Factors responsible for mortality decline

- The role of medicine

- Major changes in life expectancy prior to 1920 occurred largely in the absence of germ theory

- Throughout the 1800s, miasma was the more accepted theory of disease causation; rotten smells in the air cause disease

        - One exception was smallpox vaccine (developed in 1760)

Macro-level and micro-level changes leading to the decrease in infectious disease

Changes in exposure, resistance, and recovery all contribute

Exposure

- Macro Changes: Sanitation, pollution, population density, pasteurization, labor conditions

- Micro Changes: Refrigeration, acceptance of public health initiatives, quarantine, hand washing, boiling milk

Resistance

- Macro Changes: Vaccination, food availability

- Micro Changes: Better diet

Recovery

- Macro Changes: Drugs, medical care

- Micro Changes: Access to and use of health care

            - Levels of mortality in US by occupation

- Preston looks at levels of mortality among US children by fathers’ occupation in 1895, 1905, and 1922/4

- In 1895, farmers and manufacturing managers’ kids have lowest mortality

- Farm and manufacturing laborers’ kids have highest

- In 1922/4, doctors and teachers’ kids have lowest

- Overall in 1922/4, higher educated classes have lower mortality than lower educated classes

           - Shows differential dissemination of information

            - More educated ppl can read and adopt public health info

- Segregation of population along class lines also probably contributed to differential death rates

Levels of mortality by age

- Vallin created graph of mortality in France by age 1720-1914

- Finds that decrease in mortality happened at pretty much all ages

- Main exception: death rates among young adults higher in 1877-1881 than in 1820-1829

            - Most likely due to migrating to cities

“Routes to low mortality in poor countries.” Population and Development Review, 12(2), 171-220.

- Is economic development a prerequisite for mortality decline?

           - Caldwell says no

Examines 3 countries that have much lower levels of mortality than would be predicted based on SES: Kerala, Sri Lanka, and Costa Rica

- All three of the countries examined went through a “breakthrough” period in the mid 20^th century in which mortality, especially child mortality, declined quickly

- Argues that the provision of health care services can markedly reduce mortality, but that certain prerequisites must be met before good and efficient health care can be achieved

1. Public must demand education

     - Religious background of these three countries place value on  achieving enlightenment

    - Furthermore, in these countries girls’ education is valued as much as boys’, which increases the demand for good schooling

    - Educated population → ability to make informed decisions, later marriage, protection of indigenous cultures

2. Female autonomy

- Women must have ability to do as they please and to play a key role in decision-making

- This allows mothers to better care for their child’s health

- Furthermore, women who are better educated are able to make more informed decisions regarding their child’s health

- Ex: In Sri Lanka, British government instituted universal suffrage in 1928 with the express purpose of lowering child mortality

- Increased female autonomy also leads to higher levels of participation in labor force and delayed age of marriage

- Furthermore, when women’s position in society is good, so usually is that of children

- Sons and daughters more likely to be treated equally

- Parents more willing to send children to school rather than have them work

3. Political activity

- Political participation leads to increased social reform

- In all 3 of these countries, grass-roots social movements paved the way for social change, especially in the areas of health and education

- These three laid the groundwork for each country’s mortality breakthrough

- Sri Lanka’s breakthrough occurred 1946-53, Kerala’s breakthrough occurred 1956-71, and Costa Rica’s breakthrough 1970-1980

- During these periods, Sri Lanka’s life expectancy increased 12 years, Kerala’s increased 12 years, and Costa Rica’s increased 7 years

- These breakthroughs corresponded with dramatic improvements in health care

- All countries developed a greater density of health care clinics

- Improved efficiency of health care

- Increase in household health visits (esp. in antenatal period)

- Developed “nutritional floors” for all people (Ex: via school lunch programs)

- These developments allowed new medical technology to move seamlessly through entire population

- Caldwell emphasizes that the interaction of better health care and an educated population is what allowed for these health breakthroughs Having only one or the other doesn’t afford nearly the same benefits

- In sum, unusually low mortality can be achieved if the following inputs hold:

 - Female autonomy

 - Government inputs into health services and education for males and females

 - Health services available to all

 - Health services work efficiently

 - Basic nutrition provided to all

 - Universal immunization

 - Concentration of health care on periods right before and after birth

- Caldwell advocates that investing in education (particularly female education) and health is the route to lower mortality for all

  - Low mortality will not come as a spinoff from economic growth

Determinants of reduction in maternal mortality in Bangledesh - 30 yr cohort study

Found a decrease in maternal moraltiy in a 30 yr periods with international and gov't interventions.

