Factors such as physical activity, breastfeeding, alcohol and others can affect our risk of developing breast cancer.
Our lifestyle choices and the way we lead our day-to-day lives can affect our risk of developing breast cancer. For more information on any of the below factors, download our pdf booklet Breast cancer risk: the facts.
The following factors can reduce the risk of breast cancer developing:
Regular physical activity will help to reduce your risk of breast cancer, particularly after the menopause. Physical activity includes structured exercise and other moderate physical activity, such as walking, housework, cycling at a casual pace, actively playing with children and gardening. If you want to reduce your risk of breast cancer, we recommend you are regularly physically active. Find out more about physical activity and reducing your breast cancer risk.
Download our factsheet: Physical activity and breast cancer risk.
Breastfeeding your children slightly reduces your risk of breast cancer. The longer you breastfeed in total, the more your risk of breast cancer is reduced. For example, breastfeeding one child for one year would lower your risk of breast cancer as much as breastfeeding two children for six months each.
Breastfeeding may reduce breast cancer risk by altering the balance of hormones in the body and by delaying the return of a woman’s periods. There are many important benefits associated with breastfeeding for both mother and child, but the decision to breastfeed needs to be a personal one. While many women breastfeed, not all women choose to and others find it difficult or are unable to for a number of reasons.
National health guidelines recommend that women breastfeed exclusively for the first six months of an infant’s life as it provides all the nutrients a baby needs. After that, giving your baby breast milk alongside other food will help them continue to grow and develop healthily.
If you are breastfeeding, you should examine your breasts for any unusual changes. It is common for breasts to be lumpy during breastfeeding, but if you notice anything unusual or have any concerns, talk to your doctor.
Read our blog, 'Does breastfeeding affect your risk of breast cancer?'
The following factors increase the risk of breast cancer developing:
Regularly drinking alcohol increases your risk of developing breast cancer. The more drinks that you have each day, the greater your risk of breast cancer will be. If you want to reduce your risk of breast cancer, we recommend you limit the amount of alcohol you regularly drink throughout your life. Learn more about alcohol and breast cancer risk.
Download our factsheet: Alcohol and breast cancer risk.
Hormone replacement therapy (HRT)
Taking hormone replacement therapy (HRT) to treat menopausal symptoms increases your risk of breast cancer; this risk increases the longer you use HRT. The risk is greater with combined HRT (oestrogen and progesterone) than with oestrogen-only HRT. A steroid-based HRT called tibolone (also known as Livial) may also increase the risk of breast cancer.
The good news is that the increase in breast cancer risk begins to fall as soon as you stop taking HRT, no matter how many years you’ve taken it. Within five years of stopping HRT, your risk of developing breast cancer is about the same as if you had never taken it.
There are other ways you may be able to reduce menopausal symptoms other than by taking HRT. Some people find being physically active and cutting out caffeine and nicotine can help. If you are considering taking, or stopping taking, HRT you should speak to your doctor. Your decision should take into account the impact of menopausal symptoms on your life, your medical history, the pros and cons of HRT and your own preferences.
Experts recommend using the lowest effective dose of HRT necessary to relieve menopausal symptoms and for the shortest possible time. If you are taking HRT, you should review your therapy and general health with your doctor at least once a year.
You can find more information in our factsheet: HRT and breast cancer risk.
For more information on the recent research results from the Breast Cancer Now Generation study about combined HRT use and breast cancer risk please read our blog.
Taking the pill (combined contraceptive pill) slightly increases your risk of breast cancer. Ten years after stopping the pill this increased risk will have disappeared and your chance of developing breast cancer will be about the same as that of a woman who has never taken the pill.
It is important to keep in mind that breast cancer is rare in women under the age of 40, regardless of whether or not they use the pill.
Over the past 30 years, the levels of the female hormone oestrogen in the combined pill have decreased. It is not yet clear whether the modern, low doses in the combined pill are associated with the same breast cancer risk as the older, higher dose pills.
While the combined pill is the most commonly used contraceptive pill, some women use the progestogen-only pill (or ‘mini-pill’). Further research is needed before we can be sure Increases your risk 30 of the level of risk associated with taking this type of pill. There is currently not enough evidence to determine whether or not there is a link between other forms of hormone-based contraception and breast cancer, such as contraceptive implants and the hormonecontaining coil (levonorgestrel intrauterine system [IUS]).
