1 Accounting for Death in the Tri-national Impact Assessment UN / ECE Symposium, London 18 th / 19 th February 2001 Nino Künzli, MD PhD Assistant Professor (PD) Institute of Social and Preventive Medicine University Basel HEIFeb01.ppt

2 Focus Background of the Trinational Study General Method Attributable Death Interpretation and uncertainties Conclusion HEIFeb01.ppt

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4 Question of the Authorities of Austria, France, & Switzerland: What are the health costs of traffic- related air pollution ? UNECE1.ppt

5 Requires interdisciplinary approaches Air pollution concentrationsAir Hygiene Population exposure distributionGIS Exposure - Response functionEpidemiology Derivation of attributable cases Epi Risk Assess. CostingEconomy UNECE.ppt

6 Uncertainties –multiple sources of uncertainties –majority: not statistical uncertainties –conceptual and data uncertainties –gaps at interdisciplinary interface UNECE.ppt “At least” approache with risk function based 95% CI

7 Definition of Air Pollution Exposure –Availability of effect functions –Availability of exposure data –no multiple counting (correlated pollutants; same sources) UNECE.ppt PM 10 „at least“

8 Selected Attributable Health outcomes Attributable Death Long-term effect Hospital admissions (cardio-resp.)Short-term effect Chronic bronchitis incidence (adults) Long-term effect Bronchitis episodes (children)Short-term effect Restricted activity daysShort-term effect Asthma attacks (children & adults) Short-term effect UNECE.ppt

9 Impact Assessment Model Exposure-response function PM10 # Death Attributable death PM10 reference 7.5 ug/m3 „at least“

10 Exposure-Response Function for Mortality Weighted average of : –ACS-Study (Pope et al., 1994) –Harvard 6-City Study (Dockery et al, 1993) 4.3 % (95% CI: %) increase per 10  g/m 3 PM 10 ~ 360 ( ) attributable death per 10  g/m 3 PM 10 and 1 Mio. inhabitants UNECE.ppt

Frequency distribution of total PM10 population exposure UNECE.ppt

13 Air Pollution Attributable Death in Austria, France and Switzerland Attributable Death (adults  30 yrs.) Total # cases:40‘600 (24‘600-56'900) or:~ 6% ( %) of total deaths Traffic related:21’800 (13’ ’600) UNECE.ppt

14 See: Sommer et al, in OECD Report: Ancillary Benefits and Costs of Greenhouse Gas Mitigation, New York; 2000 Monetarization of attributable death in the Trinational Study source: Willingness-To-Pay estimates value: 900‘000 EUR per statistical fatality total:36.5 Mio. EUR UNECE.ppt

15 Air pollution related health costs ~ 50‘000 Mio. EUR per year traffic related: ~ 27‘000 Mio EUR per year UNECE.ppt

16 Key Outcome Uncertainties 1) Why cohort study estimates? 2) Attributable death and life time lost 3) Are US-Studies relevant for Europe? 4) Are effects source specific? 5) Are “attributable” death “preventable” UNECE.ppt

17 1) Why Cohort study based Attributable Death ? UNECE.ppt OR: Why not time-series based estimates, which are 5-10 times smaller ?

18 Frailty and Death Frailty (susceptibility for death) Time Birth Death Age at death

19 Frailty and Exposure Frailty (susceptibiltiy for death) Time Birth Death Age at death Start smoking

20 Contribution of Air Pollution Frailty (susceptibility for death) Time Birth Death Age at death SMOG EPISODE Cumulative exposure Chronic Bronchitis

21 Focus of the Time-series analysis Frailty (susceptibilty for death) Time Birth Death

22 Time-series: counting advancement of death UNECE.ppt Period of exposure Time Time to event Period of events Death counts Pollution SHORT PERIODS

23 Time-series 1) Time-series captures –short-term effects only –not all short-term effects 2) Life time lost not known > > incomplete impact assessment 3) Long-term effect on life shortening not measured

24 Focus of the Cohort Study Frailty (susceptibilty for death) Time Birth

25 Cohort studies capture cumulative total effects on time to death > more complet counting of effects BUT: no distinction of acute and long-term only US studies YoLL not published /QALY not assessed

26 Long-term and short-term cases (Künzli et al, Am J Epidemiol 2001 in press, adapted from COMEAP, 1998) All Death long-term effect short-term effect All Air Pollution cases Mixed effects

27 2) Number of death versus years of life lost Both: Life expectancy in a population annual number of deaths depend on: age specific death rates

28 BUT: published are only number of deaths ! Indirect estimates of years of life lost: life table approache assumptions about age structure of cases

29 Mortality in the Trinational Study 1) Direct estimates of „attributable death“ ( > age 30; non-violent death) 2) Years of life lost: Indirect estimates, used for costing assumptions: –the attributable death are due to cardiopulmonary causes –same age distribution as all cardiopulmonary death –thus: typical age of an „air pollution death“ ~75-80 yrs.

