Population Health
Effect of weather?
"Upon review of the evidence, it appears that levels of physical activity vary with seasonality, and the ensuing effect of poor or extreme weather has been identified as a barrier to participation in physical activity." Physical environment has big impact on physical activity
How to determine whether a certain risk factor plays a large role in an outcome
How many cases or deaths of a particular disease are due to a particular risk factor? POPULATION ATTRIBUTABLE RISK (PAR) Takes into account the prevalence of a risk factor in the population with the relative risk associated with that risk factor p = the prevalence of a risk factor in the population RR= relative risk of those with the risk factor vs. those without the risk factor Just taking RR and multiplying it by how many people do it in the populaiton Indicates the number of cases of lung cancer in Canada attributable to smoking •E.g. In the U.S., 101,000 out of 135,000 deaths from lung cancer are due to smoking
Prevention vs. Management with hypertension?
Increasing treatment for it, costs a lot of money No impact on prevalence We havent tackled upstream factors we keep focusing on downstream Treating people shouldnt be good since we want to reduce the need for treatment.
What are not the same?
Individual risk and population attributable risk are not the same. Leads to a different understanding of impact and prioritiesfor intervention. Clinically wow such high risk but then if not a lot of people are doing it then population doesnt care
Principle 3?
Interventions should be implemented and evaluated based upon population impact Population Impact of an intervention = Reach x Effectiveness EFFECTIVENESS Magnitude of benefit under "real world" conditions. Not controlled EFFICACY Magnitude of benefit under clinical trials. And controlled environments E.g drug trials have incentives to take. but in real world people forget and cost barriers so less strict adherence. REACH The number of people exposed to the intervention. •Clinical intervention (1 to 1) •Group counselling (1 to 10) and scale up to the population level E.g. seatbelts are huge reach
Principle 4?
Interventions should be implemented and evaluated based upon their feasibility & cost.
Describe cost effectiveness in
1. Overall economic "benefit" of prevention oThe cynics approach Everyone should die at 65 Health 18 year olds ready to do work force are more valuable 2. Relative costs of different interventions Most cost effective ways to treat diseases (go upstream or downstream) E.g. Lung cancer NICOTINE REPLACEMENT THERAPY •Cost per treatment:= $100 per person •Effectiveness: 10% •Cost per quitter= $1,000 LUNG CANCER TREATMENT The cost-effectiveness ratio (the cost of treatment to an additional year of life) was $143,614 for localized lung cancer $145,861 for regional cancer (a cancer that has spread within the lung but is contained within it) and $1.2 million for metastatic cancer.
When is a population approach needed?
A population approach is needed whenever risk is widely diffused throughout the population. (Bell curve) SO not g for asbestos exposusre since concentration
Describe feasibility
MODIFIABLE RISK FACTORS What preventiveclinical interventions may be very effective, but will have little impact on population level health? •What preventive population-based may have a large impact, but are not terribly feasible? •What preventive population-based may have a large impact and are feasible to implement? How practical can interventions work? Some interventions are more feasible than others.
Describe obesity systems map (basic understanding)
All the things associated with obesity DIfferent colours for different things Things are complicated~
Describe economic policies
Are interventions •Incentives •Taxation price Money is the currency of demand, people respond to prices •Provide incentives to individual change (to avoid high cost) •Reduce barriers and increase cues to healthy behaviours oE.g., green spaces in urban areas, product labeling, nutrition information on foods, health warnings on cigarettes Designed to make things easier for people to do and give them resources to do so •Development of personal resources oE.g. information & skills
Describe changes ot the natural and bult environment
Bike lanes •Urban planning Large reach
Describe media campaigns
Designed to get people to engaged in thinks and penetrate audiences large reach
Factors in population uptake of new social thing?
E.g with birth control RELATIVE ADVANTAGE •Is the innovation better than what it will replace? COMPATIBILITY •Does the innovation fit with the intended audience? COMPLEXITY •Is the innovation easy to use? IMPACT ON SOCIAL RELATIONS •Does the innovation have a disruptive effect o the social environment?
Health behaviors and groups?
Health behaviours differs across groups, not just individuals.
Health behaviors over time?
