Progress Test 2 PDF

Preparing For Progress Test 2 [email protected] Important Things To Note The test will have 31 questions over 45 minutes The first question is just about your test version Includes content from: Modules 3 & 4 (lectures 14-22) Tutorials 3 & 4 Essential Readings Questi...

Preparing For Progress Test 2 [email protected] Important Things To Note The test will have 31 questions over 45 minutes The first question is just about your test version Includes content from: Modules 3 & 4 (lectures 14-22) Tutorials 3 & 4 Essential Readings Questions are MCQ Test is on Friday 27th September at 7pm Test is worth 15% You will need pencil, eraser, student ID and calculator Socioeconomic Status (SES) What is it? SES is the measure of a person or groups’ relative access to resources and social position What can it be used for? By comparing SES between different groups, we can see inequities in society Relation to health Generally, the higher a groups’ SES the better their health outcomes The lower a groups’ SES the worse their health outcomes Deprivation (NZDep) What is it? A multidimensional measure of poverty based on area of ~100-200 people Can be represented as deciles: 1-2 is low deprivation and high-quality housing/income 9-10 is high deprivation and low-quality housing/income NOTE: Deprivation measures the relative poverty of areas NOT people Involves a range of aspects, but not everything that may contribute to poverty Not a label Measures relative socioeconomic deprivation Poverty Definitions Absolute poverty Income below that needed for minimum nutrition and essential non-food requirements The income level needed for the absolute basic necessities of living Relative poverty The income level needed for relative basic necessities of living, in the context of a specific society or economy Social Determinants of Health What is it? The wider parts of our environment and society that have an impact on our health Social determinants of health are superimposed upon age, sex and genetics: 1. Individual lifestyle factors E.g. Smoking, alcohol, exercise 2. Social and community influences E.g. Role models in the community 3. Living and working conditions E.g. Housing, employment 4. General socioeconomic, cultural and environmental conditions E.g. Air quality, discrimination How To Quantify Burden of Disease? Disability-Adjusted Life Year = Years of Life Lost + Years Lived with Disability DALY = YLL + YLD 1 DALY = 1 year of healthy life lost Measures the gap between a populations’ ideal health status and its’ current health status Patterns of Disease Demographic Transition: As a population develops economically their population changes due to altered birth and death rates Epidemiological Transition: As healthcare and disease prevention improves, we see increased lifespans and decreased infectious diseases Communicable disease is replaced by non-communicable chronic disease in the older age-group  Prevalence Incidence Proportion (IP) Incidence Rate (IR) Calculation Number of people with Number of people who Number of people who disease at a given time develop disease over a period develop disease over period ÷ ÷ of time Total number of people in the ÷ Number of person-years at risk population at that time Number of people at risk of of developing disease over disease at the start of that that period period Reporting The prevalence of disease in The incidence proportion of The incidence rate of outcome population at time was % disease in population in time in population is X per 100 period was % person-years Strengths It’s good at measuring burden Useful for assessing average Takes into account losses to of disease in a population risk for populations follow-up and when disease occurs Weaknesses Is influenced by duration of Assumes closed population Requires person-time which outcome Does not account for length of may not be available Doesn’t tell us about time at risk Makes calculations complex development Is dependent on time period  How To Calculate Person-Time When person-time starts: At the start of the time period (if they are at risk) When person time ends: When they become a case When they are lost to follow-up When follow-up time ends Prevalence, Incidence and Duration NOTE: Not an actual equation, just a learning device Prevalence ∝ Incidence x Duration Age Standardisation Sometimes directly comparing populations can make misleading results Age standardisation If age structures differ AND disease risk varies by age You don’t need to know how, just know that it works Cross-Sectional Studies (Descriptive) Measure exposures and/or outcomes at a specific point in time i.e., Measuring something at a particular date, event or period Measures prevalence Is affected by duration and incidence Cross-Sectional Studies: Purpose Often used for surveys on large populations (e.g., census) Describe prevalence: Of an exposure and/or outcome in a