Population and Public HealthPopulation and Public Health

ENVRE 115ENVRE 115Oct. 9, 2007Oct. 9, 2007

AnnouncementsAnnouncements

Send in student biographiesSend in student biographiesAssignment #2 dueAssignment #2 dueGraduate Student ProjectsGraduate Student Projects– Groups have been assignedGroups have been assigned– Encourage you to use discussion board to Encourage you to use discussion board to

communicate with team matescommunicate with team mates– Require topic approval by Tues., Oct. 30Require topic approval by Tues., Oct. 30 thth

– Make appointment to meet with MollyMake appointment to meet with Molly

AgendaAgenda

Demographic ToolsDemographic Tools

Drivers of population growthDrivers of population growth

Development & Epidemiological TransitionDevelopment & Epidemiological Transition

Demographic DividendDemographic Dividend

World population milestonesWorld population milestones

World population in billionsPopulation and year Time taken to add a billion1 billion in 1804 1,001,804 years2 billion in 1927 123 years3 billion in 1960 33 years4 billion in 1974 14 years5 billion in 1987 13 years6 billion in 1999 12 years7 billion in 2012 13 years8 billion in 2026 14 years8.9 billion in 2050 26+ years

A.D.2000

A.D.1000

A.D.1

1000B.C.

2000B.C.

3000B.C.

4000B.C.

5000B.C.

6000B.C.

7000B.C.

1+ million years

8

7

6

5

2

1

4

3

OldStoneAge New Stone Age

BronzeAge

IronAge

MiddleAges

ModernAge

Black Death —The Plague

9

10

11

12

A.D.3000

A.D.4000

A.D.5000

18001900

1950

1975

2000

2100

Future?

Billions

Source: Population Reference Bureau; and United Nations, World Population Projections to 2100 (1998).

World Population Growth Through HistoryWorld Population Growth Through History

Trends in Worldwide Population GrowthTrends in Worldwide Population GrowthPopulation Increase and Growth Rate, Five-Year Periods

8087

8379 76 76 75 72

0

10

20

30

40

50

60

70

80

90

1980-1985

1985-1990

1990-1995

1995-2000

2000-2005

2005-2010

2010-2015

2015-2020

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Net population added per year Annual population growth rate

Mill

ions

Per

cent

incr

ease

per

yea

r

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

Projected Growth in World PopulationProjected Growth in World Population

UN Pop.Div(2004);WRI(2006)Earthtrends.wri.org

Introduction to DemographicsIntroduction to Demographics

TerminologyTerminologyGrowth RatesGrowth Rates

Population PyramidsPopulation Pyramids

TerminologyTerminologyCount: Count: The absolute number of a population occurring in a specific The absolute number of a population occurring in a specific area in a specified time period. Provides raw data.area in a specified time period. Provides raw data.– Census data (number of people in the US)Census data (number of people in the US)

Rate: Rate: The frequency of demographic events in a population divided The frequency of demographic events in a population divided by the population “at risk” during the same time period.by the population “at risk” during the same time period.– Birth rates (number of live births/number of women of childbearing age)Birth rates (number of live births/number of women of childbearing age)

Ratio: Ratio: The relation of one population sub-group to the total The relation of one population sub-group to the total population or to another subgroup.population or to another subgroup.– Sex ratios (number of males/number of females)Sex ratios (number of males/number of females)– Dependency ratio (# of under 15 + # of 65 and over/# of 15 to 64) Dependency ratio (# of under 15 + # of 65 and over/# of 15 to 64)

Census Data: Population in USCensus Data: Population in US

Growth RatesGrowth RatesBirths/Total Population – Deaths/Total Population)*100 = Rate of Natural IncreaseBirths/Total Population – Deaths/Total Population)*100 = Rate of Natural Increase

