Exposome: Concept, Components, Importance, Disease Links, Study Methods, Human Exposome Project & Indian Context

What is the Exposome ?

The Exposome is an emerging scientific concept that refers to the totality of environmental exposures a person experiences throughout life — from conception to death — and how they influence health.

It complements the idea of the genome:

• Genome → genetic factors
• Exposome → environmental & non-genetic factors

The term was proposed in 2005 by epidemiologist Christopher Wild.

According to the International Human Exposome Network (IHEN), the exposome is: “the integrated collection of all physical, chemical, biological and psychosocial factors and their interactions affecting human health across the lifespan.”

In simple terms: While genes load the gun, the exposome pulls the trigger.

Components of the Exposome

The exposome has two broad categories: external exposures and internal exposures.

1. External Exposures

These come from the surrounding environment.

a) Environmental Factors

• Air pollution (PM2.5, ozone)
• Water contamination
• Soil chemicals
• Radiation
• Noise pollution

b) Chemical Exposures

• Pesticides
• Plastic chemicals (e.g., BPA, phthalates)
• Heavy metals (lead, mercury, arsenic)
• Industrial emissions

c) Biological Agents

• Bacteria
• Viruses
• Allergens (pollen)
• Microorganisms

d) Psychosocial Factors

• Stress
• Poverty & inequality
• Urbanization
• Workplace pressure

2. Internal Exposures

These occur within the body in response to external exposures.

• Metabolism (biochemical reactions)
• Microbiome (gut bacteria affecting immunity & nutrition)
• Inflammation & oxidative stress
• Lifestyle factors (diet, smoking, alcohol, physical activity)

These exposures accumulate across life and interact with genes to determine disease susceptibility.

Importance of the Exposome & Link with Diseases

Research suggests:

• 70–80% of diseases are influenced by environmental factors
• 20–30% by genetics

Thus, the exposome fills the gap left by genome-only research.

Major Diseases Associated

Examples

• High PM2.5 levels → respiratory illness
• Childhood lead exposure → reduced adult cognitive ability
• Social inequality → chronic disease risk

Policy relevance

• Enables personalized prevention
• Supports wearable health monitoring
• Helps preventive public health strategies

Exposomics: Methods of Study

Exposomics = scientific study of the exposome. It uses both internal and external assessment tools.

1. Internal Assessment (Biological response measurement)

Uses “-omics” technologies:

• Genomics
• Transcriptomics
• Proteomics
• Metabolomics
• Lipidomics

These identify biomarkers showing exposure effects.

2. External Assessment (Exposure measurement)

• Wearable sensors (air quality monitors)
• Environmental sampling
• Laboratory analysis
• Questionnaires & lifestyle surveys
• Satellite & geospatial data

Role of Technology

• Artificial Intelligence
• Big Data analytics
• Machine learning models

They help map complex exposure–disease relationships.

Global Efforts: Human Exposome Project

Scientists worldwide aim to map the Human Exposome, similar to the Human Genome Project.

Major Initiatives

1. International Human Exposome Network (IHEN) – 2023

• Global coordination platform
• Based on European Human Exposome Network
• Large-scale collaborative research

2. Human Exposome Project (HEP)

• Lifetime exposure mapping
• AI-driven medical insights
• Moves medicine beyond genetics

3. European Human Exposome Network (EHEN) – 2020–2025

• Focus on urbanization, workplace, mental health

4. EIRENE Infrastructure – 2021

• Pan-European exposome research system

Expected Impact

• Disease prevention
• Precision medicine
• Better environmental policies

Exposome in the Indian Context

India has a high environmental disease burden.

Key concerns:

• Severe air pollution
• Contaminated water
• Chemical exposure
• Rising non-communicable diseases (NCDs)

Environmental factors contribute significantly to public health problems.

Potential Benefits for India

• Pollution–health mapping
• Early disease prediction
• Targeted public health programs
• Integration into National Health Mission
• Rural–urban health disparity assessment

Current Status

Exposomics research is emerging in:

• Pollution mapping
• Risk assessment studies
• Environmental epidemiology

Challenges

• Data collection complexity
• Privacy and ethics concerns
• Limited infrastructure
• Funding constraints

Challenges & Future Directions

Challenges

• Complete lifetime exposure mapping is extremely difficult
• Ethical issues (data privacy)
• Standardization of measurement
• Cost and infrastructure

Future

• Wearable monitoring devices
• AI-driven health prediction
• Personalized preventive medicine
• Integration with national health systems