• What is breast cancer?
  • Being breast aware
  • Diagnosis & treatment
  • Breast cancer: the facts
  • Risk factors
  • Breast cancer screening
  • Breast Cancer Quiz
  • Breast Cancer Quiz Scores

Breast cancer risk factors

Anything which influences a person’s risk of developing breast cancer over their life time is called a risk factor. Breast cancer is a very complex disease caused by interactions between genes, environment and lifestyle. Although there have been great advances in our knowledge of the risk factors involved in breast cancer, it is not yet fully understood what causes the disease or how it could be prevented.

Having one or more risk factors does not necessarily mean you will develop breast cancer. Additionally some risk factors are out of an individual’s control, for example being a woman and growing older. Others are life style choices and an informed decision should be made by the individual by comparing the risks against the benefits to their lifestyle.

Click on the links below to find out more about risk factors for developing breast cancer:

Gender
Age
Lifetime risk
Family history
Hormones
Benign breast disease
Previous breast cancer diagnosis
Exposure to radiation
Height
Lifestyle
Breast feeding
Other possible risks

Gender

Women are the most likely to develop breast cancer. Men can develop breast cancer but it is rare.

Age

The strongest risk factor is age. The older the woman is the higher the risk (table 1)

Table 1 - Estimated risk of developing breast cancer by age group (NHS Cancer Screening Programmes 2002)

Lifetime risk

This statistic can be confusing; it means one woman in nine will develop breast cancer over the course of her life time, and only becomes applicable after the age of 85, when her total life time risk can be calculated. A woman’s actual risk particularly at a younger age is much lower.

Family history

Around five to ten per cent of breast cancers are due to inherited faulty genes for example BRCA1 or BRAC2

A significant family history generally means on one side of their family (mother or father):

• Two close family members for example mother, daughter, sister, grandmother, aunt diagnosed with breast cancer under the age of 50

• Three close family members under 60

• Four close family members of any age

• Family member(s) with breast cancer in both breasts

Hormones

The life time exposure to the female hormone oestrogen which is found naturally in the body plays an important role in the development of breast cancer.

• Menstrual periods
  Women who start menstruating at an early age (before the age 12) or who went through menopause at a late age (after the age 55) have a slightly higher risk of breast cancer.

• Reproductive history

  Women who have children after the age of 30 or who have no children at all have an increased risk of breast cancer. The risk of having breast cancer is reduced by having children at a younger age. The more children a woman has, the lower the risk.

• Oral contraceptives

  Current or recent use of oral contraceptive slightly increases the risk of breast cancer. Once a woman stops taking the pill, the risk begins to diminish and after ten years will be back to normal.

• Hormone Replacement Therapy (HRT)
  This treatment slightly increases the chance of developing breast cancer. The longer HRT is used, the higher the risk of breast cancer. However, the risk begins to decline when HRT is stopped and by five years reaches the same level as in women who have never taken HRT.

Benign breast disease

Women who have had a type of benign breast disease, (non-cancerous breast disorders), known as proliferative breast disease, are at increased risk of developing breast cancer

Previous breast cancer diagnosis

If a woman has previously been diagnosed with breast cancer her risk of developing a second primary breast cancer (a new cancer unrelated to the first) is greater than the general population developing a first primary breast cancer.

Exposure to radiation

Exposure to large amounts of radiation, for example therapeutic radiotherapy for Hodgkin’s Lymphoma, increases the risk of breast cancer. The younger the individual is when treated, and the higher the radiation exposure, the greater the risk of breast cancer at a later age.

If you are concerned about earlier treatment for Hodgkins Lymphoma, visit www.lymphoma.org.uk or call the Lymphoma Association on 0808 808555

Height

Being tall (over 5’9) may increase your risk of breast cancer. Although it is not yet fully understood why, height is influenced by your genetic make up. Nutrition and hormone levels may also affect breast cancer risk and are still being investigated.

Lifestyle

• Weight
  Being overweight after the menopause is linked with an increased risk of breast cancer. Maintaining a healthy weight throughout life will reduce the risk of many health problems including an increased risk of heart disease, high blood pressure, diabetes, arthritis and other types of cancer.

• Lack of exercise
  Regular physical exercise has been shown to reduce the risk of breast cancer.

• Diet
  Generally a diet rich in fruit and vegetables, high in fibre and low in red meat, processed foods and sugar will contribute to a protective effect against lots of diseases. This includes breast cancer. Campaign  is currently joint funding two research projects with the World Cancer Research Fund into the effects of nutrition on breast cancer risk.

• Alcohol
  Regular alcohol consumption slightly increases the risk of breast cancer, the more alcohol consumed the greater the risk. It is estimated that alcohol causes an extra one woman in 100 who drinks one unit a day to get breast cancer in her life time.

Breast feeding

Breastfeeding for more than one year reduces a woman's risk of developing breast cancer.  The amount of time can be cumulative.  For example, two children breast fed for six months each or one child for one year.

Other possible risks

Other risk factors which are currently being investigated and have been highlighted in the media, but for which there is no conclusive scientific evidence, include: IVF treatment, abortion, stress, shift work and deodorants.

Currently scientific evidence suggests: smoking, breast implants, under wired bras and bumping or bruising of the breast are not implicated with breast cancer risk.