Chapter 2

Health Determinants, Measurements, and Trends

Richard Skolnik

The Importance of Measuring Health Status

In order to address global health issues, we must understand:

• The factors that most influence health status • The indicators used to measure health status • The trends that have occurred historically

Figure 2.1: Key Determinants of Health

Data from: The Public Health Agency of Canada. What Determines Health. Available at: http://www.phac-aspc.gc.ca/ph-sp/determinants/index-eng.php#determinants. Accessed November 19, 2010.

Key Health Status Indicators

Health status indicators are useful for: • Finding which diseases people suffer from• Determining the extent to which the disease

causes death or disability• Practicing disease prevention/interventionsTo perform these functions, it is important to

use a consistent set of indicators and have accurate data

Key is a Vital Registration System

• Vital registration systems record births, deaths, and causes of death

• An accurate system is key to having quality data on a population

• Many low- and middle-income countries lack a vital registration system

• Developing a system is progress towards understanding and addressing health problems – skip to slide 29

Key Health Status Indicators

• Neonatal mortality rate – # deaths of infants under 28 days of age per

1000 births in a year

Figure 2.4: Neonatal Mortality Rate, by WHO Region, 2004Trends in neonatal mortality – more recent data

Data from World Health Organization. Neonatal and Perinatal Mortality: Country, Regional, and Global Estimates 2004. Geneva: WHO; 2007: Table 2.

Neonatal Mortality• One quarter to one half of all deaths occur

within the first 24 hours of life• 75% of deaths occur in the first week• The 48 hours immediately following birth is the

most crucial period for newborn survival• A baby's chance of survival increases

significantly with the presence of a skilled birth attendant at the birth

WHO

Neonatal (<28 days) Mortality DataPopulation Neonatal mortality rate,

deaths/1000 live birthsYear

U.S. overall 4.19 2009

Maine 4.2 2006

Black infants 8.2 2009

White infants 3.43 2009

Key Health Status Indicators

• Infant mortality rate– # deaths of infants in the first year of life

per 1000 births in a year

Figure 2.3: Infant Mortality Rate, by World Bank Region, 2008Data from The World Bank. World Development Indicators, Data Query. Available at: http://databank.worldbank.org. Accessed June 29, 2010.

Infant (<1 yr) Mortality Data

Population Infant mortality rate, deaths/1000 live births

Year

U.S. overall 6.8

5.7

6.7

6.42

2001

2004

2008

2009

Black 12.71 2009

Key Health Status Indicators

• Under 5 mortality rate– aka child mortality rate– the probability that a newborn infant will

die before reaching the age of 5, # per 1000 live births

Figure 2.5: Under-five Child Mortality Rate, by World Bank Region, 2008

Data from The World Bank. World Development Indicators, Data Query. Available at: http://databank.worldbank.org. Accessed June 29, 2010.

Under 5 Mortality - WHO

• 6.9 million children under the age of five died in 2011.

• More than half of these early child deaths are due to conditions that could be prevented or treated with access to simple, affordable interventions.

Under 5 Mortality - WHO

• Leading causes of death:– pneumonia, preterm birth complications,

diarrhea, birth asphyxia and malaria– ~ one third of all child deaths are linked to

malnutrition.

• Children in sub-Saharan Africa are about 16.5 times more likely to die before the age of five than children in developed regions.

Key Health Status Indicators

• Neonatal mortality rate - # deaths of infants under 28 days of age per 1000 births in a year

• Infant mortality rate - # deaths of infants in the first year of life per 1000 births in a year

• Under 5 mortality rate (aka Child mortality rate) – the probability that a newborn infant will die before reaching the age of 5, # per 1000 live births

Key Health Status Indicators

• Maternal mortality rate – # women who die as a result of pregnancy

or childbirth complications per 100,000 live births in a year

Figure 2.6: Maternal Mortality Ratio, by World Bank Region, 2005

Data from The World Bank. World Development Indicators, Data Query. Available at: http://databank.worldbank.org. Accessed June 29, 2010..

Worldwide Data – Maternal Mortality

• 87% deaths in Sub-Saharan Africa and South Asia

• 50 percent of all deaths occurred in six nations: India, Nigeria, Pakistan, Afghanistan, Ethiopia, and the Democratic Republic of Congo

Key Health Status Indicators

• Life expectancy at birth – average # of years a newborn could expect

to live if current mortality rates were to continue for the rest of the infant’s life

Figure 2.2: Life Expectancy at Birth, by World Bank Region, 2008Data from the World Bank. World Development Indicators, Data Query. Available at: http://databank.worldbank.org. Accessed June 29, 2010.

