@let@token Cause-of-Death Mortality: What Can Be Learned ...

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Cause-of-Death Mortality: What Can Be Learned From Population Dynamics? Héloïse Labit Hardy 1 PhD Student, University of Lausanne, Switzerland joint work with S. Arnold (-Gaille) 1 , A. Boumezoued 2 , N. El Karoui 2 available at https://hal.archives-ouvertes.fr/hal-01157900 IAA Conference, Oslo, Norway June 10, 2015 1 Department of Actuarial Science, Faculty of Business and Economics - Extranef, University of Lausanne, CH-1015 Lausanne, Switzerland [email protected], [email protected] 2 Probability and Random Models Laboratory, Pierre and Marie Curie University, 4 place Jussieu, 75005 Paris, France [email protected], [email protected] Héloïse Labit Hardy Cause-of-Death Mortality: What Can Be Learned From Population Dynamics? 1/26

Transcript of @let@token Cause-of-Death Mortality: What Can Be Learned ...

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Cause-of-Death Mortality: What Can BeLearned From Population Dynamics?

Héloïse Labit Hardy 1

PhD Student, University of Lausanne, Switzerland

joint work with S. Arnold (-Gaille)1, A. Boumezoued2, N. El Karoui2

available at https://hal.archives-ouvertes.fr/hal-01157900

IAA Conference, Oslo, NorwayJune 10, 2015

1Department of Actuarial Science, Faculty ofBusiness and Economics - Extranef, University ofLausanne, CH-1015 Lausanne, Switzerland

[email protected], [email protected]

2Probability and Random Models Laboratory, Pierreand Marie Curie University, 4 place Jussieu, 75005Paris, France

[email protected],[email protected]

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Introduction

0 20 40 60 80

−10

−8

−6

−4

−2

0

French death rates for males between 1960 and 2000 for external causes

Age

ln m

u

19601970198019902000

0 20 40 60 80

−10

−8

−6

−4

−2

0

French death rates for males between 1960 and 2000 for cancers

Age

ln m

u

19601970198019902000

Source : The World Health Organization (WHO)

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Introduction

Objective :

Study impacts of changes in cause-of-death mortality on the wholepopulation age structure

ä Model population dynamics

. By taking into account deaths and births :

� with birth and death rates depending on genderand age, invariant over time

. Reference : Bensusan, Boumezoued, El Karoui and Loisel(working paper)

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

1.1 Competing risks model1.2 Dependence assumptions

1. Cause-of-Death Mortality1.1 Competing risks model1.2 Dependence assumptions

2. Population Dynamics Model

3. Application to French data

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

1.1 Competing risks model1.2 Dependence assumptions

Let us consider two causes of death, A and B , modelled by twocompetiting clocks :

ä τA : the length of time for clock A

ä τB : the length of time for clock B

Lifetime τ of an individual :

τ = min(τA, τB)

Remark :

ä if A only possible cause, τA : lifetime of the individual

ä if B only possible cause, τB : lifetime of the individual

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

1.1 Competing risks model1.2 Dependence assumptions

ä In practice, only the lifetime τ = min(τA, τB) is observed :

The crude force of mortality for cause A :

µ̃A(a) =P(a < τ ≤ a + da, τ = τA | τ > a)

da

when causes A and B are in competition

ä We are interested by :

The net force of mortality for cause A :

µA(a) =P(a < τA ≤ a + da | τA > a)

da

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

1.1 Competing risks model1.2 Dependence assumptions

Dependence structure between causes of deathForces of mortality :

µA(a) 6= µ̃A(a)

µB(a) 6= µ̃B(a)

ä Dependence structure non-identifiable from available data

⇒ Assumptions on dependence between causes of death

ä Exemples of dependence structure :

. Independence assumption : Chiang et al. (1968)

. Independence assumption modified : Alai et al. (2013)

. Dependence modelled by copulas : Carriere (1994),Kaishev et al. (2007), Dimitrova et al. (2013)

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

1.1 Competing risks model1.2 Dependence assumptions

Independence assumption between causes of death

ä Assumption widely used

. ex : Prentice et al. (1978), Tsai et al. (1978), Willmoth(1995), Putter et al. (2007)

ä Highlight interesting effects

ä Simplification of the modelling :

. Under independence :

� µA(a) = µ̃A(a), µB(a) = µ̃B(a)

� Remove cause B : µ̃A(a)

� Reduce cause B : µ′B(a) = α.µ̃B(a), α ∈ (0, 1)

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

1. Cause-of-Death Mortality

2. Population Dynamics Model2.1 Deterministic equation2.2 Stochastic simulations

3. Application to French data

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

ä Deterministic approach :

. First population dynamics models

� McKendrick (1926), Von Foerster (1959)

. Model evolution of the average population age pyramid

� Age dependency ratio of the average population : rt

ä Stochastic approach :

. Provides scenarios of the population age pyramid

� Average age dependency ratio : E[Rt ] (non-linearquantity)

ä In large population : rt approximation of Rt

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

ä The population structure described by the vector :

g(a, t) =(

g(f , a, t)g(m, a, t)

)

. g(a, t) : average number of individual with age a at time t

ä The population dynamics is defined by :

. Deaths : ( ∂a + ∂t)g(a, t) = −(µf (a) 00 µm(a)

)g(a, t)

. Births : g(0, t) =(∫

R+g(f , a, t)bf (a) da

)( p1− p

)p : probability for a newborn to be a female

Remark : population without migrationHéloïse Labit Hardy Cause-of-Death Mortality: What Can Be Learned From Population Dynamics? 11/26

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

•N0

T0 = 0

• Start at T0 with population N0population size

time

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

T0 = 0

•N0

• Start at T0 with population N0population size

timeT1

• T1 = T0 + γ, with γ exp. r.v.

