Image copyright Getty Images Image caption Angelina Jolie revealed in May last year that she had had preventative surgery

Referrals to breast cancer clinics more than doubled in the UK after Angelina Jolie announced she had had a double mastectomy to prevent breast cancer.

The actress revealed in May last year she had had the surgery, after being told she had an 87% chance of the disease because of a high-risk gene.

The news encouraged women with genuine concerns about their family history to get advice, a study found.

About 5% of breast cancers are thought to be hereditary.

"The Angelina Jolie effect has been long-lasting and global, and appears to have increased referrals to centres appropriately," said a team led by Prof Gareth Evans of the University of Manchester.

The researchers looked at referrals to more than 20 genetic centres and clinics in the UK after the story hit the press in May 2013.

In June and July the number of GP referrals for genetic counselling and DNA tests for breast cancer mutations increased two and a half times compared with the same period in 2012.

The study, published in the journal, Breast Cancer Research, found referrals remained at twice the previous year's figure from August to October.

"Angelina Jolie stating she has a BRCA1 mutation and going on to have a risk-reducing mastectomy is likely to have had a bigger impact than other celebrity announcements, possibly due to her image as a glamorous and strong woman," said Prof Evans.

"This may have lessened patients' fears about a loss of sexual identity post-preventative surgery and encouraged those who had not previously engaged with health services to consider genetic testing."

Most breast cancers happen by chance but a small number of people diagnosed with breast cancer (5%) have inherited a fault in one of the known breast cancer genes; BRCA1, BRCA2 or TP53 which puts them at higher risk.

Jade Goody

Angelina Jolie is not alone in influencing health behaviour.

Attendance for cervical cancer screening rose in 2008 and 2009, when the celebrity Jade Goody was diagnosed with cervical cancer and died.

Baroness Delyth Morgan is chief executive at Breast Cancer Campaign, which part-funded the research.

"Without Angelina Jolie's openness in talking about her BRCA1 mutation and decision to have a risk-reducing mastectomy, followed by the publication and publicity around the updated NICE guidelines soon after, many women may not have approached health services and so would never have had their risk and risk-reducing options explained," she said.

Funding for genetic services must be able to respond quickly to demand, to ensure risk counselling and genetic testing is available for everyone in need, she added.

"The current level of funding available for this service should be reviewed, to avoid unnecessary delays, which can be very stressful for patients."

Gene risk

Women in general have a one in eight chance of developing breast cancer during their lifetime, but genes can put some at higher risk.

In the UK, about one in 1,000 people will have inherited a BRCA1 mutation and a similar proportion will have inherited a BRCA2 mutation.

Women who are tested early can take steps to prevent themselves from developing the disease.

This may mean a risk-reducing mastectomy, cancer preventing drugs, such as tamoxifen, and certain lifestyle changes like a healthy diet and more exercise.

Lester Barr, chairman of Genesis Breast Cancer Prevention, said: "While a woman's risk of developing breast cancer and/or ovarian cancer is greatly increased if she carries the harmful mutation of the BRCA1 or BRCA2 gene, preventative surgery is by no means the answer for everyone.

"Of course, a preventative mastectomy is the most effective way to cut a woman's risk of breast cancer, however other options should also be considered. These include prevention drugs, such as tamoxifen, which has been approved by NICE.

"Alternatively, many women with a mutated BRCA gene opt for annual check-ups which can be arranged through the NHS."