                             HealthBehaviors_WeightControl.pdf
                             HealthOutcomes_Falls.pdf
                             HealthOutcomes_Knees.pdf
                             HealthOutcomes_MedsInventory.pdf
                             HealthOutcomes_ReproductiveHx.pdf
                             HealthOutcomes_Symptoms.pdf
                             HealthOutcomes_UrnryIncontinence.pdf
                             HealthOutcomes_WeightHistory.pdf
                             MedicalHistory_Family.pdf
                             MedicalHistory_Personal.pdf
                             Psychosocial_Depression.pdf
                             Psychosocial_EatingDisorders.pdf
                             QALY_FeelThermometer.pdf
                             QALY_HUI.pdf
                             QOL_SF36.pdf
                             Screening_EligibilityA.pdf
                             Screening_EligibilityB.pdf
                             Screening_Prescreening.pdf
                             Sociodemographics.pdf
                             TechnologyUse.pdf
                   Intervention Questionnaire Data Set Contents
                             Contents.Costs_ResourceUse.pdf
                             Contents.HealthBehaviors_Alcohol.pdf
                             Contents.HealthBehaviors_Diet.pdf
                             Contents.HealthBehaviors_DietRaw.pdf
                             Contents.HealthBehaviors_EatingPatterns.pdf
                             Contents.HealthBehaviors_ExerciseHabits.pdf
                             Contents.HealthBehaviors_Tobacco.pdf
                             Contents.HealthBehaviors_WeightControl.pdf
                             Contents.HealthOutcomes_Falls.pdf
                             Contents.HealthOutcomes_Knees.pdf
                             Contents.HealthOutcomes_MedUse.pdf
                             Contents.HealthOutcomes_MedsInventory.pdf
                             Contents.HealthOutcomes_ReproductiveHx.pdf
                             Contents.HealthOutcomes_Symptoms.pdf
                             Contents.HealthOutcomes_UrnryIncontinence.pdf
                             Contents.HealthOutcomes_WeightHistory.pdf
                             Contents.MedicalHistory_Family.pdf
                             Contents.MedicalHistory_Personal.pdf
                             Contents.Psychosocial_Depression.pdf
                             Contents.Psychosocial_EatingDisorders.pdf
                             Contents.QALY_FeelThermometer.pdf
                             Contents.QALY_HUI_v2.pdf
                             Contents.QOL_SF36.pdf
                             Contents.Screening_EligibilityA.pdf
                             Contents.Screening_EligibilityB.pdf
                             Contents.Screening_Prescreening.pdf
                             Contents.Sociodemographics.pdf
                             Contents.TechnologyUse.pdf
                   Intervention Questionnaire Data Set Summary Statistics
                             Summary Statistics.Costs_ResourceUse.pdf
                             Summary Statistics.HealthBehaviors_Alcohol.pdf
                             Summary Statistics.HealthBehaviors_Diet.pdf
                             Summary Statistics.HealthBehaviors_DietRaw.pdf
                             Summary Statistics.HealthBehaviors_EatingPatterns.pdf
                             Summary Statistics.HealthBehaviors_ExerciseHabits.pdf
                             Summary Statistics.HealthBehaviors_Tobacco.pdf
                             Summary Statistics.HealthBehaviors_WeightControl.pdf
                             Summary Statistics.HealthOutcomes_Falls.pdf
                             Summary Statistics.HealthOutcomes_Knees.pdf
                             Summary Statistics.HealthOutcomes_MedUse.pdf
                             Summary Statistics.HealthOutcomes_MedsInventory.pdf
                             Summary Statistics.HealthOutcomes_ReproductiveHx.pdf
                             Summary Statistics.HealthOutcomes_Symptoms.pdf
                             Summary Statistics.HealthOutcomes_UrnryIncontinence.pdf
                             Summary Statistics.HealthOutcomes_WeightHistory.pdf
