Module 3 PDF

Lecture 14 - Epidemiology: A population health perspective Learning objectives: Explain the concepts of epidemiology and population health. Explain the concept of a social gradient of health. Identify the main components of the ‘Dahlgren and Whitehead model’ and how they might inte...

Lecture 14 - Epidemiology: A population health perspective Learning objectives: Explain the concepts of epidemiology and population health. Explain the concept of a social gradient of health. Identify the main components of the ‘Dahlgren and Whitehead model’ and how they might interact to affect health outcomes. Obj 1: Epidemiology and Population health Epidemiology = study of health - Has Potential to change perspective of health and health it self across the world Population health = health outcomes of group of individuals - About groups of people - Recognise a group of ppl can be from a particular geographic area or a group of people that have something in common - Distribution of such outcomes within a group; not just concerned with overall outcomes but also concerned with…. - Inst just thinking about health of an individual - ‘Helicopter view’ = allows to recognise patterns of health Pop health in NZ -is it evenly distributed within groups? Life expectancy =average number of years a person is expected to live Obj 2:concept of a social gradient of health Socioeconomic status = ‘a complex concept that involves education, income, overall financial security, occupation, living conditions, resources, and opportunities afforded to people within society’ Two important patterns of health distributions in NZ = ethnicity, socioeconomic status Why are these patterns occurring? Are they related? Can see very difference patterns between maori and non maori Left of graph high proportions of non-maori in neighbourhood deprivation to left and right proportion of maori Does this explain the inequality of health in ethnicity? Differences within the band between maori and non-maori, can be assessed in multiple ways Ie. Occupation, income, education Think about what it is assessing and critically think about the perspectives/other underlying factors NZiDep = area based measure of deprivation, based on small areas (100-200 people) → range of people, people aren't gonna have the same socio economic status - Within deciles there will be different ranges - Each area correlates with a deprivation score (areas of NZ divided) → deciles ; 1= area with least deprived, 10 = most deprived - Applies to everyone - Incorporated range of aspects but not everything - Complexity behind the measure How it's determined = usually via census questions Strength of NZiDep - Range of aspects of deprivation (not just one aspect like income) - Can be used for everyone - Can be determined just knowing someone address (don't need to answer additional questions) Important definitions Absolute poverty = “income level below which a minimum nationally Relative poverty = Social Gradient =​​“phenomenon whereby people who are less advantaged in terms of socioeconomic position have worse health (and shorter lives) than those who are more advantaged” Obj 3:‘Dahlgren and Whitehead model’how they might interact to affect health outcomes. Social determinants of health Conditions where people live, grow work and the wider set of forces and system shaping Dahlgren and Whitehead model Layers of factors that influence health (ie layer 1= age, layer 2=individual lifestyle factors, layer 3= social and community influences, layer 4, factors at a national level), (ie availability and affordability of housing) Role of health system in determining health - Access to healthcare  - Complexity into factors that determine health Lecture Review Questions: 1. What determines the health status of populations? 2. Briefly describe the distribution of health in New Zealand. 3. Briefly describe the New Zealand Deprivation Index (NZDep) and how health is patterned by NZDep Lecture 15 - Patterns of disease globally and over time Learning objectives: Describe the epidemiological and demographic transitions. Understand the trends and implications of an ageing population. Explain what “disability adjusted life years” measure. Obj 1: Epidemiological and demographic transitions Communicable =diseases that can be transferred from one person to another, Noncommunicable diseases = cancer, cardiovascular diseases group 1 disease =maternal conditions, complications during childbirth, nutrition etc London 1665 Expected life expectancy in london 1665 = 35 yrs - Life span previously was very short Demographic and epidemiological Transition theories - Separate theories but they work together Demographic Transition = change in population death and births over time - Growth and changes in population over time Ie. Helps to explain a median age changes and how it changes Epidemiological transition = changes in population disease patterns over time - Communicable Disease - Non-communicable Ie. a move of the dominance of communicable diseases to non- communicable As the population is ageing -therefore more risk of non-communicable diseases Obj 2: Trends and implications of an ageing population Global mortality rate- over time - From 2019, covid dominated the mortality rate globally - Cardiovascular system diseases are normally the cause