PH Summary-Selected Slides
Transcript of PH Summary-Selected Slides
PUBLIC HEALTH ...• The science of protecting people and health • Public health is the organized effort by society to
protect, promote, and restore the health of its citizens.
The goal of public health is to reduce discomfort, disability, and disease in society and promote the quality of life, as well as attaining the highest level of physical, mental, and social well-being, utilizing available knowledge and resources at a given time and place.
Intervention levels- prevention types
Primordial prevention
Primary prevention
Secondary Prevention
Tertiary Prevention
Risk Factors
Disease
Complications
Deterioration of quality of life, Death
Health
• A state of complete physical, mental and social wellbeing and not merely an absence of disease or infirmity / WHO... include the ability to lead a socially and economically productive life
Cannot be measured in exact measurable parameters
Characteristics of the definition
• It is a positive concept, emphasizing social and personal resources, as well as physical capacities
• Universally accepted being only an aspiration• It presumes a strong social responsibility • Emphasises the positive and complex feature of healthCriteria takes in consideration• Functional well-being• The ability to self manage and to adapt to a range of
demands /conditions (life, work etc)• Human conditions, which makes someone creative
Health statusScientific „negative ”model
• Biomedical > health = the feature of the biological (not of the human) being
• Reductionist – doesn`t deal with the context (patient), just with the disease
• Mechanical – human being viewed as a faulty/disfunctional machine made up of parts to be fixed, when broken
• Allopathic – every illness can benefit of a “cure” / drug
Health statusHealth status“Positive” model“Positive” model
well-being...• physical – a man works, feeds himself, acts in
good conditions• psychological – lives in a non-violent climate,
without fear, concern, depression, anxiety and can cope with the normal stresses of life
• social – the ability to create and maintain social relations
Health vs illness
Unhealth – unability to adapt to various physical, social and psychological conditions
• illness – ones personal experience, perception of unhealth (considers himself ill).
• disease – defined with biomedical criteria (signs and symptoms), some deviation from a biological norm.
• sickness – a public mode of unhealth, the expression of an illness related to social norms,
Factors Affecting Health
Health system
Biology
Environment
Behaviour
Health status
Contribution to:
reduce mortality health expenses/USA ,
11 % health system 90 %43 lifestyle 1.519 environment 1.627 biology 7.9
Behavioural factors /life style
• Smoking• Alcohol abuse• Other drugs• Nutrition/ gastronomic habits • Physical activity• Sexual behaviour
Social factors
• Macroeconomic indicators
• Education
• Employment
• Proffession / job
DEMOGRAPHY
Demography
The scientific study of human population, which includes the study of changes in population:
• sizes• its composition and • Distribution..affected by 3 main processes:
– fertility– mortality and – migration
Concept
• Demographic event- individual case – birth– death– marriage– divorce
• Demographic phenomena- intensity / frequency of a demographic event in a certain population, certain period of time, calculated in rates
EVENTS• Birth• Stillbirth• Death• Marriage• Divorce
• PHENOMENA• Natality• Mortinatality• Mortality• Marriage rate• Divorce rate
Demographic measurement
• Population static
• Population dynamic– Natural– Mechanical
Population static
• The study and measurement of population characteristics such as I. Size II. Composition
Age groupsSexRezidence
...
III. Distribution / Density
Size of the population
• Direct data collectionThe process of collecting data straight from statistics registries which are responsible for tracking all birth and death records,...marital status, migration.
