Lect5a - Generalized Nutritional Poverty Trap The...

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Unformatted text preview: Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Lect 5: Nutrition and Disease Prof. Nancy Qian January 24, 2011 Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Agenda 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Setting up the Poverty Trap Model poverty traps in the usual way Ali has no income because he is too sick to work. i.e. income is a function of health yt +1 = g (ht ), g ￿ > 0 Investment in health today raises income tomorrow He is sick because he can’t afford a doctor. i.e. health is a function of income ht +1 = f (yt +1 ), f ￿ > 0 Higher income today means higher investment Dynamic relationship ht +1 = f (g (ht )) The interesting case arises where f (g (·)) is S-shaped Possibility of multiple equilibria Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Setting up the Poverty Trap Model poverty traps in the usual way Ali has no income because he is too sick to work. i.e. income is a function of health yt +1 = g (ht ), g ￿ > 0 Investment in health today raises income tomorrow He is sick because he can’t afford a doctor. i.e. health is a function of income ht +1 = f (yt +1 ), f ￿ > 0 Higher income today means higher investment Dynamic relationship ht +1 = f (g (ht )) The interesting case arises where f (g (·)) is S-shaped Possibility of multiple equilibria Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Setting up the Poverty Trap Model poverty traps in the usual way Ali has no income because he is too sick to work. i.e. income is a function of health yt +1 = g (ht ), g ￿ > 0 Investment in health today raises income tomorrow He is sick because he can’t afford a doctor. i.e. health is a function of income ht +1 = f (yt +1 ), f ￿ > 0 Higher income today means higher investment Dynamic relationship ht +1 = f (g (ht )) The interesting case arises where f (g (·)) is S-shaped Possibility of multiple equilibria Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Setting up the Poverty Trap Model poverty traps in the usual way Ali has no income because he is too sick to work. i.e. income is a function of health yt +1 = g (ht ), g ￿ > 0 Investment in health today raises income tomorrow He is sick because he can’t afford a doctor. i.e. health is a function of income ht +1 = f (yt +1 ), f ￿ > 0 Higher income today means higher investment Dynamic relationship ht +1 = f (g (ht )) The interesting case arises where f (g (·)) is S-shaped Possibility of multiple equilibria Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Setting up the Poverty Trap Model poverty traps in the usual way Ali has no income because he is too sick to work. i.e. income is a function of health yt +1 = g (ht ), g ￿ > 0 Investment in health today raises income tomorrow He is sick because he can’t afford a doctor. i.e. health is a function of income ht +1 = f (yt +1 ), f ￿ > 0 Higher income today means higher investment Dynamic relationship ht +1 = f (g (ht )) The interesting case arises where f (g (·)) is S-shaped Possibility of multiple equilibria Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Setting up the Poverty Trap Model poverty traps in the usual way Ali has no income because he is too sick to work. i.e. income is a function of health yt +1 = g (ht ), g ￿ > 0 Investment in health today raises income tomorrow He is sick because he can’t afford a doctor. i.e. health is a function of income ht +1 = f (yt +1 ), f ￿ > 0 Higher income today means higher investment Dynamic relationship ht +1 = f (g (ht )) The interesting case arises where f (g (·)) is S-shaped Possibility of multiple equilibria Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Basic Problem Necessary Conditions for Poverty Trap Caveats Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Necessary Conditions The f (g (·)) map must intersect the 45◦ line from below. Let h* be this point of intersection Product of two elasticities ￿ ∗ ￿ ∗ ￿ ∗ ∗ g( h )h Then f ￿ (g (h∗ ))g ￿ (h∗ ) > 1 → f (gf ((h ())∗ )) h ) g g((h∗ ) > gh 1 because f (g (h∗ )) = h∗ By continuity, must be >1 over some range Prof. Nancy Qian Econ 325: Lect5 Basic Problem Necessary Conditions for Poverty Trap Caveats Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Necessary Conditions The f (g (·)) map must intersect the 45◦ line from below. Let h* be this point of intersection Product of two elasticities ￿ ∗ ￿ ∗ ￿ ∗ ∗ g( h )h Then f ￿ (g (h∗ ))g ￿ (h∗ ) > 1 → f (gf ((h ())∗ )) h ) g g((h∗ ) > gh 1 because f (g (h∗ )) = h∗ By continuity, must be >1 over some range Prof. Nancy Qian Econ 325: Lect5 Basic Problem Necessary Conditions for Poverty Trap Caveats Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Necessary Conditions The f (g (·)) map must intersect the 45◦ line from below. Let h* be this point of intersection Product of two elasticities ￿ ∗ ￿ ∗ ￿ ∗ ∗ g( h )h Then f ￿ (g (h∗ ))g ￿ (h∗ ) > 1 → f (gf ((h ())∗ )) h ) g g((h∗ ) > gh 1 because f (g (h∗ )) = h∗ By continuity, must be >1 over some range Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Caveats What is health? What is income? What is the right length of the period? Neither of these has a structural relationship: Many sick people can push themselves and work and higher income certainly does not necessarily translate into more investment Is there a causal link between income and health and nutrition? