Lecture 24: Epidemiological Research In Action: Obesity Flashcards
What are the four key measures in epidemiological research?
- Descriptive
- Predictive
- Explanatory
- Evaluative
What is descriptive?
Current trends and burdens
What is predictive?
Future burden
What are explanatory?
- Changes over time
2. Differences between populations
What is evaluative?
The effectiveness of interventions
What countries have highest rates of obesity?
Pacific islands, middle eastern, Caribbean
Which countries have lowest obesity rates?
Japan
Vietnam
North Korea
Are obesity trends predictable?
Yes, often follow state to state etc
Which countries have high child obesity rates?
High income countries
Describe the childhood obesity trends in low income countries?
They tend to come into the epidemic later, but they rise steeply and often have under-nutrition burden as well
What are the stereotypical obesity trends through a populations?
Women then men
Middle-age then children
High SES then low SES
Urban then Rural
What is the relationship between socioeconomic status and obesity in low income countries and women?
Strong positive
What is the relationship between socioeconomic status and obesity in low income countries and men?
Positive
What is the relationship between socioeconomic status and obesity in low income countries and children?
Positive
What is the relationship between socioeconomic status and obesity in high income countries and women?
Strong negative
What is the relationship between socioeconomic status and obesity in high income countries and men?
Mainly negative
What is the relationship between socioeconomic status and obesity in high income countries and children?
Mainly negative
What are some consequences of obesity?
- Metabolic diseases
- Mechanical disorders
- Psychological problems
- Social consequences
What are some metabolic diseases from obesity?
Type 2 diabetes
Cardiovascular diseases
Almost all cancers (esp colon, breast, uterine)
Gallbladder diseases
What are some mechanical disorders from obesity?
Arthritis
Back pain
Obstructive sleep apnoea
Skin disorders
What are psychological disorders stemming from obesity?
Low self esteem
Reduced quality of life
Depression
What are the social consequences of obesity?
Weight bias and discrimination
Reduced life opportunities
What relative risk numbers do we take seriously?
2-3 times higher
What are the relative risk increases like for obesity as your BMI increases?
As much as 10-20 times if you hit the BMI definition of obesity
Is good data important?
YES! You need good monitoring data to see specific trends and details (NZ is bad in this regard- UK is good with monitoring child obesity)
What is data important for?
Establishing predictive trends ie working out if it will flatten off etc
What are the differences in child obesity depending on deprivation?
Increased obesity in higher deprivation, lower obesity in lower deprivation
What are the benefits of monitoring childhood obesity?
- Can determine prevalence and trends
- Predict future trends
- Identify hotspots
- Contribute to policy and program evaluation
- Screening and feedback
What types of prevalence rates and trends can child obesity monitoring generate?
National, regional and local
Why is identify hotspots through childhood obesity important?
We can identify areas with low/decreasing obesity vs priority areas with high/increasing obesity
How does monitoring childhood obesity contribute to policy and program evaluation?
It’s difficult to measure impact in real world interventions
How does screening and feedback relate to childhood obesity monitoring?
Given data to parents
Referral systems for children with obesity
What are individual questions related to childhood obesity?
“Why am I getting fatter?
What are population questions to the causes of obesity?
Why is this population’s obesity prevalence going up?
Why is this populations obesity prevalence higher/lower than other populations?
What do the answer to the cause of obesity depend on?
The question
It can be: genetic, metabolic, behavioural, environmental (on individual level) or environments related to food or physical activity (macro/micro in size) and physical, economic, policy, socio-cultural in type.
What differences does the answer to what causes obesity attempt to explain? (Example)
Obesity in pacific islands
What are the determinants of obesity like?
Complex, interconnected aspects of society (think the crazy map)
Why are all countries increasing in obesity (simultaneous global rise from the 1970s across all high/middle/low income countries)?
Global drivers
What are the two main global drivers in regards to obesity?
Globalised food systems
Progressive reductions in occupational physical activity
How does globalised food systems affect global obesity rates?
- Increasingly processed, affordable, available and promoted tasty food
- Push effect from the environment (cheap etc)
- Passive consumption by population
What is passive overconsumption?
Without realising, consuming more calories than necessary
What does similar obesity trends across all age groups tell us?
It’s an environmental trend (not just a cohort)
Describe USA food energy supply 1910-2000?
