The test will focus more on post mid-term material
However, ALL course topics are covered on the exam
ALL material is fair game for exam questions.
Course material will be covered in a different order than was originally presented in the course – and will be covered in groupings, as topics were covered in section.
Please remember to complete your course evaluations
Good luck studying
Exam Format
Part 1: True/False(31.5 pts)
Part 2: Identifications (25.5 pts)
Part 3: Short answer- includes quantitative questions (53 pts)
Part 4: Short essay – choose 1 of 3 possible essays (10 pts)
Undergraduate exam:
January 18, 2007, 9:15am – 12:15pm, Lowell Lecture Hall
Extension school exam:
January 18, 2007, 6:00pm – 9:00pm, Emerson 105
(you may only bring a pen/pencil and calculator)
Read the directions for each section carefully. Be precise!
Section 1- Lectures1, 2, and 3
Section 1- Lectures1, 2, and 3
Section 10 – Lectures 22 and 23
Section 8 – Lectures 16, 17, and 18
Section 7 – Lectures 14 and 15
Section 5 – Lectures 10 and 11
Section 3 – Lectures 6 and 7
Section 9 – Lectures 19, 20, and 21
Section 6 – Lectures 12 and 13
Section 4 – Lectures 8 and 9
Section 2 – Lectures 4 and 5
Section 1- Lectures1, 2, and 3
Section 1- Lectures1, 2, and 3
9/18 – Global health: main problems and solutions
9/20 – The definition and quantification of health
9/25 – How do we know about global health?
Section 10 – Lectures 22 and 23
12/4 – Choosing the right interventions, cost-effectiveness
12/6 – Quality of care, human resources, accountability and ethical concerns
Section 8 – Lectures 16, 17, and 18
Section 7 – Lectures 14 and 15
Section 5 – Lectures 10 and 11
Section 3 – Lectures 6 and 7
Section 9 – Lectures 19, 20, and 21
Section 6 – Lectures 12 and 13
Section 4 – Lectures 8 and 9
Section 2 – Lectures 4 and 5
Section 1: How do we know about health?
Mortality
Prevalence and incidence
Sensitivity and specificity
Domains of Health
Commonly Reported Probabilities of Death
1q0
Infant mortality ‘rate’, the probability of death between birth and exact age 1.
5q0
Child mortality, the probability of death between birth and exact age 5.
45q15
Adult mortality, the probability of death between age 15 and exact age 60 conditional on being alive at age 15.
But remember that mortality is NOT the whole story. Morbidity must also be considered (think DALYs).
Length of the interval
Starting age
Prevalence and Incidence
Prevalence =
Number of individuals with disease
Population
Which is a proportion?
Which is a rate?
Incidence =
Number of NEW cases of disease
Person-time of observation
Answers
Prevalence is a proportion
Incidence is a rate
Example: Prevalence or Incidence?
Among men aged 55-69, 1% will have their first heart attack in the next year.
In 2000, 10% of women surveyed reported suffering from a migraine headache.
As of today, 12% of women have breast cancer.
Example: Prevalence or Incidence?
Among men aged 55-69, 1% will have their first heart attack in the next year. Answer: INCIDENCE
In 2000, 10% of women surveyed reported suffering from a migraine headache. Answer: PREVALENCE
As of today, 12% of women have breast cancer.
Answer: PREVALENCE
Practice Problem
In September 2006, 1,500 freshman students enrolled in a study looking at the number of back injuries associated with carrying heavy books during a school year. 100 of the students were found to have back problems at the initial examination. At the end of the first school year, 250 additional students reported back pain.
1) What was the prevalence of back injuries among the students at the initial examination?
2) What is the incidence rate of back injuries for the freshman year?
Answers
1) What was the prevalence of back injuries among the students at the initial examination?
100/1500 = .07
The prevalence of back injuries among the students at the beginning of the year is 7%.
2) What is the incidence rate of back injuries for the freshman year?
Numerator (number of new cases) = 250
Denominator (pop at risk)
At beginning of year = 1500 – 100 = 1400
At end of year = 1400 – 250 = 1150
Average over year = (1400+1150)/2 = 1275
Incidence = 250/1275 = .20 (20,000/100,000 py)
The incidence of back injuries in the freshman year is 20,000 per 100,000 person years.
