Mortality and Morbidity in the Population

Professor Michael DunneQUT School of Public Health

Director, International Health Program

Hue University of Medicine and Pharmacy

(no official position, but a good friend)

Content• Key definitions• How rates of death are changing over time• Deaths in Australia in the 21st century: What can

we learn from statistical patterns in deaths among infants, older men and women, and indigenous people?

• Major causes of death • Looking in depth: Injury and death due to road

trauma• International comparisons in life expectancy• Life expectancy in Viet Nam• Looking in depth: Cancer survival among

indigenous women• Morbidity definition• Disability and handicap• Two case studies in maternal and child health:

When public health skills are applied to save lives

Important definitions

Life expectancy • Average number of years of life remaining to a person of a particular age, if current age-specific patterns continue

• Nunber of years lived with, and without, serious disability

Health expectancy

Important definitions

Mortality

Morbidity

Disability

• Death

• Sickness or disease

• Significant loss of function that impairs daily life

A collective term for the health & disease situation in

a population

Health status• The population’s overall level of health, taking account of life expectancy, disability, morbidity, and levels of disease risk-factors.

“Epidemiology” derived from the Greek language

•epi -- upon, on•demos -- the people•logos -- study of

DEFINITION

• Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations and the application of this study to control disease and health related conditions.

• Distribution: person, place, time

• Determinants: causes, risk factors

• Health: a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity

• Disease control: to reduce the occurrence and the burden of disease (mortality and morbidity)

– Source: Webb et al, Essential Epidemiology, 2005, pages 1-2

EPIDEMIOLOGY and CLINICAL MEDICINE

EPIDEMIOLOGY– Populations– Research study– Prevention– Evaluation– Planning

CLINICAL MEDICINE– Individuals– Diagnosis– Treatment– Curing– Caring

Mortality in Australia

• There were 133,700 recorded deaths in Australia in 2006 (about 360 per day)

• Male deaths out-number females (e.g.

M=68,395; F=64,113 in 2004), although the gender difference in death rate is declining over time (ABS, 2006)

• Cancers and heart disease account for almost half of all deaths (approx 46%)

• Source: ABS, 2007

Major causes of death (Australia)

Cause % of total

• Cancers 28.7• Heart Disease 18.5• Stroke 9.1• Accidents (incl transport) 6.1• Respiratory (incl asthma) 4.4• Influenza & Pneumonia 2.5• Diabetes mellitus 2.6• Suicide 1.5• Other causes 26.6

Age and mortality

• Obviously, older people are more likely to die than young people

• Of all deaths in Australia, approximately– 2% are people aged less than 24

years– 4% are 25-44 years– 19% are 45-64 years– 80% aged 65 years and over

• Source: AIHW, 2008

Life expectancy in Australia 2009

• A boy born now should expect to live at least 79.3 years, and a girl 84.1 years (81.6 years for genders combined)

• This assumes that the current conditions relevant to health remain as good as now

Source: CIA fact Book, 2009

Change in life expectancy over time

BIRTH Age 65» females Males Female Males

• 1891 51 47 12 11

• 1910 59 55 13 11• 1934 67 64 14 12• 1955 73 67 15 12• 1977 77 70 17 13• 1996 82 75 20 16• 2002 83 77 21 17• 2004 83 78 21 18• 2009 84.1 79.3

Life expectancy at birth, Australia

Source: ABS, 2007 `Over the past century the average life expectancy of a new-born

boy has increased from 55 years in 1901-1910 to 78.7 years in 2006.

Likewise, the average life expectancy of a new-born girl has

increased from 59 to 83.5 years during the same period

Deaths from all causes throughout the 20th century in Australia

Source: CSIRO, 2001

Why has life expectancy improved

so much?

