Blogs: LASI-DAD Data Release

LASI-DAD Data Release

by Sarah Petrosyan
Apr 12, 2021

We are pleased to announce that the newest version of the Harmonized LASI-DAD data files and the raw study data are now available for download. These newly released data files include the sample from all three phases of Wave 1 data collection. Here, we highlight new additions to these data files and where to access the data and accompanying documentation.

The Diagnostic Assessment of Dementia for the Longitudinal Aging Study in India (LASI-DAD) is an in-depth study of cognitive aging and dementia for a sub-sample of the Longitudinal Aging Study in India (LASI). LASI-DAD aims to provide an interdisciplinary data resource with a focus on cognitive and physical health, and quality of life as people age.

LASI-DAD adapted its protocol from the Harmonized Cognitive Assessment Protocol (HCAP) to assess Mild Cognitive Impairment and dementia in India. The HCAP battery, originally developed in the United States, has also been successfully adapted in other countries such as, England, Mexico, China, and South Africa. Modifications to HCAP battery for different countries were necessary to make the questions more culturally relevant. However, in order to facilitate cross-country comparisons, it was imperative to develop harmonized domain-specific cognition variables. These variables for LASI-DAD have been developed and included in the Harmonized LASI-DAD data file. The method for variable creation is explained in detail in the Harmonized LASI-DAD codebook. More details on the study background and protocol can be found at the study website.

In this newest version of the LASI-DAD data, we have also provided polygenic risk scores (PRSs). PRSs provide a quantitative measure of genetic risk and increase power in genetic analyses. These were constructed for Alzheimer’s disease and general cognitive function for consenting LASI-DAD respondents who provided whole blood DNA in 2018. Detailed documentation for the construction of polygenic risk scores (PRSs) can be found in the Harmonized LASI-DAD codebook.

Lastly, data from the collection and assay of venous blood specimens (VBS) is now available in the raw data file. Venous blood specimens were collected from respondents at the time and place of the cognitive interview. Among the 4096 respondents, we were able to obtain VBS from 2,892 participants. Samples collected were shipped to the Metropolis laboratory in Delhi for processing. Assays completed included whole blood-based assays, serum-based tests, lipid profile, metabolic panel, thyroid function tests, and liver function tests.

The Harmonized LASI-DAD is an excellent and user-friendly dataset for conducting cross-country analysis and we hope this new update contains useful information to add to your research.

The data files and documentation are available at the Gateway to Global Aging Data website. Instructions for requesting access to and downloading the data can be found here.

The Journal of American Geriatrics Society published a special issue introducing LASI-DAD to the international research community. Learn more about these initial findings here.

about the author
Sarah Petrosyan is a Research Programmer for The Program for Global Health, Aging & Policy at the Center for Economic and Social Research at the University of Southern California.