                             Summary Statistics.MedicalHistory_Family.pdf
                             Summary Statistics.MedicalHistory_Personal.pdf
                             Summary Statistics.Psychosocial_Depression.pdf
                             Summary Statistics.Psychosocial_EatingDisorders.pdf
                             Summary Statistics.QALY_FeelThermometer.pdf
                             Summary Statistics.QALY_HUI_v2.pdf
                             Summary Statistics.QOL_SF36.pdf
                             Summary Statistics.Screening_EligibilityA.pdf
                             Summary Statistics.Screening_EligibilityB.pdf
                             Summary Statistics.Screening_Prescreening.pdf
                             Summary Statistics.Sociodemographics.pdf
                             Summary Statistics.TechnologyUse.pdf
             C. Cognitive Function Results
                   Cognitive Function Data Collection Forms
                             CF1_Rey Auditory Verbal Learning Test (AVLT).pdf
                             CF2_Modified Mental State Exam (3MSE).pdf
                             CF3_WAIS-III Digit Symbol Substitution Test (DSST).pdf
                             CF4_Stroop Tests 1-3.pdf
                             CF5_Trail Making Test Part A & B.pdf
                             CF6_Shipley-2.pdf
                             CF_Introduction Cognitive Testing.pdf
                   Cognitive Function Data Set Contents
                             Contents.CFQ1_ReyAVLT.pdf
                             Contents.CFQ2_3MSE.pdf
                             Contents.CFQ3_DSST.pdf
                             Contents.CFQ4_Stroop.pdf
                             Contents.CFQ5_TrailMaking.pdf
                             Contents.CFQ6_Shipley2.pdf
                             Contents.CFQ_Introduction.pdf
                             Contents.CF_AdjCogImpStatus.pdf
                             Contents.CF_ApoE.pdf
                             Contents.CF_BatterySummary.pdf
                             Contents.CF_BrainVolume.pdf
                             Contents.CF_NIHToolBox_v3.pdf
                   Cognitive Function Summary Statistics
                             Summary Statistics.CFQ1_ReyAVLT.pdf
                             Summary Statistics.CFQ2_3MSE.pdf
                             Summary Statistics.CFQ3_DSST.pdf
                             Summary Statistics.CFQ4_Stroop.pdf
                             Summary Statistics.CFQ5_TrailMaking.pdf
                             Summary Statistics.CFQ6_Shipley2.pdf
                             Summary Statistics.CFQ_Introduction.pdf
                             Summary Statistics.CF_AdjCogImpStatus.pdf
                             Summary Statistics.CF_ApoE.pdf
                             Summary Statistics.CF_BatterySummary.pdf
                             Summary Statistics.CF_BrainVolume.pdf
                             Summary Statistics.CF_NIHToolBox.pdf
             D. Physical Function Results
                   Physical Function Data Collection Forms
                             PF_400 Meter Walk Alternate Course.pdf
                             PF_400 Meter Walk.pdf
                             PF_Grip Strength.pdf
                             PF_Pepper Assessment Tool for Disability (PAT-D).pdf
                             PF_Short Physical Performance Battery (SPPB).pdf
                             PF__Physical Function.pdf
                   Physical Function Data Set Contents
                             Contents.PF_400mWalk.pdf
                             Contents.PF_400mWalkAlt.pdf
                             Contents.PF_GripStrength.pdf
                             Contents.PF_MobilityDisability.pdf
                             Contents.PF_PATD.pdf
                             Contents.PF_SPPB.pdf
                             Contents.PF__PhysicalFunction.pdf
                   Physical Function Summary Statistics
                             Summary Statistics.PF_400mWalk.pdf
                             Summary Statistics.PF_400mWalkAlt.pdf
                             Summary Statistics.PF_GripStrength.pdf
                             Summary Statistics.PF_MobilityDisability.pdf
                             Summary Statistics.PF_PATD.pdf