Table 2.11: Life Expectancy and Percentage Gain in Life Expectancy, 1960-2008, by World Bank Region

Data from the World Bank. World Development Indicators, Data Query. Available at: http://databank.worldbank.org. Accessed July 6, 2010.

Historical Trends based on Health Status Indicators

Worst country for women & children – Afghanistan

• 14% of births are attended by a health professional

• Lifetime risk of woman dying as a result of pregnancy or childbirth: 1 in 11

• Life expectancy girl born today = 45

Afghanistan

• Under 5 mortality rate: 1 in 5 children die before the age of 5

• Every woman is likely to suffer the loss of a child in her lifetime

• 39% of children moderately or severely underweight

• 52% Do not have access to clean water

Key Terms

• Morbidity – sickness/illness– physiological and/or psychological

• Mortality – death– Mortality/Death rate expressed as # deaths per

1000 in a population in a year

• Disability – “temporary or long-term reduction in a person’s capacity to function”

Key Terms• Prevalence - # of people suffering from a

particular health condition over a period of time– Generally consider at a given point in time (cross-

sectional) – point prevalence– Measure of existing cases at a given time

• Incidence rate - # of people contracting a disease per 1000 at risk in a year– Measure of new cases per year

Classification of Diseases

• Communicable diseases – spread by an infectious agent– Influenza, HIV/AIDS, measles, malaria, cholera

• Non-communicable diseases – diseases not spread by an infectious agent– Hypertension, diabetes, lung cancer, CVD

• Injuries– Accidents, violence, burns, cuts

Figure 2.10: The Burden of Disease by Group of Cause, Percent of Deaths, 2001Data from Lopez AD, et al Global Burden of Disease and Risk Factors. Washington, DC and New York: The World Bank and Oxford University Press; 2006:8.

Table 2.10: The "Demographic Divide:" The Example of Nigeria and Japan

Data from PRB. 2009 World Population Data Sheet. Available at http://www.prb.org/Publications/Datasheets/2009/2009wpds.aspx. Accessed November 24, 2010.

The Global Burden of Disease

Causes of Death by Region • Higher income countries tend to have a

greater burden of non-communicable disease • Lower income countries to have a greater

burden of communicable disease

Low and Middle Income Countries% Deaths

Rank. Cause of death, % of deaths

54 % Non-Communicable Diseases 1. Heart disease 11.8%2. Strokes 9.5%5. Perinatal conditions 5.1%6. COPD 4.9%

36 % Communicable Diseases 3. respiratory infections 7.0%4. HIV/AIDS 5.3%7. Diarrheal disease 3.7%8. TB 3.3%9. Malaria 2.5%

10 % Injuries 10. road accidents 2.2%

High Income Countries% Deaths

Rank. Cause of death, % of deaths

87 % Non-Communicable Diseases 1. Heart disease 17.3%2. Strokes 9.9%3. Trachea, lung cancers 5.8%5. COPD 3.8%6. Colon and rectal cancers 3.3%7. Alzheimer’s/dementia 2.6%8. Diabetes 2.6%9. Breast cancer 2.0%10. Stomach cancer 1.9%

5.7 % Communicable Diseases 4. Respiratory infections 4.4%

7.5 % Injuries

The Global Burden of Disease

Causes of Death by Age• Children in low- and middle-income countries

often die of communicable disease • HIV/AIDS and TB are among the leading

causes of death among adults in low and middle-income countries

Table 2.5: The 10 Leading Causes of Death in Children Ages 0-14, by Broad Income Group, 2001

Table 2.6: The 10 Leading Causes of Death in Adults 15-59, by Broad Income Group, 2001

The Global Burden of Disease

In most low- and middle-income countries: • Rural people will be less healthy • Disadvantaged ethnic minorities will be less

healthy• Women will suffer as a result of their social

positions• Poor people will be less healthy• Uneducated people will be less healthy

Measuring the Burden of Disease

• Two indicators used to compare how far countries are from a state of good health

• Health-Adjusted Life Expectancy (HALE)- summarizes expected number of years to be lived in what might be termed the equivalent of good health

• Disability-Adjusted Life Year (DALY)- a unit for measuring the amount of health lost because of a particular disease or injury

Measuring the Burden of Disease

• HALE – Health-Adjusted Life Expectancy– Calculated by a standard methodology by World

Health Organization (WHO)– Years of ill health are weighted according to

severity and subtracted from overall life-expectancy

Table 2.2: Life Expectancy at Birth and Health-Adjusted Life Expectancy,, 2004Data from WHO. Core Health Indicators. Available at: http://www3.who.int/whosis/core/core_select_process.cfm. Accessed: September 24, 2006.