Health behaviours show dramatic shifts over time within the same population.
Describe the physical enironments
Environment plays a major role too
Notes from reading: Health Impact Pyramid? (NOT COMPLETE)
Frieden T. A Framework for Public Health Action: The Health Impact Pyramid. American Journal of Public Health 2010; 100(4): 590-95. Five tiers of interventions: People who have it good dont want it to change
Describe the prevalence of a risk factor
HIGH RELATIVE RISK, LOW PREVALENCE OF RISK FACTOR E.g. Hangliding is dangerous, but not many people do it so its g LOW RELATIVE RISK, HIGH PREVALENCE OF RISK FACTOR E.g. Driving, dietary patterns, only increase relative risk by a bit, but since lots of people do it you see a big population impact HIGH RELATIVE RISK, HIGH PREVALENCE OF RISK E.g. Smoking is dangerous and lots of people are smoking
Health behaviors in populations?
Health behavioursshow dramatic differences across different populations
Important things about causes?
Not all causes can be explained by individual factors....even though they may occur at the individual level Need to consider and intervene at the broader population or environmental level. These changes aren't genetic, these changes are because of environment/behavior
Other indirect intervention objectives (population health interventions)
•Regulating product design (fireproofing children's clothing) - Cigarettes have things to keep them burning - Leading cause of housefires - Added speedbump to cigarettes, so self extinguished if not puffing, reduces fire home deaths. Good effects didnt force people to stop smoking at home, but - Alcohol glass is a nation crumbled when broken so cant cut people •Limiting conditions of sale (liquor store hours) - Close at 11 to stop hard drinking, they just drank earlier, got kicked out at closing time ot •Changes to physical environment (roadway safety) - Levels of lead in water •Mandatory water sanitation Don't require individuals to change on their own
Describe regulatory environments
Passing laws and regulations that impact social norms
Health behaviors tend to?
Poor diet, substance abuse, risky sexual behaviour, low physical activity are all more common among lower SES groups Geographically clustered
Describe levels of prevention
Population health interventions generally deals with prevention at different levels Point in the disease process at which the intervention occurs. *Tertiary prevention* Aims to reduce morbidity associated with an established disease process. •May carry its own risk and complications •May or may not "cure" or remove disease or cause. •E.g. surgery *Secondary prevention* Detect and resolve "preclinical" indicators or early stage. •Early diagnosis or treatment of a disease that is in progress. •E.g. Mammography screening •Typically based on the biomedical/clinical model More publich health than medical *Primary prevention* Aims to prevent onset of disease or pre-clinical indicators. (Usually the most upstream ones) •E.g. Healthy diet, smoking prevention •Associated with the greatest individualand population benefit. •Often targets behavioural risk factors, but not always. E.g clean water supply
Why does prevalence change over time? Why do risk factors change over time
Principle two: Not all causes can be explained by individual-level factors. Could be environmental risk factors or behavioral Lots of models, they point out theres a whole host of factors that interact to affect our behavior, which affects risk factors and prevalence
Notes from: Sick individuals and sick populations
Rose G. Sick individuals and sick populations. Int J Epidemiol 2001; 30(3): 427-32; discussion 433-4 Cases vs causes of incidence Talks about consequences of cases vs population Preventative medicine axiom A large number of people exposed to low risk may generate many more cases than a small number of people exposed to high risk Some people have low and high risk in normal bell curve, People with high risk may be twice as likely. Bell curve cut off means fewer people are at the most risk, when multply to population level, more people are fine and fewer are at high risk so its g. SO we should try to treat the normal group from going to high risk since they have the most people, but currently we typically treat the high risk since worse but there are fewer omg. Population level interventions reduce high risk invididuals and reduces risks in regular pop! Super good
Describe school-based interventions
Schools have captive audiences, lots of people 90% of peopel go to school large reach
Describe screening
Secondary level of prevention DIAGNOSIS WITHOUT A CURE... •Providing people with information on risk will not necessarily increase their motivation to change behavior. •In the case of genetic risk factors, motivation may decrease because the risk may be beyond the individual's control. Can be put on dimensions of treatability or starting early can avoid/minimize effects, while others just cant do anything Conditions: •Test is acceptable. •Risk is minimal and cost is reasonable. •Test is accurate: high sensitivity (false negative) and specificity (picking up something else positive. •Test detects the disease in an asymptomatic phase. •Evidence exists that treatment in the asymptomatic phase. improves outcomes.
