Lectures 5&6 - Global patterns of disease part 2 Flashcards
what is epidemiological transition?
changing patterns of population age distributions, mortality, fertility, life expectancy, and causes of death
explain the concept of epidemiological transition
Changes in levels and causes of mortality:
- decline in total mortality
- reduction in infectious diseases
- declined death rate in all age groups (however this increases the role of chronic non-communicable diseases due to ageing population)
- chronic diseases also due to lifestyle factors
- advances in clinical medicine and epidemiology
- disappearance/re-emergence of diseases
- emergence of new infectious disease (e.g. AIDS)
- increase in previously controlled infections (e.g. TB, dengue fever)
what are the classifications of diseases and injuries?
- communicable, maternal, perinatal and nutritional
- non-communicable
- injuries = intentional and unintentional
give examples of communicable, maternal, perinatal and nutritional diseases
- HIV and STDs
- malaria
- maternal conditions
- neonatal conditions
- nutritional deficiencies
- respiratory and intestinal infections
- TB
give examples of non-communicable diseases
- cancers
- CVDs
- chronic respiratory diseases
- cirrhosis
- congenital abnormalities
- diabetes mellitus
- neurological conditions and mental/behavioural disorders
give examples of intentional injuries
- homicide
- suicide
- war
give an example of a non-intentional injury
- road traffic injuries
what is the difference between a communicable disease and a non-communicable disease?
a communicable disease is caused by an infectious agent which can be transmitted by direct contact between individuals, bodily discharges or via a vector
Non-communicable diseases are non-infectious and non-transmissible
compare the observed demographic transition with epidemiological transition
demographic transition: high birth and death rates to low birth and death rates
epidemiological transition: infectious diseases replaced by degenerative and man-made diseases
what % of deaths worldwide did cancer cause in 2010?
15.1% (8m people)
what are the most commonly diagnosed cancers?
lung, breast and colorectal cancer
what are the most common causes of cancer death?
lung, liver, stomach and colon cancers
what do cancer rates in migrants tend to do?
converge towards local cancer rates over time, suggesting a role for modifiable risk factors
what is the largest preventable cause of cancer in the world?
smoking
why have age-specific cancer incidence and mortality rates fallen for some cancers but risen for others?
due to changes in relevant exposures, diagnosis, treatment and screening
name 4 major carcinogens
- tobacco
- alcohol
- air pollution
- occupational agents (e.g. asbestos)
describe the epidemiology of cancer in men
- leading incidence and mortality of cancer in men is lung cancer in every country, regardless of income
- more prostate cancers in HICs
- very low incidence of colorectal cancers in LICs
- liver cancer is the most frequent cause of premature cancer death
- men in sub-saharan Africa are at a major risk of liver cancer due to hepatitis prevalence
describe the epidemiology of cancer in women
- leading cancer incidence is breast cancer in every country regardless of income
- second is cervical cancer in most countries
- leading cancer mortality is breast cancer in all countries except China
- leading cancer mortality in China is lung cancer
- lung cancer is the most frequent cause of premature cancer death in women in North America
why is there a low incidence of colorectal cancers in LICs?
LICs cannot afford the high meat diets that MICs and HICs can afford
why is there a high incidence and mortality of cervical cancer in LICs?
LICs don’t have effective screening processes that are available in MICs and HICs
what are the 9 major behavioural and environmental risk factors for cancer?
- smoking
- low intake of fruit/veg
- alcohol use
- unsafe sex
- overweight/obesity
- physical inactivity
- contaminated injections in healthcare
- urban air pollution
- indoor smoke from household solid fuel use
which cancers can be due to infections?
liver - hepatitis viruses B/C
stomach - H. pylori
cervical - HPV
what % of cancer deaths are due to infections in LICs compared to HICs?
LICs - 26.9%
HICs - 8.1%
what % of deaths did CVDs account for worldwide in 2010?
29.5% (15.6m people)
what are the 1st and 2nd highest mortality-causing CVDs?
1) CHD
2) strokes
what is likely to happen to the burden of disease from non-communicable diseases in LICs?
burden is likely to rise with an estimated doubling of mortality from CHD and stroke due to demographic (ageing and population) and epidemiological transitions
describe the discrepancies in incidence and mortality from CHD between different countries
- low rates in japan
- increased rates in UK and other western countries
- high rates in formerly socialist economies of Europe
- high rates in middle east
- rates are higher in men than in women, at all ages
what do variations in CVD rates worldwide suggest?
the epidemiological patterns suggest that environmental factors provide a greater risk for CVD than genetic factors
what is the relationship between age and CVDs?
number of deaths from CHD increases with age but decreases after 80 years old (because there are less people in these age groups as they have died)
what is the relationship between ethnicity and CVDs?
there are higher death rates from CHD in black males than white males in the US
which characteristics of a person, other than age and ethnicity, influence risk of CVDs?
- sex
- socioeconomic status
- religion
- marital status
- occupation
what are established, modifiable risk factors for CHD?
- hypertension
- tobacco and smoking
- blood/serum cholesterol levels
- body weight
- physical activity
describe the role of serum cholesterol in determining the risk of CHD
- good predictive marker
- well-measured with a single measurement taken
- prognostic validity
- HOWEVER poor ability to discriminate between cases and non-cases of CHD
describe the role of BP in determining the risk of CHD
- lifestyle factors (especially diet) are key in explaining differences between populations and the rise in BP with age (e.g. lower BP in Kenya than UK due to different diet)
- BP also varies with ethnicity and gender
describe the role of smoking in determining the risk of CHD
- smokers have a cardiovascular age that is 10 years older than non-smokers
- smoking worldwide is decreasing
- proportion of smokers in LICs is increasing
describe the role of obesity in determining the risk of CHD
- obesity rates increasing in many countries (especially USA)
- obesity promotes diabetes
describe the role of physical inactivity in determining the risk of CHD
- increasing worldwide
- due to lifestyle (e.g. cars and technology)
- physical activity can prevent CHD
what happens to CHD as blood pressure/cholesterol increase? what is the best method of intervention?
- risk of CHD increases
- intervention based on BP of the whole population has proven more successful than interventions only focussed on high-risk individuals