20th century decline in deaths from infectious disease, Australia (Includes Polio, Diptheria, Whooping Cough, Measles)

These trends are similar throughout most of the world (eg USA)

Source: University of Wisconsin, USA; www.uwmc.uwc.edu

Significant rise, then decline, in coronary heart disease in Australia, 1940 - 2005

                                                                                                     

                                       

Note: Rates are age-standardised to the Australian population.Source: AIHW National Mortality Database

Deaths from stroke declined by almost half across the 20th Century

• Note: Rates are age-standardised to the 2001 Australian population.Source: AIHW National Mortality Database (ABS, 2003)

As with any other cause of death and injury, road traffic accidents can be examined epidemiologically

Epidemiology of road trauma

The Australian Transport Safety Bureau

• This federal agency regularly tracks statistics on accidental injury and deaths (road, aviation, water), as well as professional and community attitudes to safety, effects of prevention campaigns etc

• http://www.atsb.gov.au/• See January 2009 report on road deaths

Australian epidemiological data on road deaths

Risk of death on the roads is now at its lowest level

Year Road Rail Marine Aviation

1997 1767 68 46 37 1998 1755 59 46 55 1999 1764 47 51 46 2000 1817 46 42 43 2001 1737 56 59 42 2002 1715 59 48 34 2003 1621 48 41 44 2004 1583 47 41 33 2005 1627 38 39 43

2006 1599 40 na 40

The Aust Transport Safety Bureau records, investigates and helps to

prevent transport-related death and injury (see Bills, 2007)

But recently, there has been a slight increase….

ATSB, Road Deaths Bulletin, January 2009

There was a total of 120 road deaths throughout Australia in January 2009.

- this is a 7.1 per cent increase over the January 2008 figure

This increase unfortunately comes after many years of a trend for decreasing road deaths.

Clearly, we need to sustain our national efforts and think of new ways to prevent accidents

In general though, the trend is positive. Why?

• Improved road design and surface quality

• Improved vehicle design• Mandatory seat belt installation and

legal enforcement of seat belt usage• Reduction in drink driving through

education and enforcement• Cultural change in Australia; increased

belief that accidents can be prevented

Public health professionals and

prevention of road deaths

• Australian epidemiologists were among the first to show, convincingly, that seat belts save lives

• The evidence for benefits of installation, education and enforcement was so strong that Australian prevention methods were adopted in many other countries.

• QUT has a major research centre (CARSS-Q) focussed on continuing improvement

In Australia, we also see patterns for improvement in relatively rare causes

of death and injury

For example, deaths caused by guns

Decline in deaths by firearms over a decade (1991-2001) Source: Australian Institute of

Criminology, 2004

So how long is human life in Australia compared to

the rest of the world?

Life expectancy in Australia is ranked among the highest in the world

• Australia's life expectancy at birth ranks second only to Japan.

• Death rates continue to fall and life expectancy to rise, but the fertility rate remains below the replacement level—all leading to ageing of the population.

• Australian Institute of Health and Welfare, June 2008

Life expectancy in Australia and other countries

Source: WHO, 2007

• Low income economies: – Sierra Leone 39 years– Kenya 50 years– Zimbabwe 36 years– Nepal 61 years

– AUSTRALIA = 81.5 years

HIV/AIDSIn Africa

Life expectancycan be calculated forpeople with,or without,HIV/AIDS

Source: United Nations Development Program

Life expectancy in Australia and other countries

• Low to Medium income economies: – Indonesia 67 years– Costa Rica 77 years– Thailand 70 years– Vietnam 72 years– Brazil 69 years

– AUSTRALIA = 81.5 years

Life expectancy in Vietnam(2003-2009 estimates)

• 2003 70.05 years• 2004 70.61• 2005 70.61• 2006 70.85• 2007 71.07• 2008 71.33• 2009 71.58

Source: CIA World Fact Book, update September 17, 2009

LE varies WITHIN countries

Differences in life expectancy within Australia

Life expectancy among indigenous Australians

LE at birth (estimated in 2004): • Indigenous: 59.4 years (M); 64.8 years

(F) • Non-indigenous (M=78.1; F=83)

Major causes of death among aboriginal people:– Cardiovacular disease (28%)– Injury (16%)– Respiratory diseases (9%)– Cancers (8%)

• Source: Michael Adams (2008)

Cancer in indigenous and other Australians Source: MJA, 2005, 182, 277-80

• Across the decade from 1991-2000, Indigenous people with cancer in NT were more likely that non-indigenous people with cancer to be diagnosed at an advanced stage of the illness.