Sensitivity and Specificity of a Diagnostic Test
Sensitivity –
The proportion of those people with the disease that test positive (True Positives)
Specificity -
The proportion of those people without the disease that test negative (True Negatives)
Test
Positive
Negative
True disease status
Positive
A
B
Negative
C
D
Sensitivity = A / (A+B)
Specificity = D / (C+D)
Practice Problem
A newly developed diagnostic tool for determining anemia in children is 90% specific and 92% sensitive. Of the 965 children under-5 in a rural village in India, we know with certainty that 345 have the disease. Use the true prevalence to fill in the following 2 X 2 table with the values you would obtain if you applied the new diagnostic test in the village.
T+ T-
D+
D-
Test
True Disease Status
A + B =
Total children =
C + D =
Answers
A newly developed diagnostic tool for determining anemia in children is 90% specific and 92% sensitive. Of the 965 children under-5 in a rural village in India, we know with certainty that 345 have the disease. Use the true prevalence to fill in the following 2 X 2 table with the values you would obtain if you applied the new diagnostic test in the village.
T+ T-
D+
D-
Test
True Disease Status
A + B = 345
Total children = 965
965 – 345 = 620
A/345 = .92
A = 317
345 – 317 = B = 28
D/620 = .90
D = 558
620 – 558 =
C = 62
Domains of Health
Section 10: Choosing and delivering health interventions
Cost-effectiveness
Human resources
Quality of care
Cost-Effectiveness Analysis
How can we make decisions about resource allocation when we know that finances are limited?
In general, most interventions that improve health cost money, so how do we chose among them?
Cost-Effectiveness Analysis (CEA) is an analytical tool to inform decision-making processes.
It is only one input into the decision-making process - also political, distributional and ethical considerations.
Two kinds: competing and non-competing choices problems.
Two Types of CEA Problems
Non-Competing Choice
How to best spend the budget you have?
You can make many choices (i.e. NOT mutually exclusive)
Ex: choosing among multiple public health programs for different diseases or problems
Calculate the Average CER
Goal:
Spend money on programs that will help maximize total gain in health benefits.
Competing Choice
How much are you willing to pay for the next unit?
You can only make one choice (i.e. MUTUALLY EXCLUSIVE alternatives)
Ex: choosing one life-saving surgery for disease X over another
Calculate the Incremental CER
Goal:
Find the treatment closest to a person’s willingness to pay for an additional unit of health.
Two Types of CEA Problems: Mechanics
Non-Competing Choice
Step 1: Calculate average C/E ratio.
Step 2: Rank interventions by increasing C/E ratios.
Competing Choice
Step 1: Arrange treatments by increasing costs.
Step 2: Check to see if interventions increase in health benefit. Eliminate dominated treatments (i.e those that cost more but give less health benefit).
Step 3: Calculate the ICER and eliminate dominated treatments; re-calculate ICER again as needed.
CEA Sample Problem 1
You are a public health officer responsible for disbursing your budget in a way that attempts to optimize total health benefit according to cost-effectiveness principle. The interventions listed below are what is available to you. If you are able to choose more than 1 health intervention and you have a budget of $100K, which do you choose to implement?
Time for some calculations…
Intervention QALY Gained Net Cost ($)
A 400 50,000
B 850 90,000
C 300 30,000
D 900 70,000
Intervention QALY Gained Net Cost ($) Average C/E Ratio
A 400 50,000 125.0
B 850 90,000 105.9
C 300 30,000 100.0
D 900 70,000 77.8
ARRANGE BY INCREASING C/E Ratio
Intervention QALY Gained Net Cost ($) Average C/E Ratio
D 900 70,000 77.8
C 300 30,000 100.0
B 850 90,000 105.9
A 400 50,000 125.0
With a budget of only $100,000 you would choose to implement interventions D and C. If you were given more money you would then implement B followed by A depending on how much your budget was increased.
A middle-aged male visits the doctor, complaining of chest pains. After a series of tests, the patient is diagnosed with a heart condition for which 4 known treatments are available. Each treatment costs a different price, and each is associated with different gains in health units. However, the patient can only choose one treatment option of the 4 available (i.e. they are mutually exclusive).
Treatment QALY Gained Net Cost ($)
A 425 50,000
B 800 90,000
C 400 30,000
D 850 70,000
CEA Sample Problem 2
Treatment QALY Gained Net Cost ($)
A 425 50,000
B 800 90,000
C 400 30,000
D 850 70,000
ARRANGE BY INCREASING COSTS and check that HEALTH BENEFITS ALSO INCREASE
Treatment QALY Gained Net Cost ($)
C 400 30,000
A 425 50,000
D 850 70,000
B 800 90,000
D costs less than B, but has more health benefit.
