consequences of obesity - lecture

what are the primary causes of obesity?

calorie intake > calorie expenditure

influenced by:

- psyche/emotional state/behaviour

- societal/environmental

- abundance and appeal of food

- activity levels

what are the secondary/pathological causes of obesity?

- hypothyroidism

- cushings syndrome

- insulin-secreting tumour

- prader-willi syndrome

- congenital leptin deficiency

what are the 2 main fat distribution examples?

- abdominal obesity = apple

- gynaecoid obesity = pear

which out of abdominal and gynaecoid obesity has the most detrimental effects?

abdominal

why do prader-willi syndrome and congenital leptin deficiencies cause obesity?

cause insatiable appetites

what is the category for obese in terms of BMI?

30-35

what is the category for morbidly obese in terms of BMI?

40-50

what is an increase of BMI over 5 associated with in terms of mortality?

30% increased mortality for every 5 BMI increase

what are the general categories of the consequences of obesity?

- metabolic

- mechanical/physical

- sociological/ergonomic/economic

- psychological

- impacts most medical specialities

what is meant by the ergonomic effects of obesity?

being unable to fit in train and plane seats, hospital beds etc

what is the difference between a disease and a syndrome?

disease = specific cause and effect

syndrome = collection of signs + symptoms bundles together

how does obesity cause metabolic problems?

- adipose tissue is a major endocrine gland

- increase adipocytes = imbalance in hormones

what are the metabolic effects of obesity called together?

metabolic syndrome

what are the features of metabolic syndrome?

- insulin resistance

- dyslipidaemia

- hypertension

- increases risk of T2DM and CHD/CVD

what are the criteria for metabolic syndrome according to the National Cholesterol Education programme (NCEP)?

three or more of:

- waist circumference > 102cm (m) 88cm (f)

- fasting triglyceride > 1.7mmol/L

- HDL-cholesterol < 1.0mmol/L (m) < 1.3 (f)

- treated htn or bp > 130/85

- fasting plasma glucose >6.1mmol/L

how is obesity thought to cause insulin resistance?

- lipotoxicity = increase free fatty acids

- adipose tissue produces TNFa = peripheral resistance to insulin

how does lipotoxicity affect insulin resistance?

- causes insulin resistance in skeletal muscle + liver

- decrease beta-cell function

what can insulin resistance lead to in the liver?

- fatty liver

- NAFLD

- NASH

- cirrhosis

what is dyslipidaemia?

abnormal levels of lipids in blood

how does obesity cause dyslipidaemia?

body tries to remove excess triglycerides in abdominal fat - so increases very low density lipoproteins (VLDLs)

what are the levels of different lipids in dyslipidaemia?

- increase VLDL

- increase LDL

- decrease HDL

how does obesity cause hypertension?

increase sympathetic activity - leading to activation of RAAS system = sodium and water retention

how does obesity increase the risk for CHD/CVD?

combination of:

- atherosclerosis

- hypertension

- diabetes

- pro-inflammatory state

- pro-clotting state

what is the obesity paradox/reverse epidemiology?

some studies show that obese people have lower mortality from certain conditions/procedures:

- mycardial infarction

- CABG

- heart failure

- osteoporosis

what could be the explanation?

due to lack of smoking - smoking decreases appetite but has a high association with these conditions