What are we measuring? The concepts: prevalence and incidence Prevalence Incidence Population at risk The relationship between incidence and prevalence Measuring disease occurrence in practice: epidemiological studies Incidence rates versus…
Case reports and case series Vital statistics and mortality data Census data Civil registration systems National death registers Verbal autopsy Health and demographic surveillance systems Challenges in using mortality data…
The ideal study Intervention studies or trials Randomised controlled trials (RCTs) Crossover trials n-of-1 trials Cluster randomised controlled trials Community trials Non-randomised designs Observational studies Cohort studies Historical cohort studies…
Figure 1.1 Time trends in lung cancer mortality rates in the USA (age-standardised to the 1970 US population) for white men (––) and women (___). (Drawn from: CDC Wonder Database…
Looking for associations Ratio measures (relative risk) Rate ratios Risk ratios Prevalence ratios A note about relative risks Standardised incidence and mortality ratios Difference measures (attributable risk) Rate differences Risk…
Disease prevention in public health The scope for preventive medicine Population versus individual risk Strategies for prevention The high-risk strategy The mass strategy The population attributable fraction as a guide…
Why screen? The disease process Screening versus case-finding The requirements of a screening programme The disease The screening test Test quality: sensitivity and specificity Test performance in practice: positive and…
Sources of error in epidemiological studies Selection bias Some specific sources of selection bias Volunteers Low response rates Loss to follow-up Ascertainment or detection bias The healthy-worker effect Control of…
An example of confounding: is alcohol a risk factor for lung cancer? Characteristics of a confounder The effects of confounding How can we tell if an association is confounded? When…
Outbreaks, epidemics and clusters Epidemiology of infectious diseases A causal model The infectious agent The host Transmission The environment Non-infectious clusters and outbreaks Outbreak management and investigation Management of outbreaks…
