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