• Census -the most common and popular method
• Estimations • Surveys
De facto census – (where they are)– disadvantages 1- Persons in transit may not be included2- Provision of incorrect picture of the population3- Vital rates may be distorted
The de jure census - /where their permanent residence/ gives a true figure.
disadvantages 1- Expensive in time and money 2- Some individuals may be counted twice 3- Information may be incomplete
• Structure of population by age– biological generation I. 0 – 14 years II. 15 – 49 years III. 50 years and over
economic generation
I. 0 – 18 years (pre-productivity)
II. 19 – 49 years (productivity)
III. 50 and over (post-productivity)
1. Young dependency ratio :
I BG X 100 II BG
( same year & locality)
2-Old dependency ratio = III BG X 100
II BG
Total dependency ratio:BG I + III
BG II
• Age pyramid
– progressive (I. BG > III. BG)
– stationary (I. BG ~ III. BG)
– regressive (I. BG < III. BG)
Demographic stages
Describe changes in population size and composition due to increase or decrease in nr. of births and deaths
• High stationary stage (both: birth and death rates high)
• Early expansion stage I (rapid drop in death rates)
• Late expansion II mortality tend to level
• Low stationary III (a new equilibrium: birth- and death rates -low)
• Declining stage IV (contracting)
Types of population pyramidsSündberg / Burgdörfer
EXPANSIVE /PROGRESSZIV
„YOUNG NATIONS” III
STATIONARY „AGING”
CONSTRICTIVE/REGRESSIVE
„OLD POPULATIONS”
OLD
ADULTS
INFANTS/ TEENAGERS
Declining stage
• Birth rate lower than death rate• Negative growth in population
Developed countries Developing countries
Base Narrow ( Low BR) Wide (high BR)
Side Not sloping (Straight ). (low mortality )
Sloping.
(high mortality)
Height Tall (high life expectancy).
Short
(Low life expectancy)
Apex Wide (large numbers of people > 60.
Narrow(few people survive to
old age)
Median Age High (low birth) Low ( High births)
Old dependency ratio
High Low
Young dependency ratio
Low
Comparison between the Pyramids of developing & developed Countries
Factors influencing population size
• Birth rate• Death rate• Environmental sanitation• Immunization• Health and Medical care facilities• Effective pharmaceuticals• Nutrition• Occupational health and safety• Living standards
II Composition of the population
• age• sex• marital state• education• occupation
– active/passive– capacity/incapacity
• economic status etc..
Demographic measurement tools -static
• Sex ratio• Population pyramid• Marital status• Socio-economic status• Urban-rural settlements• Population distribution/ Size / Density• Age dependency rate and a.d. ratio• Life expectancy
Demographic tools -dynamic• Birth-, fertility-, fecundity rate• Death rates and ratios
– Crude death rate– Age-, sex-, cause specific mortality rate– Maternal mortality rate (MMR) ...etc– Case fatality rate
• Natural increase , Vital index, Life expectancy, Population change
• Marriage and divorce rate • Migration (imigration/emigration/net migration rate)
Natality / crude birth rate (CBR): number of births per 1000 individuals/year.
General fertility rate, the annual nr of live births per 1,000 women of childbearing age (15 to 49 years old)
Mortality rate/ crude death rate(CDR)-nr of deaths per 1,000 (or 100,000) people/year
Life expectancy : the number of years which an individual at a given age could expect to live at present mortality levels.
Life expectancy at age X-: total nr of person-years above age X/nr of individuals surviving over age X
Rate of natural increase: mortality rate subtracted from the natality rate / CBR-CDR/10
Life expectancy
Average number of years of life remaining to a person at any specified age
Life expectancy at birth = average number of years a newborn can expect to live if existing mortality patterns continue over the individual’s lifetime
Life Expectancy
e0 T0
l0
ex Txlx
Total number of person - years lived above age x
number of persons surviving to year x
From birth…
MIGRATION
• Involuntary: slavery, ethnic persecution, wars, natural disasters, famines
• Voluntary: to seek jobs, to get an education, because of marriage, upon retirement
------------------------------• Internal migration: within a country e.g. rural to
urban• International migration: skilled professionals to other
countries
DEMOGRAPHIC TRANSITIONFalling death rates are due to better nutrition and higher
standards of living
Falling birth rates are due to social and economic changes:
1) Women stay in school longer2) More women work outside the home3) Women marry later4) Women postpone childbearing5) People choose to have fewer kids
The Demographic Transition
Rubenstein textbook, Global demographics, chapter 2w birth and death rates. Population growth is most rapid in the second stage.
