Obesity Flashcards
What is the definition of obesity
• Obesity is defined as abnormal or excessive fat accumulation sufficient to adversely affect health and reduce life expectancy
what does theBMI use
a person’s weight (in kilograms) divided by the square of his or her height (in metres)
name the ranges for - underweight - normal weight - overweight - obese for BMI patients
underweight = BMI is less than 18.5 normal weight = BMI is 18.5 to 24.9 overweight = 25 to 29.9 obese = BMI is 30 or greater morbidly obese = BMI 40 or greater
what does weight circumference do
- this helps distinguish muscular people from fat people in the BMI
- weight circumference is the waist hip ratio
what is the downside of the BMI
does not distinguish between muscular and obese people
what cause the obesogenic environment
increased food intake - appetising cheap available high energy density food
less exercise - electricity, cars, TV, computers
How much of obesity is caused by medication
As many as 10% to 15% of weight issues are related to medications:
what drugs can cause obesity
Mood Stabilizers Diabetes Medicines Corticosteroids Beta Blocker Allergy Relievers Drugs That Prevent Seizures and Migraines
what else is being proposed for BMI
ethnic weight cut offs
what medication can make you gain a lot of fat
diabetes medicine such as insulin
How does insulin cause you to gain weight
- it inhibits breakdown and release from fat cells
- it decreases the rate of lipolysis in adipose tissue (this lowers the plasma fatty acid level)
- this stimulates fatty acid and triacylglycerol synthesis in tissues
- it increases the uptake of triglycerides from the blood into adipose tissue.
- it decreases the rate of fatty acid oxidation in muscle and liver
what is lipohypertrophy
Enlargement of fat cells local to where the insulin is injected
what drugs increase insulin
Insulin
sulfonylureas
- glyburdie
- glicizide
TZD
- these also increase weight
what drugs keep insulin stable
Metformin
DPP IV inhibits
- Januvia
- Onglyza
- trajenta
- these drugs keep insulin stable
what drugs decrease iuslin
- SGLT-2 inhibitor
- Acarbose
these decrease weight
Is obesity heritable
Heritability estimates for obesity are high (typically 70%),
What is the thirfty gene hypothesis
- Genes that predispose to obesity would have had a selective advantage in populations that frequently experienced starvation.
- People who possess these genes in today’s obesogenic environment might be those that ‘overreact’ not just becoming slightly overweight, but extremely obese.
name the proof for the thrifty gene hypothesis
More recent support for the thrifty gene hypothesis was provided by Pritchard et al. 2006
Many genes involved in the glucose and lipid metabolism have been subject to positive selection in the last 10 000 years, especially in Asian and African ethnic groups.
what is syndromic monogenic obesity
Syndromic monogenic obesity is exceptionally rare and characterized by mental retardation, dysmorphic features and organ specific abnormalities, in addition to obesity
how many syndromes cause syndromic monogenic obesity
More than 30 syndromes reported in the literature
name an example of syndromic monogenic obesity
Bardet–Biedl & AlstrÖm syndrome = ciliopathy
describe how bardet-biedl and alstrom can cause obesity
- the primary cilum has a key role in the differentiation of adipocytes
- the pathogensis of obesity is in part attributed to a defect in adipogensis
- the cilia mediate leptin receptor (LEPR) signalling
what is non syndromic monogenic obesity
currently 12 genes have been identified to date that have roles in energy maintenance as part of the leptin-melanocortin pathway.
what can cause polygenic obesity
Using genome wide association (GWA) 227 genetic variants involved in different biological pathways have been identified:
Central nervous system, food sensing and digestion, adipocyte
differentiation, muscle and liver biology, gut microbiota
Name two types of polygenic obesity
Adipocyte differentiation
1- Cilopathies (primary cilia dysfunction)
2- Mutations in Peroxisome-proliferator-activated receptor gamma 2 (PPARγ2): a transcription factor that has a key role in adipocyte differentiation (targeted by Thiazolidinediones drugs)
TZD drugs
what can also cause obesity
epigenetic vacation and geen environment interactions
what is the concepts of epigenetic variation
concept that environmental and nutritional influences during critical periods in development (particularly during gestation) can have permanent effects on an individual’s predisposition to obesity.
adipose tissue is a …
bonafide endocrine organ - it connects to all the organs in the body and therefore effects how all the tissues work
what are the different types of body shape
apple shape
pear shape
what shaped body is at more risk of getting weight related heath problems
Apple shape = More visceral fat
Higher risk of weight-related health problem
Pear shape = Less visceral fat
Lower risk of weight-related health problem
How much can obesity related diseases cut lifespan by
11 years
what is obesity a major risk factor for
cardiovascular diseases
pulmonary diseases (such as sleep apnoea)
metabolic diseases (diabetes & dyslipidaemia)
osteoarticular diseases
for several of the commonest forms of cancer
for serious psychiatric illness
what is child hood obesity associated with
childhood obesity is associated with early onset type 2 diabetes and with an increased mortality risk for coronary heart disease in adulthood
what are the key features of obesity and type 2 diabetes
- Chronic inflammation
- Altered adipokine levels (high level of leptin) - insensitive to leptin
- Breakdown of fat metabolism (accumulation of lipids in the tissue)
- Breakdown of the regulation of glucose metabolism due to high fat metabolism
what is non alcoholic fatty liver disease
- this is caused by the build up of fat in the liver
who is non alcoholic fatty liver disease seen in
Usually seen in people who are overweight or obese.
Also associates with high cholesterol / high BP / T2D.
Estimated to affect up to 5% of the UK population
how do you PREVENT obesity
1- to inform people about life style
2- promote/develop a “non-obesogenic” environment
what treatment is the foundation of obesity treatment
lifestyle changes
- weight loss
- physical activity programs
- diet
- these have poor adherence
name a drug treatment that can be used for obesity and how it works
Orlistat
- gastric and pancreatic lipase inhibitor which reduces absorption of dietary fat
- very unpleasant
what do you have to undergo in order to have surgery for obesity
Nobody gets surgery without undertaking a weight management course, in which they are taught about diet and nutrition, fitness and exercise
what patients does surgery happen in
Surgery is performed laparoscopically in patients with:
- Morbid obesity (BMI >40 kg/m2)
- BMI >35 kg/m2 AND obesity-related complications
(after conventional medical treatments have failed)
what are the types of surgery
restrictive surgery
malabsorptive procedures
what conditions cause syndromic monogenic obesity
bardet bidel
Alstrum
- these are both diseases that affect the cilia
what do restrictive surgery do
- they remove a portion of the stomach
what does a malabsorption procedure do
- these reduce the ability to absorb nutrients
causes nutrient deficiencies, malnutrition and, in some cases, anastomotic leaks and the dumping syndrome*.
name some examples of malabsorption procedures
e.g. biliopancreatic diversion and Roux-en-Y gastric bypass
what is dumping syndrome
rapid gastric emptying)
name some examples of restrictive procedures
adjustable gastric banding,
vertical banded gastroplasty
sleeve gastroplasty
name some expamples of restrictive plus malabsorption procedures
duodenal switch,
Roux-en-Y gastric bypass,
intragastric balloon
what is non syndromic monogenic obesity cause
- linked to the hypothalamus of the brain and the arcuate nucleus and the neurones that can cause food intake and decreased food intake
if you fat is subcutnaoues and pear shaped
lower risk of health problem
if you have more visceral fat..
higher risk of health problems
90% of obese patients as children will
be obese as adults
what can diet changes do
- make you constantly hungry and don’t feel as satisfied as you would
- maintenance of a body weight at. level of 10% below the initial weight was associated with a reduction in total expenditure
