Estimating the Global Death Toll from Tobacco

1
Estimating the Global Death Toll from Tobacco
Michael Thun, MD, MS Lindsay Hannan,
MSPH American Cancer Society
WCTOH July 12, 2006
2
Overview

• In the 20th century, smoking caused an estimated
  100 million deaths.
• In the 21st century, if current usage patterns
  persist, smoking will cause approximately 1
  billion deaths

Peto R, Lopez AD. Future worldwide health effects
of current smoking patterns. In Koop CD, Pearson
C, Schwarz MR, eds. Critical issues in global
health. New York, NY Jossey-Bass 2001.
3
Global cigarette consumption Billions of
sticks, 1880-2000
Source The Tobacco Atlas, World Health
Organization 2002.
4
Objectives

• Describe how the burden of smoking-attributable
  deaths is estimated
• Describe major global trends in the burden of
  smoking attributable deaths
• Describe which factors and disease conditions
  have the greatest impact on the burden

5
What studies are used to estimate the number of
deaths attributed to smoking?

• WHO Global Burden of Disease (GBD) mortality
  database
• IARC Globocan database
• American Cancer Society CPS-II
• Developing countries and China
• Liu B, Peto R et al. BMJ, 1998.

6
How is the number of deaths attributed to smoking
estimated?
7
Peto-Lopez Indirect Method for Calculating Deaths
Attributed to Smoking

• Required data
• Age-specific lung cancer deaths rates for study
  country and age-specific counts of deaths from
  diseases of interest
• Age-specific lung cancer mortality rates for
  CPS-II never smokers and current smokers
• Age-specific or age-standardized (depending on
  disease of interest) relative risk estimates for
  current vs. never smokers in CPS-II, adjusted for
  age.

8
1. Calculate SIR

• SIR Smoking impact factor
• Lung cancer mortality used as indirect indicator
  of accumulated risks from smoking
• This ratio corresponds to the absolute excess
  lung cancer death rate in the country of interest
  relative to the absolute excess among a known
  reference group of smokers (CPS-II)
• Approximates the proportion of ever smokers in
  the study country

Ezzati M, Lopez AD. Measuring the accumulated
hazards of smoking global and regional estimates
for 2000. Tob. Control 2003 1279-85.
9
How the SIR is estimated for economically
developed countries
Lung cancer death rate in excess of never smokers
in country of interest
CLC NLC
SIR
SLC NLC
Excess lung cancer death rate for known reference
group of smokers
CLC lung cancer mortality rate in country of
interest NLC lung cancer death rate among
never-smokers in CPS-II SLC lung cancer
mortality rates for smokers in CPS-II
10
How the SIR is estimated for developing countries
Lung cancer death rate in excess of never smokers
in country of interest
Adjustment for differences in lung cancer
mortality rate among nonsmokers in the two
populations
CLC - NLC
x
SIR
SLC NLC
Excess lung cancer death rate for known reference
group of smokers
CLC lung cancer mortality rate in country of
interest NLCWeighted estimate of lung cancer
mortality rate in non-smokers in country of
interest SLC lung cancer mortality rates for
smokers in CPS-II NLClung cancer mortality
rates for nonsmokers in CPS-II
11
2. Estimates reduced by a constant to get a more
conservative estimate of risk

• Excess risk in relative terms RR-1
• Multiply excess risk in CPS-II by constant c
  (smoking attributable mortality fraction
  estimate)
• Peto-Lopez use c0.5
• Ezzati uses c0.7
• Calculate RR
• RR c(RR-1) 1
• This underestimates the attributable risk

12
3. SIR and RR are inserted into the following
equation
(RR-1)
p (RR-1)
SIR
AFs

p (RR-1) 1
SIR
(RR-1)
13
4. Smoking attributable mortality (SAM)
SAM number of deaths x AFs
14
What diseases does smoking cause?
15
Diseases included in estimation of deaths
attributed to smoking

• Lung cancer
• Cardiovascular diseases (IHD, stroke, etc)
• COPD
• Upper aerodigestive cancers (mouth, pharynx,
  larynx, esophagus)
• Other cancers (pancreas, kidney, stomach, liver,
  cervix, bladder)
• Other respiratory diseases
• Other medical causes

Ezzati M, Lopez AD. Estimates of global
mortality attributed to smoking in 2000
16
Composition of diseases attributed to smoking
varies by country/region

• COPD predominates in China ( 35 of all deaths
  from smoking)
• TB predominates in India ( 23 of deaths from
  smoking)
• CVD is the leading cause of death attributed to
  smoking in developed countries ( 42 of deaths
  from smoking)