Birth
Death
MORBIDITY
• Frequency –incidence, prevalence• Duration –average duration/case or disability
rate (days per person)• Severity –case fatality rate
Why indicators?
Analyze the present situation Make comparison Measure changes over time
Key measures/indicators of health
• Incidence• Prevalence• Life expectancy• Health adjusted life expectancy (HALE)• Burden of disease• Disability adjusted life years (DALY), YLL/YLD
Concepts and their application
• Incidence: the number of new cases, episodes or events occurring over a defined period of time, commonly one year.
• Prevalence: the total number of existing cases, episodes or events occurring at one point in time, commonly on a particular day.
Relationship between prevalence and incidence
Prevalence depends upon 2 factors • the incidence and duration of illness .
P= I х D=incidence х mean durationUses of prevalence: Helps to estimate the
magnitude of ill health
Burden of disease
• The impact of a particular disease or condition in relation to the amount of healthy life lost due to premature death, illness or disability
• Provides information about health conditions with the biggest impact and where the most gains can be made, so that health resources can be allocated effectively
Disability adjusted life years (DALYs)
A unit of measure developed to compare the impact of different diseases and injuries on an equal basis
One DALY = one healthy year of life lost due to mortality or illness
DALY
Disability adjusted life year = years of life lost + years of life living with a disability
Relation between QALYs and DALYsDALYs = healthy years lost
QALYs = healthy years gained
NO DISABILITY
82,5 YEARS
Calculation
Number of healthy life years × the disability weight of full health (0) + life years with disability (x) × disabilty weight (i) + life years lost (30) × the weighting of death (1)
Ex.DALY= 40x 0 + 45x0.33 +30x1
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 (d2)
• 77.5 × 0.3 × a1 × d2 = 10.5 DALYs
Ethics
• rules of behavior based on ideas about what is morally good and bad
4 Basic Principles
Autonomy: the right to control what happens to your own body.
Beneficence: All healthcare providers must strive to improve their patient’s health, to do the most good for the patient in every situation. But what is good for one patient may not be good for another, so each situation should be considered individually.
Nonmaleficence: “First, do no harm” - the bedrock of medical ethics. The doctrine of double effect...
Justice: to be fair as possible when ..ex limited resourc. Be able to justify your actions in every situation.
Fertility Rate for Los Alamos County 2001
= __number of live births in Los Alamos in 2001__ X 1,000 population of Los Alamos females 15-44 in 2001
= __169__ X 1,000 3,105
= 54.4 /1,000 females ages 15-44
Mortality /Crude death rate (CDR)
number of deaths in Grant County in 2001 = 301total population Grant County 2001 = 30,726
CDR= 301__ X 1000 = 30,726
= 9,79/ 1000 population
Rate of growth of a population
• rate of natural increase (RNI) is the crude birth rate minus the crude death rate of a population
• CBR-CDR/10Ex:Afghanistan2.8% Macedonia 0,3%Greece 0.1% Australia 0.7%Germany – 0.2% Sweden 0.3%Eritrea 2.6% Romania – 0,2%USA 0,5% Sri Lanka 1,3Spain 0,2
Suppose that age-specific mortality rates above age 50 are reduced by 20 per cent (with no change in fertility rates or mortality below age 50).
Will the following demographic indices be higher, lower or the same 10 years later, than they would be if no mortality change had occurred? Explain briefly.
• Life expectancy at birth• Crude birth rate
e0 T0
l0
ex Txlx
Total number of person - years lived above age x
number of persons surviving to year x
From birth…
Life expectancy of a villageOf ten people…
6742892
798361175993
592
592 person-years___________10 persons
= 59.2 years
1. Answer using the statistics given at the bottomA. Calculate the following:• a) birth rate• b) death rate• c) rate of natural increase• d) doubling time B. Draw the outline of a characteristic population pyramid for this
country.C. Explain what stage of demographic transition this country would be
in, and discuss what demographic challenges it might be facing.
• population = 31,639,091 • 911,522 births in 2003• 506,542 deaths in 2003• life expectancy = male: 45.02 years ; female: 45.43 years