Initially, physical activity decreased and so did energy consumption (as mechanics became more normal eg cars-needed less energy), but then food energy supply began to rise again, demonstrated by increase in food waste
Where is there the biggest reduction in physical exercise?
In occupational activity (is jobs)
What is the biggest plausible reason for the simultaneous global increase in obesity?
The changes in global food supply (price, product, placement, promotion) creating population “passive consumption” of energy
How is obesity shaped by the economic environment?
Income
Income disparities
How is obesity shaped by physical environments?
Food
Physical exercise
How is obesity shaped by socio-cultural environments?
Food
Physical activity
Body size
How is obesity shaped by policy environments?
Market regulation
What four types of environments affect obesity levels?
Economic environment
Physical environment
Socioeconomic environment
Policy environment
What are two contrasting local environments?
Japan: social/fashion to be thin, small portions
Pacific islands: love, hospitality shown through big portions
AKA a cultural thing, there was no health promotion in Japan for decreasing obesity in young women
What is age distribution in pacific islands of obesity like?
Kids are relatively lean until they hit around 20
Are there ethnic disparities in NZ childhood obesity?
Yes, Pacific Islanders and Maori are more at risk
Where are health and social problems worse? (Obesity included as a social problem)
In countries with higher inequality (eg income inequality)
So, if global drivers are pushing global obesity up, why are there differences between populations?
Because different local environments determine the trajectories of obesity in different populations
Where is obesity intervention more important and difficult, with more uncertain evidence?
At the environmental stage, with policy interventions (before people get disease, at physiology stage interventions won’t help)
What are 4 ways obesity can be reversed?
- Clinics (controlled clinical studies of treatment)
- Settings eg school (controlled prevention studies in setting)
- Communities (quasi-experimental prevention interventions in communities)
- States/countries (natural experiments, understand heterogeneity)
What study exemplifies reversing obesity in children?
The Cochrane meta-analysis
What are three examples of preventions in children?
Romp and chomp
Be active be well
It’s your move
(All implemented in schools)
Did the healthy eating in schools programme curb obesity in pacific islands?
No
What are three new system approaches to fighting obesity?
- Progression of interventions over time
- Healthy Together Victoria
- Healthy families NZ
How does progression of intervention over time work?
Generation 1: implement programs and projects
Generation 2: build community capacity
Generation 3: re-orient existing systems
What is health together Victoria?
Taking a systems approach in 12 local government areas in Victoria
What is healthy families NZ?
Using htv model
10 sites around NZ
Added dimension of Maori and pacific populations with high obesity prevalence
What does the natural experiment of the Cuba economic downturn in the 1990s show?
Decrease in population obesity strongly associated with economic crisis, as increased physical activity, less dietary intake. Obesity levels started to rise as Ebonics restabilised
Did mortality rates increase or decrease due to the Cuban economic crisis?
Decreased, the rose as economics got better
What’s the brief timeline of solving obesity epidemic?
1980s: scientists identify epidemic
1990s: advocacy to get obesity on public/political agenda
2000s: increased awareness and some action- largely program based
2010: evidence of effectiveness of interventions, plateaus, declines in some populations, increasing battles over food policies
What are three environmental determinants for obesity?
Systemic drivers (eg policy and economic enabling/promoting high growth and consumption) Env drivers (food supply and marketing promoting high energy intake) Env moderators (socioeconomic/cultural/transport which amplify drivers
What are behaviour patterns in the obesity determinant model?
High energy intake with low physical activity
What is the physiology aspect of the obesity determinant model?
Energy imbalance: high total energy intake pushing energy imbalance (hard to fix, only drugs and surgery really)
Are upstream obesity determinants easy to change?
No, they’re complex, governments don’t want much to do with it etc
Does NZ use the WHO definition of obesity?
No, so our child obesity rates are probably actually higher
What is the BMI classification of obese?
30 (and you are 15-20 times for likely to get type 2 diabetes)
What are examples of changes in the global food supply?
Price
Promotion
Product
Placement
What is heterogeneity?
A word that signifies diversity
What does the Cuban economic decline exemplify?
A natural experiment, showing how lack of resources resulted in lower obesity which also correlated with decreased mortality, decreased disease etc obesity and so on, quite quickly