population Compare prevalence: Of an exposure and/or outcome between populations or over time Generate hypothesizes: Usually done by asking a population a range of questions about possible symptoms and seeing if any interesting trends show up Plan: Using the data future trends can be predicted and plans can be made Cross-Sectional Studies: Limitations Temporal sequencing: Exposure and outcome was measured at the same time Measurement of prevalence instead of incidence: Influenced by outcome incidence and duration While gives burden of disease it doesn't give risk Not good for studying rare outcomes or exposures: Would need huge sample and still only get a couple of the rare exposure or outcome Not good for assessing variable and transient exposures or outcomes: Would give different results depending on the time the study was done Cross-Sectional Studies: Strengths Can assess multiple exposures and outcomes May suit the research question: If wanting to know prevalence the distribution of prevalence in the population If wanting to measure stable exposures and outcomes If wanting to form a hypothesis Can be less expensive than other study designs Relatively quick Ecological Studies What are they: Compare exposures and outcomes across groups not individuals i.e. every data point is a population not an individual What are they used for: Comparing exposure and disease status across populations Assessing population level factors Considering hypothesises Ecological Studies Strengths May suit the research question Population level exposures Consideration of hypothesises Data is often routinely collected May be relatively easy to do May be relatively inexpensive Weaknesses Ecological fallacy Giving the characteristics of the group upon the individual Cannot control for confounding Cannot show causation  Relative Risk Risk Difference (RD) Using IP Risk Difference (RD) Using IR Calculation Incidence of the exposed Incidence Proportion of the Incidence Rate of the exposed ÷ exposed - Incidence of the comparison - Incidence Rate of the (may use IP or IR) Incidence Proportion of the comparison comparison Null Value 1 0 0 Reporting Exposed population is X times There were X fewer/greater There were X fewer/greater as likely to develop outcome cases per Y over Z years of cases per Y person-years of compared to comparison outcome in exposed outcome in exposed population population compared to population compared to comparison population comparison population Strengths Gives clues to aetiology and Shows impact of adding or Shows impact of adding or strength of association removing exposure removing exposure and the benefits of using person-years Weaknesses Does not show impact of Does not show aetiology or Does not show aetiology or adding or removing exposure strength of association strength of association Relative Risk vs Risk Difference Usefulness Relative Risk Clues to aetiology (causes) Strength of association Risk Difference Impact of exposure Impact of removing exposure Cohort Studies: PECOT Population: First a source population is identified, and a sample population is recruited Sample must NOT have outcome already Exposure: The sample population is then measured to see if they have the exposure Comparison: If someone doesn’t have the exposure, they are in the comparison group Outcome: See who develops the outcome, and who does not Time: The sample population is followed-up over a specific amount of time Things To Keep In Mind When Recruiting Selection of sample population: Ideal: Getting a sample population based on random chance, independent of exposure status What might be more practical: Selecting a bunch of people with the exposure from the source population into the sample population Selecting a bunch of people without the exposure to be part of the comparison group You must ensure: The sample population does not already have the outcome Participants are correctly identified by exposure status Participants are properly followed-up Recognise if participants have exposure changes over follow-up Outcome is properly classified Cohort Studies Strengths Determine temporal sequence between exposure and outcome Can examine multiple outcomes from an exposure Can calculate incidence Therefore, relative risk and risk difference Good for studying rare exposures Weaknesses Loss to follow-up If people are more/less likely to be lost to follow-up due to the exposure that would introduce bias Potential for misclassification of exposures/outcomes Not good for studying rare or transient outcomes Time consuming Can be expensive Prospective vs Historical Cohort Studies Prospective You start by recruiting a population, assessing exposure status and waiting for the follow-up time Could potentially be a very long (and expensive!) follow-up time If it is a rare outcome, or an outcome that takes a long time to develop, it could end up being many decades long