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