The role Obesity and Physical activity Increases Cancer Risk

Question 1

What are High risk cancers associated with obesity?

Answer 1

1. Endometrial (lining of the uterus)
2. Esophageal (due to acid reflux)

Question 2

What is endometrial cancer strong relationship between obesity?

Answer 2

Strongest relationship with increasing BMI. Each 5kg/m2 increase of BMI increases cancer risk of 60%

Question 3

What is endometrial cancer independent to?

Answer 3

Independent of menopausal status

Question 4

Why is esophageal cancer increasing in North America at a high rate?

Answer 4

More number of obese people who experience higher rate of acid reflux

Question 5

What relationship does esophageal cancer have with obesity and mortality?

Answer 5

Does-effect relationship. The more people who are obese, more likely to die from cancer

Question 6

How does obesity relate to breast cancer?

Answer 6

• Obesity is a major risk factor for postmenopausal breast cancer
• Higher risk of reoccurrence
• Poorer overall survival (55% 5-year survival if obese vs 80% if lean)

Question 7

What is protective when of the breast cancer risk when obese?

Answer 7

Obese Women when they are Premenopausal

Question 8

What increases risk of breast cancer in obese women?

Answer 8

Obese women who are postmenopausal

Question 9

What is Colorectal linked to?

Answer 9

Early stage tumourigenesis, may or may not turn into cancer

Question 10

How is obesity related to colorectal cancer?

Answer 10

May be interaction with physical activity, people with highest BMIs and lowest PA are at the greatest risk of colorectal cancer

Question 11

What other factors independently increase risk of Renal-Cell cancer?

Answer 11

Diabetes and Hypertension

Question 12

What type of relationship does renal-cell cancer have with mortality?

Answer 12

Dose-effect - the bigger the BMI the more likely to die from renal-cell cancer

Question 13

What is the research and info behind prostate cancer and obesity?

Answer 13

Currently limited information/research.
- Obesity protective for low grade PC and increased risk for high grade PC

Question 14

What are pathophysiological mechanisms related to obesity and cancer risk?

Answer 14

Best understood in endocrine cancers
- Hyperinsulinemia/IGF-1
- Endogenous sex steroids
- Inflammation and oxidative stress

Question 15

What is Hyperinsulinemia/Insulin-like Growth Factor-1?

Answer 15

Linked to insulin resistance, present when Muscle/liver tissues have a reduced response to insulin and Overcompensation of the pancreatic insulin occurs

Question 16

What cancers is chronic hyperinsulinemia & IGF-1 linked to?

Answer 16

• Colon
• Endometrium
• Pancreas
• Breast

Question 17

What does Hyperinsulinemia and IGF-1 promote?

Answer 17

Tumour development and inhibit apoptosis

Question 18

What do Endogenous Sex Steroids do?

Answer 18

• Stimulate cell proliferation
• Inhibit apoptosis
• Increase risk of tumour development

Question 19

How is TGF-1 and Insulin related to sex steroids?

Answer 19

• They stimulate synthesis of sex steroids
• Inhibit synthesis of sex hormone-binding globulin (gets “rid of” sex steroids)

Question 20

What sex steroid does body fat primarily produce?

Answer 20

Body fat is a primary producer of estrogen (a sex steroid) in postmenopausal women

Question 21

How does obesity increase endogenous sex steroids?

Answer 21

• Increased production of androgens, causing less ovulation, lower progesterone
• This increases risk of endometrial cancer

Question 22

Is obesity related to inflammation?

Answer 22

Yes, associated with chronic inflammation

Question 23

What causes inflammation?

Answer 23

High production of certain cytokines

Question 24

Why can inflammation increase risk of cancer?

Answer 24

Overproduction of cytokines can increase tumour initiation, growth and progression

Question 25

When is physical activity associated with cancer risk?

Answer 25

- Caloric Intake - Free Radicals - Trauma - Pulmonary Function - Immune Function

Question 26

How is Caloric Intake a risk factor due to physical activity and enhancing cancer?

Answer 26

Very Active people eat more food where they can be exposed to more carcinogens and toxins. Not normally an issue for moderately active people

Question 27

Is food restriction harmful for increasing risk of cancer?

Answer 27

No, food restriction reduces risk of cancer due to the physiologic state of body shifting from cellular proliferation to maintenance

Question 28

How is High Protein intake a risk factor due to physical activity enhancing cancer?

Answer 28

Competitors in some sports consume a high quantity of animal protein, this is associated with increase cancer risk

Question 29

Are vegetarians less likely to develop cancer?

Answer 29

60% less risk of cancer compared to meat eaters

Question 30

What do Free Radicals do?

Answer 30

They cause cellular damage

Question 31

Why are free radicals related to physical activity and cancer risk?

Answer 31

Vigorous physical activity associated with increased free radicals causing excess damage to cells

Question 32

How can trauma due to physical activity increase cancer risk?

Answer 32

Vigorous physical activity can: - Increase risk of injury - Cause more cell division All increases risk of cancer

Question 33

Is trauma and physical activity increasing cancer risk conclusive?

Answer 33

No, not enough research. Trauma can increase some kinds of cancer

Question 34

Example of Physical activity trauma increasing cancer risk?

Answer 34

Sitting on a bike for long periods of time cause trauma to the testicular region increasing risk of testicular/prostate cancer

Question 35

Is trauma a problem for cancer risk in moderately active people?

Answer 35

No. More harmful for vigorous exercisers

Question 36

How is pulmonary function increase cancer risk during physical activity?

Answer 36

Competitors in some endurance sports have larger lung space, increasing cancer risk: - More epithelial cells, more space for tumour growth - Altered pattern of air flow (particles get into lungs easier)

Question 37

Is pulmonary function harmful for moderate exercisers?

Answer 37

No

Question 38

Is physical activity harmful to the immune function?

Answer 38

Yes

Question 39

What can happen to extreme exercisers immune function?

Answer 39

Can develop the same kind of immunedepression as patients with HIV infection

Question 40

Who develops immunedepression?

Answer 40

Vigorous exercisers who participate in high levels of physical activity Not harmful for moderate exercisers