Overweight and Obesity

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• health risks of obesity
• costs of obesity
• obesity discrimination

 

 

Introduction

Obesity is increasing around the world, and in many locations is replacing or adding to the devestation of malnutrition and infectious diseases.

 

Childhood obesity is defined as in the 95th percentile, or a BMI >30, while overweight is between 85-95 percentile. Worryingly, the proportion of children aged 6-11 who are overweight has doubled over the past 25 years, while the percentage of overweight adolescents has tripled.

 

In most of Canada, over 20% of the adult population is obese, while the prevalence of overweight is 59%. Arya Sharma, Alberta doc, says, based on Australian estimates, annual cost of obesity in Canada is $95 billion. The rate in aboriginal Canadians is 1.6x higher than the national average.

 

 

Depending on region, between 17.6-27.9% of Nova Scotians are obese.

According to Katzamarzyk and Ardern, over 9% of adult deaths in Canada can be attributed to overweight and obesity.

 

there is a term 'fatism' describing negative views of obese people by society, employers, and customers. It is more significant in women than men and can be powerful and devestating.

 

 

 

Measures of Obesity

 

Body Mass Index (BMI)

The BMI is useful for predicting future health risk.

underweight is less than 18.5

normal is 18.5 - 25

overweight is 25 - 30

obese is 30+

severe obesity

morbid obesity

 

It is calculated as weight over height squared, given in kg/m².

Make sure person is wearing no shoes, is standing tall (give their neck a tug upwards) and heels are against the wall. No tiptoes! Use a horizonal bar to measure.

BMI is the most common measure, and is correlated with body fat, but does not provide important information on fat distribution. People can jump to silly conclusions if they perform a BMI on athletes, pregnant women, or folks with ascites.

 

 

 

Waist Circumference (WC)

WC is increasingly recognized as a critical measure of health. It is highly correlated to BMI and total adiposity, but is also, importantly, correlated with intra-abdominal obesity and insulin resistance.

 

Men should be below 40 inches (102 cm), while women should be below 35 in (80-90 cm), depending on guidelines and ethnicity.

 

Measure WC at the top of the iliac crest, with the tape snug and parallel to the floor. Measure when the person has breathed out.

 

People of different ethnicities have different cutoff points. At a given WC, black women have less risk than white women, while Asian men have more risk than white men.

 

 

 

Children

In children, overweight and obesity are calculated on growth charts; overweight between 85-95th percentile; obesity is over 95th percentile

 

 

 

The Case of...

a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.

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Causes and Risk Factors

Obesity is caused by an energy intake greater than expenditure.

Secondary causes are rare, but include:

• Cushing's syndrome
• hypothyroidism
• Prader-Willi, Carpenter, Turner syndromes

 

eating a lot

not exercising enough

genes

SES

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The Costs of Obesity

 

Obesity can lead to increased short term disability claims, health care costs, and days off work.

“Obesity cost the Nation as much as $102 billion for direct costs alone in 1999”
• $6.7 - $7.4 billion for arthritis;
• $25.5 - $30.6 billion for heart disease;
• $18.4 - $20.5 billion for type 2 diabetes;
• $8.3 - $9.6 billion for hypertension; and
• $6.1 - $8.1 billion for stroke.

American Obesity Association/The Lewin Group. Costs of Obesity. September 13, 2000.

 

 

 

Pathophysiology

 

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Obesity and Pregnancy

In Canada, almost 25% of women of childbearing age are obese.

 

 

Signs and Symptoms

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Investigations

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Managing Patients with Obesity

Need a good understanding of mental, mechanical, metabolic, and monetary challenges patients face.

 

Measure and assess weight

Clincial exam: blood pressure, heart rate

Lab investgations: fasting glucose, lipid profile

Assess and screen for depression, eating disorders

Assess readiness to change

Come up with program to lose 5-10% of body weight, or 0.5-1 kg (1-2lb) per week for 6 months

Bring in the health care team

CBT

reduce calories by 500-1000 cal/daily

start exercise, with medical evaluation beforehand

 

Anti-obesity drugs are designed to:

• inhibit absorption
• reduce appetite
• increase satiety
• increase metabolic rate

 

include:

• sibutramine (Meridia) increases satiety and metabolic rate
  • blocks serotonin and NA reuptake
• oristat (xenical) a pancreatic lipase inhibitor, blocks maybe 30% in the SI
  • approved for long term use
  • can cause diarrhea
  • can decrease absorption of fat-soluble vitamins (do't mix drugs and supplements!)
• rimonabant - cannabionoid receptor blocker

 

 

bariatric surgery

Surgery is an option for adults when

• less invasive methods have failed
• BMI >40
• BMI >35 with co-morbid conditions

 

for children:

• documented failure of weight loss attempts
• completion of growth (Tanner 4-5; minimum age 13 female, 15 male; 95% of adult height)

restrictuve: assist in portion control and early satiety

adjustable gastric band (AGB)

• lower morbidity and mortality; adjustable; avg weight loss 25-35%

gastric sleeve resection

• significant weight loss; less complications than the RYGB
• mechanism of weight loss not understood

malabsorptive: biliary-pancreatic switch

 

Roux-en-Y gastric bypass (RYGB)

• restrictive - malabsorption
• more rapid and greater wright loss
• permanent
• mortality 0.5%
• anastamotic leaks
• nutritional complications (Fe, Ca, vit B and D)

 

it can

• cure or dramatically improve type II diabetes in the vast majority of people (MacDonald KG, et al. J Gastrointest Surg. 1997;1:213-220)
• decrease 5 year risk of death by 89% (Christou NV, et al. Ann Surg. 2004;240:416-424)
• reduce health care costs

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Consequences and Course

Life expectancy drops with obesity. The link between obesity and coronary artery disease is not straightforward, though it appears diabetes and hypertension are critical linkages.

 

cardiovascular

• coronary heart disease
• dyslipidemia
• hypertension
• stroke

insulin resistance and type II diabetes

 

pulmonary disease

• abnormal breathing
• obstructive sleep apnea
• hypoventilation syndrome

cancer

• breast
• uterus
• cervix
• colon
• esophagus
• pancreas
• kidney
• prostate

Other increased infammatory markers effects

• early maturation
• orthopedic issues
• severe pancreatitis
• phlebitis
• fatty liver disease, steatohepatitis, cirrhosis
• gall bladder disease
• reproductive problems
  • abnormal menstrual cycle
  • infertility
  • polycystic ovarian syndrome
• osteoarthritis
• low back pain
• gout
• psychological imapirment
• social and economic consequences

overweight children

70% become overweight or obsese as adults

80% if one or more parents is overweight

increased cardiovascular risk

social consequence: fewer married, lower jobs

 

• hypertension, dyslipidemia, SCFE, T2DM, asthma, OSA
• decreased self-esteem, unhealthy coping, depression

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Resources and References

 

Ogden et al, 2008. JAMA (pediatric obesity)

Katzmarzyk & Ardern. Can J Public Health 2004;95:16-20.

Story MT, Neumark-Stzainer DR, et al. 2002. Pediatrics

 

Fontaine et al. 2003. JAMA - years of life lost due to obseity

 

Harris CMAJ 2009 - school-based activities don't work for weight loss

 

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Topic Development

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