Epidemiology, biostatistics, screening programmes, health promotion, disease surveillance, and evidence-based medicine.
Case-control studies compare the exposure history of individuals with a disease (cases) to those without (controls), providing an efficient method for investigating rare diseases and measuring the odds ratio as a proxy for relative risk.
Cohort studies follow groups of individuals with differing exposures over time to determine incidence of outcomes, providing the strongest observational evidence for establishing causal relationships through measurement of relative risk.
Environmental health encompasses the assessment, correction, and prevention of environmental factors that can adversely affect human health, including air and water quality, housing, food safety, radiation, climate change, and occupational exposures.
Epidemiology is the study of the distribution and determinants of health-related states in populations and the application of this knowledge to control health problems, forming the scientific foundation of public health practice and evidence-based medicine.
Health inequalities are systematic, avoidable differences in health outcomes between population groups arising from unequal distribution of social, economic, and environmental determinants, with the most deprived communities experiencing significantly worse outcomes across nearly all measures.
Health promotion is the process of enabling people to increase control over and improve their health, encompassing individual behaviour change strategies, community development, and population-level policy interventions as defined by the Ottawa Charter.
Notifiable diseases are infections that must be reported to the local authority proper officer by the attending registered medical practitioner, enabling public health surveillance, outbreak detection, and timely implementation of control measures.
The number needed to treat is a clinically intuitive measure of treatment effect that represents the number of patients who must be treated for one additional patient to benefit, calculated as the reciprocal of the absolute risk reduction.
The randomised controlled trial is the gold standard for evaluating the efficacy of interventions, using random allocation to minimise bias and confounding, with intention-to-treat analysis preserving the integrity of randomisation.
Relative risk and odds ratio are fundamental measures of association in epidemiological studies, with relative risk used in cohort studies and randomised trials, and odds ratio used in case-control studies, each requiring careful interpretation in clinical context.
Screening is the systematic application of a test to identify individuals at sufficient risk of a specific disorder to warrant further investigation or treatment, with UK programmes following the Wilson-Jungner criteria and requiring rigorous evaluation of benefits against harms.
Sensitivity and specificity are intrinsic properties of diagnostic tests that measure the ability to correctly identify individuals with and without disease respectively, with predictive values additionally dependent on disease prevalence in the tested population.
Understanding study design is fundamental to evidence-based medicine, with each design having characteristic strengths and limitations that determine its position in the hierarchy of evidence and its applicability to clinical questions.
Systematic reviews use explicit, reproducible methods to identify, appraise, and synthesise all relevant research on a specific question, with meta-analysis providing a quantitative pooled estimate of effect that sits at the apex of the evidence hierarchy.