Overweight and Obesity
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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 (88-90 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.
Causes and Risk Factors
Obesity is caused by an energy intake greater than expenditure.
It is important to consider, and screen for, other conditions, such as:
- eating disorders
- depression
- anxiety
- diabetes (co-morbidity)
- hypertension (co-morbidity)
- hypercholesterolemia (co-morbidity)
Secondary causes are rare, but include:
- Cushing's syndrome
- hypothyroidism
- Prader-Willi, Carpenter, Turner syndromes
- medications: antipsychotics, antidepressants, steroids, antiepileptics
- hypothalamic injury
Primary causes include:
- increased caloric intake
- decreased level of physical activity
- sedentary lifestyle
- technology
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
Obesity and Pregnancy
In Canada, almost 25% of women of childbearing age are obese.
Signs and Symptoms
- history
- physical exam
History
Assess readiness to change
Assess and screen for depression, eating disorders
The motivational interviewing approach will be used here, though there are many other paradigms that can be adopted and adapted.
Risk factors that may pose a challenge include:
- low education
- low SES
rural vs urban - media
- culture
- family history
- occupation
Pediatric obesity
Ask parents:
- "are you concerned that he/she is heavy for their height?"
- how much screen time do they have? - tv, video games, computer...
- look into dietary habits, ie portions - don't look into dieting in kids.
Health Canada recommends children have 90 minutes of moderate or vigorous activity daily.
For kids who are getting less activity, or who are overweight,
sometimes parents need permission to impose limits
Physical Exam
BMI 85-95% - at risk of overweight
BMI above 95% - overweight (obese in the US)
Raise BMI concerns gently with parents
Clincial exam: blood pressure, heart rate
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
fasting glucose, lipid profile
Diagnostic Imaging
Managing Patients with Obesity
Need a good understanding of mental, mechanical, metabolic, and monetary challenges patients face.
- goals and motivation
- diet
- physical activity
- medications
- surgery
Goals and Motivation
It is vital that the patient be fully involved in goal-setting.
Numerically, it is reasonable to aim for decreases of 5-10%, or 0.5-1kg/week, for six months.
Bring in the health care team
CBT
Ongoing Progress
Ongoing self-awareness is important. This includes regular weigh-ins, documentation of successes and failures.
Addressing anxiety and depression should occur.
Diet
It is helpful to work with a dietitian in setting nutritional goals. Some helpful strategies include:
- decreased fat content, sugar, and alcohol
- increased fibre
- increased water consumption
- regular meals, including breakfast
- decreased fast food
- reduce calories by 500-1000 Cal/daily, or 300-500 Cal/day if overweight
Physical Activity
Regular exercise is important, to increase basal metabolism and calorie expendature.
After physical exam to ensure no cardiac risk factors are present, begin with 30 minutes of moderate activity, 3-5 days/week, and increase this to 60 minutes daily, most days.
Medications
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
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)
restrictive: 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
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.
The Edmonton Obesity Staging System appears to be one of the most effective means of predicting mortality (Padwal et al, 2011).
cardiovascular
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respiratory
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cancer
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endocrine/gastrointestinal
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musculoskeletal
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reproductive
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mental health/social
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Resources and References
Padwal et al. 2011. Using the Edmonton obesity staging system to predict mortality in a population-representative cohort of people with overweight and obesity. CMAJ. 183(14).
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
Topic Development
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