Obesity

Question 1

Definition of obestiy

Answer 1

• XS body fat to such extent that it may compromise health
• exceeding optimal body wt by 15-20%

Question 2

DDx for abd distension

Answer 2

• Organomegaly
• masses neoplastic or non-neoplastic
• organ fluids, ascites
• gas contained in organs or free in abd
• obesity, lipoma
• weakened abd musculature - hyperadrenocorticism
• faeces - obstipation, megacolon

Question 3

Prevalence of obesity

Answer 3

Prev in dogs: 25-44%
Prev in cats: 25-40%
increasing prevalence

Question 4

How to assess obesity?

Answer 4

• estimation: quantitative, dual energy absorptiometry scanning (DXA scan)
• BCS scoring
• morphometric methods

Question 5

Poor correlations between trained indiviuals and

Answer 5

owners regarding weight

Question 6

O’s tend to underestimate if an animal is

Answer 6

overweight

Question 7

O’s tend to overestimate if an animal is…

Answer 7

underweight

Question 8

Risk factors of obesity related to animal

Answer 8

• age: middle-aged to older (d/c)
• breed: labs, cockers, CKCS, DSH
• Sex: female (d), male (c)
• hormone staus: spayed/neutered
• related disorders: hypothyroidism (d), hyperadrenocorticism

Question 9

Risk factors related to iatrogenic effects

Answer 9

• Meds: anticonvulsants, steroids (D/C), etc.
• Sx: thyroid gland removal (d), spay/neuter Sx, etc.

Question 10

Risk factors related to O

Answer 10

• older or elderly
• overweight/obese
• women
• high earners
• underestimating problem
• overprotective
• etc.

Question 11

Risk factors related to food & diet

Answer 11

• non-commercial food, canned food, table scaps (D/c), feeding v. often, lots of treats (d/c), free feeding (c)

Question 12

Risk factors related to lifestyle & behaviour

Answer 12

• living indoors, humanisation (d/c), begging, inactivity, substitute for human companionship, anxiety, little time to play

Question 13

Obesity and hypothyroidism

Pathogenesis, wt gain due to…

Answer 13

• Pathogenesis: decreased prod’n of [T3/T4] secondary to lymphocytic thyroiditis or idiopathic atrophy of thyroid gland
• Wt gain due to: decreased metabolic rate, exercise intolerance, lethargy

Question 14

Obesity & hyperadrenocorticism

Pathogenesis, due to…

Answer 14

• Pathogenesis: increased endogenous [cortisol] secondary to pituitary tumour or adrenal carcinoma/adenoma
• gain due to: polyphagia, lethargy, exercise intolerance due to muscle weakness, wastage

Question 15

Obesity & hypersomatotropism (acromegaly)

Answer 15

• Pathogenesis: cats - pituitary tumour assoc’d w/ increased GH secretion; dogs - XS GH secreted by mammary tissue to endogenous/exogenous P4
• Due to: polyphagia, anablic effects of GH mediated by IGF-I, decreased exercise tolerance due to OA or dyspnoea

Question 16

Pathophysiology of obesity

Answer 16

• Adipose tissue: complex active organ, comprised of 50% adipocytes, 50% other cell types
• Adipose tissue as endocrine organ: prod’n of adipokines, exert local & systemic effects, classified based on inflammatory effects & effects on energy balance

Question 17

Adipokines involved in obesity

Answer 17

Leptin, adiponectin, resistin, aspelin, visfatin

Question 18

Leptin

Answer 18

• anti-obesity hormone
• plasma conc. increase w/ increased adipose tissue
• primary action - brain receptors: suppress appetite & energy expenditure; leptin resistance?
• promotes angiogenesis & mitogenesis, suppresses apoptosis
• reg of immune & repro fxns, modulated insulin sensitivity, pro-inflamm & prothrombotic effeects, inhibits adiponectin

Question 19

Adiponectin

Answer 19

• synthesized & secreted by adipocytes
• conc’s are decreased in obesity -> caused by inhibition of secretion by letpin & inflamm cytokines
• Effects: anabolic that increase insulin sensitivity & decrease serum glucose