Social factors
Social norm is my belief about what other people believe from fashion to behavioral norms (texting and driving) Nor driven by laws, but by societal expectations
Show levels of causeation
Some are modifiable and some arent modifiable Some things are indirect (proxy measures) for things
Describe migrant patterns
The most traditional group of Japanese-Americans had a CHD prevalence as low as Japan. •The group that was most acculturated to Western culture had a 3-5 fold excess in CHD prevalence. Migrating to a country you adopt the risk profile of that nation, if adopt acquire the risks
Describe stress and conflict?
US works a lot on helping veterns but its not very good mental illness, sub-clinicalissues like substance abuse neglected
Principle 1?
Understanding of risk and harm should be considered on a population level. Not individual cases ABSOLUTE RISK The risk of developing a particular disease over a defined time period. e.g Risk of dying from HIV/AIDS RELATIVE RISK Comparison of risks across two conditions, often presented as the "increase" in risk with a condition or risk factor present •E.g. presence vs. absence of health behaviour E.g. If you use a condom regularly reduces risk of STI by ___% LOW ABSOLUTE RISK, LOW RELATIVE RISK •E.g. ...who cares? Low risk low increase cause of behavior LOW ABSOLUTE RISK, HIGH RELATIVE RISK E.g. Lung cancer rates low without cigarettes, then if smoke regularly increases rate like crazy
Intervention pyramid?
Width means people reached Effectiveness would be the inverse wher eindividual treatment most effective, and population is least effective The target group narrows at each level of prevention and increasing focuses upon a "higher risk" group
Define population health
•A population health approach focuses on improving the health status of the population. •Action is directed at the health of an entire population, or sub-population, rather than individuals. •Focusing on the health of populations also necessitates the reduction in inequalities in health status between population groups. An underlying assumption of a population health approach is that reductions in health inequities require reductions in material and social inequities. (Horizontal vertical) •The outcomes or benefits of a population health approach, therefore, extend beyond improved population health outcomes to include a sustainable and integrated health system, increased national growth and productivity, and strengthened social cohesion and citizen engagement. Too "Lets make te world a better place"
Describe environment and heritability
•Heritability of height is the proportion of variance, across individuals, due to genetic factors. •Anglo-American studies= 0.80 •West Africa=0.56 (only 56% of height caused by parents) A recent Finnish twin study, based on 3466 identical and 7450 fraternal adult twin-pairs, examined changes in the heritability of height over several decades, as Finnish life changed greatly (over 50 years) *This change is because of nutrition, better nutrition allows people to achieve maximum height, so its more about nutrition than genetics* *Our environment is important and changes based on genetic factors*
How do populations change? Tipping point
•Sociological term that refers to the moment when something unusual becomes common. •"social epidemics", or sudden and often chaotic changes from one state to another. Can be applied to health behaviors THE LAW OF THE FEW Some people have disproportionate influence. •Connectors: Those with wide social circles. They are the "hubs" of the human social network and responsible for the small world phenomenon. •Mavensare knowledgeable people. While most consumers wouldn't know if a product were priced above the market rate by, say, ten per cent, mavens would. DIFFUSION •Process of communication through channels over time in a social system INNOVATION •idea, practice, service or other object that is perceived as newby an individual or other unit of adoption (group) Like with smoking or usage of social media •Social norms and the acceleration of change. •Change isn't always equally distributed within society. •Change often occurs first among higher SES individuals.
Describe screening as a level of prevention
•The public health concern is the risk/benefit/cost balance sheet of extending screening to much larger, lower risk populations. •Screening is efficient when numbers needed to screenper resultant clear beneficiaryare relatively small.
Issues with population healt?h?
•What constitutes a population? Reach is on a spectrum •Implications for "high risk" strategy and current practice Its not either or its complementry (medical vs public health) High-risk and population-risk approaches are notincompatible