Ezzati M, Lopez AD. Lancet 2003
Ezzati M, Lopez AD. Tobacco control 2004
Gajalakshmi V, Peto R et al. Lancet 2003
17
Differences in the composition of deaths
attributed to smoking in developed and developing
countries, 2000
Developed countries
Developing countries
Upper aerodigestive cancers, 6.6
Upper aerodigestive cancers, 3.7
Total 2.41 million deaths
Total 2.43 million deaths
Ezzati M, Lopez AD. Regional, disease-specific
patterns of smoking-attributable mortality in
2000. Tobacco control 13(4), 388-94 (2004).
18
Where are the smokers?
19
Most smokers in 2000 lived in economically
developing countries
Developed countries Japan, Canada, US, Australia,
New Zealand, Western Europe (24 countries)
Developing countries (84 countries)
Transitional countries Former Soviet bloc /
Eastern Europe (23 countries)
Guindon GE, Boisclar D. Past, Current and Future
Trends in Tobacco use. HNP discussion paper
Economics of Tobacco Control Paper No. 6 March
2003.
20
Numbers of smokers, 2000, by country or region,
(Ages 15 years)
Modified from Guindon GE, Boisclair D. Past,
Current and Future Trends in Tobacco use. HNP
discussion paper Economics of Tobacco Control
Paper No. 6 March 2003.
21
Smoking-attributable deaths worldwide
22
80 of deaths attributed to smoking in 2000 were
among men
Ezzati M, Lopez AD. Estimates of global
mortality attributed to smoking in 2000
23
The number of deaths attributed to smoking in
2000 were approximately equal in developed and
developing countries
Ezzati M, Lopez AD. Estimates of global
mortality attributed to smoking in 2000
24
The number of smoking attributable deaths is
increasing worldwide
Murray CJL, Lopez AD. Alternative projections of
mortality and disability by cause 1990-2020
Global Burden of Disease Study
25
By 2030, 7 of every 10 tobacco attributable
deaths projected to be in developing countries
The global burden of deaths from tobacco is
shifting from developed to developing countries
World Health Organization. 1999. Making a
Difference. World Health Report. 1999. Geneva,
Switzerland
26
Rear View Mirror- Trends in Cigarette Consumption
and Lung Cancer Mortality in the US
Lung cancerdeath ratesMen
1964
Per capita cigarette consumption
Lung cancerdeath ratesWomen
Per 100,000, age-adjusted to 2000 U.S. standard
population. Data Source Death rates US
Mortality Public Use Tapes, 1960-2002, US
Mortality Volumes, 1930-1959, National Center for
Health Statistics, Centers for Disease Control
and Prevention, 2006. Cigarette
consumption US Department of Agriculture,
1900-1987, 1988, 1989-2003.
27
All developed countries
Mortality from smoking in developed countries,
1950-2000. http//www.ctsu.ox.ac.uk/tobacco/C0003
.pdf
28
Smoking-attributed number of deaths per year,
1955-2000, in established market economy
countries (EME) and in former socialist economy
countries (FSE)
Men - EME
Men - FSE
Women - EME
Women - FSE
Modified from Peto R, Lopez AD et al. BMJ, 1996
with data from Peto R, Lopez AD et al.
http//www.ctsu.ox.ac.uk/tobacco/index.htm
29
Lung cancer mortality age 35-69, for selected
countries, 1960-2000
US
UK
France
Hungary
Peto R, Lopez AD et al. http//www.ctsu.ox.ac.u
k/tobacco/index.htm
30
Deaths attributed to tobacco use in 1990 2020
by region,
Murray CJL, Lopez AD. Alternative projections of
mortality and disability by cause 1990-2020
Global Burden of Disease Study
31
Largest absolute increase in deaths attributed to
smoking from 1990 to 2020
China 1.4 m In 2020, 2.2 million deaths from
smoking will occur
China 1.4 m In 2020, 2.2 million deaths from
smoking will occur
India 1.4 m In 2020, 1.5 million deaths from
smoking will occur
32
Where is the burden increasing the fastest, 1990
to 2020?
33
Estimated cancer deaths attributed to smoking in
developed and developing countries in 2000, WHO
and IARC (estimates in thousands)
Ezzati M, Lopez AD. Role of smoking in global
and regional cancer epidemiology current
patterns and data needs. In J Cancer 116,
963-971 (2005)
34
Distribution of smoking caused cancer mortality
for males and females in developed regions, 2000
Upper aerodigestive cancers 9
Upper aerodigestive cancers 13
Women
Men
WHO 630,000 deaths IARC 664,000 deaths
WHO 165,000 deaths IARC 161,000 deaths
Ezzati M, Lopez AD. Role of smoking in global
and regional cancer epidemiology current
patterns and data needs. In J Cancer 116,
963-971 (2005)
35
Distribution of smoking caused cancer mortality
for males and females in developing regions, 2000
Upper aerodigestive cancers 21
Upper aerodigestive cancers 30
Women
Men
WHO 75,000 (50,000-112,000) deaths IARC 64,000
deaths
WHO 549,000 (435,000-637,000) deaths IARC
464,000 deaths
Ezzati M, Lopez AD. Role of smoking in global
and regional cancer epidemiology current
patterns and data needs. In J Cancer 116,
963-971 (2005)
36
Estimated cardiovascular deaths attributable to
smoking in developed and developing countries in
2000, WHO (estimates in thousands)
Ezzati M, Lopez AD. Role of smoking in global
and regional cancer epidemiology current
patterns and data needs. In J Cancer 116,
963-971 (2005)
37
Note All of the above calculations based on
smoking. Large disease burden caused by use of
smokeless products in India and Southeast Asia
not considered.
38
How is this information useful?
39
Communication tool to politicians
4 stages of the smoking epidemic
40
Can help shape public health priorities
Federal Expenditures on Health Problems, US,
1994-1995
Illicit Drugs
Dollars (billions)
AIDS
Tobacco
Alcohol
Preventable Deaths in 1989, Thousands
41
Counteract Complacence
Factors with the greatest impact on the burden of
deaths from tobacco

• Length of time people have been smoking seriously
• Background disease risks from factors other than
  smoking

42
(No Transcript)