• Cancer survival rates were very much lower among indigenous people.

• This lower survival was caused by later diagnosis AND (perhaps) because of poorer response to treatment and more “aggressive” cancers in indigenous people (Condon et al, 2005).

5-year survival rates after diagnosis

• Site Non-indigenous Indigenous

• Colon/rectum 55% 31%• Lung 12% 5%• Breast 84% 68%• Cervix 70% 27%• Lymphoma (N-H) 65% 16%

– Data from Condon et al, 2005, Medical Journal of Australia

The bottom line

• “Our results suggest that health services could, and should, be performing better than they currently are for indigenous people with cancer in the Northern Territory, and probably elsewhere in Australia (Condon et al, 2005, p280)

• The analysis and reporting of cancer stage at diagnosis and cancer survival can be used to assess the performance of health services.

Health in Western Countries

What may happen in the future?

Will life expectancy continue to improve in western countries?

• Poirier et al (2006) in the journal Circulation and Simons-Morton et al (2006) in JAMA (among others) discuss the warnings that life expectancy may decline in the USA and similar countries as the obesity epidemic gets worse.

Epidemiologists study the problem and try to find solutions

Latest findings regarding obesity and risk of death

• The Lancet, March 20, 2009• Combined analysis of data from 900,000 people

followed up in 57 separate cohort studies (mainly North America & Europe)

• Excess risk of death after median 8 year follow-up was found among people with high body mass index, increasing in a linear “dose-response’ fashion

Obesity and Risk of DeathThe Lancet, March 20, 2009

• At 30–35 kg/m², median survival (to normal healthy life expectancy) is reduced by 2–4 years;

• At 40–45 kg/m², it is reduced by 8–10 years (which is comparable with the effects of smoking)

Other indicators of population health

Morbidity

• Defined as “any departure, subjective or objective, from a state of physiological and psychological well-being” (AIHW, 2000)

• The Australian National Health Survey found that 78% of the adult population reported having one or more long term health conditions, lasting 6 months or more (ABS, 2004)

Morbidity assessed by national

health surveys

• Random population surveys routinely gather data on self-reports of;– recent illness– long-term conditions– minor and serious conditions– self-assessed health status

Morbidity in Australia: most frequently reported

conditions

MALES FEMALES– Sight problems Sight

problems– Hay fever Arthritis– Hearing problems Headache– Arthritis Hay fever– Asthma Asthma– Headache Sinusitis– Hypertension

Hypertension

Health-related actions

• In the preceding two weeks…– 75% took some action for their health– medication use (69%)– consulting a doctor (27% females;

21% males)– dentist or other health professional

(13%)

Sources: ABS (2006)

Disability

• Defined as the presence of one or more of a list of 15 conditions, including;– sensory problems – learning difficulty– physical disfigurement or deformity– restricted physical activity– mental illness, emotional problems

Disability

• Males: 19.8% Females: 20.0%

• Most serious problems:– sensory disease (3.2%)– arthritis (2.9%)– other musculoskeletal disorders (2%)– intellectual or other mental disorders

(1.6%)– Respiratory disease (1.6%)

Source: ABS (2006)

Healthy life expectancy

• HLE is the expected number of years to be lived without reduced functioning because of poor health (World Health Organisation)

• Australia’s HLE is among the highest in the world

Males: Healthy Life Expectancy

Source: World Health Organisation

0

10

20

30

40

50

60

70

80

JPN SWE Aust Italy USA Pol S.Afr

Country

Australian men (est=70.1y) are ranked number 3

Females: Healthy Life Expectancy

Source: World Health Organisation

0

10

20

30

40

50

60

70

80

JPN SWE Aust Italy USA Pol S.Afr

Country

Australian women (est. 73.2y) are also ranked number 3

You are a student in Public Health, and study within a medical school

How does the science of PUBLIC HEALTH save

lives?

Case study: Control of Sepsis

One of the first times epidemiology was used to

improve the practice of medicine

• Sepsis is a severe illness caused by overwhelming infection of the bloodstream by toxin-producing bacteria.

