What causes breast cancer? 11 risk factors to know about

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It is estimated that about 1 in 8 women will develop Breast Cancer during her lifetime.

It is not easy to pinpoint why Breast Cancer develops, as there is no single cause or factor that triggers it. Knowing the risk factors may help you take preventive measures to reduce your risk and to be more vigilant.

Being a woman

Over 99% of cases occur in women


Risk increases with age, with women over 50 years being the most susceptible

Previous diagnosis of Breast Cancer

There is a higher chance of developing another cancer, in the same or in the other breast.

Family History

Incidence of Breast Cancer increases if one or more family member has been diagnosed, on either the maternal or paternal side.

Genetic mutations

Women who have inherited genetic changes in certain genes such as BRCA1 and BRCA2, are at a higher risk.

Breast Density

Denser breasts have less fatty tissue. High breast density hinders the detection of Breast Cancer signs on a screening mammogram. 

Hormonal factors

  • Menstruations before the age of 12 and menopause after the age of 55 prolong the exposure to hormones and hence increase the risk.
  • The risk is higher in women who had their first born after the age of 30 or for women who are nulliparous.

Ionizing Radiation

Treatment with ionizing radiation, especially at puberty, increases the risk.

Hormone replacement therapy

While prescribed to manage menopause symptoms, the estrogen content elevates the risk.


Obese postmenopausal women are at a higher risk.

Alcohol Consumption

Alcohol intake increases the risk of Breast Cancer. The level of risk rises with the amount of alcohol consumed.

Although several factors may contribute to an increased risk of developing Breast Cancer, most women who develop Breast Cancer are not exposed to known risk factors.

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