Child deaths: Causes and epidemiological dimensions

Robert E. Black, M.D., M.P.H.Johns Hopkins Bloomberg School of

Public Health

10.5 milllion annual child deaths

Where are they?

How much progress is there?

What are the causes?

UNICEF/WHO methods for estimating the child mortality envelope

Age-specific mortality rates

Under-5 and adult mortality rates

Complete vital registration

Sample registration system

DHS, MICS and other surveys Life tables

Country-level all-cause mortality envelope

by age and sex

Incomplete vital registration

Censuses

UN estimatesUN population

estimates

Child mortality trends in Egypt

Source: UNICEFSource: UNICEF

Trends in child mortality relative to MDG-4

Sub-Saharan Africa

South Asia

Latin America

East Asia

Under-Five

MortalityRate

244

188

171

62

206

129

92

42.6

122

5431

17.8

123

58

36

19.1

1970 1990 2004 2015

MDG-4Goals

Source: The State of the World’s Children, 2006

Average annual rate of reduction

UNICEF

Region

1970-1990

%

Current

1990-2004

%

Needed to Achieve MDG4

2005-2015

%

L. America/ Caribbean

4.1 4.0 1.2

E. Asia 3.7 3.4 1.5

Mid-East/ N. Africa

4.4 2.6 2.7

S. Asia 2.3 2.4 4.5

Sub Saharan Africa

1.3 0.7 9.9

Current and needed annual rate of reduction in child mortality

to achieve MDG-4

SourceSource: The State of the World’s Children, 2006: The State of the World’s Children, 2006

Where do we need to focus to achieve MDG-4?

Achievement of MDG-4 will depend on accelerating

interventions in South Asia and sub-Saharan Africa.

Trends in childhood mortality in Bangladesh

0

20

40

60

80

100

120

140

1989-93 1992-6 1995-9 2000-4

Under-5 mortalityNeonatal mortality

Relation between U5MR and percentage of deaths in neonates

SourceSource: Black et al., Lancet 2003: Black et al., Lancet 2003

Age group focus

Currently nearly 4 million neonatal deaths

Achievement of MDG-4 will depend on success with neonatal interventions

WHO methods for estimating cause-specific child mortality

Country-level all-cause mortality envelope

by age and sex

Cause-specific mortality patterns

Independent studies/reports/models,

e.g.,CHERG

WHO program estimates

UNAIDS estimates

Global and regional level age, sex and cause specific

mortality estimates

Country level age-, sex- and cause-

specific mortality estimates

Causes of under-five child mortality

Source: Bryce J. et al., Lancet, 2005

Causes of Under 5 Mortality by WHO Region

Source: Bryce J. et al., Lancet, 2005

New evidence on causes of death

Advances in building the evidence base on causes of child deaths must be incorporated into policies and programs:

• Five causes (pneumonia/sepsis, diarrhea, malaria, preterm birth, and birth asphyxia) account for 73% of all under-five deaths.

• Role of undernutrition must also be considered.

Relative Risk (RR) of death by cause due to underweight, estimated from

random effects models

0

2

4

6

8

10

12

14

-3.5 -2.5 -1.5

Average weight-for-age z-score

Diarrhea

Pneumonia

Malaria

Measles

OverallRR

Source: Caulfield L, et al., Am J Clin Nutr, 2004

Prevalence of underweight in children 0 - 4 years old, by WHO region

Source: de Onis and Blossner, Int J Epi, 2001

2 - 1111 - 2020 - 2828 - 3737 - 46

Prevalence (%)

Major causes of death in neonates and children aged 28 days to 5 years

(yearly average for 2000-03)Deaths among children

aged 28 days to five years ( 6.6 million/year)

Neonatal deaths ( 4 million/year)

Preterm

Congenital

Asphyxia

Other

Diarrhoea

Tetanus

Pneumonia/ sepsis

The % of deaths due to maternal and neonatal undernutrition is under study

Diarrhoea

Measles

HIV/AIDS

Other non-communicable

Injuries

Pneumonia

Other infectious

Malaria

52%

61%

57%

UnderStudy

UnderStudy

45%

The % of deaths from this infection that are due to the presence of undernutrition

Global distribution of disease burden attributable to 20 selected risk factors

0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 10.0%

Underweight Underweight Unsafe sex

High blood pressure

Tobacco

Alcohol

Unsafe water, sanitation & hygiene

High cholesterol

Indoor smoke from solid fuels

Iron deficiency

High BMI

Zinc deficiencyZinc deficiency Low fruit and vegetable intake

Vitamin A deficiencyVitamin A deficiency Physical inactivity

Occupational injury

Lead exposure

Illicit drugs Unsafe health care injections

Lack of contraception

Childhood sexual abuse

Attributable DALY (% of global DALY - Total 1.46 billion)

High-mortality developing

Lower-mortality developing

Developed

Source: Ezzati M et al., Lancet 2002

Implications for child survival

1. Focused acceleration of child survival interventions is critical now to achieve MDG-4

• South Asia and sub-Saharan Africa

• Neonatal deaths, nearly 40% and more important as child mortality declines

2. Evidence on causes of child deaths must be incorporated into policies and programs: Five causes in particular must be addressed

- Pneumonia/sepsis, including in neonates- Diarrhea- Malaria- Preterm birth- Birth asphyxia

Implications for child survival

3. Undernutrition is an underlying cause in half of deaths from diarrhea, pneumonia, malaria and measles. Interventions to improve nutrition can have a large

effect because of reduced fatality from several major infectious causes.

The role of undernutrition in cause-specific deaths in the neonatal period needs further study.

Implications for child survival

Conclusion

Knowledge of the causes of child

deaths, especially at the country level, can lead to rational choices of interventions and delivery strategies to have the greatest impact on child mortality.