B is dominated by D, so we get rid of B.
CALCULATE THE INCREMENTAL COST-EFFECTIVENESS RATIO and check that the ICER goes from SMALLEST to BIGGEST, if not, a strategy is DOMINATED
Treatment QALY Gained Net Cost ($) ICER
C 400 30,000 75
A 425 50,000 800
D 850 70,000 47
A is dominated so remove it and re-calculate the ICER
Treatment QALY Gained Net Cost ($) ICER
C 400 30,000 75
D 850 70,000 89
Here we have two options left, so which do we choose? That depends on our patients threshold willingness to pay. If he will pay $75 or less per additional QALY gained, then he would choose C. If he is willing to pay $88 or less he would still choose C over D. However, if he is willing to pay $89/QALY or more then he will opt for D instead of C.
Human resource for Health
With efforts to scale up health programs such as ARVs for HIV, DOTS for tuberculosis and maternal mortality interventions, there is a widespread recognition that there is an absolute shortage of health workers in many low-income countries. But there are also problems with human resources for health in developed countries as well (e.g. rural areas with no doctors).
This is an area that has only recently received attention and the evidence base on short to medium-term solutions is poor.
Solutions to HR Shortages in Low-Income Countries
Import health workers – a common solution in better off Sub-Saharan African countries such as Botswana, Zimbabwe, Namibia or South Africa. Not feasible for all countries in need.
Redistribute existing health workers from urban to rural areas (easier said than done).
Lower the skills level required to deliver a health intervention – village doctors, village health workers, community participation.
Increase health worker retention rates.
Increase production of health workers – only effective in the long-term
Dealing with Geographic Inequality
Extensive experience in many countries with schemes to increase the number of health workers in rural areas or smaller metropolitan areas.
Build medical and nursing schools outside capital cities – Mexico, Iran.
Financial incentives – Thailand pays multiples of standard salaries for rural postings.
Quality of life interventions – housing, schooling, home leave.
Required service after medical school
Nurse/Doctor Migration Loss or Gain?
Highly politicized topic – clear evidence for Ghana, Zimbabwe and South Africa of emigration to UK, US, with vocal complaints by countries losing staff.
Commonwealth Ministers of Health call for convention; World Health Assembly resolutions.
BUT Philippines, South Korea, India, and Thailand see health workers as an export that brings back remittance income.
Quality: What is it?
Most of the literature on quality defines quality in terms of lists of desirable attributes for quality care: appropriateness, timeliness, effectiveness etc..
Two dimensions:
Technical quality of care—e.g. was a procedure done correctly, was a correct diagnosis made, etc.
Responsiveness—Interpersonal quality of care. Above and beyond the health gain from interacting with the health system, individuals are concerned with the nature of their interaction. Includes Respect of Persons (dignity, autonomy, confidentiality, communication) and Client Orientation (prompt attention, access to social support networks, quality of basic amenities, choice)
Measuring Quality: The Challenges
Risk adjustment – tertiary referral hospitals (often teaching hospitals) have higher risk patients with more comorbidity. Taking this into account is difficult or at least contentious.
Small numbers problems – assessing quality of an individual provider or even a small hospital is very difficult because there are too few events to monitor.
No direct measurement of health gain.
To Err is Human and Crossing the Quality Chasm IOM Reports
Release in the United States of the Institute of Medicine Report To Err is Human triggered enormous media and political response on patient safety.
The sub-component of variation in quality that is due to medical error has received intense intervention and policy engagement (Crossing the Quality Chasm).
Shifting From Blame to Systems
Patient safety movement is a paradigm shift from blaming the healthcare provider who makes a mistake to creating systems that prevent medical errors.
Analytical approach and ethos has been borrowed from airline safety field.
For example, if drug misdosing is a common error, systems should be created that minimize or stop misdosing at the time the medical order is written through to better labelling of products.
Section 1- Lectures1, 2, and 3
Section 1- Lectures1, 2, and 3
Section 10 – Lectures 22 and 23
Section 8 – Lectures 16, 17, and 18
11/13 – Road traffic accidents, homicide, suicide and war
11/15 – Environment of the poor
11/17 – Tobacco and alcohol
Section 7 – Lectures 14 and 15
Section 5 – Lectures 10 and 11
Section 3 – Lectures 6 and 7
Section 9 – Lectures 19, 20, and 21
Section 6 – Lectures 12 and 13
Section 4 – Lectures 8 and 9
Section 2 – Lectures 4 and 5
Injuries: What to know
Who is affected?
