Flashcards in Obesity Deck (17):
What is obesity defined as?
Abnormal/excessive fat accumulation sufficient to adversely affect health and reduce life expectancy
What BMI indicates obesity and morbidly obesity?
Morbidly obese >40
What is the limitation of BMI?
Body builders/people with a lot of muscle mass have a large BMI but are not obese
Have a thin waist so use waist circumference instead
What is the obesogenic environment?
- increased food intake: appetising, cheap, available, high energy density, socio-economic dependent access to healthy diet, food industry more interested in profit than public health
- less exercise: sedentary life style
What medications are related to weight issues?
drugs for migraines/seizures
What is the effect of insulin on weight?
insulin makes you fat
- inhibits breakdown and release from fat cells:
decreases lipolysis rate in adipose tissue
stimulates FA and TG synthesis
increases uptake of TG from blood into adipose tissue
decreases rate of FA oxidation in muscle and liver
lipohypertrophy: enlargement of fat cells local to where insulin is injected
What is syndromic monogenic obesity?
Mental retardation, dysmorphic features, organ specific abnormalities, obesity
Prader-Willi, Fragile X are examples
1 mutation of 1 gene affecting a wide range of body functions/processes
What is Bardet-Biedl & Alstrom syndrome?
2 strong links to obesity:
- primary cilium has key role in differentiation of adipocytes -> defect in adipogenesis
- cilia mediate leptin receptor signalling
What is non-syndromic monogenic obesity?
1 mutation in any 1 of 12 genes
genes part of leptin-melanocortin pathway
How do adipocytes differentiate?
- ciliopathies (primary cilia dysfunction)
- mutations in PPARgamma2
What is PPARgamma2
Transcription factor that has a key role in adipocyte differentiation, targeted by TZD drugs
How is obesity a heritable trait?
- monogenic obesity
- polygenic obesity (227 genetic variants)
- epigenetic variation
What is the difference between apple shape and pear shaped individuals?
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 can obesity lead to type 2 diabetes?
- chronic inflammation
- altered adipokine levels as high leptin levels
- breakdown of fat metabolism (lipid accumulation in tissue)
- breakdown of glucose metabolism regulation
What drugs treatments are there for obesity?
Orlistat - reduces amount of fat absorbed from food eaten by acting as a lipase inhibitor
What surgery can be done for obesity?
- weight management course first so taught about diet/nutrition/fitness/exercise
- laproscopically after conventional treatments failed
- if morbidly obese or BMI>35 and have obesity related complications
- restrictive procedures: restrict food passage with gastric banding/vertical banded gastroplasty and sleeve gastroplasty
- malabsorptive procedures: reduce ability to absorb nutrients
- restrictive plus malabsoprtive procedures (duodenal switch, Roux-en Y gastric bypass, intragastric balloon)