Consequences of obesity Flashcards
What are the main ways of assessing obesity?
BMI WHR WHH (waist: height) waist circumference hydrodensitometry dual energy x-ray absorptiometry
What are the benefits of using BMI to assess obesity?
correlates significantly with body fat, morbidity and mortality
What are the main categories of weight classification by BMI?
Underweight < 18.5
Normal 18.5 – 24.9
Overweight 25.0– 29.9
Obesity_1 30.0- 34.9
Severely obese 35.0-29.9
Morbidly obese >40
What is defined as being SUPER OBESE?
BMI >50
What are the complications associated with being super obese?
- osteoarthritis
- cardiopulmonary failure
- metabolic syndrome (DM, NASH, HTN, hyperlipidaemia)
Are there specific Rx to combat the complications of superobesity?
No
Metabolic syndrome improves with 5-10% weight loss
What are the main causes of obesity?
- nutrient and energy imbalance
- genetics
- behavioural and culture factors
What are the main contributors to weight gain?
- socio-economic status
- smoking cessation
- hormonal
- inactivity
- psychosocial/emotions
- medications
What can the increasing prevalence of obesity over past 20-30 years be attributed to?
Reduced resting metabolic rate Reduced muscle mass Increased fat mass Increased accumulation of abdominal adipose tissue
What 3 process are dysregulated in obesity?
energy intake
adipose tissue formation
energy expenditure
What are the main complications of obesity?
Hypertension Stroke Diabetes mellitus, Type 2 Metabolic syndrome CV mortality Cancer – endometrium, breast, prostate, and colon. Gallbladder disease Osteoarthritis Respiratory diseases and sleep-apnea
What are the 2 main types of body patterns observed in obesity?
APPLE SHAPED
- intra-abdominal or visceral
- visceral fat deposition
PEAR SHAPED
- lower body or external type
- subcutaneous fat deposition
both are linked to elevated levels of FFAs
What is the nature of adipocytes found in the visceral depots?
- large insulin-resistant adipocytes
- increased adrenergic receptors
- catecholamine mediated lipolysis
inverse correlation between visceral fat % and insulin sensitivity
What is the nature of adipocytes found in the subcutaneous depots?
- small insulin-sensitive adipocytes
- reduced adrenergic receptors
What is the insulin resistance syndrome?
= physiologic response is inadequate for the amount of insulin secreted
What are other names for metabolic syndrome?
- syndrome X
- dysmetabolic syndrome
- insulin resistance syndrome
What are the main components of insulin resistance?
- complex dyslipidaemia
- endothelial dysfunction
- systemic inflammation
- atherosclerosis
- disordered fibrinolysis
- hypertension
- T2DM
- visceral obesity
When is dysmetabolic syndrome thought to occur?
When insulin resistance results in atherosclerosis
What are clinical manifestations of insulin resistance syndrome?
Central obesity Glucose intolerance Atherosclerosis Hypertension Polycystic ovary syndrome
What are the biochemical abnormalities of insulin resistance?
Insulin resistance
Hyperinsulinemia
High TG
Low HDL-C
Small, dense LDL
Increased PAI-1
How does hyperglycaemia and hyperinsulinaemia result in hypertension?
Activation of the sympathetic nervous system
Increase of arterial tone
Na+ reabsorption
How does hyperglycaemia and hyperinsulinaemia result in T2DM?
Overstimulation of pancreatic -cell function
Reduction of insulin secretion
What is the correlation between high BMI and BP?
70% in men
60% women
association between excess adiposity and hypertension
What 3 metabolic mechanisms promote hypertension in obesity?
INCREASED
- vasconstriction
- cardiac output
- sodium reabsorption
What are the mechanisms by which obesity influences cancer risk?
- sex steroid hormone synthesis (oestrogen, androgen)
- reduced insulin sensitivity and increased production of IGFs
- action of leptin + adiponectin on adipose tissue
- increased oxidative stress
- increased chronic low-grade inflammation
Which cancers are obese people most at risk of?
MALES: oesophageal adenocarcinoma, thyroid, colon, renal
FEMALES: endometrium, gallbladder, oesophageal adenocarcinoma, renal
Which cancers do obesity reduce the survival from?
- breast
- colon
- endometrium
- ovary
- prostate
What are the main risk factors for sleep apnoea?
Family history Obesity: 80 % of sleep apnea patients Increasing age Male gender Large tonsils / adenoids Small mandible, large neck Smoking, alcohol, sedatives
What are the consequences of sleep apnoea?
Social / Psychological: work, family Personal: fatigue, tired, depression, irritability, impotence, memory More accidents: work home motor vehicle Higher death rates with severe apnea Hypertension, Congestive Heart Failure Heart Attacks, Strokes, A Fib Promotes obesity and diabetes
What is NAFLD?
Non-Alcoholic fatty liver disease
spectrum of pathology
- ranging from fatty liver to cirrhosis
When is drug therapy for obesity considered?
consider when
BMI > 30
or
BMI > 27 with comorbid illness
What drugs can be used to treat obesity?
- sibutramine (appetite suppressant)
- orlistat (lipase inhibitor)
- Rimonabant
- Incretins (slows gastric emptying)
What are the benefits of using orlistat?
- useful as adjunct in weight loss
- improved glycaemic control
- reduced serum lipid levels
- reduced BP
used in conjunction with metformin for T2DM
What are the incretins?
GI hormones released post-prandially, that stimulate GSIS
GLP1: effective
GIP: not effective in GSIS
What are the physiological effects of GLP-1?
- GSIS
- reduced gluconeogenesis
- cardioprotective
- increased satiety
- reduced gastric emptying
- improves insulin sensitivity
What is an example of SGLT2i?
dapafliflozin
inhibits SGLT2 in the PCT
How does amylin in the exocrine pancreas aid insulin?
- effectively slowing doen intestinal absorption of glucose
- suppresses GCG
What is the goal of gastric bypass surgery?
achieve and maintain a healthier body weight
most weight loss occurs in first 6 months post-surgery
then gradual loss in 18-24 months
Data suggest that if weight loss has been maintained for 5 years, there is a > 95% likelihood that the patient will keep the weight off over the long term.
