Ecological trend analysis is a type of descriptive epidemiological study that examines changes in disease rates, exposures, or health outcomes over time using population-level (grouped) data, rather than individual-level information.
Key Features
Unit of analysis: groups or populations (e.g., countries, regions, age cohorts), not individuals.
Objective: to assess temporal patterns and trends in disease burden, risk factor exposure, or health outcomes.
Data sources: often derived from national registries, surveys, census data, international databases (e.g., WHO, GBD).
Commonly used in:
Global burden of disease studies
Environmental health (e.g., air pollution, climate)
Socioeconomic or policy impact assessments
Methods:
Time series analysis
Regression models (e.g., Joinpoint, Poisson, or age–period–cohort models)
Age-standardized rate comparisons across time
Strengths
Useful for generating hypotheses
Enables cross-national or global comparisons
Can identify public health priorities and monitor progress over time
Limitations
Subject to ecological fallacy — associations at the group level may not hold at the individual level.
May be affected by confounding variables that vary between groups or over time.