                             Summary Statistics.PF_SPPB.pdf
                             Summary Statistics.PF__PhysicalFunction.pdf
             E. Post-Intervention Results
                   Post-Intervention Measures Data Collection Forms
                             PI_ECG Questionnaire.pdf
                             PI_Michigan Neuropathy Screening Instrument (MNSI).pdf
                             PI_PhysicalMeasures - BloodPressure BMI Waist.pdf
                   Post-Intervention Measures Data Set Contents
                             Contents.PI_ECG.pdf
                             Contents.PI_ECG_Questionnaire.pdf
                             Contents.PI_LaboratoryMeasures.pdf
                             Contents.PI_MNSI.pdf
                             Contents.PI_PhysicalMeasures_BP_BMI.pdf
                   Post-Intervention Measures Summary Statistics
                             Summary Statistics.PI_ECG.pdf
                             Summary Statistics.PI_ECG_Questionnaire.pdf
                             Summary Statistics.PI_LaboratoryMeasures.pdf
                             Summary Statistics.PI_MNSI.pdf
                             Summary Statistics.PI_PhysicalMeasures_BP_BMI.pdf
                   Post-Intervention Questionnaire Data Collection Forms
                             PI_Health Behaviors.pdf
                             PI_HealthBehaviors ExerciseHabits.pdf
                             PI_HealthOutcomes Falls.pdf
                             PI_HealthOutcomes Knees.pdf
                             PI_HealthOutcomes MedsInventory.pdf
                             PI_HealthOutcomes Symptoms.pdf
                             PI_HealthOutcomes Urinary.pdf
                             PI_MedicalHistory Neuropathy.pdf
                             PI_MedicalHistory.pdf
                             PI_Psychosocial Depression (Beck).pdf
                             PI_Pyschosocial (PHQ9).pdf
                             PI_QALY FeelThermometer.pdf
                             PI_QALY Health Utilities Index (HUI).pdf
                             PI_QOL SF36.pdf
                   Post-Intervention Questionnaire Data Set Contents
                             Contents.PI_HealthBehaviors.pdf
                             Contents.PI_HealthBehaviors_ExerHabits.pdf
                             Contents.PI_HealthOutcomes_Falls.pdf
                             Contents.PI_HealthOutcomes_Knees.pdf
                             Contents.PI_HealthOutcomes_MedUse.pdf
                             Contents.PI_HealthOutcomes_MedsInventory.pdf
                             Contents.PI_HealthOutcomes_Symptoms.pdf
                             Contents.PI_HealthOutcomes_Urinary.pdf
                             Contents.PI_MedicalHistory.pdf
                             Contents.PI_MedicalHistory_Neuropathy.pdf
                             Contents.PI_Psychosocial_Depression.pdf
                             Contents.PI_Pyschosocial_PHQ9.pdf
                             Contents.PI_QALY_FeelThermometer.pdf
                             Contents.PI_QALY_HUI.pdf
                             Contents.PI_QOL_SF36.pdf
                   Post-Intervention Questionnaire Summary Statistics
                             Summary Statistics.PI_HealthBehaviors.pdf
                             Summary Statistics.PI_HealthBehaviors_ExerHabits.pdf
                             Summary Statistics.PI_HealthOutcomes_Falls.pdf
                             Summary Statistics.PI_HealthOutcomes_Knees.pdf
                             Summary Statistics.PI_HealthOutcomes_MedUse.pdf
                             Summary Statistics.PI_HealthOutcomes_MedsInventory.pdf
                             Summary Statistics.PI_HealthOutcomes_Symptoms.pdf
                             Summary Statistics.PI_HealthOutcomes_Urinary.pdf
                             Summary Statistics.PI_MedicalHistory.pdf
                             Summary Statistics.PI_MedicalHistory_Neuropathy.pdf
                             Summary Statistics.PI_Psychosocial_Depression.pdf
                             Summary Statistics.PI_Pyschosocial_PHQ9.pdf
                             Summary Statistics.PI_QALY_FeelThermometer.pdf
                             Summary Statistics.PI_QALY_HUI.pdf
                             Summary Statistics.PI_QOL_SF36.pdf