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Uncovering the Exposome: A Pilot Study of Aging and Environmental Exposure in Malawi 

Investigators:

Helene Purcell 

Funding:

CACHE Seed Funding 

Data sources:

  • Long-term individual-level panel data from the Malawi Longitudinal Study of Families and Health (MLSFH), with repeated cognitive and health measures spanning over 15 years;
  • Geocoded administrative and infrastructure data from the National Statistics Office (NSO) of Malawi.
  • Environmental and other Geospatial Information Systems (GIS) datasets from NOAA and other environmental data sources.

Measures:

  • Climate Measures: historic rainfall and drought data
  • Physical Environment: road access, sanitation and water sources
  • Social environment: family structure and social network data
  • Policy environment: exposure to fertilizer subsidies, access to Anti-retroviral therapy (ART) for HIV/AIDS
  • Community services: proximity to health facilities and schools
  • Life experiences: economic shocks, migration history, adverse childhood experiences (ACEs)
  • Longitudinal MLSFH socioeconomic and health data: cognitive assessments, epigenetic clock measurements, other mental and physical health/aging measurements(frailty, activities of daily living (ADLs), blood pressure, etc.)

Project Summary:

In recent years, the exposome, encompassing the totality of environmental, socioeconomic, and health-related exposures throughout one’s life,1 has emerged as a pivotal yet understudied dimension in the understanding of aging trajectories, longevity, and Alzheimer’s Disease and Alzheimer’s Disease-Related Dementias (AD/ADRD) risk, resilience, and disparities. This project addresses a critical gap in global aging research by extending exposome science to a low-income Sub-Saharan African population that faces high climate vulnerability, socioeconomic change, and health system constraints. The overarching goal is to build foundational infrastructure and analytic methods to study how cumulative, multi-domain exposures shape cognitive aging and Alzheimer’s Disease and Alzheimer’s Disease-Related Dementia (AD/ADRD) risk in this context.

This includes developing a modular, geospatially-coded exposome database in Malawi, which will link historical census, environmental/climate data, and other administrative data to longitudinal household data from the Malawi Longitudinal Study of Families and Health (MLSFH) that are precisely geo-coded for integration. By launching the development of this database, we can begin to evaluate the association between exposomal factors and the aging process, with a particular focus on cognitive decline and AD/ADRD, using the Harmonized Cognitive Assessment Protocol (HCAP) survey measures in the MLSFH, forthcoming epigenetic data, and other ADRD risk factors.

Outputs:

Phase 1: Data cleaning, geocoding, aggregation of NSO and MLSFH data; construct first version of exposome database with documentation

Phase 2: Link exposures to longitudinal cognition data and implement analytic strategies to evaluate cumulative and life course effects

Phase 3: Finalize modeling of cognitive decline and indicators for ADRD risk, draft manuscript, and prepare data products for dissemination

References:

[1] Christopher Paul Wild. The exposome: from concept to utility. International Journal of Epidemiology, 41(1):24–32, 01 2012. doi: 10.1093/ije/dyr236.