Historical/Retrospective Historical cohort studies start at the end of the follow-up period Existing data is then used to recreate how the study would’ve gone as if it were a prospective one This can condense a cohort study from decades long into just a short while to sort out the data Historical Cohort Studies Strengths: Less time consuming compared with prospective cohort studies Good for outcomes that take a long time to develop Less expensive Weaknesses: Use existing data (collected for other reasons) Quality might not be great May not know about all relevant factors Selection bias? Case-Control Studies Type of study Analytic observational study Process 1. A source population is identified 2. Individuals with the outcome are recruited as cases, and individuals without the outcome are recruited as controls 3. The researchers determine exposure status of cases and controls 4. The odds of exposure and Odds Ratio are calculated Interpreting Case-Control Results Identifying Controls The problem of controls: We start by selecting a population, then we define people based on their outcome status and then find out their exposure status So, if they are a control (-ve outcome status), how do we measure exposure?? Index dates We pretend that control had the event on the same date as the case Controls must represent the exposure distribution in the source population i.e. Controls must be capable of becoming a case! Many controls per case increases statistical power Case-Control Strengths and Weaknesses Strengths: Useful for rare outcomes and transient exposures Useful for multiple exposures Can show temporal sequencing Often comparatively quick and inexpensive Weaknesses: Usually, can only study one outcome Difficult to select appropriate control group Can be susceptible to selection and recall bias Randomised Controlled Trials (RCTs) What are RCTs? At the top of the hierarchy of evidence An analytic intervention study Making an RCT Randomised: Participants are randomly allocated into groups Controlled: There is a comparison (control) group Trials: The effects of the treatment/intervention is tested Benefits of Randomisation - Confounding Many things can influence who goes to intervention group, who goes to control and who gets the outcome E.g. What if the intervention group was young and fit and the control group was old and had comorbidities? The fairest way to do a trial is to have both intervention and control groups be equal in every possible way except the intervention being measured This can be done via randomisation where everyone in the sample has a 50/50 chance of being in either the intervention or control group This controls for both known and unknown confounders Randomisation ≠ Random Selection Randomisation: The random allocation of the sample population into either intervention or control groups Random selection: The random selection of people from the source population into the sample population Protecting Randomisation Large numbers Better balances confounding factors between groups Concealment of allocation Make sure that people don’t know if they are in the intervention or the control group Intention-to-treat analysis: Once you choose what group a person is in, they can’t be changed There might be an important reason why a person may be lost to follow-up or want to change groups (side-effects of the intervention) This is important and relevant to the final results because this will reflect how people act in the real world If they can change groups, this will introduce confounding If need be, can use per-protocol analysis (analyse as treated) But this loses the benefits of randomisation and introduces confounding Potential Sources of Bias What is bias: Systemic errors in a study due to the way it’s conducted Lack of blinding: If participants (or researchers) know which group participants are assigned they may act differently Loss to follow-up: If people withdraw because of side effects, we may underestimate the harms of treatment Non-adherence: If people don’t take the treatment, we will not learn about its true benefits and harms Strengths of RCTs The best study design to test an intervention Well conducted studies should eliminate confounding and bias You can calculate Incidence, Relative Risks, and Risk Differences The strongest design for testing cause-and-effect associations Weaknesses of RCTs Exposures must be modifiable Some can’t be changed, hard to be allocated, or are hard to randomise They can be very expensive Need large numbers and good follow-up Often funded by big pharma May introduce bias due to wanting a big profit Participants may not be representative of the source population Participants must meet all inclusion criteria and be willing to participate Affects generalisability Not efficient for rare outcomes Rare drug events are unlikely to be found in an RCT You need to be ethical Clinical equipoise Clinical Equipoise