• It is caused by bacterial infection that can originate anywhere in the body. Common sites include:– The kidneys, liver or the gall

bladder– The bowel, lungs, skin

Sepsis: external signs

Triptych of a European hospital in the 16th Century

“Childbed fever”

• Hospitals that took women in labour opened throughout Europe in the 17th Century

• There were many recorded outbreaks of puerperal fever, leading to many deaths

• The death rate for women who gave birth in hospital was up to 20% (that is, about one in every five women never made it home)

• Compares to the recent maternal death rate in Australia of 0.0082%, 2004, Medical Journal of Australia

How was it prevented?

• The cause was unknown, but by the late 1700s some doctors suspected that contagion was the cause, as opposed to “bad air”, hysteria (the women’s disturbed state of mind) or mechanical pressure on the uterus.

• For many years, the contagion theory was rejected by most doctors.

Dr Oliver Wendell Holmes,American physician

Investigated sepsis after a doctor and a med student died of blood poisoningafter performing an autospy on a dead mother.

In 1842, he proposed rigorous hand-washing after each medical procedure to prevent contagion

The idea that the infection was acquiredin hospital, and transmitted by doctorswas ridiculed by some, including anobstetrician Charles Meigs, who said:

“Doctors are gentlemen, and gentlemen’s hands are clean”

Source: De Costa, 2002. Medical Journal of Australia

Meanwhile, in Austria,a Hungarian doctorIgnaz Semmelweis, devotedmany years to prove a linkbetween hospital hygiene and sepsis deaths

Semmelweis and the control of maternal sepsis

My doctrine is produced inorder to banish the terror from lying-in hospitals, to preserve the wife to the husband,and the mother to the child... Ignaz Semmelweis, 1861

Mortality rate of mothers who delivered in Vienna

hospital, 1841-3

• Obstetric division: 16% died

• Midwifery division: 2% died

• Deaths were rare among women who delivered prior to arriving in hospital

Semmelweis conducted the first epidemiological study of

sepsis

• Found death rate of women treated by doctors was best explained by the fact they also had performed autopsies the same day

• Midwives did not perform autopsies and had a tradition of better hygiene

• Semmelweis also investigated the death of his friend Prof Kolletschka who had a sharps injury during an autospy

• He concluded that the causes of death were the same

Epidemiological analysis of an intervention in the obstetrics ward of the

hospital• Semmelweis ordered all doctors to wash their

hands in chlorinated water after operations. Within 3 years, deaths from Sepsis in his ward declined 18% to 3%

• However, his idea that the infections were acquired from contact with doctors was dismissed by the broader profession

• His contract at the hospital was not renewed. For the next 15 years he campaigned to change practice, and mostly, his ideas were rejected.

• Semmelweis became depressed, was admitted to a psychiatric asylum and died three weeks later, probably due to septicaemia from a cut finger (DeCosta, 2002)

Maternal deaths: The current situation

• In rich nations, like the USA, Australia, UK, between 8-12 mothers die during pregnancy out of every 100,000.

• In Africa, the chance that a mother will die is one hundred times greater, with a death rate of about 1000 women per 100,000

– Source: Mavalankar & Rosenfield, 2005, American Journal of Public Health, 95: 200-203.

Case study 2

Modern Example

How epidemiology and public health action has saved the lives of children

Sudden Infant Death Syndrome

Sudden Infant Death Syndrome

.

The sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history

What causes SIDS?

• Throughout history, the assumed major cause was overlaying, when the caregiver accidentally lies on top of an infant. Overlaying as a cause of infant death was mentioned in the Christian Bible:

And this woman's child died in the night; because she overlaid it.Kings I 3:19

• In some medieval societies mothers were blamed and sometimes punished if their child died in bed.