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

T0 = 0

•N0

• Start at T0 with population N0population size

timeT1

• T1 = T0 + γ, with γ exp. r.v.• Select an individual (εi , ai ) uniformly

and identify the event

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

T0 = 0

•N0

• Start at T0 with population N0population size

timeT1

• T1 = T0 + γ, with γ exp. r.v.• Select an individual (εi , ai ) uniformly

and identify the event :- Birth : add a new individual N1 = N0 + 1•

N1

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

T0 = 0

•N0

• Start at T0 with population N0population size

timeT1

• T1 = T0 + γ, with γ exp. r.v.• Select an individual (εi , ai ) uniformlyand identify the event :- Birth : add a new individual N1 = N0 + 1- Death : remove the individual N1 = N0 − 1

N1

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

T0 = 0

•N0

• Start at T0 with population N0population size

timeT1

• T1 = T0 + γ, with γ exp. r.v.• Select an individual (εi , ai ) uniformlyand identify the event :- Birth : add a new individual N1 = N0 + 1- Death : remove the individual N1 = N0 − 1- No event : N1 = N0•N1

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

2.1 Deterministic equation2.2 Stochastic simulations

T0 = 0

•N0

population size

timeT1

No event

•N1

T2

Birth

•N2

T3

Death

•N3

T4

Death

•N4

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

3.1 Scenarios : All causes3.2 Scenarios : Cause removal3.3 Scenarios : Cause reduction

1. Cause-of-Death Mortality

2. Population Dynamics Model

3. Application to French data3.1 Scenarios : All causes3.2 Scenarios : Cause removal3.3 Scenarios : Cause reduction

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1. Cause-of-Death Mortality2. Population Dynamics Model3. Application to French data

3.1 Scenarios : All causes3.2 Scenarios : Cause removal3.3 Scenarios : Cause reduction

Population dynamics : 10 000 individuals, 100 years horizon

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Population dynamics : 100 000 individuals, 100 years horizon

Age pyramidAge pyramid

1000 500 0 500 1000

07

1524

3342

5160

6978

8796

107

119

Number of males Number of females

Initial population in 2008Final men population in 2108Final women population in 2108

0 20 40 60 80 100

2530

3540

4550

Age Dependency ratio from 2008 to 2108 (10 scenarios)

Time

Dep

ende

ncy

ratio

(%

)

All causes

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Cause removal : Cancers

0 20 40 60 80 100

2530

3540

4550

Age Dependency ratio from 2008 to 2108 (10 scenarios)

Time

Dep

ende

ncy

ratio

(%

)

Ignoring cancersAll causes

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Cause removal : External causes

0 20 40 60 80 100

2530

3540

4550

Age Dependency ratio from 2008 to 2108 (10 scenarios)

Time

Dep

ende

ncy

ratio

(%

)

Ignoring external causesAll causes

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Cause reduction : Deterministic age dependency ratio

0 20 40 60 80 100

2530

3540

4550

Time (years)

Dep

ende

nce

ratio

(%

)

Ignoring cancers (e0h=82.2, e0f=87.7)Reduction of cancers (e0h=79.1, e0f=85.1)Ignoring external causes (e0h=79.1, e0f=85.1)All causes (e0h=77.7, e0f=84.4)

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Conclusion

ä With a population dynamics model, we study impacts ofcause-of-death reductions on the population age structure :

. Model deaths and births, with rates invariant over time

. Under independence assumption between causes of death

⇒ Study the whole population dynamics give additionalinformations :

. With the same life expectancy at birth, cause reductionscan have different impacts on the age dependency ratio

ä Following :. Study dependence between causes of death. Take into account mortality improvement over the time. Study cause-of-death mortality by age, gender and

socio-economic variable

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Bibliographie

[1] Alai, D.H., Arnold(-Gaille), S., Sherris, M. (2015) Modelling Cause-of-DeathMortality and the Impact of Cause-Elimination. Annals of Actuarial Science

[2] Arnold, S., Boumezoued, A., Labit Hardy, H., El Karoui., N. (2015)Cause-of-Death Mortality : What Can Be Learned From Population Dynamics ?Working paper, https ://hal.archives-ouvertes.fr/hal-01157900

[3] Bensusan, H. (2010) Risques de taux et de longévité : Modélisationdynamique et applications aux produits dérivés et á l’assurance vie. PhDthesis, Ecole Polytechnique

[4] Chiang, C. L. (1968) Introduction to Stochastic Process in Biostatistics.John Wiley and Sons, New York

[5] Bensusan, H., A. Boumezoued, N. El Karoui, S. Loisel. Impact ofheterogeneity in human population dynamics. working paper

[6] Tran, V.C. (2006) Modéles particulaires stochastiques pour des problémesd’évolution adaptative et pour l’approximation de solutions statistiques. PhDthesis, Université Paris X - Nanterre

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