Overview of Public Access Data Sets - Intervention Phase
Data from the Look AHEAD trial, Action for Health in Diabetes, are now available and 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. Data collection on the cohort continues and is planned for release in future updates. This release includes data from screening, baseline and follow-up for approximately 10 years.
The trial cohort began with 5145 participants. Consented and randomized participants, only, are included in this release; those participants participating from Native American sites are excluded, per consent limitations, resulting in a cohort of 4901. Study outcome data describing: primary, secondary, and other cardiovascular events are included. However, the adjudication process for determining additional study outcomes (Cancer, Fractures, Gall Bladder surgery) is in process; these data are not available at this time, but there are plans to release them in future updates.
Descriptions of available data are provided in pdf files and organized as follows:
| Overview | A brief orientation to the Look AHEAD Trial and data available in the archive |
| Available Data | 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. |
| Key Data | Descriptions of essential variables that can be mapped to all data sets |
| Measures | Descriptions of data relating to physical measurements, study assessments, or electronically captured data |
| Questionnaires | Descriptions of data relating to most data collections forms |
In general, collection of data for each participant includes recurring visits starting with screening, covering randomization, and biannual visits; 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 release.
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. Study centers and geographic locations have been suppressed. All dates have been exchanged with variables expressed in relation to days according to randomization.