Examples of population growth rates (2003)Examples of population growth rates (2003)– Belgium: 0.1% (10,318,000)Belgium: 0.1% (10,318,000)– United Arab Emirates: 1.4% (3,800,000)United Arab Emirates: 1.4% (3,800,000)– Uganda: 3% (25,632,794)Uganda: 3% (25,632,794)

How long would take for these populations to double?How long would take for these populations to double?– Belgium Belgium 700 years 700 years– United Arab Emirates United Arab Emirates 50 years 50 years– Uganda Uganda 23 years 23 years

The “Rule of 70” is used to calculate doubling timeThe “Rule of 70” is used to calculate doubling time– Doubling Time = 70/rate expressed as a percentageDoubling Time = 70/rate expressed as a percentage

Assumption of constant growth rate during the time frameAssumption of constant growth rate during the time frame

Math Behind Exponential GrowthMath Behind Exponential Growth

The basic differential equation for exponential growth: dN/dt = rN, over the period from t=0 to t The basic differential equation for exponential growth: dN/dt = rN, over the period from t=0 to t = the time period in question, where N is the quantity growing and = the time period in question, where N is the quantity growing and rr is the growth rate is the growth rate

The integral of this equation is NThe integral of this equation is Nt t = N= N0 0 x ex ertrt where N(t) is the size of a quantity after where N(t) is the size of a quantity after tt intervals intervals have elapsed, N(0) is the initial value of the quantity, have elapsed, N(0) is the initial value of the quantity, ee is the base of the natural logarithm, is the base of the natural logarithm, rr is is the average growth rate over the interval in question, and the average growth rate over the interval in question, and tt is the number of intervals is the number of intervals

If one knows the final and initial values of N and the average growth rate, one can find the time If one knows the final and initial values of N and the average growth rate, one can find the time it takes at that average growth rate for the quantity to grow from its initial value to the final it takes at that average growth rate for the quantity to grow from its initial value to the final valuevaluet = ln [ N(t)/N(0) ] / r t = ln [ N(t)/N(0) ] / r

A special case is the doubling time, which is the time when N(t)/N(0) = 2. At that point rt = ln A special case is the doubling time, which is the time when N(t)/N(0) = 2. At that point rt = ln 2 = 0.69. If one knows the growth rate as a decimal fraction, then the Doubling Time = 0.69 / r.2 = 0.69. If one knows the growth rate as a decimal fraction, then the Doubling Time = 0.69 / r.– This can be further simplified…if the growth rate is given in percent, then 0.69 must be This can be further simplified…if the growth rate is given in percent, then 0.69 must be

multiplied by 100, and the doubling time = 69/r. This can then be rounded up to 70 (which multiplied by 100, and the doubling time = 69/r. This can then be rounded up to 70 (which is why it is called the rule of 70)is why it is called the rule of 70)

ExamplesExamples

Familiar example- compound interest on your Familiar example- compound interest on your bank accountbank account1. How long would it take for your bank account to 1. How long would it take for your bank account to

double when invested at 3.5%double when invested at 3.5%

Doubling Time

Time = 70/3.5 = 20 years

Time = 70/7 = 10 years

2. You invest $100 at 7% interest. How long will it take to have $200?

Consider a country with 100 people, Consider a country with 100 people, growing at 7% per year. In 10 years, growing at 7% per year. In 10 years, the population will double to 200 the population will double to 200 people, in another 10 years it will people, in another 10 years it will double again to 400 people, etc (see double again to 400 people, etc (see graph)graph)3. How long will it take this country to reach 1 million?

0.00200,000.00400,000.00600,000.00800,000.00

1,000,000.001,200,000.001,400,000.001,600,000.001,800,000.00

0 20 40 60 80 100 120 140

Years

Popu

latio

n

t = ln [N(t)/N(0)] / r

t = ln (1,000,000/100)/0.07t = ln (10,000)/0.07t = 9.2103/0.07t = 131.5 years

Doubling Time

4. In a country where the GDP is growing at 4.5% per annum and the 4. In a country where the GDP is growing at 4.5% per annum and the population is growing at 1.0 % per annum, how long will it take for population is growing at 1.0 % per annum, how long will it take for the per capita GDP to double?the per capita GDP to double?