What are the major risk factors?
What interventions are effective?
Road Traffic injuries
Who is affected?
Young adults
Males (80% of victims)
Motorcyclists, pedestrians and cyclists
What are the major risk factors?
Vehicle-pedestrian mixture
Speed, alcohol
Poor road or vehicle design
Road Traffic injuries
What are effective interventions?
There are many—see your class notes!
Decreasing exposure
Vehicle design
Road design
Enforcement of safety laws concerning speed, alcohol, seatbelt and helmet use
Education alone is not very effective
Global Distribution of Major Risk Factors
Attributable and Avoidable Burden
Attributable Burden –
Current burden of disease due to past exposure. Calculated with data on:
Exposure to the risk factor
Hazard (how dangerous is the risk factor)
Total burden of disease
Avoidable Burden –
Future burden of disease avoidable if current and future exposure levels are reduced.
Exposure Disease?
Risk Factor
Anything that changes the probability of a health outcome (note: some diseases are risk factors, i.e. HepB, iron deficiency)
Relative Risk
Magnitude of association between exposure and disease. It indicates the likelihood of developing the disease in an exposed group relative to an unexposed group.
Calculating Relative Risk
RR = Probability of Disease in the Exposed
Probability of Disease in the Unexposed
E+ E-
D+
D-
A
B
C
D
Practice Problem: What is the relative risk of head injuries experienced in the following cohort of 100,000 Chinese high school students?
No Helmet Helmet Total
Injury 500 900 1400
No Injury 9,500 89,100 98,600
Total 10,000 90,000 100,000
For each risk factor covered in class, review:
Exposure: What is the exposure of interest?
Health Risks: Which diseases are caused by exposure to the risk factor?
Mitigation: What interventions reduce the health burden caused by the risk factor? Which interventions are less effective?
Example: Indoor Air Pollution
Exposure: Combustion of solid fuels (firewood, coal, other biofuels) in poorly ventilated homes
Health Risks:
Acute Respiratory Infections in children under 5
COPD among adults
Example: Indoor Air Pollution
Mitigation:
Behavioral change: keep children away from the fire
Improve ventilation in cooking areas
Improve stove quality (mixed effectiveness; women sometimes refuse to use them)
Shift to cleaner fuels, such as kerosene or LPG (where economically viable)
Tobacco: Unique mitigation method
As tobacco consumption has declined in the US and other Western markets, focus of marketing of tobacco has turned to developing countries.
In 1998, WHO began effort to create a binding global treaty on tobacco control: the Framework Convention for Tobacco Control.
After nearly 5 years of negotiations, the FCTC was passed by the World Health Assembly in May 2003 and entered into force in February 2005.
The FCTC includes provisions to impose restrictions or bans on advertising, sponsorship and promotion; establish new packaging and labelling of tobacco products, establish clean indoor air controls and strengthen legislation to clamp down on smuggling.
Cancer is a general term for more than 100 diseases that are characterized by uncontrolled, abnormal growth of cells. Cancer cells can spread locally or through the bloodstream and lymphatic system to other parts of the body.
Etiology of Cancer is Complex
Molecular pathway that is disrupted may be different for cancers that appear to be the same.
At the same time cancers in different sites may share the same molecular or genetic origin.
Cancer: Epidemiology
There are 10 million new cases every year, from which there will be 7 million deaths
China has 20% of the world's total cancer cases (2.2 million), and the US accounts for the 14.5% of the world's total cancer cases (1.6 million cases)
Risks are determined by environmental exposures, diet and genetic susceptibility
Developing countries face higher risks of cancers in: stomach, liver, cervix, mouth, esophagus, prostate, While developed countries face higher risks of lung and colon C.
The most common cancer for men world wide is “Lung Cancer” and “Breast cancer” for women
If we aggregate men and women, “Lung Cancer” is the most common.
Epidemiology of Each Specific Cancer
Stomach Cancer
High incidence and mortality in East Asia
Major decline in stomach cancer incidence and morality in Western countries In past 50 years
Decline may be the result of refrigeration and the declining use of preservatives
H. pylori is a risk for stomach cancer and may account for 40 percent of stomach cancers worldwide
Liver Cancer
High incidence and mortality in Africa and East Asia
Major risk factor is chronic infection with Hepatitis B and Hepaitis C viruses
85 percent of cases in developing countries are attributable to Hep B and Hep C infections.
