Obesity Flashcards
1
Q
Learning objectives
A
- Describe the physical, psychological and social consequences of obesity
- Discuss common theories regarding causes of obesity
- Describe current evidence-based interventions for preventing and managing obesity
2
Q
Define obesity
A
Accumulation of fat stores to an extent that compromises health – WHO 2006
3
Q
Describe the calculation and categories for the antrhometrif measurement - body mass index (BMI)
A
- Formula: weight (kg) / Height (m2)
- Overweight: BMI ≥ 25
- Obesity: BMI ≥ 30
- Severe (‘morbid’) obesity: BMI ≥ 40
4
Q
What are the problems with using BMI as ‘proxy measure’ of body fat?
A
- Does not distinguish between weight in muscle and fat
- 400 metre sprinter and silver medallist, Christine Ohuruogu, had a BMI over 27, which would mean she would be classified as overweight using BMI as an indicator of body fat.
5
Q
What is another problem with using BMI
A
- BMI is less accurate in elderly population due to muscle loss
- Our bodies change with age – lose muscle mass
- BMI becomes less precise measure of excess fat due to these changes in muscle mass – which can often lead to unintentional weight loss.
- In addition associations between obesity (or body fat) and health risks (diabetes, CVD, cancers) are different in older populations;
- Winters et al found for older populations being overweight is not associated with increased risk of mortality – risks increase for obesity
6
Q
What is the importance of the location of fat?
A
- BMI cannot determine where fat is being stored
- Type and location of fat are important predictors of cardiovascular and metabolic risks
- Subcutaneous fat – located in front of abdomen
- Visceral fat – located within abdominal cavity, surrounding vital organs
- Visceral fat strongly associated with chronic disease risk
7
Q
How is the use of BMI cut offs used in different ethnic groups?
A
- Large prospective cohort study (n=60,000 adults)
- Followed up for 12 years
- Risk of diabetes was significantly higher among South Asian adults (nearly 4x higher) than white participants at a given BMI
- Important changes to recommendations for health professionals
8
Q
What was the lancet commission for redefining obesity?
A
- Commission made up of 56 world experts from LIC, MIC and HIC (represents broad range of expertise)
- Evidence based definition of “Clinical Obesity”: chronic, systemic disease state directly caused by excess adiposity
- “Preclinical obesity”: a condition of excess adiposity without current organ dysfunction or limitation in daily activities but with increased future health risk.
- Limitations of using single measure of BMI – sues other measurements of body size (WC, W-t-H or W-t-H ratio) in addition to BMI
- Changes must be applicable to range of settings (address equal access to care)
9
Q
Describe the scale of the global problem with obesity?
A
- Obesity pandemic shifted global patterns of malnutrition
- 2015 – obesity estimated to affect 2 billion worldwide
- Research on developmental origins of health and disease suggest a ‘critical window’ which leads to undernourished babies at increased risk of obesity in adulthood
10
Q
Describe the urban-rural differences in obesity
A
- Parallel rises of urbanisation and obesity led to assumptions that urbanisation was one of the most important drivers of global rise in obesity.
- However, large-scale population datasets indicate similar or faster increasing BMI in rural areas (particularly in low- and middle-income countries, and women)
- In many countries (high-income and industrialised countries) mean BMI is higher in rural areas, especially in women
11
Q
Describe low- and middle- income rural communities
A
- Outdated idea of rural communities ‘living off the land’ - many areas of manual work have been automated (farming, mining, forestry)
- Rural communities in LMICs have been targeted by food companies - increasing access to cheap, highly processed, energy dense foods
- HICs: Rural communities in HICs are disadvantages with lower income and education, limited availability and high cost of healthy foods, sewer leisure/sports facilities
12
Q
Describe the UK obesity epidemic
A
Around three quarters of people ages 45-74 in England are overweight or obese
13
Q
View diagrams for obesity trends
A
14
Q
What is the impact of international disasters on obesity?
A
- Weight gain is correlated with time spent out of school during holiday closures
- Increased food insecurity – cost of living crisis (more families needing to buy cheaper and often more energy dense foods
- Physical activity reduced during Covid-19 (parks were closed!)
- Stress related eating, disruption to food supply/system, re-focusing of public health attention, changes in income, housing, eating habits
15
Q
What is the health impact of obesity in terms of mortality and adiposity?