Doubling time = 70/(4.5%-1% ) = 70/3.5 = 20 years

5. In 1971, global population was 3.8 million and it is currently 6.8 million. What 5. In 1971, global population was 3.8 million and it is currently 6.8 million. What was the global population growth rate during this time frame? was the global population growth rate during this time frame?

Doubling Time

Time= 70/rate(%)36 years = 70/raterate = 70/36rate= 1.9%

Crude and adjusted ratesCrude and adjusted rates

Crude rates are affected by population characteristics, Crude rates are affected by population characteristics, particularly age structureparticularly age structure

Adjusted rates allow for valid comparisonsAdjusted rates allow for valid comparisons– In 2002 Sweden’s crude death rate was 11 per 1,000 compared In 2002 Sweden’s crude death rate was 11 per 1,000 compared

to Panama’s crude death rate of 5 per 1,000.to Panama’s crude death rate of 5 per 1,000. Does this mean Panama has a lower mortality rate?Does this mean Panama has a lower mortality rate?

No. Sweden has 18% of its population in the 65-year or older category where deaths are more likely to occur compared to Panama where 6% of its population are 65+.

Population PyramidsPopulation PyramidsWhat can they tell us?What can they tell us?

Graphically displays a population’s age and sex Graphically displays a population’s age and sex compositioncomposition

Horizontal bars present the numbers or Horizontal bars present the numbers or proportions of males and females in each age proportions of males and females in each age group.group.

The sum of all the age-sex groups in the The sum of all the age-sex groups in the population pyramid equals 100 percent of the population pyramid equals 100 percent of the populationpopulation

What can we infer from this data?What can we infer from this data?

JapanJapan1995 Census1995 Census

Drivers of Population GrowthDrivers of Population Growth

Birth Rate/FertilityBirth Rate/FertilityAge structure of populationAge structure of population

MortalityMortality

1. Birth Rate1. Birth Rate

Birth rate is defined as the number of live births Birth rate is defined as the number of live births per 1,000 women aged 15-49 in a given yearper 1,000 women aged 15-49 in a given year

Replacement level fertilityReplacement level fertility– Net reproduction rate of 1 Net reproduction rate of 1

Every woman of childbearing age has 1 daughterEvery woman of childbearing age has 1 daughter

– Total fertility rate of 2.1Total fertility rate of 2.1Every woman of childbearing age has 2.1 childrenEvery woman of childbearing age has 2.1 children

Fertility Rates Are DecliningFertility Rates Are DecliningAverage number of children per woman

5.75.25.4

6.46.4

8.5

5.3

3.3

6.2

3.12.4 2.1

4.3

2.5

Egypt India Indonesia Iran Pakistan Turkey Yemen

1970-1975 2000-2005

Source: United Nations, World Population Prospects: The 2004 Revision, 2005.

Four factors that influence fertilityFour factors that influence fertility

1.1. The proportion of women of childbearing age who are The proportion of women of childbearing age who are married or in a sexual unionmarried or in a sexual union

2.2. The percent of women using contraception and the level The percent of women using contraception and the level of abortionof abortion

3.3. The proportion of women of childbearing age who The proportion of women of childbearing age who currently are unable to conceive a child (usually from currently are unable to conceive a child (usually from postpartum infecundity from breastfeeding)postpartum infecundity from breastfeeding)

4.4. Educational attainment of girls and womenEducational attainment of girls and women

Age at MarriageAge at MarriageMedian Age at First Marriage, Women 20 to 24 at Time of SurveyYears

16

18

16

18 18

19 19

Bangladesh2004

Cameroon2004

Chad 2004

Eritrea 2002

Mozambique2003

Nicaragua2001

Nigeria 2003

Source: Measure DHS STATcompiler: accessed online at www.statcompiler.com on June 2, 2006.

