Lecture 33. Obesity Flashcards
How can epidemiology be used in relation to obesity?l
Descriptive: 1. current prevalence and burden
Predictive: 2. future burden
Explanatory: 3. changes over time
4. differences between populations
Evaluative: 5. effectiveness of interventions
Global obesity trends
-rise in all countries at different rates
Trends in US
every year from 1986 the prevalence of obesity increases
South have higher rates( due to socioeconomic status and ethnicity)
What groups get first affected by obesity?
Women
Urban
High income
middle-aged
The obesity transition
Stage 1: Prevalence high in women in high SES, then men and children are the least affected
Stage 2: Everyone is gaining weight. Still women in high SES are more affected.
Stage 3: Socio-economic gradient flip. Women are more affected, but now in low SES. Men in low SES are also more affected
Stage 4: Has not yet happened. The prevalence of obesity declines in all groups. The first people to get out of the epidemic- children and high-income women.
The burden in NZ
- 3rd most overweight countries among OECD after USA and Mexico
- 2nd most overweight children
childhood obesity prevalence in response to pandemic
Increase
childhood obesity by age
- <5 yo trends were declining in the past 1- years
- Increasing in over 5 yo
Affects of lockdown on weight gain
- Increase in both children and adults
- Increase in all ethnic groups
-the amount of yearly weight increase by nation is 10 times bigger
why does lockdown has a negative effect on weight gain?
- less exercise
- higher food consumption
- marketing of junk food
- home deliveries
- food insecurity increased!( loss of income)
What is the health burden of obesity?
The main contributor to the health burden
DALYS
- High BMI-> cardiovascular, cancer, diabetes, musculoskeletal
- Dietary risks-> high sugar, fat, low fiber and vege
- Malnutrition->contibutes to communicable disease
All added together- the biggest health burden is caused by the food system
Health Consequences of obesity
• Metabolic diseases
– Type 2 Diabetes, cardiovascular diseases, almost all cancers
(esp colon, breast [PM], uterine), gallbladder diseases
• Mechanical disorders
– Arthritis, back pain, obstructive sleep apnoea, skin disorders
• Psychological problems
– Low self-esteem, reduced quality of life, depression
• Social consequences
– Weight bias and discrimination, reduced life opportunities
Relationship between the relative risk of type 2 diabetes and BMI
- even before you get to the end of the normal range -already 2-3 fold increase in RR of diabetes
- an exponential increase in RR with BMI increase
What are the causes of obesity?
- Individual factors( genetic, metabolic, behavioral)
- Population factors. Why are some populations more obese than others?
- Global factors(environment)
OBESITY IS NOT PATHOLOGICAL, IT IS ENVIRONMENTAL
How do we know that global obesity increase is caused by environments?
A sharp simultaneous increase across all populations and age groups
What is obesogenic environments?
“The sum of influences that the surroundings, opportunities, or
conditions of life have on promoting obesity in individuals or populations”
Micro-environments vs macro-environment
micro- downsteam( food places/cafes)
macro-upstream( food suppliers)
How do food environments influence people?
How does food industry influence food environments?
-products, placement, price and promotion
-especially true for ultraprossesed foods(oils, flour, sugar, salt)
tap into psychology, tastes and price perfectly
What influences food environments on a large scale?
- Food industry- products, price, psychology
- Government. -regulations and laws, fiscal policies, health promotion
- Society- traditions, religions, values
All work together
What drives the obesity pandemic?
-the food system
– The most plausible explanation for the simultaneous, global
increase in obesity is that it has been driven by the changes
in the global food supply creating a population ‘passive
overconsumption’ of total energy
– Hyper-palatable, heavily-promoted, readily available,
cheaply-priced, highly-profitable ultra-processed foods
- reduced occupational activity
- more liberal governments, less engaged and in control
What are the reasons for differences in obesity prevalence between populations?
• Obesity prevalence is driven up by global drivers
but different local environments determine the
trajectories of different populations
– Moderators attenuate or accentuate the rise in
• Economic environments
– Income
– Income disparities
• Physical environments
– Food
– Physical activity
• Socio-cultural
environments
– Food, PA, body size
• Policy environments
– Market regulations
Why is Japan less affected?
- traditions, food
- philosophy
- media influences, the fashion industry
relationship between drivers, mediators, moderators, and outcomes
What population group has declining obesity rates
the youngest 4-5 yo kids in the least deprived households
disparities in obesity prevalence in kids
-kids are the first to come out of an epidemic but major differences
kids in the least deprived households are less affected
kids in more deprived and rural areas still have increasing rates
• For boys and girls, for 1, 2, 3.5 y/o children:
– Urban reductions, rural increases
– Consistently lower for most advantaged children
trends in NZ before lockdown
increase in disparities and prevalence in 4 yo kids
Policy inertia on implementing food policies
- Food industry opposition
– Direct opposition (especially Coca Cola & Pepsi on SSB taxes)
– Self-regulatory pledges/codes etc - Government reluctance to regulate/tax
– Weak governance systems, conflicts of interest
– Belief in education approaches and market solutions
– Unwilling to battle the food industry (chill effect) - Lack of sufficient public demand for policies
– Usually supportive of policy actions
– Not translated into pressure for change
when was the first sugar tax fight back in the US
2009
Coca colas corporate response plan to fight back policies
How does industry influence NZ policies?
big industry money behind harmful products (tobacco, alcohol. unhealthy food)
- -> Dirty PR
- -> attacks of public health advocates
Top obesity prevention policies for NZ
• Junk food marketing to children – promised regulations
• Tax on sugary drinks – none
• Healthy food policies in schools – voluntary with low
uptake but current consultation on Regulations
• Healthy food policies in early childhood settings – yes
but poorly implemented
• Front of pack labeling – yes but only ~30% uptake
Why are recommended policies not implemented?
– Industry opposition, political timidity, lack of public
pressure, intimidating advocates
History of obesity pandemic
• 1980s – scientists identifying the epidemic
• 1990s – advocacy to get obesity on public and political
agenda
• 2000s – increased awareness and some action –
largely program-based
• 2010s – evidence of effectiveness of interventions
strengthening, plateaus and declines in some
populations, ongoing battles over food policies
• 2020s – promised policies
