Research studies around the world have shown a link between weight and the risk for breast cancer after menopause. Maintaining a healthy weight throughout your life will help reduce your risk.

The research:

Fat cells produce estrogen and other hormones that cause your cells to divide. For people with higher weights, the body produces more of these hormones than needed. This increases the chance that cells in the breasts will become cancer cells.

Your risk of breast cancer increases with weight. Factors that increase your risk include:

• a Body Mass Index (BMI) of 25 or more
• a high percentage of body fat
• carrying excess weight around your waist and abdomen, rather than on your hips and thighs
• weight gain later in life.
  

The research shows quite clearly that after menopause, people with higher weights have a higher risk of breast cancer. It is true that before menopause, excess weight appears to protect against breast cancer. However, because extra weight increases your risk of many other diseases, it's always better to maintain a healthy weight throughout your life.

What you can do:

Healthy bodies come in different shapes, sizes and weights, and a healthy weight is different for everyone. Be kind to yourself and recognize that many factors can affect your weight, including genetics, income, education, social support, where you live and work, and experiences of weight bias. It’s important to remember that weight is only one indicator of health risk. Healthy habits can benefit your well-being at any size.

You can use a Body Mass Index (BMI) calculator to find out whether your weight falls within the healthy range for your height. A BMI of between 18.5 and 24.9 is generally considered to be a healthy weight range.

Eating a variety of healthy foods and regular physical activity are the best ways to manage your weight. There are many resources available online that offer information and support to help you achieve and maintain a healthy body weight. You can also ask for advice from your health care provider.

Learn more:

BC Cancer Prevention – Nutrition and Exercise 
Health Link BC –Food & Nutrition

Canadian Cancer Society

Physical activity is good for your entire body, including your breasts. Physical activity protects you against developing breast cancer, no matter how old you are. Even if you have never exercised before, it's never too late to start.

The research:

Regular physical activity helps to keep hormones in your body at healthy levels. This is important because when you produce high levels of hormones such as estrogen, your risk of breast cancer can increase.

Research has shown that regular exercise reduces the risk of breast cancer. This is especially true during adolescence, as well as after menopause. By promoting physical activity, it's possible to prevent more than 7,800 breast cancer cases by 2042.

When it comes to reducing your risk of breast cancer through physical activity, studies suggest some may benefit more, including those who:

• have previously given birth
• have a healthy body weight
• have no family history of breast cancer.
  

What you can do:

It is important to maintain regular physical activity throughout your life. Most experts agree that to effectively reduce your risk of breast cancer, you need to engage in moderate activity most days of the week. Vigorous activity is even better for your breast health.

Learn more:

BC Cancer Prevention – Nutrition & Exercise
Health Link BC – Physical Activity

Canadian Cancer Society 

When it comes to reducing your risk of breast cancer, less alcohol is better, and no alcohol is best. Drinking alcohol increases your risk of developing breast cancer, as well as other types of cancer such as colon, mouth and throat. 

The research:

Drinking alcohol is a risk factor for many diseases, including breast cancer. While we still don't know exactly how alcohol leads to cancer, it is thought that alcohol damages DNA in cells. DNA damage increases the risk of cancer.

There is a large amount of research showing that alcohol increases risk for breast cancer before and after menopause. Studies also suggest that the more you drink, the greater your risk. Those who drink at high-risk levels (more than three standard drinks a week) and who take hormone therapy for menopause symptoms are especially at risk for breast cancer.

When it comes to breast cancer, no amount of alcohol has been found to be "risk-free."

What you can do:

 If you do drink alcohol, consider reducing the amount you drink. According to Canada's Guidance on Alcohol and Health, there is a continuum of risk with weekly alcohol use, where the risk of harm increases with each drink consumed. For example: 

• 0 drinks per week (no risk) – Not drinking at all has benefits, such as better health and sleep.
• 2 standard drinks or less per week (low risk) will likely help you avoid alcohol-related consequences for yourself or others. 
• 3-6 standard drinks per week (moderate risk) increases your risk of developing several types of cancer, including breast and colon cancer. 
• 7 standard drinks or more per week (high risk) significantly increases your risk of heart disease and stroke.  
  

Learn more:

BC Cancer Prevention – Limit Alcohol 

Canadian Centre on Substance Use & Addiction – Canada's Guidance on Alcohol and Health 

Several months of breastfeeding can reduce your risk of breast cancer. Although not everyone has the opportunity to breastfeed, it is important to know that breastfeeding is not just best for a baby's health — it can also reduce a mother's risk of developing breast cancer.

