Chitwan Valley Family Study on Cognition and Aging in Nepal (CVFS-SCAN)

Study Overview

The Longitudinal Aging Study in Nepal is a comprehensive research initiative aimed at understanding the impact of aging on cognitive health, specifically focusing on Alzheimer’s Disease and Related Dementias (ADRD), in Nepal. The study seeks to explore how factors such as international labor migration and exposure to armed conflict contribute to the risk of dementia and cognitive impairments in older adults.

In addition, we are exploring how chronic psychological stress impacts the transition to adulthood. Using hair cortisol concentration (HCC), a reliable and non-invasive biomarker, we measure long-term stress in young adults. This study is part of the Chitwan Valley Family Study (CVFS), a 25-year longitudinal study of community, household, and individual factors.

Study Objectives

Build Research Capacity

Train local researchers to conduct systematic research on ADRD, including culturally appropriate cognitive assessments and advanced statistical analysis of longitudinal data.

Large-Scale Testing of Hair Cortisol

Test large-scale self-collection of hair samples vs professional collection to measure cortisol levels and analyze chronic stress in young adults aged 18-21.

Investigate Risk Factors

Analyze how long-term labor migration and exposure to armed conflict impact the risk of developing ADRD and other cognitive impairments, while linking hair cortisol data to life transitions.

Study Methods

The study employs a stratified two-stage cluster sampling technique to survey a representative sample of 4,000 older adults and their caregivers. In addition, we use a randomized experiment to compare self-collection of hair samples to professional collection for cortisol analysis. Data collection includes:
  • Harmonized Cognitive Assessment Protocol (HCAP) instruments for cognitive and physical function assessments.
  • Hair sample collection for cortisol analysis to measure long-term stress.
  • Biomarker collection involving plasma, serum, and red blood cells.

Timeline and Current Status

2022 Study Commencement

The study commenced in 2022 and is projected to conclude by 2027. Initial data collection is completed and follow-up assessments are planned, including hair cortisol sampling and biomarker collection for stress analysis.

Potential Problems and Alternative Strategies

Participant Burden

We anticipate that the survey interview, including cognitive tests, will take 1.5 – 2 hours to complete. This may cause fatigue for middle-aged to older adults. Our strategy is to offer multiple settings for the interview to reduce burden while maintaining high participation rates.

Privacy of Interview

In rural areas, it is often difficult to conduct interviews in private. Our staff will move interviews to outdoor locations and send two-person teams to ensure privacy. We will also collect data on the presence of others during interviews.

Limited Statistical Power

While recognizing potential limitations in statistical power, this study lays the groundwork for future ADRD research in Nepal. We plan to continue enrollment as participants become age-eligible.

Biomarker Data

We plan to collect biomarker data, though we have not yet committed to specific assays. Frozen samples will be stored for future analysis as scientific advances clarify the relevance of biomarkers for ADRD.

Broader Implications

Understanding stress through hair cortisol measurement offers a new way to explore how stress influences key life transitions. The results of this study will help establish protocols for self-collection in large-scale research, reducing costs and making stress measurement more accessible in population studies.