Trends in Contraceptive PrevalenceTrends in Contraceptive Prevalence% of women in union aged 15-49 who are using contraception% of women in union aged 15-49 who are using contraception

UNICEF Region

1990

2000

% chg.

Sub-Saharan Africa 16 23 +46

Middle East/North Africa 37 54 +45

South Asia 39 48 +25

East Asia/Pacific 71 84 +20

Latin America/Caribbean 62 73 +19

CEE/CIS and Baltic States 63 66 +4

Developing countries 54 65 +20

Least developed countries 18 32 +80

Industrialized countries 71 78 +9

World 57 67 +18

Sources:  UN Population Division database, data available as of 1 March 2001.

Association Between Fertility and Association Between Fertility and Education of GirlsEducation of Girls

0

20

40

60

80

100

120

0 1 2 3 4 5 6 7 8

Percent of Girls Enrolled in Secondary School

Source: Population Reference Bureau, Population & Economic Development Linkages 2007 Data Sheet.

Total Fertility Rate

Association Between Fertility and Association Between Fertility and Female Labor Force ParticipationFemale Labor Force Participation

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8

Female Labor Force Participation Rate 2004

Source: United Nations, World Population Prospects: The 2004 Revision, 2005; International Labor Organization, Yearbook of Labor Statistics 2006.

Total Fertility Rate 2000-2004

Association between fertility and wealthAssociation between fertility and wealth

6.4

4.9

4.1

4.9

3.2

2.42.8

2.4

1.4

Ghana 2003 Cambodia 2005 Colombia 2005

Poorest Quintile Middle Quintile Richest Quintile

Average Number of Children Born to a Woman During Her Lifetime

Source: ORC Macro, Demographic and Health Surveys.

Complex associations between female Complex associations between female education, economy, and fertilityeducation, economy, and fertility

2. Age Structure of a Population2. Age Structure of a PopulationA large proportion of young people A large proportion of young people guarantees that population will guarantees that population will continue to grow even with continue to grow even with declining fertilitydeclining fertility

Takes two or three generations Takes two or three generations (70-100 years) before each new (70-100 years) before each new birth is offset by a deathbirth is offset by a death

Referred to as Referred to as population population momentummomentum

Women of Childbearing AgeWomen of Childbearing Age There is a growing population of women in their childbearing years There is a growing population of women in their childbearing years that will contribute to future world population growth even if fertility that will contribute to future world population growth even if fertility

continues to declinecontinues to decline

0.60.9

1.82.0 2.0

1.3

0

1

2

3

1950-1955 1970-1975 1990-1995 2010-2015 2030-2035 2045-2050

Bill

ions

0

1

2

3

4

5

6

Chi

ldre

n pe

r wom

an

Women 15 to 49 Average number of children per woman

Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

3. Mortality3. Mortality

Death is the ultimate determinant of population growthDeath is the ultimate determinant of population growth

Falling mortality precedes a decline in fertilityFalling mortality precedes a decline in fertility

Death rate

Population growth rate

Birth rate

Time

Rat

e

Development and public healthDevelopment and public healthEpidemiological TransitionEpidemiological Transition

Non-communicableDiseases

Mor

talit

y R

ates

Infectiousdiseases

Development

Systematic Shift in Disease PatternsSystematic Shift in Disease PatternsM

orta

lity

Rat

es

Infectious diseases

Development

TraumaType 2

Diabetes CHD Cancers

Global Burden of Disease – MortalityGlobal Burden of Disease – Mortality

Global Burden of Disease – DALYsGlobal Burden of Disease – DALYs

How To Shift Causes of MortalityHow To Shift Causes of MortalityImproved sanitation and drinking water suppliesImproved sanitation and drinking water supplies

Medical advances (vaccination, antibiotics)Medical advances (vaccination, antibiotics)