The research:

Breastfeeding causes changes in the body's chemical balance, which may provide protection from breast cancer. It lowers pH levels and reduces the production of estrogen, which are both linked to lower breast cancer risk. Milk production may also help to "flush out" cancer-causing substances in breast tissue.

The more times you can breastfeed in your lifetime, the less your risk of breast cancer. Studies have shown that compared to those who have never breastfed, those who breastfeed for a total of three years have a 10-20% reduction in breast cancer risk. If you breastfeed for less time, you won't get as much benefit, but your risk will still be lower compared to those who have never breastfed. The research also suggests that breastfeeding is especially protective for those who have a family history of breast cancer.

What you can do:

If you are planning to have a family, educate yourself about the many health benefits of breastfeeding for baby and mother. Look into the resources that are available to help you breastfeed successfully. If you are currently breastfeeding your baby, try to continue for as long as possible – ideally for at least several months.

Learn more:

Breastfeeding and Breast Cancer

Susan G. Komen for the Cure

Breastfeeding Information and Support

BC Ministry of Health

BC Women's Hospital & Health Centre

Tobacco use is strongly linked with many cancers. While there are mixed research findings about the link between smoking and overall breast cancer risk, what has clearly emerged in recent years is the importance of avoiding tobacco smoke. Higher rates of premenopausal breast cancer are linked with tobacco smoke exposure during adolescence and young adulthood – either from direct smoking or exposure to environmental smoke. There are positive general health benefits of not smoking, and not being around tobacco smoke also extends to breast cancer prevention. ‎

In the last 10 years, greater attention has been focused on identifying links between toxic chemicals and pollutants in the environment and cancer. Some recent studies by Canadian researchers have found evidence of an association between the development of breast cancer and work in several industries including agriculture.¹ These results need to be confirmed and replicated by other researchers before firm conclusions or recommendations can be drawn. While this issue understandably invokes a great deal of public concern, at this time research does not show a clear link between breast cancer risk and exposure to these substances.

¹ Breast cancer risk in relation to occupations with exposure to carcinogens and endocrine disruptors: a Canadian case–control study, Environmental Health November 2012 Brophy et al.

Most studies have shown no significant increase in risk of breast cancer for those who take oral contraceptives when compared to those who do not. Some studies have suggested a small increase in risk in those who mainly used older types of oral contraceptives, which contained more estrogen than those commonly used today. Also, studies have shown that the risk goes down after a woman stops taking oral contraceptives.

Other types of contraceptives that are estrogen/progesterone based (topical, injectable, patches, implants, etc.) have been less well-studied. The risk may be similar to oral contraceptives but this has not been proven.

There is growing evidence that vitamin D may reduce the risk of some types of cancer, particularly colorectal and breast cancers. You can get vitamin D from exposure to sunlight, in your diet (especially if you eat foods fortified with vitamin D), or by taking vitamin supplements. For more information, talk to your health care provider.

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Breast implants do not increase the risk of breast cancer, but they can make early detection more difficult. Before getting implants, you are strongly advised to have a mammogram. These baseline images can be used to compare against future mammograms with your implants.

If you have implants, talk to your health care provider about your options around screening for breast cancer. While screening mammography recommendations are the same for those with breast implants, you won't be able to make an appointment directly with the Breast Screening program. Those with breast implants require special positioning and additional images. Contact your health care provider to refer you for a screening mammogram at a diagnostic imaging office.

Further tests may include:

• Diagnostic mammograms: further x-rays of the area of concern.
• Ultrasound: uses sound waves to produce an image of the area of concern. It does not use radiation
• Biopsy: a sample of tissue from the area of concern.

Friends and family play an important role in supporting women to take steps that can reduce their risk of developing breast cancer.

Important facts about breast health & breast cancer

• Risk of getting breast cancer nearly triples between the ages of 40 and 70. About one in eight women in BC will develop breast cancer in her lifetime.
• Most who develop breast cancer don't have a family history of the disease. Only 5-10% of all breast cancers have a genetic cause; up to 42% are linked to lifestyle factors.
• Only 54% of BC women aged 50-69 currently go for a mammogram every two years as recommended.
• Advances in early detection have increased survival rates. Today, 89% of women are alive five years after a breast cancer diagnosis.
• Women in BC have one of the lowest breast cancer rates in the country and the highest survival rates in the country.

We all have a role to play:

Women value the support and encouragement of the people who love them. In fact, in a survey we conducted, women listed family and friends as one of the top factors that would motivate them to take steps to reduce their risk of breast cancer.

• If you're a woman, make a personal commitment to look after your breast health. Remember that by taking care of yourself, you are in a better position to take care of the people you love.
• Encourage the women in your life to reduce their risk through prevention and screening. Be there to support her health decisions.