You should speak to your doctor if you are thinking of taking, or stopping taking, the pill. The decision to use the pill needs to be an informed choice, made by you, with the help of your doctor or family planning clinic. This decision should take into account the pros and cons of taking the pill, medical history, lifestyle, individual preferences and alternative methods of contraception.
Download our factsheet: The pill and breast cancer risk.
Having children has a complex effect on breast cancer risk. Overall, in the long term, pregnancy reduces the risk of breast cancer.
Having children affects breast cancer risk in different ways:
- Women who have had children are at lower risk of breast cancer in the long term than women who have not had children. The more children you have, the greater the decrease in risk.
- The age at which you have children affects your risk of developing breast cancer. The earlier a woman begins her family, the lower her risk of breast cancer.
- In the short term, research studies suggest that your risk of breast cancer slightly increases after you give birth, regardless of your age. We don’t know the reasons for this, but it may be caused by hormone changes. This increase in risk is temporary, lasting a number of years, and it is important to remember that breast cancer is rare in women under 50.
There are three known links between weight and breast cancer:
- Putting on weight in adulthood (after the age of 18) increases your risk of developing breast cancer after the menopause.
- Being overweight or obese before the menopause slightly reduces your risk of developing breast cancer before the menopause.
- Being overweight or obese after the menopause increases your risk of breast cancer.
Download our factsheet: Weight and breast cancer risk.
For the following factors, there is some scientific evidence that suggests they may affect the chances of developing breast cancer
More research is needed before we can be sure whether or not they are definitely linked to the disease.
Maintaining a healthy diet might help to reduce your risk of breast cancer, as well as other cancers. However, we still aren’t sure whether any specific dietary factors influence the chance of developing the disease.
It is unlikely that phyto-oestrogens (found in soya and some other foods) increase your risk of developing breast cancer.
For more information on how to maintain a healthy, balanced diet, you may wish to speak to your doctor or visit the NHS Choices website.
Aspirin and ibuprofen
Taking aspirin or ibuprofen might slightly reduce the risk of breast cancer, but we don’t recommend that women take these drugs solely to lower their risk of breast cancer.
Aspirin and ibuprofen are types of non-steroidal antiinflammatory drugs (NSAIDs). Taking these drugs might slightly reduce the risk of breast cancer, but not all studies agree. In addition, we do not know how different doses of these drugs affect breast cancer risk or for how long they would need to be taken to have an effect.
NSAIDs, including aspirin and ibuprofen, can have serious side effects when taken over a long period, including stomach ulcers, anaemia and, less commonly, heart problems. It is important that women who want to take these drugs regularly for any reason consult their doctor first.
Because we don’t know enough about how these drugs affect breast cancer risk, Breast Cancer Now does not recommend that women regularly take them in order to lower their risk of breast cancer.
In vitro fertilisation treatment (IVF)
It is unclear whether IVF treatment affects the risk of breast cancer because only a very small number of studies have looked into this. IVF treatment increases the levels of female hormones such as oestrogen in the body, which is why some people speculate it may increase the risk of breast cancer.
One study suggests that, overall, women who have received IVF treatment are no more likely to develop breast cancer than women who have not had IVF. Although women undergoing IVF may have a slightly higher risk of breast cancer in the first year after treatment, this risk disappears in the following years.
It may be that having IVF over the age of 30 or 40 slightly increases your risk of breast cancer, but until more research is available we will not know whether or not this is the case. IVF is a relatively new procedure and we don’t know its long-term health effects.
If you are worried about IVF treatment and breast cancer risk you should discuss your concerns with your doctor or fertility specialist.
Smoking may increase your risk of developing breast cancer but there is not enough evidence for us to be sure. Recently, some studies have shown that smoking increases the risk of breast cancer; however, some older studies did not find a link.
Regardless of any potential breast cancer risk, smoking is a major cause of lung cancer and other cancers, as well as heart disease – all women and men are strongly advised not to smoke by health professionals, the government and health charities.
For information and advice on stopping smoking, contact your doctor or visit the NHS Choices website.
What should I do if I am worried about the risk factors mentioned here?
If you are worried about any of the breast cancer risk factors mentioned here you should discuss your concerns with your doctor.
Where can I get more information?
Breast Cancer Now has developed several free fact sheets that look in more detail at the effect of some factors on breast cancer risk. For an up-to-date list of the fact sheets available to download or order printed copies visit our breast cancer resources.
Information last reviewed: July 2015
Next review due: July 2018
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