Blogs: The Longitudinal Aging Study in India-Diagnostic Assessment of Dementia (LASI-DAD)

The Longitudinal Aging Study in India-Diagnostic Assessment of Dementia (LASI-DAD)

by Sarah Petrosyan
Sep 17, 2020

Global efforts in studying Alzheimer’s and other dementias are paramount due to the increase in life expectancy around the world. With this growth in the older population, it becomes vital to better understand risk factors contributing to late-life cognitive decline.

The Harmonized Cognitive Assessment Protocol (HCAP) was developed to assess dementia risk and cognitive function and allow for cross-country comparisons. It has been used by several HRS-family studies, including the Longitudinal Aging Study in India-Diagnostic Assessment of Dementia (LASI-DAD), an in-depth study of late-life cognition and dementia in India. The HCAP protocol has been modified for the LASI-DAD study to better suit the population of India, considering the higher levels of illiteracy and innumeracy.

The Journal of American Geriatrics Society, Volume 68, Supplement 3, introduces the LASI-DAD to the international research community. With collaborators from across the globe, researchers set out to investigate late-life cognition, dementia, and their risk factors in India. The high-quality data collected will allow them to estimate the prevalence of dementia in India and enable cross-country analysis of late-life cognition and dementia with other HCAP studies around the world.

Main Findings

A comprehensive assessment of dementia in a large population-based study was made possible through the development and validation of an online clinical consensus diagnosis platform. This cost-effective method allows for a consistent clinical expert diagnosis of dementia, alternative to in-person evaluations.

Researchers explored modifiable risk factors for dementia by looking into the relationship between cognitive function and hypertension. Two-thirds of the 60 and older Indian population were found to have hypertension, with one-third of them undiagnosed. Though the study did not find any statistically significant association between hypertension and cognition, future research is needed to assess hypertension as a possible mediator between socioeconomic disadvantage and worse cognitive function.

Comparability of these cognitive test batteries are well established, as shown through the results from Alden et al. Using these comparable data, Perry et al. investigated the association between cardio-metabolic-inflammatory risk factors and cognition among LASI-DAD respondents in India to HRS-HCAP respondents in the United States. There was a significant difference in the distribution of total cognition scores and risk factors between the two countries.

Researchers also investigated sex differences in late-life cognition in India. Findings suggest the disadvantage in cognitive performance of women can be largely attributed to early-life factors, such as nutrition and education. These disparities highlight the importance for public policy aiming at reducing dementia.

The role of genetic factors in Alzheimer’s Disease and cognitive aging in India was examined, showing a moderate association between risk loci identified in European ancestry populations and LASI-DAD cognitive measures. Results suggest a critical need for further assessment to identify genetic variants associated with Alzheimer’s Disease and cognition in the South Asian population.

This introduction to the LASI-DAD sets the tone for future research and innovations as researchers begin to better understand the scope of cognitive decline and dementia in India.

Featured Articles

  1. New Insights and Knowledge on Cognition and Dementia from Population-Based Cohort of Older Adults in India
  2. Introduction to LASI-DAD: The Longitudinal Aging Study in India-Diagnostic Assessment of Dementia
  3. Design and Methodology of the Longitudinal Aging Study in India‐Diagnostic Assessment of Dementia (LASI‐DAD)
  4. Measurement and Structure of Cognition in the Longitudinal Aging Study in India–Diagnostic Assessment of Dementia
  5. Sex Differences in Cognitive Health Among Older Adults in India
  6. Hypertension and Cognitive Health Among Older Adults in India
  7. Cognitive Function and Cardiometabolic‐Inflammatory Risk Factors Among Older Indians and Americans
  8. Association Between Episodic Memory and Genetic Risk Factors for Alzheimer's Disease in South Asians from the Longitudinal Aging Study in India–Diagnostic Assessment of Dementia (LASI‐DAD)
  9. Online Clinical Consensus Diagnosis of Dementia: Development and Validation

As part of our Gateway Blog Series, we have compared the Harmonized Cognitive Assessment Protocol across the HRS family of studies, including LASI-DAD. Read more here.

Interested in using the data? Visit the Gateway to Global Aging data download webpage for LASI-DAD data access instructions.

about the author
Sarah Petrosyan is a Research Programmer for The Program for Global Health, Aging & Policy at CESR.