PoplHlth Module 3

• Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems
• Epidemiology can play a central role in preventing disease (injury) by: unravelling the causal pathway, directing preventive action, and evaluation of effectiveness
• The need for prevention is growing as the limitations in curing disease become apparent and as the costs of medical care escalate
• Population Health Actions

  • Health Promotion
  • Disease Prevention
  • Health Protection
• Population-based (mass) strategy

  • Focuses on the whole population
  • Aims to reduce the health risks/improve the outcome of all individuals in the population
  • Useful for a common disease or widespread cause
• Population-based (mass) strategy


  • Immunisation programmes
  • Legislated use of seatbelts
  • Low salt foods at supermarkets
• High-risk (individual) strategy


  • Focuses on individuals perceived to be a high risk
  • The intervention is well matched to individuals and their concerns
• High-risk (individual) strategy


  • Intervention targeting obese adults
  • Intervention targeting intravenous drug users
• The NZ Needle Exchange Programme is the first of its kind in the world, running for over 30 years
• The Health (Needles and Syringes) Regulations 1987 decriminalised the sale of needles and syringes to Injecting Drug Users (IDUs) provided their sale was part of the Needle Exchange Programme
• In 2006, the national distribution of injecting equipment was >2 million units/pa
• The NZ Needle Exchange Programme has been extremely successful at preventing the spread of HIV amongst IDUs, and NZ has one of the lowest rates of HIV infection amongst injecting drug users in the OECD
• Advantages of population-based (mass) strategy

  • Radical - addresses underlying causes
  • Large potential benefit for whole population
  • Behaviourally appropriate
• Disadvantages of population-based (mass) strategy

  • Small benefit to individuals
  • Poor motivation of individuals
  • Whole population is exposed to downside of strategy
• Advantages of high-risk (individual) strategy

  • Appropriate to individuals
  • Individual motivation
  • Cost effective use of resources
  • Favourable benefit-to-risk ratio
• Disadvantages of high-risk (individual) strategy

  • Cost of screening, need to identify individuals
  • Temporary effect
  • Limited potential
  • Behaviourally inappropriate
• Health Promotion


  • Acts on determinants of wellbeing
  • Health/wellbeing focus
  • Enables/empowers people to increase control over, and improve, their health
  • Involves whole population in everyday contexts
• The Alma Ata 1978 Declaration for primary health care outlined prerequisites for health including peace, shelter, education, food, income, ecosystem, and social justice
• The Alma Ata Declaration advocated for a health promotion approach to primary care, to protect and promote the health of all
• The Ottawa Charter for Health Promotion


  Acknowledges health as a fundamental right for everybody, requiring both individual and collective responsibility, with equal opportunity for good health as an essential element of social and economic development
• 3 basic strategies of the Ottawa Charter

  • Enable: Provide opportunities for healthy choices
  • Advocate: Create favourable environments by promoting health and equity
  • Mediate: Facilitate individuals, groups and parties to work together
• 5 priority action areas of the Ottawa Charter


  • Develop personal skills
  • Strengthen community action
  • Create supportive environments
  • Reorient health services towards primary health care
  • Build healthy public policy
• Disease Prevention


  • Disease focus
  • Looks at particular diseases (or injuries) and ways of preventing them e.g. the incidence, the prevalence, risk factors, or impacts
• Levels of Disease Prevention

  • Primary: Limit the occurrence of disease by controlling specific causes and risk factors
  • Secondary: Early detection to reduce the more serious consequences of disease
  • Tertiary: Reduce the complications of established disease
• Health Protection


  • Predominantly environmental hazard focused
  • Risk/Hazard assessment
  • Occupational health & Monitoring
  • Risk communication
• Health promotion acts on the determinants of wellbeing, disease prevention focuses on particular diseases and their prevention, and health protection focuses on environmental hazards and their management
• Population-based (mass) prevention strategies can provide large potential benefits for the whole population, while high-risk (individual) strategies are more appropriate and motivating for individuals
• The Ottawa Charter provides guidance for health promotion through its strategies of enabling, advocating and mediating, as well as its priority action areas
• Health protection strategies focus on environmental hazards