of increase in mortality rate globally - Non communicable diseases are the leading cause before covid Global mortality rate- by income - in low income countries a heavy burden of communicable diseases - In high income countries a heavy burden of non communicable diseases The overall global picture is different to what you can view in categorised groups Living with the consequences of health conditions Obj 3: What “disability adjusted life years” measure DALY (disability adjusted life years) 1 DALY = 1 year of life loss due to condition Components of DALY - Years lived with disability (YLDs) - Years of life lost (YLLs) Mortality = whereas mortality is the number of deaths that occur in a population. Morbidity = is the state of being unhealthy for a particular disease or situation - Physiological or psychological well being NZ pop burden of disease over time  - Nz has a increase in DALY’s due to increase of lifespan, (years of life lost prematurely decreases due to good health facilities, however they are not living in good health just longer) - Hence our facilities will be in stringer demand - DALY rate per 100 000 decreases overtime, hence we have adjusted for changes in population (ie age related) Due to reduction in early deaths, living longer but living with disability Lecture Review Questions: 1. Describe the broad patterns of change in the epidemiological and demographic transitions. 2. Briefly describe what an ‘ageing population’ is, and the possible implications of an ‘ageing population’. Lecture 16 - Measuring disease occurrence Key Learning Objectives: Explain why it is useful to measure disease occurrence in populations. Define, calculate and interpret epidemiological measures of occurrence (prevalence, incidence proportion and incidence rate). Understand the relationship between prevalence, incidence and disease duration. Understand the concept of age standardisation and when it should be used. Obj 1:why it is useful to measure disease occurrence in populations - Helps to calculate and measure occurrences in populations and compare data - Understand how epidemiology contributes to health models - Begin to understand stage of health and disease in a population - Why is this helpful? Due to interest in health status: who has a disease and pattern of disease Disease occurrence To figure out if a certain area is having a larger impact by disease (impact amongst certain groups) Trends over time Obj 2:Define, calculate and interpret epidemiological measures of occurrence Prevalence = the proportion of pop who have the disease at a point in time Why do we want to know this? Info about burden of disease, almost diff groups, areas, so we can allocate resources to the specific areas Calculating prevelnce 5 specific aspects when reporting prevalence - Measure of occurrence (prevalence) - Exposure or outcome (ie asthma) - Population (in POPH192 class) - Time point (date) - Value (value of prevalence) Need all 5 aspects to understand the concept, and group in regards the data Limitations to prevalence 1. Does Not specify development of the disease 2. Is influenced by the duration of the disease Only diff is disease lasts longer which affects prevalence in graph 2 - Both include same assessment point and disease contracted at same time Incidence = the occurrence of new cases of an outcome in a pop during a specific period of follow up Incidence proportion = the proportion of an outcome-free pop that develops the outcome of interest in a specified time Difference between the 2 is what is used as denominator Incidence proportion calculation Concerned with people that develop the disease during the time period (new cases of the disease) Incidence rate = how quickly new cases are developing in population Incidence rate calculation Sum of everyone in the pop’s time at risk of becoming a case Obj 3:relationship between prevalence, incidence and disease duration Prevalence is influenced by duration but also incidence, and this approximates the incidence * duration - Changes to duration or incidence can affect prevalence Obj 4:concept of age standardisation and when it should be used Age standardisation = Standardise both populations to one populations “both populations are mathematically adjusted to have the same age structure as a third population” - Removes confounding cases caused by age 2 aspects needs to be met for this to occur - age structures differ - disease risk varied by age Lecture Review Questions: 1. Think of some health conditions. Consider whether the condition has a high or low incidence, and a long or short duration. Can you think of some ways to reduce their incidence and/or duration? What effect would these different scenarios have on prevalence over time? 2. Pick two population groups in New Zealand that you think have different age structures. When would you age standardise the measures of occurrence for these groups? 3. At the start of 2022, there were 1,500 people in a study* of people living in aged-care facilities, 200 of whom had type II diabetes. Thirty participants developed type II © University of Otago, 2024 8 diabetes during 2022. Calculate the incidence rate (IR) for type II diabetes if 15 of the cases occurred three months into the study period and the rest of the cases occurred nine months into the study period.