Why Nuns are more likely to get breast cancer...

Back in 1842, it was found that nuns were more likely to get breast cancer than other populations of women.

Today, Doctors now have an understanding as to why this is the case.

I recently went to the Europa Donna UK, Breast Cancer Symposium, titled:

 Breast Cancer: Risk Factors, Prevention, Lifestyle.

Picture from Source.

It was fascinating.

Professor Cuzick who has been analyzing the risk factors associated with breast cancer for years, and says that Breast Cancer is the cancer epidemic of this century.  It is the cancer on the biggest increase and it's doing so pretty rapidly.

But Why?

Professor Cuzick outlined the following risk factors for increasing a persons Relative Risk of getting breast cancer.

Family History:

The more people affected by breast cancer in your family, and the more closely that they are related to you, the higher your risk of breast cancer. If 1 person related to you in the first degree (ie your parent, sibling or child) gets breast cancer your risk of getting it is 1,8 times higher than if they didn't. 2 relatives in first degree, you are twice as likely to get it, 3 relatives, three times as likely and so on.

The younger the affected person is, the higher your risk is.  Especially if your family member was diagnosed with cancer before they were 40 years old.  

Having a Baby.

You are less likely to get breast cancer if you have had a baby, this is where the Nuns are at higher risk.

The number of Children that you have and if you Breast Feed:

Every baby that you have, reduces your relative risk of getting breast cancer by 7%, and the longer that you breast feed, the lower risk your becomes by 4,3% per year.

Age that you first give birth:

The younger you are when you have your first child, the more you reduce your relative risk of getting breast cancer.  A women who has their first baby at age 20, is 30% less likely to get breast cancer than someone who has their first baby at age 30.

Age you got your first period:

The younger you are when you first menstruated, the higher your risk of breast cancer is, by 4 % per year.

Your age at Menopause:

Ladies who experience menopause later are at a higher risk of 3% per year, with a lady who reaches menopause at age 55 years having a 30% more likely relative risk of breast cancer than a lady who is already menopausal at 45 years.

Oral Contraceptive:

Relative risk of getting breast cancer increases by 24% if you are currently taking the pill, this risk is eliminated a year after discontinuing the pill.

Hormone Replacement Therapy:

Relative risk increases by 2,3% in oestrogen only, and increases to 5% in combined oestrogen and progesterone users.  This risk returns to baseline levels a year after discontinuing it.

Weight:

Being obese increases your risk of breast cancer significantly.  every kilogram that you are overweight increases your risk by 1%.

Height:

The taller you are the higher your risk of getting breast cancer, with a 1% increase in risk for every 1cm.  The reason for this is unknown, but perhaps to do with increased levels of growth hormones.

Alcohol:

Excess alcohol consumption increases your chances of breast cancer, but a moderate amount of alcohol has been shown to be preventative against cancer.  A bottle of wine per week is considered optimum for cancer prevention. 

The Developing World:

Women in the developing world are more likely to be younger when they have their first child, generally breast feed for longer and usually have more children than us living in first world countries.  They are thus less likely to develop breast cancer than we are, for the reasons above.

As I look over this list my heart sinks a little...

I'm nearly 30 and I haven't had a child yet, I'm unlikely to have lots of children and I'm on the pill.

Oh dear.

Good thing I'm not the tallest.

Best I keep my weight down and consume a bottle of wine a week then.

More about the weight loss stuff from this talk soon... 

Ps Read here for a more detailed account of these risk factors by Professor Cuzick.