Exam 3 - Obesity I

Question 1

Describe the term PREVALENCE in relation to obesity

Answer 1

• The total number of existing cases of a disease/condition in a given population at a designated time
• Eg: amount of people in a room having their period right now

Question 2

Describe the term ODDS RATIO in relation to obesity

Answer 2

• A way of comparing whether the probability of a certain even is the same for two groups
• Odds ratio = 1 - implies the event is equally likely in both groups
• Odds ratio > 1 - implies the event is more likely in the first group

Question 3

Describe the rise of obesity rates in US

Answer 3

• 1980 - no state had adult obesity rate > 15%
• 1991 - no state had adult obesity rate > 20%
• 2010 - no state had adult obesity rate < 20%
• 2015 - 22 states have rates >30%; 4 states > 45%

Question 4

Which age group has the most obesity in US?

Answer 4

40-59; more women than men

Question 5

Who is the most likely to have extreme obesity (BMI>40) in US men?

Answer 5

Does not differ by age, race, smoking status or education

** Does differ by age and race in women; not by smoking or education
•• More women than men BMI>40

Question 6

What percent of children are obese according to 2015-2016 NHANES data? How has this changed in recent years?

Answer 6

18.5% obese (BMI>95th %ile)

It hasn’t changed; BUT significant increase in extreme obesity (BMI>120%)

Question 7

Describe body fat percent

Answer 7

The amount of adipose tissue in your body as a percentage of total body weight

Question 8

Describe ESSENTIAL FAT. What is its purpose? Where is it? How much do men and women have?

Answer 8

Needed for normal physiologic functioning

• Stored in small amounts in bone marrow, heart, lung, liver, spleen, etc
• Men - 3% total body fat is essential
• Women - 12% (bc includes fat in breasts, pelvis, and thighs that support repro process)

Question 9

Give the body fat percentages for men and women in the RISKY (HIGH BODY FAT) body fat rating

Answer 9

Men: >30%
Women: >40%

Question 10

Give the body fat percentages for men and women in the EXCESS FAT body fat rating

Answer 10

Men: 21-30%
Women: 31-40%

Question 11

Give the body fat percentages for men and women in the MODERATELY LEAN body fat rating

Answer 11

Men: 13-20%
Women: 23-30%

Question 12

Give the body fat percentages for men and women in the LEAN body fat rating

Answer 12

Men: 9-12%
Women: 19-22%

Question 13

Give the body fat percentages for men and women in the ULTRA LEAN body fat rating

Answer 13

Men: 5-8%
Women: 15-18%

Question 14

Give the body fat percentages for men and women in the RISKY (LOW BODY FAT) body fat rating

Answer 14

Men: <5%
Women: <15%

Question 15

BMI for Underweight category

Answer 15

<18.5

Question 16

BMI for Normal category

Answer 16

18.5-24.9

Question 17

BMI for OVERWEIGHT category. How does a normal vs large WC affect disease risk in this?

Answer 17

Overweight: 25.0-29.9
•Normal (Men <40”; Women<35”): Increased
• Large (Men >40”; Women>35”): High

Question 18

BMI for OBESE I category. How does a normal vs large WC affect disease risk in this?

Answer 18

Obese I: 30.0-34.9
• Normal (Men <40”; Women<35”): High
• Large (Men >40”; Women>35”): Very high

Question 19

BMI for OBESE II category. How does a normal vs large WC affect disease risk in this?

Answer 19

Obese II: 35.0-39.9
• Normal (Men <40”; Women<35”): Very high
• Large (Men >40”; Women>35”): Very high

Question 20

BMI for EXTREMELY OBESE category. How does a normal vs large WC affect disease risk in this?

Answer 20

Extremely obese: >40
• Normal (Men <40”; Women<35”): Extremely high
• Large (Men >40”; Women>35”): Extremely ery high

Question 21

Describe some limitations of BMI

Answer 21

• Very muscular people may fall into “overweight” category
• People who lost muscle mass (like elderly) may be in “healthy weight” category
• May not detect edema
• Assumes adipose tissue is distributed evenly over body (apple vs pear)

*Useful as general guideline, not as diagnostic of person’s health

Question 22

Describe CT imaging in measuring body fat distribution

Answer 22

Can be used to identify lean mass and visceral adipose tissue
•Shows cross-sectional slices distinguishing bone, muscle, and adipose tissue and calculate the cross-sectional areas

Question 23

Describe MRI imaging in measuring body fat distribution

Answer 23

• No exposure to radiation
• More $$, but give cleaner, 3D diagnosis
• Can discern between visceral and subcutaneous fat

Question 24

Describe DXA imaging in measuring body fat distribution

Answer 24

• Does not discriminate well btwn visceral and subcutaneous fat, but can esimate

Question 25

Describe Waist:Hip ratio. What are the cut points and what do they signify?

Answer 25

Increased abdominal WC related to hip girth shown to be predictive of >CHD and T2DM
• Men: 0.90-0.95
• Women: 0.80-0.85
• Elevated WHR represent elevated risk for disease development

Question 26

Give the pros and cons of using waist circumference. Give the cut points.

Answer 26

PRO - only one measurement (less error than WHR)

CON
• May avoid population specific trends in hip size, unrelated to visceral fat amount
•More dependent on total adiposity than WHR

• Central obesity: >35” women; >40” men
• No J-shaped curve like in BMI

Question 27

Which measurement identifies CVD risk best? T2DM? HTN? CVD?

Answer 27

• WC and WHR - CVD risks better than BMI

* WHR - T2DM, HTN, and CVD better than WC

Question 28

Describe metabolically obese normal-weight (MONW)

Answer 28

Have normal BMI but suffer from complications assoc with obesity (often identified if someone gains weight but is still in “normal” BMI)

Question 29

Describe metabolically healthy obese (MHO)

Answer 29

Have BMI>30 but no complications associated with obesity

• characterized by high generation of new adipocytes and low hypertrophy

Question 30

What is a key factor in differing between MONW and MHO?

Answer 30

The amount of VAT

•Most MONW with low BMI have significant excess VAT; most MHO with high BMI have less VAT

Question 31

Describe Hypertrglyceridemic waist. What is the risks associated with it and cut-off points?

Answer 31

Simple clinical phenotype predictive of excess VAT
• Men with low WC and Tg were at less risk of being VAT obese, while 80% of those with hypertriglyceridemic waist had high VAT
• Cut-off: WC of 90cm in men; 85cm women; 1.5mM/L for TG in men

Question 32

List some obesogenic factors

Answer 32

• Healthy food availability
• Screen time
• Food choices
• Doing other things while eating
• Portion sizes
• Less exercise