Better health care, midwives, safer abortions helped

But women's education and financial assitance for the poor and poverty reduction are essential.

 “Child mortality differences, personal health care practices, and medical technology.”

- Purpose of paper is to examine the role of behavioral factors (as opposed to economic development and public health measures) in changes in child mortality

- Begin with finding that French-Canadians had highest rates of child mortality and Jews had the lowest; why?

- Most likely attributable to differences in childcare, cleanliness, and medical knowledge

            - Diarrheal diseases were the most common cause of child mortality

- In the early 1900s health officials began educating mothers on taking proper care of kids

- Medical experts were unsure about exactly what caused young children and infants to contract diarrhea (was it a direct effect of heat or something caused by heat?)

- Debate over whether or not germs caused disease

- Nevertheless, many of the treatments and precautions recommended to mothers were effective at reducing kids exposure to bacteria, even though medical experts were unaware that this is what was happening

- Areas of advice given to mothers included 1) advice on feeding infants, especially the promotion of hygiene among those who were not breastfeeding, 2) Advice on isolating children from sick family members, 3) advice on handwashing and general hygiene, and 4) advice on when to consult a physician

- Authors conclude that decrease in child mortality was primarily due to advances in disease prevention rather than disease treatment

  “Economic growth, population theory, and physiology: The bearing of long-term processes on the making of economic policy.” American Economic Review, 84(3), 369-395.

Fogel argues that nutrition is the key mechanism via which income influences health

- Purpose of paper is to develop a theory to account for the secular decline in morbidity and mortality that takes account of changes induced in physiological functioning since 1700

- Decline in mortality in Britain and France took place in 2 waves

- First wave began during second half of 18^th century and lasted until beginning of 19^th century

- 2^nd wave began in the late 19^th century and continued until the present day

- Fogel argues that high prevalence of disease can cause malnutrition even if food supply is adequate by impeding the uptake of nutrients from food

- Caloric intake estimates from 1790 in Britain and France suggest that the population must have been pretty short and slim

- Even accounting for small stature, low calorie intakes also suggest that a substantial proportion of the population would not have been very productive in the labor market

- Fogel uses 2 indices—height and BMI—as proxies for malnutrition and health to predict risk of death at middle and late ages

- Height reflects health throughout life whereas BMI reflects more current nutritional intake

- Height and weight are likely predictive of mortality because they are associated with nutritional factors that affect the chemical composition of organ tissues, electrical transmission across membranes, the fxning of vital organ systems, etc.

- Finds that gains in BMI accounted for most of the reduction in mortality prior to 1870 and that gains in height accounted for most of the reduction after 1870

- Nutritional state not only affects risk of death due to infectious diseases but also affects risk due to chronic diseases

- This study suggests that childhood malnutrition may affect health throughout life (both vulnerability to infectious diseases and risk of chronic diseases)

- Increased caloric intake affects labor productivity both directly (more energy) and indirectly (disease)

            - Implications for economic growth

Looked at height of veteran of war and modern norwegians.

The taller have lower mortality.

posit that better educated mothers may seek medical care more actively, may be more aware of sanitary precautions, nutritional info, and health services, and may be better able to recognize serious health conditions

ASDR in 1890-1910

Lowest for forestry, fisherman, and agriculture professionsal

Increased for labourers and servicemen

Next highest in transportation and communication.

 “Epidemiological transitions in human history.” In Health and Mortality Issues of Global Concern. Proceedings of the Symposium on Health and Mortality. Pp. 54-71.