Lung Cancer
Most common cancer and the largest cause of cancer mortality
Nearly all variation in lung cancer incidence can be attributed to tobacco smoking
Main strategy for tackling lunch cancer is to reduce tobacco consumption
If lifestyle change interventions are rarely successful, what are some other mechanism to reduce smoking?
Breast Cancer
Most common incident cancer in women
Incidence is recorded as higher and increasing in high income countries
Screening with mammography is believed to contribute to five-year survival
Cervical Cancer
Highest in poor developing countries
HPV is the main risk factor for cervical cancer
Most young women who are sexually active are infected with HPV (about 80 percent)
Estimating Cancer-Specific Survival
Absolute survival The percentage of individuals diagnosed with cancer alive after 5 years
Relative survival The percentage of individuals diagnosed with cancer alive after five years divided by the percentage of the age-sex matched general population alive after five years (most common method)
Cumulative Probability of Death The probability of death from cancer assuming there are no other causes of death
Prevention and Treatment
Prevention Effort
War on Cancer are initiated by National Cancer Institute, International Agency for Research on Cancer
Tobacco control efforts – Framework Convention on Tobacco Control by WHO
Cervical and breast cancer screening were included in discussions of the Cairo Reproductive Health agenda
Hepatitis B vaccination included in The Global Alliance for Vaccines and Immunization (GAVI)
Treatment Effort
Dramatic increase in understanding of cancer biology and genetics over the last 20 years.
Targeted therapy – imatinib (Gleevec) induces nearly complete and sustained remission in patients with early stage chronic myeloid leukemia.
Lots of promise for new generation treatments but they may be many years away.
2. CVD: Biology
King of Mortality but not so in GBD
In COM, Ischemic Heart Disease(#1), Cerebrovascular Disease(#2)
In GBD, Ischemic Heart Disease (#6) and Cerebrovascular Disease (#7)
It is the leading cause of mortality in both developed/developing countries.
Biology
Ischemic Heart Disease
Heart is deprived from oxygen (e.g. myocardial infarction)
Cerebrovascular Disease (a.k.a stroke)
Brain is deprived from oxygen
Two main form of stroke
Hemmorhagic: blood vessel in brain ruptures
Thrombotic: blood vessel occluded because of blood clot
Direct interventions for known major risks: blood pressure and cholesterol
Intervention
Prevention: Targeting Blood Pressure and Choleserol
Stepwise reductions of salt content of processed foods with either legislation or voluntary agreements and food labelling
Health education through mass-media
Threshold based treatment
The Polypill
Statin, low-dose aspirin & blood pressure drugs
65% reduction in heart attack & stroke risk
Very safe and tolerable
~$20 a year
Treatment
Treatments developed over the last 35 years are effective in reducing the disability associated with angina pectoris and congestive heart failure. Emergency therapy of MI has also reduced the case-fatality rate.
Main treatment strategies:
Pharmacological management of angina, Cognitive Heart Failure
Pharmacological management of Blood Pressure, cholesterol, plus aspirin and/or beta-blockers
Revascularization of the heart muscle using angioplasty or coronary artery bypass graft
Emergency revascularization through thrombolytic agents (clot busters)
Section 1- Lectures1, 2, and 3
Section 1- Lectures1, 2, and 3
Section 10 – Lectures 22 and 23
Section 8 – Lectures 16, 17, and 18
Section 7 – Lectures 14 and 15
Section 5 – Lectures 10 and 11
10/23 – Major Childhood Infectious Disease
10/25 – Reproductive Health Challenges
Section 3 – Lectures 6 and 7
10/11 – A framework for thinking about drivers in health
10/13 – HIV/AIDS
Section 9 – Lectures 19, 20, and 21
Section 6 – Lectures 12 and 13
Section 4 – Lectures 8 and 9
Section 2 – Lectures 4 and 5
Child health: Diarrhea
Biology: 3 types of diarrhea (bloody, watery, and epidemic)
Prevention:
breastfeeding
water & sanitation
complementary feeding
zinc, vitamin A supplements
rotavirus vaccination
Treatment
Oral Rehydration Therapy (ORT): solution of sugar and salt
Shift in 1980s from prepackaged Oral Rehydration Salts (ORS) to home-made solutions of ORT
Child health: ARI
Biology: major burden is lower respiratory infection (i.e. pneumonia)
Prevention:
breastfeeding
complementary feeding
vaccination (Hemophilus influenza type B, conjugate pneumococcal)
zinc
Treatment:
antibiotics
Child health: IMCI
Integrated Management of Childhood Illness, WHO-led effort begun in 1992
