National and subnational mortality effects of major metabolic risk factors and smoking in
Iran: a comparative risk assessment
Scientific Webinars
Farzadfar et al PHM 2011
May 11 2012
Presented by Goodarz Danaei
• What is the most common cause of death and disabilities in Iran in men?a. Ischemic heart disease
b. Stroke
c. Lung cancer
d. Road traffic injuries
• What is the most common cause of death and disabilities in Iran in women?a. Ischemic heart disease
b. Stroke
c. Lung cancer
d. Road traffic injuries
• What is the most important NCD risk factor for mortality in Iran?a. Overweight/obesity
b. High blood pressure
c. Smoking
d. High serum cholesterol
e. Diabetes and high blood glucose
Outline
• Background
• Data sources and methods
• Findings
• Conclusion and future directions
Outline
• Background
• Data sources and methods
• Findings
• Conclusion and future directions
Global epidemiological transition
Lopez et al. Lancet 2006
Cardiovascular mortality in high-income countries
Vital registration data from WHO
0
4
8
12
16
20
1950 1960 1970 1980 1990 2000 2010
Year
Dea
th R
ate
(per
1,0
00)
Male - CVD
Male Female
0
4
8
12
16
20
1950 1960 1970 1980 1990 2000 2010
Year
Dea
th R
ate
(per
1,0
00) USA
Denmark
Finland
Sweden
UK
Australia
Female - CVD
Regional trends in blood pressure
North America
North America
Mal
eF
emal
e
Danaei et al. Lancet 2011
Regional trends in blood pressure
North America
North America
Mal
eF
emal
e
North Africa and Middle East
Danaei et al. Lancet 2011
North Africa and Middle East
Ma
le F
em
ale
Trends in CVD risk factors in Iran
TC BMI SBP
Farzadfar et al. Lancet 2011, Finucane et al. Lancet 2011, Danaei et al. Lancet 2011
4.0
4.4
4.8
5.2
5.6
6.0
1980 1990 2000 2010
mm
ol/L
20
22
24
26
28
30
1980 1990 2000 2010
kg/m
^2
20
22
24
26
28
30
1980 1990 2000 2010kg
/m^2
115
120
125
130
135
140
1980 1990 2000 2010
mm
Hg
4.0
4.4
4.8
5.2
5.6
6.0
1980 1990 2000 2010
mm
ol/L
115
120
125
130
135
140
1980 1990 2000 2010
mm
Hg
Selected risk factors
• Systolic blood pressure (SBP)
• Body mass index (BMI)
• Fasting plasma glucose (FPG)
• Total cholesterol (TC)
• Smoking
Outline
• Background
• Data sources and methods
• Findings
• Conclusion and future directions
Data sources
• Risk factor exposure: Non-communicable diseases surveillance survey (2005)
• Relative risks:
Danaei et al 2009
Law 2003
Prospective Studies Collaboration 2007
• Mortality:
Death registration system (2005)
Tehran cemetery
Non-communicable diseases surveillance survey 2005
• Multistage systematic cluster sampling
• 89,400 adults aged 15-64 years
– Questionnaire and physical measurements
• 50,200 adults aged 25-64 years
– lab data including fasting blood sample
Analytical framework
Relative risksRisk factor exposure
Optimal exposure level
Population attributablefraction
Analytical framework
Relative risksRisk factor exposure
Optimal exposure level
Population attributablefraction
Analytical framework
Relative risksRisk factor exposure
Optimal exposure level
Disease-specific attributable
deaths
Disease-specific deaths
Correction for incompleteness
Redistribution of deaths with
unspecified cause
Analytical challenges
• Risk factor exposure:No exposure data in older age groups
• Disease-specific deaths: Incompleteness of death registration system Redistribution of deaths with unspecified cause
• Uncertainty in estimates: Sampling uncertainty Etiological effects uncertainty Uncertainty in the model for missing older age groups Completeness estimation uncertainty Uncertainty in proportional redistribution of deaths with unspecified cause
Analytical challenges
• Risk factor exposure:No exposure data in older age groupsInsufficient data on smoking history
• Disease-specific deaths: Incompleteness of death registration system Redistribution of deaths with unspecified cause
• Uncertainty in estimates: Sampling uncertainty Etiological effects uncertainty Uncertainty in the model for missing older age groups Completeness estimation uncertainty Uncertainty in proportional redistribution of deaths with unspecified cause
Smoking Impact Ratio
•The accumulated hazards of smoking depend:the age at which smoking begannumber of cigarettes smoked per dayand cigarette type
These data are extremely rare.
•Estimation of Disease Burden
CLC= Age-sex specific lung cancer mortality rate in a populationNLC= Age-sex specific lung cancer mortality rate of never-smokers in thesame populationS*LC and N*LC = Age-sex specific lung cancer mortality rates forsmokers and never-smokers in a reference population (Cancer Prevention Study II (CPS-II) )
Analytical challenges
• Risk factor exposure:No exposure data in older age groupsInsufficient data for smoking history
• Disease-specific deaths: Incompleteness of death registration system Redistribution of deaths with unspecified cause
• Uncertainty in estimates: Sampling uncertainty Etiological effects uncertainty Uncertainty in the model for missing older age groups Completeness estimation uncertainty Uncertainty in proportional redistribution of deaths with unspecified cause
Analytical challenges
• Risk factor exposure:No exposure data in older age groupsInsufficient data for smoking history
• Disease-specific deaths: Incompleteness of death registration system Redistribution of deaths with unspecified cause
• Uncertainty in estimates: Sampling uncertainty Etiological effects uncertainty Uncertainty in the model for missing older age groups Completeness estimation uncertainty Uncertainty in proportional redistribution of deaths with unspecified cause
Selected regions for subnational analysis
Outline
• Background
• Data sources and methods
• Findings
• Conclusion and future directions
Exposure to selected risk factors in 2005, by region and sex
SB
P (
mm
Hg
)
Southeast North-Northeast West Central National
Exposure to selected risk factors in 2005, by region and sex
SB
P (
mm
Hg
)
Southeast North-Northeast West Central National
Southeast North-Northeast West Central National
FP
G (
mm
ol/
L)
Exposure to selected risk factors in 2005, by region and sex
SB
P (
mm
Hg
)
Southeast North-Northeast West Central National
BM
I (K
g/m
^2
)
Southeast North-Northeast West Central National
Southeast North-Northeast West Central National
FP
G (
mm
ol/
L)
Number of deaths attributable to each risk factor in 2005, by sex (in thousands)
Risk factor Male Female
Smoking 9 (8.6, 9.4) 2 (1.9, 2.1)
BMI 13 (11, 15) 17 (14, 20)
TC 18 (16, 20) 16 (14, 18)
FPG 17 (14, 20) 17 (14, 20)
SBP 41 (38, 44) 39 (36, 42)
Risk-deleted life expectancy in 2005, by risk factor and region
Risk-deleted life expectancy in 2005, by risk factor and region
Conclusions
• Few metabolic risk factors account for a substantial loss of life from non-communicable diseases in Iran
• Non-optimal blood pressure was the most important risk factor and accounted for almost 1 in 6 deaths in adults
• The selected risk factors did not account for much of the variation in longevity across gender or region.
Future directions
• Conducting a comprehensive burden of disease study including estimation of role of a wider set of risk factors
• Evaluating the determinants of exposure to risk factors
• Designing interventions to reduce exposure to risk factors
• Conducting experimental studies to evaluate the effectiveness of interventions
• Implementing interventions and monitoring and evaluation