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