- Epidemiological Transition: long-term change in the overall distribution of diseases, injuries, and their risk factors

5 epidemiological transitions

1. External injuries to infectious diseases

- External injuries were the most common cause of death in hunter-gatherer societies

- Infectious diseases common among agricultural societies

- Some characteristics of farming societies that made it easier for pathogens to infect more people include greater population size of communities, higher population density, longer periods of residence at the same location, storage of foods, domestication of animals, and extended contact with other communities

- Also important are the rise of urbanization and decreased dietary diversity

- Common infectious diseases included tuberculosis, smallpox, cholera, etc.

2. Infectious diseases to degenerative diseases

- 2 phases of this transition

- First, crisis mortality due to epidemics reduced

- Second, mortality declines even in normal mortality years

- Many reasons for the decline in infectious diseases, such as improved nutrition, public health, and personal hygiene

- Increased proportion of deaths due to degenerative diseases occurred in the mid-1900s

- Common degenerative diseases include heart disease, stroke, cancers, diabetes, chronic liver disease, and chronic kidney disease

3. Decline of cardiovascular disease mortality

- This shift primarily affected old-age mortality, whereas previous shift contributed to gains in life expectancy by primarily reducing mortality at young and middle ages

- In some countries the periods of the second and third transitions are very distinguishable and in other countries they’re not

4. Decline of cancer mortality

- Expected to occur in the future

- Deaths due to some types of cancer (ex: lung cancer) have been declining in recent years, but whether this is the beginning of a long-term decline remains to be seen

5. Slowing of senescence

- Expected to occur in the future

- Senescence refers to a state of non-specific vulnerability; essentially old-age frailty

- 3 factors that may lead to delays in senescence are

1. maintain a healthier life style,

2. increased use of medical technologies, and

3. gerontological research on the fundamental biological mechanisms of senescence

- Demographic patterns associated with epidemiological transitions

- Drastic increase in life expectancy occurred between the 2^nd and 3^rd transitions

- In the early stages of the 2^nd transition mortality reduction was large for infants and young children, in the later stages of the 2^nd transition mortality decreased at reproductive ages (due to decrease TB), and in the 3^rd transition mortality decline was mainly seen among the elderly

- Sex differentials in life expectancy are relatively recent, and seem to have occurred due to unhealthier lifestyles among men

 - 5 reverse transitions (periods of increased mortality)

          1. Early stages of the industrial revolution

             - Industrialization -> urban poor -> diseases such as TB

          2. Unhealthy lifestyles among wealthy

              - High-fat diets, smoking, drinking, sedentary

          3. Re-emergence of infectious diseases

              - Reasons for this include

1) the emergence of new drug-resistant strains of old diseases,

2) technological advances that have allowed for increased global contact à faster spread,

3) only rapidly diffusing diseases can be deadly and continue to evolve at the same time, and

4) ecological advancement à contact with new diseases

           4. Pollution

               - Likely to increase mortality in the future

           5. Social alienation

               - Likely to increase mortality in the future

- Alienation may lead to mortality due to

1) lack of self-control and long-term plans increasing homicides, suicides, and accidents,

2) low concerns about health care,

3) unhealthy life styles during pregnancy and inadequate care of young kids, and

4) reduction of positive health effects stemming from positive attitudes

- Purpose of book is to outline the history of population growth and to understand the mechanisms that have contributed to population growth, stagnation, or decline

Population size can be viewed as a proxy for prosperity

The size of the human species varies relatively slowly compared to other species

The growth potential of a population is a fxn of

1) # of births per woman and

2) life expectancy at birth

- Increasing life expectancy even beyond reproductive age might have biological effects (example: helping to care for the younger generation)

- High life expectancy and low TFR or low life expectancy and high TFR may produce = population growth rates

            - (20) Population growth is limited by the availability of resources

- The Neolithic revolution (i.e. the development of agriculture) -> increased potential for human growth

- The Industrial Revolution had a similar effect

- One environmental factor that continues to check population growth is degradation stemming from technology

- (30) Forces that constrain population growth include climate, disease, land, energy, food, space, and settlement patterns

- Choices that affect population growth include nuptiality, fertility, and migration

- (33) There exists a debate over why population growth occurred in the Neolithic period

- The classic hypothesis states that increased nutrition -> decreased mortality

-The alternative hypothesis states that mortality actually increased due to less varied diet and increased transmission of diseases, but that fertility increased by a larger amount

What were the effects of various historical “shocks” on population growth?

