Understanding the Risk Factors of Breast Cancer

Breast cancer is the number one cancer in Singapore with more than 3,500 new cases diagnosed every year. Breast cancer is the most common cancer among young women under 40 years old. Data from the UK suggests that about 25 per cent of all breast cancers can be prevented. 

Risk Factors (Fixed and modifiable risk factors)

To understand how we can prevent breast cancers, we need to identify the risk factors that lead to an increased risk of developing the disease.

Some of these risk factors are fixed, such as:

• Being female – Men can also develop breast cancers but it is rare.
• Age – Cancers are more common as you get older.
• Age where one starts menstruation.
• Genes – You cannot change the genes you inherit from your parents.

Risk factors that you can control and change are called modifiable risk factors. This is where every person who is concerned about getting breast cancer can put in effort to minimise their personal risk.

1. Watch your weight

Women who are overweight with a body mass index (BMI) of over 25 have a higher risk of breast cancer compared to women who maintain a healthy weight, especially after menopause.

2. Start a family sooner

Women who have their first child after 35 years old have a higher risk of breast cancer compared to women who never gave birth. Having children under 20 years old can lower breast cancer risk by as much as 50 per cent.

3. Breastfeed your baby

Breastfeeding can lower breast cancer risk. This effect is more pronounced in women who breastfeed for more than a year. The World Health Organization (WHO) recommends at least six months of breastfeeding in new mothers.

4. Avoid or reduce alcohol intake

Women who have three alcoholic drinks a week have a 15 per cent higher risk of breast cancer. Those who drink more than 14 alcoholic drinks per week have a 70 per cent higher risk of breast cancer compared to non-drinkers.

5. Women who have reached menopause should take precaution when using combined hormone replacement therapy

The prolonged usage (more than four or five years) of some kinds of hormone replacement therapy can increase the risk of breast cancer. Participation in breast screening such as mammogram is highly encouraged. Menopausal hormone therapy is not recommended in women with a personal history of breast cancer.

6. Maintain sufficient vitamin D levels

Research suggests that older women with low levels of vitamin D have a higher risk of breast cancer. Oily fish (like salmon) and cod liver oil are good food sources of vitamin D. Sun exposure (between 10am to 3pm) for around five to 30 minutes twice a week is usually adequate to maintain vitamin D levels.

7. Choose a healthier diet that is plant-based and low in total fat

An unhealthy diet is thought to be at least partly responsible for about 30 to 40 per cent of all types of cancers. No food or diet can prevent you from getting breast cancer. Breast cancer is less common in countries where the typical diet is plant-based and low in total fat (polyunsaturated fat and saturated fat).

Dispelling Myths

There is no evidence to back up claims that drinking coffee, using hair dyes, antiperspirants, or even underwire bras cause breast cancers. While taking supplements can improve the nutritional status of some people, consuming extra vitamins A, E, or C does not lower one’s breast cancer risk. Breast implants for cosmetic reason does not cause breast cancer.