Epidemiology Of Respiratory Disease Flashcards
John Snow and Cholera (1853)
Cholera outbreak in 1853
He had the 1st attempt to systematically map outbreak loci = found a sig. feature in all households (no outbreak in specific location, unless ppl drank from a specific pump well) - Start of Epidemiology
Current Day Epidemiology
Covid, flu, smoking, walking (step count) etc. = on the rise and saturated field of study
Importance of Epidemiology
River and drowning analogy:
good doctor doesn’t just look at acute symptoms and treatment, but also why and how!!!
What is Epidemiology?
Public health (population medicine):
Prevention (cause and precipants)
Medical Care at population Level (Duration of Onset (episodic or continuous) / the number of people)
Clinical relevance
What is Prevalence and how do you work out the two types?
POINT: Measure of disease, especially chronic continuous disease
no. of affected ppl in defined population @ specific point in time / no. of population @ same point in time
e.g. @ end of 2014 red disease point prevalance = 3 per 100 (3%)
PERIOD: Measure of disease, especially episodic (spell based) disease
no. affected over defined period of time / no. in the population over the same period
e.g. 12 month period prevalence of black disease @ end of 2014 = 6 per 100 (6%)
What is incidence and how do you work it out?
Measure of people or spells (recurrence)
Number of becoming diseased in time period / total persona-time at risk in time period
e.g. 2 per 100 person-yrs (Continuous)
Mortality rate types
Crude rate: All mortality rates seen due the given variable (e.g. lung cancer)
Age-standardised rate: All mortality rates seen due the given variable, but they have age distribution and structure
Risk Pyramid of Disease introduced
Fluid distribution of disease based on factors such as public health campaigns, diagnostic awareness, new methods of detection, new treatments and illness behaviour etc.
e.g. top third of pyramid = recognised disease
bottom two thirds = unrecognised disease (image)
What affects the pool of people with the condition? (Risk Pyramid of Disease)
2x images (normal and A+E)
pyramid with many factors
What is the difference between causes and precipitants?
causes:
environment / genetic
in-utero
later life
e.g. infections (causing pneumonia, TB, Bronchiolitis caused by RSV) , smoking (causing Lung cancer) , airborne particles (causes mesothelioma pneumoconioses), nutrition
precipitants:
environment
e.g. infections, smoking, airborne particles, nutrition
What variations are present between people, and how can they help us?
Marked variations in disease between individuals by:
Age, gender, socioeconomic position, ethnicity
- Help with process of diagnosis (e.g. age)
- Can provide clues to causation of disease
- Identify groups who will especially benefit from disease
prevention
Specific Respiratory diseases
Upper respiratory: (High burden in GP)
– rhinovirus (common cold)
– allergic rhinitis (incl hay fever)
Lower respiratory: (High Morbidity and Mortality)
– chronic airways disease (asthma, COPD)
– acute infections (pneumonia, bronchiolitis,
bronchitis, tuberculosis)
– lung tissue disease (pulmonary fibrosis,
sarcoidosis)
– circulatory (pulmonary embolism)
– cancers
What are variations of time and how can they help us?
Variations by TIME
Short-term especially seasonal
Longer-term trends: period & cohort effects
- Tell us that disease not inevitable
- Provide clues in identifying causes of disease
What are variations by place and how can they help us?
Variations by PLACE
Geographic variations occur at different levels :
e.g. ward, countries, global regions
- Tells us that high rates of major common diseases (e.g.
asthma) are not inevitable - Provides clues to the nature of biological normality
- Provides clues in identifying causes of disease
Global risk factors
smoking