Social advances (improved nutrition, access to health care)Social advances (improved nutrition, access to health care)

Occupational Health & Safety (injury prevention, chemical safety)Occupational Health & Safety (injury prevention, chemical safety)

Infrastructure Improvements (roadways, housing, energy)Infrastructure Improvements (roadways, housing, energy)

Consumer Safety (injury prevention, chemical safety)Consumer Safety (injury prevention, chemical safety)

Economic growthEconomic growth

Demographic TransitionDemographic Transition

Public HealthPublic Health

Where disease, demographics and Where disease, demographics and development meetdevelopment meet

PremisePremiseFertility has a fixed upper limit but not mortality so mortality is the Fertility has a fixed upper limit but not mortality so mortality is the fundamental factor that controls population dynamicsfundamental factor that controls population dynamics

Diseases and injuries control mortalityDiseases and injuries control mortality

Investment in public health shifts the causes of death Investment in public health shifts the causes of death (Epidemiological Transition) and this will influence population (Epidemiological Transition) and this will influence population structure where women and children benefit the moststructure where women and children benefit the most

During the late phase of the demographic transition when fertility and During the late phase of the demographic transition when fertility and dependency rates fall countries can harness the demographic dependency rates fall countries can harness the demographic dividend when output per capita risesdividend when output per capita rises

Great Sanitary AwakeningGreat Sanitary AwakeningCornerstone of Public HealthCornerstone of Public Health

Increased immigration to cities during Increased immigration to cities during the Industrial Revolutionthe Industrial Revolution

Analysis of 19th century England Analysis of 19th century England revealed urban mortality rates were revealed urban mortality rates were much higher than rural rates dubbed much higher than rural rates dubbed the “Urban Penalty”the “Urban Penalty”

The concept that a government had The concept that a government had the moral and ethical responsibility to the moral and ethical responsibility to protect the general welfare of its protect the general welfare of its citizenscitizens “Scourge of the Poor”

Improved Sanitation and Municipal Water SupplyImproved Sanitation and Municipal Water SupplyVirtually eliminated typhoid fever and choleraVirtually eliminated typhoid fever and cholera

Redirected sewage discharges away from drinking water intake andwater filtration went online in 1906 Philadelphia, USA

Typh

oid

Dea

ths

Public Health Benefits From Municipal Public Health Benefits From Municipal Water SupplyWater Supply

In the United States from 1900-1940In the United States from 1900-1940– Mortality from diarrheal disease decreases from 140 to 20 per Mortality from diarrheal disease decreases from 140 to 20 per

100,000100,000– Child mortality rates decrease from 130 to 60 per 1,000 live births Child mortality rates decrease from 130 to 60 per 1,000 live births – Life expectancy at birth increased by 16 yearsLife expectancy at birth increased by 16 years– Typhoid fever – one of the top 5 causes of death – virtually Typhoid fever – one of the top 5 causes of death – virtually

eliminatedeliminated

Cost-benefit analysis conducted by Cutler & Miller, 2005Cost-benefit analysis conducted by Cutler & Miller, 2005– 1:23 cost-benefit ratio 1:23 cost-benefit ratio – Every life saved cost $500* resulting in $11,500 gainEvery life saved cost $500* resulting in $11,500 gain

* 2002 US$

Factors contributing to diarrheal diseaseFactors contributing to diarrheal disease

Access To Safe WaterAccess To Safe WaterThe source is less than 1 kilometer away from its place of use and reliably The source is less than 1 kilometer away from its place of use and reliably produces at least 20 liter per member of a household per dayproduces at least 20 liter per member of a household per day– 1.1 billion people in developing countries have inadequate access to water1.1 billion people in developing countries have inadequate access to water

Access To SanitationAccess To SanitationAn excreta disposal system is considered adequate if it is private or shared (but An excreta disposal system is considered adequate if it is private or shared (but not public) and if it can effectively prevent human, animal, and insect contact with not public) and if it can effectively prevent human, animal, and insect contact with excretaexcreta– 2.6 billion people in developing countries lack basic sanitation2.6 billion people in developing countries lack basic sanitation