Focus on 3 levels:
Caregivers (family and community health practices)
Health providers (standardized algorithms for diagnosis of diarrhea, malaria, and ARI)
Health system (planning, regulation, management)
Maternal and reproductive health
A problem of definition:
an aspect of a discipline (within demographics that focus on fertility and contraception)
a movement within women’s advancement, feminism (Reproductive rights, Cairo ‘94, Beijing ‘95, women’s decade)
a set of health conditions (maternal mortality, sexual problems)
a constellation of services (contraception, abortion, human sexuality, STD prevention and treatment, infertility)
Total Fertility Rate (TFR) = the number of children that would be born to each woman if she were to live through her child-bearing years, given current birth rates
Maternal mortality ratio = number of maternal deaths during a given time period per 100,000 live births during the same time period
= # of maternal deaths X 100,000
# live births
Maternal mortality rate = number of maternal deaths in a given time period per 100,000 women aged 15-49 (or woman-years of risk exposure) in the same time period
= # of maternal deaths X 100,000
# women aged 15-49
Lifetime maternal deathrisk = cumulative probability of death from a maternal cause between ages 15-50, often expressed in terms of odds
10/30 – Epidemics, surveillance, response and eradication
11/1 – Mental Health
Section 4 – Lectures 8 and 9
10/16 – Tuberculosis
10/18 – Malaria
Section 2 – Lectures 4 and 5
9/27 – Global burden of diseases, injuries and risk factors
10/2 – Inequalities in health
Trends in Measured Obesity
Changing US income-BMI relationship
Nutrition Transition
Shift to ‘Western’ high-fat, low fibre diet due to higher incomes and globalization of the food industry – focus on fat composition of caloric intake
Urbanization and decrease of physical activity associated with shift from manual labour to industry and service sectors combined with technology revolution decreasing physical activity within any occupation.
Snacking Theories
Main change in the energy balance is the rise of eating between meals which has been facilitated by food processing technologies (good tasting long lasting) and increased availability of snack foods sales points throughout society.
Some studies identify the main culprit at liquid carbohydrates (soft drinks and sweetened fruit juices) which have increased enormously in the last decades. Liquid carbohydrates may not trigger normal satiety mechanisms.
Culture of Food
In previous times, food accounted for 80% or more of household income. Food consumption was associated with elaborate rituals.
Patterns of food consumption have been changing dramatically: rise of eating out of the home, eating prepared food in the home, increased portion size (especially in the US), fast food restaurants as a global phenomenon.
Genes Environment Mismatch
Humans are the only higher primate that cooks their own food starting 1.6 million years ago. They likely ate one meal a day after hunting/gathering during the rest of the day. Humans also faced famines. Both probably led to a highly effective capacity to store excess energy as fat.
These thrifty genes in an environment of constant plenty lead to excess weight gain.
Population Strategies
Decrease availability of energy-dense snacks especially beverages to children in school.
Promote physical activity in schools, make the environment more conducive to physical activity, e.g. sidewalks.
Change national diet recommendations to reduce percent of free sugars; work with food industry to provide alternatives.
More aggressive state intervention to shift the national diet through taxes and regulatory mechanisms.
Summary OR: 0.72
Perinatal mortality: OR’s for each 1 g/dL Hb increase
From Stoltzfus et al, 2005
Effect of Iron/Folic Acid (IFA) Supplementation on Adverse Events in Children 1-48 Months Old
Nepal (19,299 child-years IFA, 9,799 placebo) – no effect on deaths1
Zanzibar (16,950 child-years IFA, 8,574 placebo) – 12% increase in all hospitalizations/deaths, 16% in malaria, 33% in pneumonia2
1Tielsch et al, submitted
2Sazawal et al, submitted
Effects of Vitamin A on Infectious Disease Morbidity
Possible effect on diarrhea severity, but not all morbidity
No effect on pneumonia morbidity
Effect on measles complications
Major Trials of Vitamin A to Prevent Mortality
Over 165,000 children participated in these 8 trials
Vitamin A Implementation
Widespread implementation of Vitamin A supplementation often linked to immunization programs.
Is coverage sustainable outside of immunization campaigns?
