1. What are the three core functions of public health? Name one essential service for each function. - Answer: The three core functions of public health are assessment, policy development, and assurance. One essential service for each function is: - Assessment: Monitor health status to identify and solve community health problems. - Policy development: Develop policies and plans that support individual and community health efforts. - Assurance: Enforce laws and regulations that protect health and ensure safety. - Rationale: These core functions and essential services provide a framework for public health practice and describe the roles and responsibilities of public health agencies and professionals. 2. What are the four main types of epidemiological studies? Briefly explain the main features and advantages of each type. - Answer: The four main types of epidemiological studies are: - Descriptive studies: These studies describe the distribution of a disease or a health outcome in a population, using variables such as person, place, and time. They can generate hypotheses about possible causes or risk factors, but they cannot test them. An advantage of descriptive studies is that they are relatively simple and inexpensive to conduct. - Analytical studies: These studies test hypotheses about the association between a disease or a health outcome and one or more exposures or interventions. They can be divided into observational studies (such as cohort, case-control, and cross-sectional studies) and experimental studies (such as randomized controlled trials). An advantage of analytical studies is that they can provide evidence of causality or effectiveness, depending on the study design and quality. - Interventional studies: These studies evaluate the impact of an intervention (such as a drug, a vaccine, a policy, or a program) on a disease or a health outcome in a population. They are usually experimental studies (such as randomized controlled trials or cluster randomized trials), but they can also be quasi-experimental studies (such as non-randomized controlled trials or interrupted time series). An advantage of interventional studies is that they can measure the direct effect of an intervention on a specific outcome, controlling for confounding factors. - Ecological studies: These studies compare the aggregate data of groups or populations, rather than individuals, to examine the relationship between a disease or a health outcome and one or more exposures or interventions. They can be descriptive or analytical, depending on the research question. An advantage of ecological studies is that they can explore the effects of environmental or social factors that are difficult to measure at the individual level.