- The Black plague greatly reduced the size of the European population; took nearly 400 years for the population to rebound to pre-plague levels

- Smallpox brought by Spanish invaders to the New World came close to decimating many indigenous populations

          Why did mortality decline between 1750 and 1850?

- McKeown hypothesizes that it was due to increased nutrition, but this is debatable

 Fatal Years: Child Mortality in Late 19^th Century America. Princeton, NJ: Princeton University Press.

Preface

- Prehistoric man lived an average of 20-25 years; today average life expectancy in the US is 75 years

- Approximately half of the gains in life expectancy occurred in the 20^th century, as life expectancy around 1900 was approximately 50 years

- One aim of book is to provide info on the levels, trends, and differences in child mortality in the US at the turn of the century

- Second aim is to explain these trends

Chapter 1

- At the turn of the century nearly 2 out of 10 children died before reaching their 5^th birthday

- This level of mortality is much higher than in either Asia or Latin America today

- Most deaths due to infectious diseases (diarrheal, respiratory, etc.)

- In the late 19^th century germ theory became increasingly accepted, however old medical practices were slow to change

- Overall, for most diseases, prevention was more important than specific therapy

- The biggest advance related to the new knowledge on disease mechanisms came in the form of public health (sewage disposal, milk cleanliness, pure water, health education)

- Parenting practices (particularly of the mother) exceedingly important for child health

- This is illustrated by the fact that the infant mortality rate for babies whose mother died within 2 months of childbirth was 625 per 1000

- Children whose mother worked outside of the home also had much higher mortality rates

- Breastfeeding reduced child mortality by preventing exposure to unclean milk

- Contemporary reports suggest that parents were motivated to increase their children’s survival chances but often lacked the knowledge to do so

Social and economic influences on mortality

Urbanization: Concentration of many people accelerated spread of disease, but it also facilitated the deployment of health services

Occupation: Percent of population employed in industry positively correlated with infant mortality; mothers’ labor force participation positively correlated with infant mortality

Ethnicity and Nativity: Immigrants tended to have higher death rates than natives, but lots of variability existed in death rates across immigrant groups

Literacy and Income: Inverse relationship between fathers’ earnings and child mortality: appears to operate through access to better housing

Diet: Children’s diets probably improved at the turn of the century as did the diets of the adult population; urban residents likely had access to a greater variety of food

Chapter 5

- In order to better understand the factors that influence child mortality, the authors compared child mortality differentials in England and Wales in 1911 to a set of 11 developing countries in the 1970s

- In England and Wales, large child mortality differentials existed between urban/rural areas, by fathers’ occupational status, by whether the mother worked, by # of rooms in house, and between Irish immigrants and native born

- Compared to the US at the turn of the century, England and Wales had greater health inequality by SES

- This is partially attributable to the fact that professional and white-collar groups in the US had a smaller mortality advantage than those in GB, maybe because these groups in GB had higher social standing

- In general, GB had greater income inequality than the US

 - GB may also have had greater residential segregation by occupational class than the US

- Mortality differences between US at the turn of the 20^th century and developing countries today

- In the US in 1900, urban residents had 28% higher mortality compared to rural residents; in developing countries today, urban residents have 23% lower mortality

- Lower mortality attributable to urban residents’ higher social standing

- Occupational differences in mortality much smaller in the US in 1900 than in developing countries today

- Overall, the US in 1900 had much higher child mortality than today’s developing world in every occupational class except agricultural workers

- Even though occupational differences in mortality were relatively small, racial differences in mortality in the US in 1900 were enormous

- Preston and Haines conclude that the widespread failure to achieve satisfactory child mortality at the turn of the century was due to a lack of knowledge about disease and a failure to implement techniques that had become recently available

- It wasn’t until the first 3 decades of the 20^th century that a recognition of the value of preventative hygienic measures such as handwashing, isolating the sick, boiling milk, and using clean water became widespread