Question 20

Resistin

Answer 20

• Secreted by macrophages, lesser by adipocytes
• increase in obesity - proportional to body fat
• Effect: stim’s pro-inflamm cytokine prod’n by macrophages

Question 21

Aspelin

Answer 21

• increases in obesity
• cardioprotective effects via vasodilation (reducing BP) & reducing vasoconstrictive actions of angiotensin II

Question 22

Visfatin

Answer 22

• produced by adipocytes, lymphocytes, bone mamrrow, liver & muscle tissue
• Effect: stims uptake of glucose by adipocytes & myocytes & suppresses release of glucose from hepatocytes

Question 23

Low grade inflammation pathophysiology of obesity

Answer 23

• may represent chronic inflamm dz
• rapid increase in adipose tissue -> exceeds blood supply, decreased available O2 -> stims adipose macrophages to produce & secrete cytokines & angiogenic factors
• imbalance btw M1 (pro-inflam) & M2 (anti-inflam) macrophages
• may explain increased [TNF-alpha] & [IL-6]

Question 24

Reproductive hormone pathophysiology in obesity

Answer 24

• sex hormones affect energy balance in CNS/PNS
• E2s: CNS - reduce food intake & increase energy expenditure; systemically - reg lipid/glucose metabl, inhibit lipogenesis, det no. of adipocytes
• Neutering: CNS - direct action on satiety/metab centres; systemically - affects cell metab & interaction w/ hormones (leptin)

Question 25

Diseases assoc'd w/ obesity

Answer 25

* OA * insulin resistance & Type 2 DM * Dyslipidaemias, CV dz, cancer, kidney dz, resp dz

Question 26

OA & obesity

Answer 26

* due to metabolic & mechanical effects of obesity * leptin triggers inflammation & cartilage degradation * chondrocytes stim'd by leptin to synthesis GF's * overwt -> XS strain on jts

Question 27

Insulin resistance & Type 2 DM

Answer 27

* via endocrine, inflamm, neurologic pathways * Endocrine: increased FA's -> active protein kinases, affect mediators of insulin receptor fxn; role of adipokines in insulin resistance * inflamm: increase in cytokines reduces glucose tolerance & increse insulin resistance * **Cats 4x more likely to dvlp DM if overwt**

Question 28

weight loss strategy

Answer 28

1. initial assessment 2. est. wt & BCS - current & ideal 3. Det calorie intake 4. reduce calorie ntake, increase energy expenditure 5. engage client w/ regular follow-ups

Question 29

Estimation of RER

Answer 29

70 x (Bw kgs ^0.75) based on ideal weight

Question 30

Food take unknown

Answer 30

wt loss = 0.8 x RER

Question 31

food intake known

Answer 31

Reduce food qty by 20% & reassess after 1 mos

Question 32

Diet change strategy for obesity

Answer 32

* high protein, low fat/carb diets - satiating, preserve lean muscle mass despite calorie restriction * commercial diet vs home-cooked * small freq meals * AIM: 0.5-2% Bodywt loss/wk

Question 33

Exercise wt loss strategy

Answer 33

* increase energy expenditure * Dogs: walk, swim, hydrotherapy, treadmills, food balls, hiding food * cats: play, motorised toys, food balls, laser pointers

Question 34

Drugs licensed for canine wt loss

Answer 34

* Microsomal triglyceride transfer protein inhibitors (MTTP) -> Dirlotapide (Slentrol) * Effective in intestinal epithelial cells (decrease fromation chylomicron) * decreases lipid absorption + appetite suppressive effect * effect & safe * best if used w/ low fat balanced diet + exercise * Indications: dogs unable to exercise & need to lose wt prior to orthopaedic Sx * Side effects: GI upset, lethargy

Question 35

Monitoring for obesity

Answer 35

* every consultation take wt & BCS * more freq monitoring if risk factors * montly reassessments * easier to avoid wt fgain than achieving wt loss