Health Hazards of Obesity Part 1(Dr Ciara O'Sullivan)
Health Hazards of Obesity Part 1(Dr Ciara O'Sullivan)
Health Hazards of Obesity Part 1(Dr Ciara O'Sullivan)
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<strong>Health</strong> hazards <strong>of</strong> obesity<strong>Dr</strong> <strong>Ciara</strong> O’SullivanOctober 2007Flight to Kintore
Flight to Kintore
Key points• Definition• Prevalence• Metabolic associations• <strong>Health</strong> hazards & risk reduction
Flight to Areyonga
Introduction• Excess bodyweight is an issue for all<strong>of</strong> us, not just our patients!•6 th most important risk factor inworldwide burden <strong>of</strong> disease• 1·1 billion adults and 10% <strong>of</strong> childrenare overweight or obese
Aetiology <strong>of</strong> obesity•Genes•Diet• Activity – inactivity• Environment• Socioeconomic factors
Definition <strong>of</strong> obesity• BMI - weight in kg divided by height in m 2• WHO criteria for BMI; Caucasian;• normal; BMI <strong>of</strong> 20 – 25 kg/m 2• overweight: BMI <strong>of</strong> 25 - 29.9 kg/m 2• obesity: BMI <strong>of</strong> >30 kg/m 2• morbid obesity: BMI <strong>of</strong> >40 kg/m 2 (or 35kg/m 2 if comorbidities present) Asian BMI criteria for overweight is > 23kg/m 2
Waist circumference (WC)• WC predicts metabolic risk in obesity• WHO criteria for WC; Caucasian;• normal; WC < 94 cm () & < 80 cm ()• overweight: WC <strong>of</strong> 95 – 101 cm () &81 - 87 cm ()• obesity: WC <strong>of</strong> > 102 () & > 88 cm ()– Asian WC criteria for obesity; < 90 cm ()& < 80 cm ()
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Prevalence<strong>of</strong> obesityworldwidePrevalence <strong>of</strong> obesityworldwide by age and sex;Lancet 2005; 366; 1197 – 1209
Incidence <strong>of</strong> obesity according tobaseline body mass index6.05.04.03.02.01.00.000.10.13.14.93.91.921.9Incidence (% per year)Normal Overweight AllMalesFemalesAllBaseline BMIAusDiab2005
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Metabolic associations<strong>of</strong> obesity• Metabolic syndrome• Insulin resistance syndrome• Syndrome X• Deadly quartetThey all refer to the samesyndrome!
Metabolic syndrome• A clustering <strong>of</strong> clinical & metaboliccharacteristics which increase therisk <strong>of</strong> developing type 2 diabetes &cardiovascular disease• Strongly linked to abdominaladiposity & sedentary lifestyle• Central role <strong>of</strong> “insulin resistance”
Metabolic syndrome is stronglylinked to abdominal adiposityEndocrine Review 2000; 21; No 6; 697 - 738
Clinical criteria formetabolic syndromeAdult Treatment Panel (ATP III: JAMA 2002; 287; 356)• WC > 102 cm () & WC > 88 cm ()• Hyper-trigliceridaemia > 1.69 mmol/l• HDL < 1.04 mmol/l () & HDL < 1.29mmol/l ()• Blood pressure > 130/85 mmHg• Fasting plasma glucose > 6.1 mmol/l• Diagnosis requires 3+ features
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What is insulin resistance?…. an orchestra without a conductor ….
Usual role <strong>of</strong> insulin as ametabolic regulatorLancet 2005; 365: 1333 - 46
Abdominal adipocytes & insulinresistance
Abdominal adipocytes & insulinresistance insulin insulinresistance sensitivityFFA’s leptin++TNF– +- adiponectinresistincomplement+++ + +++prostaglandins IL – 6 PAI – 1 steroids TGF–
Mechanisms <strong>of</strong> insulin resistance• Role <strong>of</strong> metabolically activeabdominal adipocytes–excessive lipolysis causes flux <strong>of</strong> freefatty acids which impair function <strong>of</strong> keyinsulin sensitive tissues–release <strong>of</strong> inflammatory substances(also accelerates cardiovasculardisease)
Free fatty acids impair function<strong>of</strong> insulin sensitive tissuesLancet 2005; 365: 1415 - 28
Inflammation• Abdominal adipocytes release proinflammatorycytokines includingIL-6, resistin, (TNF-a) & CRP• Role <strong>of</strong> activated macrophages inabdominal adipose tissue• Inflammation acceleratescardiovascular disease
Inflammation acceleratescardiovascular diseaseLancet 2005; 365: 1415 - 28
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Mortality• <strong>Obesity</strong> decreases life expectancy by7 years at the age <strong>of</strong> 40 years• Curvilinear relationship betweenmortality & BMI• Increased morbidity due to chronicobesity related health conditions
MorbidityDisability-adjusted-life-years (DALY’s) in men and women lost due to obesityLancet 2005; vol 366; p 1199
<strong>Obesity</strong> &mortalityProspective study <strong>of</strong>457,785 men& 588,369 women;201,622 deaths occurredduring14 yrs <strong>of</strong> follow-upNEJM 1999; 341; 1097-1105
Effects <strong>of</strong> voluntary weight losson mortalitySwedish Obese Subjects Study;NEJM 2007; Vol 357; p 741 - 752NEJM 2007; Vol 357; p 753 - 761
Effect <strong>of</strong>fitness onmortality21,925 men who had abody-compositionassessment + treadmillexercise test;428 deaths occurredduring 8 yrs <strong>of</strong> follow-upAm J Clin Nutr 1999; 69; 373 – 380
Flight to Epenarra
Economic costs <strong>of</strong> obesity• Swedish <strong>Obesity</strong> Study;- obese subjects had 1.4 - 2.4 x the number<strong>of</strong> sick days c/w normal weight subjects- obese subjects were 1.5 - 2.8 x morelikely to be on a disability pension• Increased health care expendituresamong overweight & obese subjects• Inability <strong>of</strong> future healthcare systemsto cope with obesity related disease
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