Individual Disability-Adjusted Life Year: A Summary Health Outcome Indicator Used for Prospective Studies

  • P. Zhang
  • M. Woodward
  • J. Shen
  • Y. Wu
Reference work entry


In order to assess global health at individual level in prospective studies, a standard summary indicator of health – Individual DALY was established. It integrated all kind of disease into one measure, reflecting the healthy years lost during a period of time for an individual, with consideration of societal “ideal.”

Similar to Disability-Adjusted Life Year (DALY), Individual DALY used disability and disability weight to measure health problem and its severity after adjusting age and  time preference. Following assumptions were made: (1) individual DALY be defined as the cumulated  healthy life years lost for an individual during follow-up; (2) health status during a certain period of time kept stable, and the corresponding disabilities and disability weights could be assessed either by standard assessment tools during follow-up, or using the disease specific disability weights reported by  Global Burden of Disease study, with the precondition that the synthetic disability weight of  comorbidity had been resolved; (3) death be regarded as a special disability and assumed to be followed up until the end-point of follow-up. As a supplement to traditional population health assessment indicators, Individual DALY provides individual data and hence leads approaches in finding determinant factors of overall health more directly, evaluating effect of intervention more reasonably, and allocating health resource more effectively.

The calculation procedure, results, possible application and attentions were also illustrated using individual cases as an example.


Time Preference Disability Weight Discount Function World Health Survey World Health Organization Disability Assessment 

List of Abbreviations:


 body mass index


coronary heart disease


 disability-adjusted life expectancy


disability-adjusted life year


disability weight


global burden of disease


healthy life year


international classification of impairments, disabilities and handicaps

Individual DALY

 individual disability-adjusted life years


quality-adjusted life year


 relative risk


standard expected years of life lost


WHO’s disability assessment schedule


years lost due to disability


years of life lost


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Copyright information

© Springer Science+Business Media LLC 2010

Authors and Affiliations

  • P. Zhang
    • 1
  • M. Woodward
    • 2
  • J. Shen
    • 3
  • Y. Wu
    • 4
    • 5
  1. 1.Department of Quality ControlBeijing Management Center for Community Health ServiceBeijingChina
  2. 2.Director of Epidemiology and Biostatistics, the George Institute for International Healththe University of SydneyNSWAustralia
  3. 3.Pharmaceutical Product DevelopmentWilmingtonNC
  4. 4.Department of Epidemiology and BiostatisticsPeking University School of Public HealthBeijingChina
  5. 5.The George InstituteBeijingChina

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