confounding factors in evaluation of age related changes

Introduction

Factors include:

• disease
  • is a change secondary to aging or disease?
  • clinical vs subclinical disease
  • is no disease really normal?
• covariate effects
  • % body fat
  • activity level
  • smoking history
  • environmental exposures (i.e. sun)
• cohort effect
  • level of education
  • importance of regular bowel movements
• secular trends
  • diet
    • fat consumption
    • salt consumption
  • exercise
• individual variability
  • elderly are not a homogeneous group
  • variability increases with age among individuals
  • variability decreases with age within a given individual (biological rhythms)
• data collection
  • cross-sectional
  • longitudinal

Additional terms

• cross-sectional population study
• longitudinal population study