Hygiene PracticesHygiene PracticesIncrease water quantity allows for more frequent washing practices (hand, food, bathing) which blocks transmission of disease causing pathogens

Municipal water supplies are the cheapest Municipal water supplies are the cheapest source of water for the consumersource of water for the consumer

UNDP, 2006

Advanced sanitation is the most expensive for Advanced sanitation is the most expensive for the consumer but has the most health benefitsthe consumer but has the most health benefits

Estimated cost per person (US$)

0 100 200 300 400 500 600 700 800 900

Tertiary w astew ater treatment

Sew er connection and secondary w astew ater treatment

Connection to conventional sew er

Sew er connection w ith local labor

Septic tank latrine

Pour-flush latrine

Ventilated improved pit latrine

Simple pit latrine Data from Peru:Having a pit latrine in the home lowersthe incidence of diarrhea by 50% whilehaving a flush toilet lowers the risk by 70%

UNDP, 2006

Sanitary Ladder

Method of disposing of human excreta is one of the Method of disposing of human excreta is one of the strongest predictors of child survivalstrongest predictors of child survival

UNDP, 2006

Access to improved water source

Access to improved sanitation

WHO Global water supply and sanitation assessment 2000

Current Burden of Waterborne Current Burden of Waterborne DiseaseDisease

22ndnd largest cause of global child mortality largest cause of global child mortality

1.8 million children die from diarrhea each year1.8 million children die from diarrhea each year– 4931 children a day4931 children a day– 3.4 children a minute3.4 children a minute– 410 children died during this lecture410 children died during this lecture

Over half of the hospital beds in the developing Over half of the hospital beds in the developing world are occupied by people suffering from world are occupied by people suffering from preventable waterborne diseasepreventable waterborne disease

Inequalities in the Use of Health ServicesInequalities in the Use of Health Services

1.3

2.3

3.1

4.44.8

Use of OralRehydration

Therapy

ChildVaccinations

Use of AntenatalCare (3+ visits)

Use of ModernContraception

SkilledAssistance at

Delivery

Surveys 1992-2001Average rich/poor ratio

The average of the ratios of the richest quintile to poorest quintile Not weighted for population size and excluding countries with use less than 1%

42 countries50 countries 53 countries 47 countries

53 countries

Source: D.R. Gwatkin, S. Rutstein, K. Johnson, E.A. Suliman, and A. Wagstaff, Initial Country-Level Information about Socioeconomic Differences in Health, Nutrition, and Population, Volumes I and II (Washington, DC: The World Bank, November 2003).

Childhood Vaccination CoverageChildhood Vaccination Coverage

3

56

85

4

69

88

9

78

90

11

72

90

40

8391

Nigeria 2003 Philippines 2003 Egypt 2005

Poorest Quintile 2nd Quintile 3rd Quintile 4th Quintile Richest Quintile

Children 12-23 Months Receiving Full Basic CoveragePercent

Source: ORC Macro, Demographic and Health Surveys.

Annual Cost per Fully Immunized Child Annual Cost per Fully Immunized Child for the Traditional Childhood Vaccinesfor the Traditional Childhood Vaccines

By Immunization Strategy, 2001By Immunization Strategy, 2001BCG (TB), Diptheria, Tetanus, Pertussis, Polio, & MeaslesBCG (TB), Diptheria, Tetanus, Pertussis, Polio, & Measles

27 26

14

7 6

17

0

10

20

30

Campaign Mobile FixedFacility

Outreach ExtendedOutreach

Mean for All

Strategies

Cost ($) Mean Cost of all strategies $17

Note: Numbers are rounded. Mean values are used. Costs are weighted by population.Source: Disease Control Priorities in Developing Countries, second edition, 2006, Table 20.4

People’s Republic of ChinaPeople’s Republic of ChinaChina began investing in social development projects including education and health care under Maoist Government

– 1952-1982: Invested in rural health through network of clinics and ‘barefoot’ doctors

Infant mortality decreased from 200 to 34/1000 live birthsLife expectancy rose from 35 years to 68 yearsFertility rates declined from 6 births/woman (1970) to 3 birth/woman(1979) to “one child” policy in 1980Universal primary education

– 1980s saw major economic reform characterized by deregulation and liberalization opened up their economies to international trade and attracted foreign investment.

