Global Disease Burden:

Dr Zahid KhanKing Faisl University,KSA.

Two public health questions:

• What is the total impact of disease and injury in the population? -- the overall target for public health interventions?

• How do we compare the impacts of different diseases, risk factors, and interventions that affect different populations?

Ultimate Measure of Ill-health?

• Death is most common• Easy to determine• Commonly tabulated

• Severe problems• Everyone dies• Health never achieved• Age is clearly important

• Deaths + Illness = ?

Global Burden of Disease Database

• Developed at Harvard University originally for the World Bank

• Extended greatly in the mid-1990s and now adopted by the World Health Organization

• Dozens of countries now have NBDs

Quality Adjusted Life YearsQALY

• Basically the number of fully healthy life years lost to a particular disease or risk factor.

• Considers the age at which the disease or death occurs and the duration and severity of any disability created.

Disability Adjusted Life YearThe DALY, a kind of QALY

• The only differences in the rating of a death or disability should be due to age and sex, not to income, culture, location, social class.

• Everyone in the world has right to best life expectancy in world

• DALY = YLL + YLD• Years of Lost Life (due to mortality)• Years Lost to Disability (due to injury & illness)

Schema for Assessing Non-fatalHealth Outcomes

Disability Handicap

Inability Unemployed

to walk

Difficulty Social isolation

learning

Disease Impairment

Polio Paralyzed legs

Brain Mild mental

injury retardation

Disability Adjusted Life YearThe DALY,s calculation.

Sample DALY CalculationsDiseases A and B

• A. 100,000 children are stricken for 1 week with a disability weighting of 0.3; 2% die at 1 year old.

• B. 100,000 adults are stricken for 2 years with a disability weighting of 0.6; 20% die at 80 years old.

• A: YLL (= 2000 x 80) + YLD (=100k x (7/365) x 0.3) = 160,000 + 575 = 160,600

• B: YLL (= 20,000 x 1) + YLD (=100k x 2 x 0.6) = 20,000 + 120,000 = 140,000

Definitions

• Impairment: loss or abnormality of psychological, physiological, or anatomical structure or function

• Disability: any restriction or lack of ability to perform an activity in the manner or within the range considered normal.

• Handicap: disadvantage resulting from impairment or disability that limits or prevents the fulfillment of a role that is normal (depending on age, sex, social, and cultural factors).

Deaths attributed to 19 leading factors,by country income level, 2004

Percentage of disability-adjusted life years (DALYs)

attributed to 19 leading risk factors, by country income level, 2004

Changing in causes of death

Respiratory Diseases

Cardiovascular diseases

OtherInfectiousDiseases

TB DiarrhoealDiseases

Injuries Cancer

Source: WHO 1999

1909 1999

Percentage distribution

1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050

Period

90

80

70

60

50

40

30

Exp

ecta

tion

of li

fe a

t bi

rth

(yea

rs)

More developed

World

Less developed Least developed

Source: Population division of the Dept. of Economic and Social Affairs, United States Secretariat (2003). World Population Prospects: The 2002 Revision Highlights. New York: United Nations.

Life expectancy trends

Population growth

0

1

2

3

4

5

6

7

8

9

Source: United Nations Populations Division, World Population Prospects, The 2004 Revision, medium variant.

Developing countries

Billions

Developed countries

Conclusions

• Inequality• Universal coverage• Nutrition transition: high levels of child under-nutrition and

adult obesity coexist• Double burden of diseases• Communicable, maternal, perinatal and nutritional

conditions• Non communicable diseases• Injuries• Health promotion can play important role

Any Queries !!!

• Thank You