Global Burden of Disease and the Role of Environmental Risk Factors Kirk R. Smith

1. Global Burden of Disease and the Role of Environmental Risk FactorsKirk R. Smith October 30, 2002

2. 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? For example, what is the burden of disease from environmental factors in populations at different levels of development?

3. 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 = ?

4. Need for a C4 Database • Combined mortality and morbidity • Complete • Much of the world unrepresented • Many important disabilities unaccounted • Consistent definitions of disease states • Coherent • Deaths by disease add to total • Statistics match by age and sex

5. Combined Measure • What else to use? • Money? Are you kidding? • Most fundamental deprivation is loss of time: life length shared by all humans Can be used for disabilities, but need to weight relative severity of disabilities

6. 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.

7. 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 • Even states (provinces) and cities have them, including SF and LA

8. Distribution of Global Deaths

9. 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)

10. Years of Lost Life: Examples

11. Examples of Disability Weights 1: 0-0.02 Vitiligo on face 2: 0.02-0.12 Diarrhea, sore throat 3: 0.12-0.24 Radius fracture in stiff cast 4: 0.24-0.36 Below the knee amputation 5: 0.36-0.5 Down syndrome, COPD 6: 0.5-0.7 Unipolar depression, tetanus 7: 0.7-1.00 Psychosis, quadriplegia

12. Disease Impairment Polio Paralyzed legs Brain Mild mental injury retardation Disability Handicap Inability Unemployed to walk Difficulty Social learning isolation Schema for Assessing Non-fatalHealth Outcomes

13. 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).

14. Sequence (can be bidirectional) • Exteriorization of symptoms at organ level • Objective alteration of behavior or performance at the individual level • Changed interaction with others at the social/environmental level

15. Neuropsychiatric Conditions • Unipolar depressive disorders • Bipolar disorder • Schizophrenia • Epilepsy • Alcohol use disorders • Alzheimer and other dementias • Parkinson disease • Multiple sclerosis • Drug use disorders • Post-traumatic stress disorder • Obsessive-compulsive disorder • Panic disorder • Insomnia (primary) • Migraine • Other neuropsychiatric disorders

16. Whom do you ask? • Patient • Family • Caregiver • Health professional • Public at large • Insurance companies

17. When do you ask? 1.0 Reported Health State Utility Accident Time

18. Comparative Disability Weights • Unipolar/bipolar depression ~ 0.6 • Schizophrenia ~ 0.6-0.7 • Terminal cancer ~ 0.8 • Blindness ~0.6 • Congestive heart failure ~ 0.3 • Down syndrome ~ 0.6 • Burns >60% of body: ~ 0.3-0.5 • Symptomatic COPD ~ 0.4

19. Total(millions) Per cent of total All causes 472.7 1. Unipolar major depression 50.8 10.7 2. Iron deficiency anaemia 22.0 4.7 3. Falls 22.0 4.6 4. Alcohol use 15.8 3.3 5.Chronic obstructive pulmonary disease 14.7 3.1 6. Bipolar disorder 14.1 3.0 7. Congenital anomalies 13.5 2.9 8. Osteoarthritis 13.3 2.8 9. Schizophrenia 12.1 2.6 10. Obsessive compulsive disorders 10.2 2.2 The leading causes of years lived with disability, worldwide, 1990

20. 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 8) + YLD (=100k x 2 x 0.6) = 160,000 + 120,000 = 280,000

21. 2000 Deaths vrs DALYs

22. World DALYS Lost (1990)

23. Impact on Women and Children

24. 2000 2000

25. 2000 2000

26. 2000 2000

27. 2000 2000

28. Top Ten Diseases - 1990 Africa = Sub Saharan Africa

29. Disease Categories • I - Traditional, Communicable • Infectious, maternal, perinatal, nutritional • II - Modern, Non-communicable • Cancer, heart, neuro-psychiatric, chronic lung, diabetes, congenital • III - Injuries, Non-Transitional • Unintentional • Motor vehicle, poisoning, falls, fire, drowning • Intentional • Suicide, violence, war

30. Epidemiologic Transition

31. Epidemiologic Transition-B

32. Epidemiologic Transition-C

33. Comparison of GBD Estimates for 2000 with GBD for 1990 • Population: 5.3/6.0 billion (+15%) • Deaths: 50/56 million (+10%) • DALYs: +6.7% • DALYS/capita: -7% • I = 44/42%; • II = 41/46%; • III = 15/12% World Health Report, 2001

34. Changes in Important Diseases: 1990-2000 • HIV: 0.8/6.1% (8.1x in absolute terms) • TB: 2.8/2.4% (0.93x) • Malaria: 2.3/2.7% (1.3x) • ARI: 8.5/6.6% (0.84x) • Diarrhea: 7.3/4.2% (0.62x) • Lung Cancer: 0.65/0.8% (1.3x) • Depression: 4.7/5.3 (1.21x) World Health Report, 2001

35. Overview 2002: SF YLLs (2000)

37. 1997 Los Angeles Burden of Disease DALY Rank Death Rank

38. Total(thousands) Per cent of total All causes 419,144 1. Unipolar major depression 42,972 10.3 2. Tuberculosis 19,673 4.6 3. Road traffic accidents 19,625 4.7 4. Alcohol use 14,848 3.6 5. Self-inflicted injuries 14,645 3.5 6. Bipolar disorder 13,189 3.1 7. War 13,134 3.1 8. Violence 12,955 3.1 9. Schizophrenia 12,542 3.0 10. Iron-deficiency anaemia 12,511 3.0 The leading causes of DALYs at ages 15-44 years worldwide, 1990

39. DALYs(1000s) Per cent of total All causes 160,944 1. Ischaemic heart disease 15,950 9.9 2. Unipolar major depression 9,780 6.1 3. Cerebrovascular disease 9,425 5.9 4. Road traffic accidents 7,064 4.4 5. Alcohol use 6,446 4.0 6. Osteoarthritis 4,681 2.9 7. Trachea, bronchus and lung cancers 4,587 2.9 8. Dementia and other degenerative and hereditary CNS disorders 3,816 2.4 9. Self-inflicted injuries 3,768 2.3 10. Congenital abnormalities 3,480 2.3 Ten leading causes of DALYs in developed regions, 1990

41. Can we reach public health?

42. Harvard Burden of Disease Unit http://www.hsph.harvard.edu/organizations/bdu/ SF Burden of Disease and Injury Study http://www.medepi.org/sfbdi/ World Health Report – 2002 http://www.who.int/whr/ WHO Comparative Risk Assessment Methods http://www.ctru.auckland.ac.nz/CRA/ Thank you.