Preventive Effect of Zinc Supplementation on Pneumonia Incidence in Continuous Supplementation Trials
3
India(S)
Peru
Vietnam
Jamaica
India(B)
Pooled
0
0.5
1
1.5
2
2.5
Relative Risk and 95% CI
Effect of Zinc Supplementation on Malaria in Children
Location
Reduction in Clinic Visits for Malaria
The Gambia1
32% (p=0.09)
Papua New Guinea2
38% (p<0.05)
Combined
36% (CI 9-55%, p<0.05)
1Bates et al, Brit J Nutr, 1993
2Shankar et al, Am J Trop Med Hyg, 2000
Trial in Bangladesh Evaluating the Preventive Effect of Weekly Zinc Supplementation
1-23 mo. old children, weekly zinc (70 mg)
6% less diarrhea, 17% less pneumonia, 49% less severe pneumonia and 42% less otitis media,
All actors, institutions and resources that undertake health actions.
Health actions: all actions whose primary intent is to improve health.
Primary Intent
Not all policies and actions that have an important influence on health, such as educating young girls or poverty reduction programs, are part of the health system according to this definition.
A wide range of actions targeting individuals and communities would meet this definition: from surgery to campaigns to raise tobacco taxes to random breath testing for drunk driving.
HEALTH SYSTEM GOALS
Health
Responsiveness
Fairness in Financial Contribution
LEVEL
DISTRIBUTION
Quality
Equity
Efficiency
What determines effective coverage?
Price of health care
Perceived need and knowledge
Geographic proximity of providers - travel time
Cultural and social acceptability of intervention - responsiveness of health systems
Availability of necessary technology and resources
Technical quality of providers
Choice of an intervention
Adherence
Demand on health care
Quality of providers
Health outcomes
Main Revenue Generation Mechanisms
General taxation
Social insurance – payroll taxes
External assistance
Private insurance
Out-of-pocket payments
Direct care from private organizations
Composition of health expenditure
Risk Pooling
Systems that primarily use taxes or social insurance protect households, particularly poor households, most effectively from catastrophic health payments.
Epidemics, Surveillance, and Pandemic Flu
Know the nuances of the definitions
Epidemic = disease for which incidence of new cases is greater than expected; less predictable. (example, diarrhea is steady in the developing world, except when there is a cholera outbreak).
Endemic = a disease is maintained in the populations without introduction of cases outside the population
Understand the differences in response
Control = taking measures to reduce the disease to some stated objective; if we removed the control intervention, the disease could come back; no permanent change. For this reason, continuous intervention is needed.
Elimination of disease= reduce the incidence of the disease to zero in some defined area. If we stopped this type of intervention, the disease would come back. Again, continuous intervention is necessary.
Responses (cont’d)
Eradication = PERMANENT reduction to zero of the worldwide incidence of infection caused by a specific antigen. Intervention efforts are no longer needed.
Herd Immunity = when vaccination of a large fraction of a population is conducted, it provides protection to non-vaccinated individuals. The percent coverage needed to achieve herd immunity differs by disease.
Challenges in responding to epidemics
To respond to epidemics, we need to understand their origin—we need quick identification of outbreak and tracking trends.
MoH have legal obligations to report notifiable cases
What do you think are the limitations of this type of reporting???
WHO scans local media sources about local outbreaks (to supplement poor reporting)
Influenza Antigen
Need to understand structure of influenza antigen to understand concern over pandemic influenza
No definitive biological, immunological, or radiological tests
Symptom-based as opposed to etiologic or pathologic
Epidemiological measurements and clinical diagnostic practice has varied widely over time and across cultures.
Culture and diagnosis
Challenges
Cultural Variation in Presentation:
Manifestation of depression and other mental health problems and symptoms vary by culture.
E.g. East Asia it is much more common for patients to report somatic symptoms as opposed to feeling sad or blue.
Differential Item Functioning Across Cultures:
People from different cultures may interpret questions differently).
This makes it difficult to distinguish real variation in the way a mental disorder is manifested from variation in the way individuals from different cultures respond to the same survey questions.
Treatment
Trxt options exist; combinations have been proposed and tested.
Tricyclic antidepressants (3-4 wks before impact); effectiveness?
Psychotherapy—equally effective in studies
SSrIS- more effective then tricyclics,, less side effects, good for youth
Other things that are being researched: cranial magnetic resonance, electroconvulsive therapy.
BIG POINT: If we were to fully utilize all interventions that are currently available to us, we would only be able to reduce the avoidable burden by 20-30%.