People born in the 1965 cohort People born in the 1965 cohort with improved health care and with improved health care and education are now in their 40’s education are now in their 40’s and in their productivity peakand in their productivity peak

Harnessed demographic dividend Harnessed demographic dividend due to low ratio of dependentsdue to low ratio of dependents

2005 GDP growth was 9%2005 GDP growth was 9%

1/3 of income growth per capita in SE Asia (about 2 percentage points) during 1965-90 is attributable to the independent influence of changes in age structure

Cover from the book by David Cork and Susan Lightstone:The Pig and the Python, How to Prosper from the Aging Baby Boom

http://www.iiasa.ac.at/Research/LUC/ChinaFood/data/anim/pop_ani.htm

Period of Potential Demographic BonusPeriod of Potential Demographic Bonus

Countries with increasing numbers of working-age adults relative to dependent elderly and children have an opportunity to increase employment, investment, and savings

Whether or not the demographic bonus is realized depends on economic policies and economic opportunities

1989 2011

1980 2008

1986 2050

1964 2024

1974 2047

1965 2014

1969 2037

1965 2013

2005 2050

1985 2048

2014 2050

1950 1975 2000 2025 2050

Chad

Ghana

Malawi

China

India

South Korea

Bolivia

Brazil

Guatemala

Czech Republic

Poland

Source: Population Reference Bureau, Population & Economic Development Linkages 2007 Data Sheet.

ResourcesResources““Improving the health of the world's poor” Improving the health of the world's poor” BMJ BMJ No 7107 Volume 315No 7107 Volume 315– http://www.bmj.com/archive/7107/7107e1.htmhttp://www.bmj.com/archive/7107/7107e1.htm

Population health in transition by John CaldwellPopulation health in transition by John Caldwell– http://whqlibdoc.who.int/bulletin/2001/issue2/79(2)159-170.pdfhttp://whqlibdoc.who.int/bulletin/2001/issue2/79(2)159-170.pdf

World Health ReportsWorld Health Reports– http://www.who.int/whr/en/http://www.who.int/whr/en/

Preventing disease through healthy environments: Towards an estimate of the Preventing disease through healthy environments: Towards an estimate of the environmental burden of diseaseenvironmental burden of disease– http://www.who.int/quantifying_ehimpacts/publications/preventingdisease.pdfhttp://www.who.int/quantifying_ehimpacts/publications/preventingdisease.pdf

Health and Economic Growth: Findings and Policy Implications. Edited by G.Health and Economic Growth: Findings and Policy Implications. Edited by G. López-Casasnovas, B. Rivera and L. Currais. MIT PressLópez-Casasnovas, B. Rivera and L. Currais. MIT Press– http://http://mitpress.mit.edu/catalog/item/default.asp?ttypemitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10711=2&tid=10711

Why Has China’s Economy Taken Off Faster than India’s?Why Has China’s Economy Taken Off Faster than India’s? David E. Bloom, David E. Bloom, David Canning, Linlin Hu, Yuanli Liu, Ajay Mahal, and Winnie YipDavid Canning, Linlin Hu, Yuanli Liu, Ajay Mahal, and Winnie Yip– http://http://www.hsph.harvard.edu/pgda/Bloom_Canning_China_India.pdfwww.hsph.harvard.edu/pgda/Bloom_Canning_China_India.pdf