Definition: Genuine uncertainty about benefit or harm of intervention Researchers should only provide an experimental treatment if the evidence for the experimental treatment is equal to that available for the standard treatment i.e., Participant should not suffer any substantial disadvantage from being in the study. Why is clinical equipoise important? It is unethical to harm, not give adequate treatment or waste resources on people if we know better Practice Questions What does the epidemiological transition describe? a) As healthcare and disease prevention improves, we see increased lifespans and decreased infectious diseases b) Measures the gap between a populations’ ideal health status and its’ current health status c) As a population develops economically their population changes due to altered birth and death rates d) The wider parts of our environment and society that have an impact on our health including What does the epidemiological transition describe? a) As healthcare and disease prevention improves, we see increased lifespans and decreased infectious diseases b) Measures the gap between a populations’ ideal health status and its’ current health status a) DALYs c) As a population develops economically their population changes due to altered birth and death rates a) Demographic transition d) The wider parts of our environment and society that have an impact on our health including a) Social determinants of health Incidence rate of cancer in Australia from 1982-2018 Incidence rate of cancer in Australia from 1982-2018 Which of the following is correct? a) In 1982 approximately 310,000 females were diagnosed with cancer in Australia b) In 1994 approximately 600,000 males died of cancer in Australia c) In 2006 the age-standardised incidence rate of cancer for persons was approximately 500 per 100,000 per year d) In 2018 the age-standardised incidence rate of cancer for males was 450 per 100,000 per year Incidence rate of cancer in Australia from 1982-2018 Which of the following is correct? a) In 1982 approximately 310,000 females were diagnosed with cancer in Australia b) In 1994 approximately 600,000 males died of cancer in Australia c) In 2006 the age-standardised incidence rate of cancer for persons was approximately 500 per 100,000 per year d) In 2018 the age-standardised incidence rate of cancer for males was 450 per 100,000 per year Incidence rate of cancer in Australia from 1982-2018 Which of the following is the most likely reason why the rates of cancer are increasing in Australia over time? a) Improving cancer detection techniques b) An aging population in Australia c) An increasing population size in Australia d) Globalisation Incidence rate of cancer in Australia from 1982-2018 Which of the following is the most likely reason why the rates of cancer are increasing in Australia over time? a) Improving cancer detection techniques b) An aging population in Australia a) The rates are age-standardised c) An increasing population size in Australia a) The rates are per 100,000 d) Globalisation Disease X is a deadly disease without a cure that is not transmissible between people. A new drug, Rad-X, is provided to a stable and closed population. Rad-X prolongs the lives of those with Disease X. Which of the following would NOT occur? a) Incidence of Disease X does not change b) Prevalence of Disease X decreases c) Average duration of Disease X increases Disease X is a deadly disease without a cure that is not transmissible between people. A new drug, Rad-X, is provided to a stable and closed population. Rad-X prolongs the lives of those with Disease X. Which of the following would NOT occur? a) Incidence of Disease X does not change a) Incidence would change if Rad-X prevented/caused the development Disease X b) Prevalence of Disease X decreases a) Prevalence ∝ Incidence x Duration b) Prevalence increases as duration increases c) Average duration of Disease X increases a) Duration increases because Rad-X increases the amount of time persons had to live with Disease X b) Duration would decrease if Rad-X cured Disease X or caused people to die faster from Disease X Which of the following is NOT one of the criteria for age standardisation? a) The outcome is rare b) Populations are being compared c) Age structures differ between populations d) Outcome risk varies by age Which of the following is NOT one of the criteria for age standardisation? a) The outcome is rare a) OR = RR when outcome is rare b) Populations are being compared c) Age structures differ between populations d) Outcome risk varies by age What is an example of the ecological fallacy? a) The study findings are generalised too broadly b) The study loses too many people to follow-up c) The study applies group data to the individual d) The researchers slap you with a fish What is an example of the ecological fallacy? a) The study findings are generalised too broadly a) Bad external validity b) The study loses too many people to follow-up a) Bias – Bad internal validity c) The study applies group data to the individual d) The researchers slap you with a fish a) Red herring fallacy – attempt to redirect a conversation away from the original topic A study was conducted to measure the rate of tooth decay in NZ children over a 12-month period. 