Mycobacterium tuberculosis
Transmission through the air – not behavior
Pulmonary versus extrapulmonary TB
HIV is changing risk of breakdown, case fatality, and transmission
Latent infection versus active disease
What is the difference?
How do we test for each?
TB has a long memory – difficult to estimate incidence
Tuberculosis
Two types of pulmonary clinical disease: sputum-smear positive (more infectious) and sputum culture positive.
Diagnosis
Chest x-ray
Pulmonary sputum smear
Pulmonary sputum culture
PPD skin test
New interferon-γ blood test, more specific
Diagnosis
Decreasing probability of transmission: UV lights, negative air-pressure rooms, isolation
Tuberculosis incidence continues to rise in communities with high HIV sero-prevalence.
Insisting on direct observation of therapy is not necessary and distracts from other efforts to increase case-detection.
Preventive therapy is being ignored.
Case-detection rates cannot be increased over 45% without addressing fundamental health system issues.
Some Criticisms of DOTS Strategy
There are four types of human malaria falciparum, vivax, ovale, malariae, first two cause most human disease
Malaria is a disease that requires the presence of a vector which in this case is the anopheline mosquito.
Transmission happens at night
The severity of the attack is determined by the species and the strain, on age, genetic constitution, immunity, general health, nutritional status and use of antimalarial drugs
Human Malaria
Thick and thin smears of blood can be used to detect Plasmodium.
In developing countries, most malaria is diagnosed presumptively on the basis of fever and other symptoms.
False positives are common because in some endemic areas more than 50% of adults have parasites.
Malaria Diagnosis
The focus of most of is on malaria in endemic communities, endemic meaning where there is regular transmission each year.
In some communities, malaria transmission may occur under unusual environmental circumstances (heavy rains) and inmigration of infected individuals.
Individuals in these communities have not acquired immunity and are at high risk of severe malaria.
Preventing the malaria epidemics requires surveillance and appropriate vector control and prophylactic interventions.
Epidemic Malaria
Most of the malaria burden is
from deaths in young children
Natural exposure to P falciparum gradually elicits, in human hosts, short-lived strain-specific malaria immunity: first to severe disease and death, and then to mild disease.
Repeated infections are required to maintain immunity, which is both antibody and T-cell based.
Acquisition of immunity in endemic areas explains why clinical episodes are often more severe in children in these communities.
Impact of all intervention strategies requires long-term consideration of the consequences for acquired immunity.
Acquired Immunity
Vector control – DDT use recommended again
ITNs – also vector control
Prophylaxis for children - some fear may lead to increased mortality at older ages due to decreased acquired immunity.
Prophylaxis for pregnant women –reduced incidence of severe anaemia and reduced low birth weight.
Prophylaxis for Travellers
Management of Malaria epidemics
Prevention
Prompt treatment of clinical episodes decreases their duration and severity.
In children, cerebral malaria requires extremely rapid treatment. The main strategy to avoid progression to cerebral malaria is to presumptively treat episodes early.
Treatment has little or no effect on community transmission levels of malaria.
Treatment
Chloroquine has been the mainstay of treatment for clinical episodes for the last 4 decades. Because of drug resistance it is no longer effective in many areas. In vitro drug resistance is often higher than treatment failure rates.
Other agents such as SP have developed resistance rapidly.
Artemisin and Artemisin combination therapy (ACT) appears to be the only major agent with little resistance at the population level.
ACT costs 10-20 times more than chloroquine
Antimalarials
WHO launched a global eradication programme that was the centerpiece of global health in the 1960s.
In 1998, WHO launched the Roll-Back Malaria
RBM strategy: 1) Prompt effective treatment; 2) ITN; 3) Prophylaxis for pregnant women through antenatal clinics; 4) epidemic management.
Recent return of DDT
Control
Global Burden of Disease (GBD)
What is disease burden?
Gap b/w a population’s actual health status and some ideal/reference status
Mortality does not capture disease status while a person is alive
Implications for resource allocation
DALYs are a better measure of GBD
DALYs
DALY = YLL + YLD
YLL = years of life lost to premature death
YLD = years lived w/ a disability of specified severity and duration
1 DALY = 1 year of healthy life lost
Premature death = occurs before age to which the dying person would have expected to live if they were a member of the standardized population.
DALY Value Choices
Assumes standard life table for all populations
Age-weighting: peaks in early twenties
Age discounting-future healthy life is valued less than healthy present life
Health Inequalities
Inequality-no normative judgment
Inequity-invokes the concept of social justice; normative judgment