30 Average reduction in population life expectancy For a population with a 10  g/m 3 higher PM 10 Sommer et al. (Trinational Study) : ~0.5 yr other estimates:~6 mo. to ~2 yrs. (Brunekreef; Pope; Leksell; Hurley; Miller; Rabl etc.)

31 3) We transfered the US cohort results to Europa ! UNECE.ppt Consistency for other outcomes between US and European countries Coherence between different outcomes

32 Mortality (adjusted Relative Risk) and long-term mean pollution (PM2.5) Harvard Six-City Cohort Study, Dockery et al, NEJM 1993; 329 (24): Relative Risk mean PM2.5 UNECE.ppt

33 Annual mean PM10 and expiratory capacity (FVC) in the 8 SAPALDIA areas Ackermann-Liebrich et al, AJRCCM 1997; 155 (1): PM10 annual mean (  g / m 3 ) FVC % deviation from predicted UNECE.ppt

34 Other Evidence? UNECE.ppt Europe French PAARCsuggestive abstract Dutch cohortsuggestive abstract SAPALDIA ??Needs other 10 yrs. ECRHS ??? USA: Abbey et al1999interaction with sex? Krewski et al 2000interaction with SES?

35 4) Are attributable death source specific? UNECE.ppt Assumption in tri-national study: PM 10 effects are independent of PM source -> one single effect slope

36 Percent Change (and 95th CI) in Daily Death per 10  g/m 3 PM2.5 mass an source specific elements , Harvard Six Cities; Laden et al, Env Health Perspect 2000; 108 (10): PM2.5 mass Crustal (Si) Motor (Pb) Coal (Se)

37 Percent Change (and 95th CI) in Daily Death per 10  g/m 3 PM2.5 mass an source specific elements , Harvard Six Cities; Laden et al, Env Health Perspect 2000; 108 (10): PM2.5 mass Crustal (Si) Motor (Pb) Coal (Se)

38 Percent Change (and 95th CI) in Daily Death per 10  g/m 3 PM2.5 mass an source specific elements , Harvard Six Cities; Laden et al, Env Health Perspect 2000; 108 (10): PM2.5 mass Crustal (Si) Motor (Pb) Coal (Se)

39 Percent Change (and 95th CI) in Daily Death per 10  g/m 3 PM2.5 mass an source specific elements , Harvard Six Cities; Laden et al, Env Health Perspect 2000; 108 (10): PM2.5 mass Crustal (Si) Motor (Pb) Coal (Se)

40 5) Are „attributable death“ also „preventable death“? UNECE.ppt

41 Unknown time domaines Duration of ‘long-term’ exposure Relevant time window of exposure Time between exposure and effect  Time between intervention and benefit? UNECE.ppt

42 Time-to-Benefit (death, long-term) (Sommer et al., 1999) UNECE.ppt Attributable Costs Time (yrs) Clean air intervention 1020

43 Competing risks Removal of one long-term health risk factor will modify the importance of the remaining risks “attributable death” > “preventable death” UNECE.ppt

44 TSP decrease and reduction in bronchitis prevalence (Germany, 1993 versus 1995, children, age 5-14 yrs) annual mean of TSP  g/m bronchitis prevalence (%) Year: Hettstedt Bitterfeld Zerbst (Heinrich et al, AJRCCM 2000; 161: ) COP6DenHaag.ppt

Jahresmittel PM10(  g/m 3 ) Montana Payerne Langnau Rheintal Biel Lugano Genf Zürich Bern Anières Annual mean PM10  g/m 3 Acute bronchitis in children and annual mean PM10 The SCARPOL Study C. Braun-Fahrländer; AJRCCM 1997 UNECE.ppt

46 Conclusion Air pollution accounts for 4-8% of death “Attributable death” from cohorts: adequate approache BUT: gaps in evidence and uncertainties: Best effect estimate? Years of life time lost? European long-term studies? Source attribution ? How many are “preventable death”? When? UNECE.ppt

47 Thanks Institute of Social and Preventive Medicine University Basel

48 Susceptibility and Time-to-event Probability of event Time High susceptibility Early response Low susceptibility Late response Exposure