10 children were included in the study. 2 children were lost to follow-up after 3 months 4 children got tooth decay after 8 months 1 child got tooth decay after 10 months 3 children never got tooth decay What measure of occurrence can be calculated from this study? a) Prevalence b) Relative Risk c) Risk Difference d) Incidence Rate A study was conducted to measure the rate of tooth decay in NZ children over a 12-month period. 10 children were included in the study. 2 children were lost to follow-up after 3 months 4 children got tooth decay after 8 months 1 child got tooth decay after 10 months 3 children never got tooth decay What measure of occurrence can be calculated from this study? a) Prevalence a) Moment in time b) Relative Risk a) Measure of association c) Risk Difference a) Measure of association d) Incidence Rate A study was conducted to measure the rate of tooth decay in NZ children over a 12-month period. 10 children were included in the study. 2 children were lost to follow-up after 3 months 4 children got tooth decay after 8 months 1 child got tooth decay after 10 months 3 children never got tooth decay How many person-years were at risk? a) 4 person-years b) 5 person-years c) 6 person-years d) 7 person-years  A study was conducted to measure the rate of tooth decay in NZ children over a 12-month period. 10 children were included in the study. 2 children were lost to follow-up after 3 months 4 children got tooth decay after 8 months 1 child got tooth decay after 10 months 3 children never got tooth decay What was the incidence rate? a) 42 cases per 100 person-years b) 71 cases per 100 person-years c) 100 cases per 100 person-years d) 114 cases per 100 person-years  A study was conducted to investigate the prevalence of blonde hair in POPH192 students. 500 POPH192 students were interviewed, and 150 students were found to be blonde. The researchers also asked the blonde students if they had dyed their hair. 25 of these students had dyed their hair. What kind of study is this? a) Cohort b) Randomised controlled trial c) Cross-sectional d) Case-control e) Ecological A study was conducted to investigate the prevalence of blonde hair in POPH192 students. 500 POPH192 students were interviewed, and 150 students were found to be blonde. The researchers also asked the blonde students if they had dyed their hair. 25 of these students had dyed their hair. What kind of study is this? a) Cohort b) Randomised controlled trial c) Cross-sectional d) Case-control e) Ecological A study was conducted to investigate the prevalence of blonde hair in POPH192 students. 500 POPH192 students were interviewed, and 150 students were found to be blonde. The researchers also asked the blonde students if they had dyed their hair. 25 of these students had dyed their hair. What is the prevalence of dyed blonde hair amongst POPH192 students? a) The prevalence of dyed blonde hair in POPH192 students was 5% at the time of the study b) The prevalence of dyed blonde hair in POPH192 students was 30% at the time of the study c) The prevalence of dyed blonde hair in POPH192 students was 16.6% at the time of the study A study was conducted to investigate the prevalence of blonde hair in POPH192 students. 500 POPH192 students were interviewed, and 150 students were found to be blonde. The researchers also asked the blonde students if they had dyed their hair. 25 of these students had dyed their hair. Researchers want to investigate the association between developing a rare pancreatic cancer and alcohol consumption. What would be the best study design for this research? a) Cross-sectional b) Cohort c) Randomised controlled trial d) Case-control e) Ecological Researchers want to investigate the association between developing a rare pancreatic cancer and alcohol consumption. What would be the best study design for this research? a) Cross-sectional a) Look out for measuring ‘how common’ or ‘the prevalence’ of something b) Cohort a) Look out for rare exposures and looking for causal associations c) Randomised controlled trial a) Look out for testing an intervention d) Case-control a) Outcome is rare and the research is looking for a causal association e) Ecological a) Look out for comparing populations What is the main advantage of randomisation? a) Controls for known and unknown confounders b) Controls for known and unknown biases c) Controls for chance d) Controls for sample size What is the main advantage of randomisation? a) Controls for known and unknown confounders b) Controls for known and unknown