A
- European Prospective Investigation into Cancer and Nutrition (EPIC) – 9 countries
- Adjusted RR of mortality according to BMI
- J-shaped association
- Lowest risk of death was seen for participants at a BMI of 25.3 (men) and 24.3 (women)
16
Q
List the physical impacts of obesity
A
- Head: Risk of major depression
- Throat: Most morbidity obese develop obstructive sleep apnoea
- Breasts: Increase in breast cancer
- Pancreas: Increased risk of diabetes
- Kidney: Increased risk of kidney stones
- Lungs: 85% increase in risk of asthma
- Heart: Increased risk of hypertension
- Liver: Non-alcoholic fatty liver disease, increased risk of cirrhosis
17
Q
Describe Obesity and type 2 diabetes
A
- 90% of adults in UK with type 2 diabetes (aged between 16-54yrs) were overweight or obese
- Diabetes causes considerable morbidity and serious vascular complications – extremely costly to health care systems (£10 billion per year costs to the NHS)
- Around 85 deaths per day from heart and circulatory diseases are attributable to high BMI – similar to proportions attributed to smoking!
18
Q
Describe Obesity and the risk of cancer
A
- Link between body weight and cancer is firmly established
- Meta-analysis 89 prospective studies:
- Overweight and obesity associated with increased risk of breast, colorectal, endometrial, kidney and ovarian cancers
19
Q
What are the different types of cancers that obesity increases the risk of?
A
- Thyroid gland
- Oesophagus
- Stomach Cardia
- Kidney
- Multiple myeloma
- Pancreas
- Colorectum
- Ovary and endometrium
- Gallbladder
- Liver
- Breast
- Meningioma
20
Q
What are the impacts of obesity on healthcare systems?
A
- High BMI estimated to cost health services globally US$ 990 billion per year (13% healthcare expenditure)
- Highest costs in Eastern Mediterranean and America regions
- VD
21
Q
Describe the impact of obesity on the cost of healthcare
A
- People with obesity are more likely to develop conditions such as type 2 diabetes, heart disease and cancer – all associated with high healthcare costs
- Often require more complicated or costly care
- E.g. increasing length of stay for hip replacement
22
Q
How can obesity affect mental health and wellbeing?
A
- Affects young people and adults
- Body dissatisfaction
- Lower self-esteem in community samples
- Higher rates of depression at higher grades of obesity
23
Q
How does obesity cause Discrimination and social exclusion?
A
- Educational access:
- Lower college attendance
- Lower teacher ratings of ability for obese girls
- Bullying and teasing at school
- Marriage and social position:
- Less likely to get married
- Downward SES trajectory for obese women
- Employment
- Employers less willing to take obese people as employees
24
Q
Describe the obesity systems map: Role of individual and environmental factors
A
- Each sector has its own roles ranging from:
- Biology
- Food consumption
- Food production
- Individual activity
- Activity environment
- Individual psychology
- Societal influences
25
What are the causes of obesity?
- Genetics:
- Quantitative genetic studies (e.g. twin studies)
- Molecular genetic studies (e.g. genome-wide association studies – MC4R variants)
- Environmental factors:
- Obesogenic environment
- Modifiable
- Psychology and eating behaviour:
- Developmental models
- Cognitive models
- Theories of eating behaviour
26
What is meant by the obsogenic environment?
- Food environment: Availability, Cost, Variety, Portion sizes, High energy density (kcal/g), High fat, Low fibre (not filling), Food advertising
- Activity environment: High cost of activity, Labour saving devices, Sedentary travel, Enjoyable sedentary pastimes
27
What other measures can be taken to reduce calorie consumption?
- Reduces Portion sizes
- Fries before: 75g, 230 calories. Now: 155g 500 calories
- Popcorn before: 5 cups, 270 calories. Now: 11 cups, 630 calories
- Cola before: 200ml, 85 calories. Now: 950ml, 310 calories
- Burgers before: 330 calories. Now: 590 calories
28
What is the trends in changing dietary habits: snacking behaviour?
- Meals are less bound to particular times
- People are eating when and where it is convenient
- More than a quarter of adults and one fifth of children eat food from out of home outlets at least once a week
- VD
29
30
Describe the takeaway meal consumption and disease risk markers in 9-10 year old children
- Nearly three quarters of children ate a takeaway meal regularly, over 1/3 ate once or more than once a week
- Boys and children from lower socioeconomic groups consume more takeaway meals
- Children who consume more takeaway meals have higher total and LDL-cholesterol, higher fat mass
31
Using the case study on Japan, what were the health outcomes in terms of obesity?
- Lowest rates of obesity seen in high income countries (~4%)
- HOW? - Public health policies focused on prevention:
National screening programme for metabolic syndrome (aged 40-74)
- National School Lunch Programme: Education and cultural/societal healthy food norms
32
What is the UK governments strategy to tackling obesity?
- Improving access to weight loss programmes through Primary care
- Changes to the ‘Food Environment’
- Banning adverts for high fat, salt or sugar products on TV and online before 9pm.
- Calorie labelling in large restaurants, cafes and takeaways.
- Ending promotion of high fat, sugar or salt products in store and online.
- Consultation on ‘traffic lights’ nutritional information and calorie labelling on alcohol
