Obesity Flashcards
What is obesity?
A condition of abnormal or excessive fat accumulation in adipose tissue, to the extent that health is impaired
What are the different categories for weight with reference to BMI?
What environmental factors may be drivers of obesity?
Food/energy intake - increase in high fat, sugar and salt foods
Ability to play outside - access to parks and playgrounds
Car use
Screen time
Education level and educational achievement
Poverty
Social deprivation
NOTE: These are correlations not causations - hard to say what drives what
Describe genetic involvement in propensity to obesity
Genes predict 60-80% of the variation in somebody’s propensity to obesity in a given environment
In 2016, how many adults were estimated to be overweight and amongst these, how many were estimated to be obese?
More than 1.9 billion adults overweight
Of these, more than 650 million obese
What comorbidities are associated with obesity?
Depression
Stroke
MI
Hypertension
Diabetes
Peripheral vascular disease
Sleep apnoea
Bowel cancer
Osteoarthritis
Gout
How is obesity assessed and managed?
Describe the approach to deciding the initial level of intervention for overweight/obese patients
What are some of the effects of leptin deficiency?
Infertility
Stunted linear growth
Decreased body temperature
Decreased energy expenditure
Decreased immune function
Why is leptin important for normal physiological function?
Contributes to
- Activation of immune cells
- Regulation of appetite, control of metabolism and energy homeostasis
- Regulation of bone mass
- Regulation of the menstrual cycle
- Regulation of thyroid hormone synthesis
- Heart rate, BP
- Decreases glucose-stimulated insulin secretion
In absence of leptin, what does the brain think about the body’s condition?
Starvation
Leptin is released from adipose tissue - lack of leptin, lack of adipose tissue - starvation?
Why isn’t leptin an effective obesity drug?
Leptin is an anti-starvation hormone rather than anti-obesity
Presence of leptin suggests system has sufficient fat reserves for normal functioning but high leptin has little effect
People with obesity are leptin resistant
What is Orlistat and how does it work?
Derivative of an endogenous lipstatin produced by Streptomyces toxytricini
Inhibits gastric and pancreatic lipase
Reduces dietary fat absorption by around 30%
Why may compliance be low in those taking Orlistat?
Unpleasant side effects:
Fatty and oily stool
Faecal urgency
Oily spotting
Faecal incontinence (7%)
High attrition rates in randomised trial
What is another disadvantage of taking Orlistat?
Possible deficiencies of fat-soluble vitamins
Is Orlistat effective?
Not very effective
Around 2.9% weight reduction
What are the effects of GLP-1 on the body?
Give an example of a long-acting GLP-1 receptor agonist
Saxenda (liraglutide)
How is Saxenda taken and what are its effects on weight loss?
Daily injection
Double the dose used for T2DM
4-5% weight loss
However has GI side effects
What are the BMI requirements for bariatric surgery?
BMI of 40 kg/m2 or more
BMI of 35-40 kg/m2 and other comorbidities
BMI of 30-34.9 kg/m2 for newly diagnosed T2DM
BMI >50 kg/m2 - consider surgery as first-line option
What other conditions must be met for an individual to be considered for surgery?
- Non-surgical measures have failed to achieve or maintain adequate clinically beneficial weight loss for at least 6 months
- Receiving or will receive intensive specialist management
- Generally fit for anaesthesia and surgery
- Commit to the need for long-term follow-up
What are the common types of types of bariatric surgery?
How does a gastric bypass work?
Top part of stomach is joined to small intestine
Feel fuller sooner
Absorption of less calories
What is semaglutide?
Long-acting GLP-1 receptor agonist
Up to 15% weight loss
What is Tirzepatide?
Long-acting GLP-1 receptor and GIP receptor co-agonist
How does a gastric band work?
Band is placed around stomach
Do not need to eat as much to feel full
How does a sleeve gastrectomy work?
Part of stomach is removed
Cannot eat as much as before
Feel full sooner
