What are risk factors?
A risk factor is something that can increase your chances of developing a cancer. Different cancers have different risk factors although there are some risks associated with more than one cancer.
When you know the risk, you're empowered to make choices to reduce that risk. It’s not about scaring people, it’s about giving them the chance to be realistic.
There are a number of possible causes of ovarian cancer but these are not yet fully understood. The most important risk factors are age and a family history of ovarian or breast cancer.
This information is not intended to provide information about risk or prevention of ovarian cancer returning for women already diagnosed.
It's worth noting that nine out of ten cases of ovarian cancer are a type called epithelial ovarian cancer and the risk factors explained here are specific to this type of cancer. Find out more about types of ovarian cancer
As with most cancers the risk of developing ovarian cancer increases as a woman gets older. Women over the age of 50 have a higher risk, and most cases of ovarian cancer occur in women who have already gone through the menopause. More than half the cases of ovarian cancer diagnosed are women over 65 years.
Although it's not common for younger women to get ovarian cancer, there are instances of ovarian cancer in pre-menopausal women; 1000 women under the age of 50 develop ovarian cancer every year which is why it's important that all women should be aware of the symptoms of ovarian cancer. This is especially important if women have a family history of ovarian or breast cancer.
80–85 per cent of ovarian cancer cases are 'sporadic'. This means they are one-offs, not inherited and close female relatives face no significant increase in their risk of developing the disease themselves. This is important to remember, as it can be worrying if a close family member is affected by ovarian cancer. In most cases women can be reassured.
The remaining 15–20 per cent of cases are believed to be caused by an inherited faulty (or mutated) gene, which is often the BRCA1 or BRCA2 gene. Women who inherit a mutated copy of the BRCA1 or BRCA2 gene (BReast CAncer 1 and 2) have a much higher risk of developing breast and/or ovarian cancer than the general population.
There are some other genes which have also been linked to ovarian cancer such as RAD51C and RAD51D, STK11, BRIP1 (FABCJ) and those linked to Lynch Syndrome (also known as hereditary non polyposis colorectal cancer, HNPCC). The chance of developing cancer of the stomach, liver, kidney, bladder, skin and brain can also be increased by having a mutation in one of the Lynch Syndrome genes.
If there are two or more cases of ovarian cancer and/or breast cancer on either your mother or father's side of the family, you should speak to your GP who will offer you more information about your level of risk. Your GP may then refer you to a genetic counsellor to help you decide whether or not to undergo genetic testing to see if you carry a mutation in a gene such as BRCA1 or BRCA2, which may increase your risk of developing ovarian or breast cancer.
Your genetic counsellor and specialist team will support you through this process and help you to understand your risk and offer advice on risk management options.
More about hereditary ovarian cancer
Other ovarian cancer risk factors
Media stories sometimes appear to demonstrate links between the risk of ovarian cancer and various activities, foods or physical traits. Often when examined closely the increase in risk is very small or evidence is limited.
There's a slight increased risk of developing ovarian cancer for an obese person. For an obese person without a family history, a 2014 study found that their lifetime risk increases from 2 per cent to 2.24 per cent. This study found that women with a body mass index (BMI) above 28 seem to have a slightly higher risk of developing the disease. This supports earlier work that indicated that a healthy lifestyle can reduce your risk of ovarian cancer. Calculate your BMI
- Using talcum powder
Various studies have shown a link between using talcum powder between the legs and ovarian cancer. The talcum powder could possibly travel into the vagina through the cervix and into the womb. Once in the womb it could then possibly reach the fallopian tubes and then the ovaries. The powder could then cause irritation and over a period of time cause cancerous changes to the cells of the ovaries.
We'd therefore generally advise against using talcum powder on this area of the body. However, it's important to note that the increased risk is very small. For someone without a family history of ovarian cancer the lifetime risk of developing the disease is two per cent. Or put another way, four women out of two hundred. For those that used talcum powder it could be five in two hundred.
- Use of hormone replacement therapy (HRT)
Taking HRT increases a woman's risk of developing ovarian cancer by 40 per cent compared to a woman who has never taken HRT. To put this in context, the lifetime risk of developing ovarian cancer is one in fifty (two per cent) and a 2015 study showed that five years use of HRT, starting at around 50 years of age, would result in around one additional case of ovarian cancer per 1,000 users of HRT. However, this small increase in risk needs to be carefully weighed against the overall benefits of taking HRT and should be discussed with your GP. It's also important to note that the additional risk of ovarian cancer reduces again five years after stopping taking HRT.
There's evidence to suggest that women with endometriosis have an increased risk of developing ovarian cancer. The level of this risk fluctuates from study to study, and seems to be associated with certain types of ovarian cancer such as clear cell and endometrioid epithelial ovarian cancer. However, very many more women have endometriosis than are diagnosed with ovarian cancer and so having endometriosis need not necessarily be a cause for concern.
Smoking can increase the risk of certain types of ovarian cancer. Approximately three per cent of some types of ovarian cancer seem to be linked to exposure to tobacco smoke. Other types of ovarian cancer are not associated with smoking.
Research has shown that diabetics have an increased risk of 20–25 per cent compared with non-diabetics of developing ovarian cancer. Additionally the risk may be slightly higher in diabetics who use insulin as opposed to diet or tablet controlled diabetics.
This information is reviewed regularly and is in line with accepted national and international guidelines. All of our publications undergo an expert peer review and are reviewed by women with ovarian cancer to ensure that we provide accurate and high-quality information. To find out more take a look at our information standards.
Last reviewed: February 2020
Next review: April 2022