DALY – Disability Adjusted Life Year

– First measured by World Bank as a “health gap measure”

• Used by World Bank and WHO – controversial measure

– DALYs are thought to be a better indicator of the health of a population than mortality rates

– DALY takes into account that many conditions associated with poor health are not fatal

– A higher DALY value indicates a greater health burden

DALYs

• “This time-based measure combines years of life lost due to premature mortality and years of life lost due to time lived in states of less than full health.

• The DALY metric was developed in the original Global Burden of Disease 1990 study to assess the burden of disease consistently across diseases, risk factors and regions.”

DALYs

• A DALY is a measure of years of fully healthy life lost due to disease, death, …….disability…..– The higher the DALY value the more years lost due

this “condition” – or the more years living with compromised health

DALYs• DALYs are intended to provide a comparable

measure of the burden of disease• Used to:

– Aid in setting health care priorities• Treatment and prevention

– Aid in setting research priorities– Identify high need populations and target health

interventions– Measure success/effectiveness of interventions

DALYs…put another way

• Measures how many healthy years of life are lost between the population being studied and the healthiest possible populations

– Consider• Communicable diseases• Maternal, perinatal (1st weeks after birth)• Nutritional disorders• Non-communicable disorders• Injuries/accidents

Grouped together

Table 2.3: The 10 Leading DALYs

Low and Middle-Income High-Income Countries

Table 2-4 on page 30 shows DALYs in low and middle-income countries by regions

Calculating DALYs• Disabilities/health conditions are weighted by

one of 6 values based on the limitations or reduction in years of life associated with the “condition”

• The more serious the “condition” the higher the weighting– Deaf, weighting = .33– Dead, weighting = 1 (most serious!)

• Calculating DALYs

WEIGHTING of DISABILITIES• Weightings quantify societal preferences for

health states in relation to the societal ideal of good health.

• On average, society judges a year with blindness (weight 0.43) to be preferable to a year with paraplegia (weight 0.57), and a year with paraplegia to be preferable to a year with unremitting unipolar major depression (weight 0.76).

• Source this slide and next http://www.who.int/quantifying_ehimpacts/publications/en/9241546204chap3.pdf

WEIGHTING of DISABILITIES

• On average, society would prefer a person to have a year in good health followed by death, than a year with paraplegia followed by death.

• Society would prefer a person to live three years with paraplegia followed by death (3 years x 0.57 = 1.7 lost “healthy” years), than have one year of good health followed by death (2 lost years of good health).

Calculation of DALYs (without age-weighting and discounting)

• The calculation of DALYs of a woman who has been deaf since she was 5 and dies when she is 50: (deafness is set at 0.33; life expectancy 80) :

• Number of healthy life years × the disability weight of full health (0) + life years with disability (50) × disability weight for deafness (0.33) + life years lost (30) × the weighting of death (1)

• (5 × 0)+ (45 × 0.33) + (30 × 1) = 47.35 DALYs

Other choices behind DALY• In addition to adjusting the value of life

years with disability weights, and choosing a particular life expectancy, the value of a life year is modified by

• Age weighting– life years of children and old people are

counted less

• Discounting – the value of a life year now is set higher than

the value of future life years

Age-weights

Calculating DALY score,with age weighting and discounting.

• Girl, 5 years old, with below-knee amputation who lives until she is 82.5:

• DALYs= life years lived with disease (77.5) × disability weight (0.3) × age- weight (a1)× discounting factor (3%/year)

• 77.5 × 0.3 × a1 × d2 = 10.5 DALYs

The Young

• The 5-year-old girl in the prior example yielded 10.5 DALYs.

• However, the DALY score without age-weight and discounting would be

• 77.5 × 0.3 = 23.3 DALYs • This result is twice as high, and would give

her a higher priority.

DALYs - Justice Issues? • The DALY approach has been

criticised for discriminating– the young– the elderly– the disabled– women

Finding Health Statistics

• WHO - – WHO Health Statistics and Health Information

Systems website is a rich source of data• Data is available by country and by region of the world• Could spend the entire semester just mining this data!