• From: Berkowitz (2006) Pediatrics for Parentshttp://www.pedsforparents.com/articles/2828.shtml

Combined efforts by public health and medical

researchers• Over time, it became clear that the problem was much

more complicated • In the 1960s and 1970s, the first systematic

epidemiological research into risk factors for SIDS commenced

• The researchers studied the characteristics of the children, their families and their environments

• By the end of the 1980s, there was evidence that many social and behavioural factors were linked with risk of sudden infant deaths

Public health researchers examined the social and

behavioural factors influencing SIDS

…To provide the evidence needed for prevention campaigns

Age distributions of SIDS and explained sudden and unexpected deaths in infancy infants

Source: LEACH, C.E.A. et al (1999) Epidemiology of SIDS and Source: LEACH, C.E.A. et al (1999) Epidemiology of SIDS and Explained Sudden Infant Deaths. Explained Sudden Infant Deaths. Pediatrics Pediatrics 104:43104:43

At about three months, SIDS can equal all other causes

Mother’s Age by Risk of Sudden Infant Death

Relative Risk

of SIDS

Under 20 1.8

20-24 1.3

25-29 0.7

30-34 0.6

35+ 0.7

Sudden Infant Death by Mother’s Ageand Birth Order

(Relative Risk Of Death)

RR LESS THAN 20 YEARS 1ST CHILD 1.3

2ND CHILD 2.9 3RD CHILD 7.0

20-24 YEARS 1ST CHILD 0.8 2ND CHILD 1.5 3RD CHILD 1.6 4TH CHILD 3.3

Sudden Infant Death by Mother’s Ageand Birth Order

(Relative Risk Of Death)

RR 25-29 YEARS 1ST CHILD 0.3

2ND CHILD 0.6 3RD CHILD 1.0 4TH CHILD 1.4

30 YEARS OR MORE 1ST CHILD 0.2 2ND CHILD 0.4 3RD CHILD 0.5 4TH CHILD 0.9

SOCIAL CLASS RELATIVE RISK OF SUDDEN INFANT DEATH

I (PROFESSIONALS) 0.7 II (SEMI-PROFESSIONALS) 0.7 III (SKILLED) 0.8 IV (SEMI-SKILLED) 1.1 V (UNSKILLED) 1.9

Seasonal Incidence of SIDS(Southern Hemisphere)

Main risks for SIDS identified by social research (from

Homeier, 2005)• child sleeping on stomach• mother smoking, drinking, or drug use during

pregnancy • poor prenatal care • prematurity or low birth-weight • mothers younger than 20 • household/car smoke exposure following birth • overheating from excessive sleepwear and

bedding • http://www.kidshealth.org/parent/general/sleep/sids.html

Other biological risks include….

(from Weese-Mayer et al, AJHG, 2007)

• Genetic abnormalities

• Complex gene-environment interactions

• Bacterial and viral infections

• As yet unknown biological causes

Remember one essential thing about your

profession

Public Health

It is about understanding, then changing, the social

conditions that affect diseases, heath care and well-being of

individuals, families and society as a whole

Health Promotion and Disease Prevention in Action

Design, Implementation and and Evaluation the effectiveness of SIDS

prevention

“BACK TO SLEEP”: A Better Way to Make Up Baby’s Cot to Reduce the Risks

http://raisingchildren.net.au/articles/preventing_sids.htmlhttp://raisingchildren.net.au/articles/preventing_sids.html

The main things parents can do to Reduce the Risks

•Baby should not go to sleep on his or her Baby should not go to sleep on his or her stomachstomach

•Neither clothing nor bedding should be tightNeither clothing nor bedding should be tight

• Under-blankets should be covered with a cotton Under-blankets should be covered with a cotton sheetsheet

•  make sure the baby is not exposed to smoke make sure the baby is not exposed to smoke

• Mother should avoid alcohol and tobacco during Mother should avoid alcohol and tobacco during pregnancypregnancy

•Access to prenatal and postnatal careAccess to prenatal and postnatal care

“Back to Sleep” campaign

• Simple, clear messages• Public Health professionals design,

manage and evaluate the programs;

• Pre-natal and post-natal carers spread the message and skills

• The affected community raises funds for more research

Decline in SIDS deaths over a 15 yr period (USA, similar in Aust)

Through Public Health Action

• Between the early 1980s and 2009, the risk of Sudden Infant Death has decreased by half

• Think about the benefits for children and especially their mothers, fathers and families

Health problems in the population change over time, but they will never disappear

• As a future Public Health graduate, you can also make a real and

important difference to the lives of people