biases a) Must design and conduct the study well c) Controls for chance a) Must increase sample size d) Controls for sample size A study was conducted to investigate the incidence of Type 2 Diabetes in US adults over 1 year. 218 million adults were Diabetes free at the beginning of the year. By the end of the year there were 1.5 million new diagnoses of Type 2 Diabetes Calculate the incidence proportion of Type 2 Diabetes in US adults over 1 year a) 688 per 100,000 adults over 1 year b) 688 per 100,000 person-years c) 0.688% over 1 year d) 68.8 per 100,000 adults over 10 years A study was conducted to investigate the incidence of Type 2 Diabetes in US adults over 1 year. 218 million adults were Diabetes free at the beginning of the year. By the end of the year there were 1.5 million new diagnoses of Type 2 Diabetes  Which is the best study to research a rare outcome from common exposure(s)? a) Cohort study b) Randomised controlled trial c) Case-control d) Ecological study e) Cross-sectional study  Which is the best study to research a rare outcome from common exposure(s)? a) Cohort study a) Best for rare exposure and common outcomes b) Randomised controlled trial c) Case-control d) Ecological study e) Cross-sectional study A study was conducted to investigate whether smoking increased the risk of Syndrome Y. 250 people with Syndrome Y were compared with 1000 people without Syndrome Y who were index matched. Of those with Syndrome Y 100 were current smokers. Of those without Syndrome Y 200 were current smokers. What type of study is this? a) Cohort study b) Randomised controlled trial c) Case-control d) Ecological study e) Cross-sectional study A study was conducted to investigate whether smoking increased the risk of Syndrome Y. 250 people with Syndrome Y were compared with 1000 people without Syndrome Y who were index matched. Of those with Syndrome Y 100 were current smokers. Of those without Syndrome Y 200 were current smokers. What type of study is this? a) Cohort study b) Randomised controlled trial c) Case-control a) Note ‘index matched’ d) Ecological study e) Cross-sectional study A study was conducted to investigate whether smoking increased the risk of Syndrome Y. 250 people with Syndrome Y were compared with 1000 people without Syndrome Y who were index matched. Of those with Syndrome Y 100 were current smokers. Of those without Syndrome Y 200 were current smokers. What is the OR for developing Syndrome Y among those who are current smokers, compared with non-smokers? a) Current smokers were 2 times as likely to develop Syndrome Y compared to non-smokers. b) Current smokers were 2.67 times as likely to develop Syndrome Y compared to non-smokers. c) Current smokers were 3 times as likely to develop Syndrome Y compared to non-smokers. d) Current smokers were 5 times as likely to develop Syndrome Y compared to non-smokers.  Outcome: Syndrome Y Cases Controls exposed 100 200 a b comparison 150 800 c d A study was conducted to investigate whether smoking increased the risk of Syndrome Y. 250 people with Syndrome Y were compared with 1000 people without Syndrome Y who were index matched. Of those with Syndrome Y 100 were current smokers. Of those without Syndrome Y 200 were current smokers. What is the OR for developing Syndrome Y among those who are current smokers, compared with non-smokers? a) Current smokers were 2 times as likely to develop Syndrome Y compared to non-smokers. b) Current smokers were 2.67 times as likely to develop Syndrome Y compared to non-smokers. c) Current smokers were 3 times as likely to develop Syndrome Y compared to non-smokers. d) Current smokers were 5 times as likely to develop Syndrome Y compared to non-smokers. A study was done on the effects of daily sugar-free bubble-gum and the development of tooth-decay. The study found a Risk Difference of 0 Which is the correct interpretation of the study findings? a) The study estimate was below the null value and suggests daily sugar-free bubble-gum use is a protective factor against tooth-decay b) The study estimate was equal to the null value and suggests no association between daily sugar-free bubble-gum use and tooth-decay c) The study estimate was above the null value and suggests daily sugar-free bubble-gum use is a risk factor for tooth-decay A study was done on the effects of daily sugar-free bubble-gum and the development of tooth-decay. The study found a Risk Difference of 0 Which is the correct interpretation of the study findings? a) The study estimate was below the null value and suggests daily sugar-free bubble-gum use is a protective factor against tooth-decay b) The study estimate was equal to the null value and suggests no association between daily sugar-free bubble-gum use and tooth-decay c) The study estimate was above the null value and suggests daily sugar-free bubble-gum use is a risk factor for tooth-decay Good Luck! [email protected]