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Caveats What is health? What is income? What is the right length of the period? Neither of these has a structural relationship: Many sick people can push themselves and work and higher income certainly does not necessarily translate into more investment Is there a causal link between income and health and nutrition? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Caveats What is health? What is income? What is the right length of the period? Neither of these has a structural relationship: Many sick people can push themselves and work and higher income certainly does not necessarily translate into more investment Is there a causal link between income and health and nutrition? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Caveats What is health? What is income? What is the right length of the period? Neither of these has a structural relationship: Many sick people can push themselves and work and higher income certainly does not necessarily translate into more investment Is there a causal link between income and health and nutrition? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Basic Problem Necessary Conditions for Poverty Trap Caveats Caveats What is health? What is income? What is the right length of the period? Neither of these has a structural relationship: Many sick people can push themselves and work and higher income certainly does not necessarily translate into more investment Is there a causal link between income and health and nutrition? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Historical Roles of Nutrition and Disease Preston curve shows link between income and life expectancy (figure 1 in Cutler et al.) There is a debate in what contributed to the historic rise in population in the past three centuries. Population growth rates were very low until approximately the 1600s, when it quadrupled The traditional explanation is that medical innovations decreased mortality (most of which is child mortality) and increased life expectancy More recently, economists such as Fogel have argued that the main cause is the improvement in nutrition Today, we will focus on the decline in mortality (increase in life expectancy) discuss an overview of the existing evidence And we will start to discuss one paper which provides evidence for the nutrition hypothesis in detail. Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Facts Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Population was similar, around 4 million between 100,000 BC until 10,000 BC Life expectancy was similar, around 25 years until around 1700 In the 18th Century, life expectancy increased to 41 years in England In the next 100 years, it increased to approximately 50 Today, it is around 77. Life expectancy, which did not change for 100,000 years, tripled in 300 years. What segment of the population has experienced the largest reduction in mortality? See Figure 2 from Cutler et al. (2006). What does it mean? How can you differentiate cohort vs. age effects? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Sanitation Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Preston (1976) argues that there must be some driving force other than income growth because China today has the income per capita of the U.S. from 1880s but the life expectancy from the 1970s..... He argues that public sanitation improved public health and reduced mortality What were some improvements in public health? Cutler and Miller (2005) have argue that water purification alone can explain half of the mortality reduction in the U.S. during the first 30 years fo the 20th Century Public sanitation cannot be used to explain change before the mid 1800s. Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Vaccination Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Medical innovations are the traditional explanation of the rapid decline in mortality Since the late nineteenth century, diseases addressed by new vaccines include rabies (1885), plague (1897), diphtheria (1923), pertussis (1926), tuberculosis (1927), tetanus (1927), yellow fever (1935), polio (1955 and 1962), measles (1964), mumps (1967), rubella (1970), and hepatitis B (1981). What did McKeown and later researchers conclude about the effect of vaccines on explaining the historical rise in life expectancy? How did they come to this conclusion? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Medicine in 20th Century Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Outline 1 Generalized Nutritional Poverty Trap The Basic Problem Necessary Conditions for Poverty Trap Caveats 2 The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Mortality from infectious disease and cardiovascular disease declined dramatically in the past 100 years. See Fig 3 (Cutler et al., 2006) Antibiotics (1930s) reduced mortality from infectious disease from 300 per 100,000 deaths to less than 50 in 20 years Since 1950, mortality from cardiovascular disease declined by 50% More recently, the decline in smoking and the decline in infant mortality has contributed to lower mortality. What were other contributing factors? Prof. Nancy Qian Econ 325: Lect5 Generalized Nutritional Poverty Trap The Historical Roles of Nutrition and Disease Some facts Public Sanitation Medicine - Vaccination Other Medical Treatments Conclusion Public sanitation, vaccinations and more recent medical developments all contribute to the decline in mortality However, we still need to explain the rise in population before the mid-1800s Prof. Nancy Qian Econ 325: Lect5 ...
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