• World Bank• Gapminder – World Data• MDG related data

– Gapminder MDG data

Figure 2.11: Gross Domestic Product Per Capita and Female Life Expectancy at Birth, Selected Countries, 2004

Data from WHO. Core Health Indicators. Available at: http://www3.who.int/whosis/core/core_select_process.cfm. Accessed: September 24, 2006.

Hans Rosling

• Hans Rosling on Health Statistics and Child Mortality– http://www.gapminder.org/videos/reducing-

child-mortality-a-moral-and-environmental-imperative/

Figure 2.9: The Demographic Transition: (A) High Fertility/High Mortality, (B) Declining Mortality/High Fertility, (C) Reduced Fertility/Reduced Mortality

Reprinted from U.S. Census Bureau, International Population Reports WP/02, Global Population Profile: 2002. Washington, DC: U.S. Government Printing Office; 2004, p. 35.

Figure 2.7: Percentage of Children 0 -5 Whose Births Have been Registered, by Income Quintile

Data from UNICEF. Progress for Children: Achieving the MDGs with Equity. Available at: http://www.unicef.org/media/files/Progress_for_Children-No.9_EN_081710.pdf. Accessed September 17, 2010. .

Figure 2.8: World Population - 1950 to 2050

Adapted from: Haub, Carl and PRB. Data from United Nations Population Division. World Population Prospects, The 2008 Revision. Available at: http://esa.un.org/UNPP/. Accessed December 4, 2010.

Table 2.1: Key Health Status IndicatorsAdapted from: Haupt A, Kane TT. Population Handbook. Washington, DC: Population Reference Bureau; 2004; World Bank. Beyond Economic Growth Student Book: Glossary. http://www.worldbank.org/depweb/english/beyond/global/glossary.html. Accessed April 15, 2007.

Table 2.3: The 10 Leading Causes of Death and DALYs 2001Adapted with permission from Lopez AD, Mathers CD, Murray CJL. The Burden of Disease and Mortality by Condition: Data, Methods, and Results for 2001. In: Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL, eds. Global burden of disease and risk factors. Washington, DC and New York: The World Bank and Oxford University Press; 2006.

Table 2.4: The Ten Leading Causes of the Burden of Disease in Low- and Middle-income Countries, by Region, 2001

Reprinted with permission from Lopez AD, Mathers CD, Murray CJL. The Burden of Disease and Mortality by Condition: Data, Methods, and Results for 2001. In: Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CJL, eds. Global Burden of Disease and Risk Factors. New York: Oxford University Press 2006:91. Washington, DC and New York: The World Bank and Oxford University Press

Table 2.5: The Ten Leading Causes of Death in Children Ages 0-14, by Broad Income Group, 2001

Adapted with permission from: Lopez A, Begg S, Bos E. Demographic and Epidemiological Characteristics of Major Regions, 1990-2001. In: Lopez A, Mathers C, Ezzati M, Jamison D, Murray C, eds. Global Burden of Disease and Risk Factors. Washington, DC and New York: The World Bank and Oxford University Press; 2006:70.

Table 2.6: The Ten Leading Causes of Death in Adults 15-59, by Broad Income Group, 2001

Adapted with permission from: Lopez A, Begg S, Bos E. Demographic and Epidemiological Characteristics of Major Regions, 1990-2001. In: Lopez A, Mathers C, Ezzati M, Jamison D, Murray C, eds. Global Burden of Disease and Risk Factors. Washington, DC and New York: The World Bank and Oxford University Press; 2006:70.

Table 2.7: The Ten Leading Causes of Death by Sex, in Low- and Middle-Income Countries, 2001

Data from Lopez A, Begg S, Bos E. Demographic and Epidemiological Characteristics of Major Regions, 1990-2001. In: Lopez A, Mathers C, Ezzati M, Jamison D, Murray C, eds. Global Burden of Disease and Risk Factors. Washington, DC and New York: The World Bank and Oxford University Press; 2006:70.

Table 2.9: Percentage of the Population Projected to be Over 65 Years of Age

Based on Haub, Carl and PRB. Data from United Nations Population Division. World Population Prospects, The 2008 Revision. Available at: http://esa.un.org/UNPP/. Accessed December 4, 2010.

Table 2.12 (cont.): Trends in the Ten Leading Causes of the Burden of Disease, by Income Group, 2004 - 2031 continued

Data from World Health Organization. Global Burden of Disease (GBD). Available at: http://www.who.int/healthinfo/global_burden_disease/en/. Accessed September 14, 2010.