- “Advances in science, diffusion, of knowledge of preventative measures, and improvements in social organization, rather than economic growth per se, appear primarily responsible for the dramatic successes that were to come, both in the US and in much poorer countries.” (p. 207)

Chapter 6

- Despite being the richest country in the world, and having a population that was highly literate and exceptionally well-fed, the US at the turn of the 20^th century had a death rate for children below age 5 that would rank in the bottom quarter of contemporary societies

- One reason for this is that infectious disease processes were poorer understood by public officials, physicians, and parents and the few effective medical technologies that had been developed were slow to diffuse

- Lack of dramatic social class differences in child mortality suggests that a lack of know-how rather than a lack of resources were primarily responsible for child mortality

- Ex: the literate and professionals enjoyed a much smaller mortality advantage than they do today (the mortality of children of doctors was only 6% below the national average)

- Race was the single most important variable in predicting child mortality which suggests that social and economic factors certainly played a role in child mortality, even though growth of income and living standards was not the principal factor causing mortality to decline

- The second most predictive variable was size of place: child mortality much higher in cities than in rural areas

- Suggests that people remained susceptible to natural forces until later in the 20^th century when medical knowledge really expanded

“Urban French mortality in the nineteenth century.” Population Studies. 32(2), 275-297.

- In the paper, rather than studying mortality at the national level the authors examine mortality in 3 regions in France—Seine (Paris), Rhone (Lyon), and Bouches-du-Rhone (Marseille)

- Comparing life expectancy in these 3 regions to life expectancy in France as a whole reveals that deaths in urban areas are greater than in rural areas

- Authors hypothesize that this is because disease spreads faster in urban areas due to greater frequency of interpersonal contact and sharing common resources

- However, region variation in urban death rates suggests that factors other than improvements in living standard (which occurred in all regions) are at play

- The most appealing candidate for comparing regional variation in death rates is the quality of the water supply and the techniques of sewage disposal

- Lyon improved water supply first and saw earliest drop in death rates, Paris was second, and Marseille third

- Mortality advantage did not occur immediately after cities improved their water supply because it took a while for households to implement new water facilities

- In addition, children saw the benefits more than adults, so mortality really improved on a cohort-by-cohort basis, rather than all at once

- Cause of death statistics confirm favored position of Lyon and disadvantaged position of Marseilles with respect to water-borne diseases (mostly diarrhoeal diseases like cholera and typhoid fever)

- However, air-borne diseases also related to quality of water supply because presumably people who are more sickly due to poor-quality water are more susceptible to these diseases as well

- In sum, the authors propose that improved water supply and sewage disposal, most likely in conjunction with improved nutrition, reduced the incidence of diarrhoeal disease among children and the incidence of other infectious disease

- These factors resulted in improved physical growth and development, which protected cohorts from later death from many causes, both infectious and non-infectious

- This argument accords with McKeown’s in that it finds little evidence that improvements in scientific medicine caused the reduction in death rates at the end of the 19^th century

- However, the authors place much greater emphasis on hygienic factors, which were largely the result of public health measures, and less on standards of living than does McKeown

In 1895 and 1905 farmers kids had highest survival

farmers> professionals (doctors) > laborers

By 1922 teachers, drs and managers kids had better survial

i.e. until recently where you live is more important than your class

The change started in the 20th centure with medical advances.

- Preston looks at levels of mortality among US children by fathers’ occupation in 1895, 1905, and 1922/4

- In 1895, farmers and manufacturing managers’ kids have lowest mortality

- Farm and manufacturing laborers’ kids have highest

- In 1922/4, doctors and teachers’ kids have lowest

- Overall in 1922/4, higher educated classes have lower mortality than lower educated classes

           - Shows differential dissemination of information

            - More educated ppl can read and adopt public health info

- Segregation of population along class lines also probably contributed to differential death rate

Levels of mortality by age

- Vallin created graph of mortality in France by age 1720-1914

- Finds that decrease in mortality happened at pretty much all ages

- Main exception: death rates among young adults higher in 1877-1881 than in 1820-1829

- Most likely due to migrating to cities

Cutler and miller 2004