Sunday, July 21, 2013

Why ARE high-flying women more at risk of developing breast cancer?

Nobody seems to know why.  I note however that fat is protective against breast cancer and career women would be mostly slim

Jan O'Mahony loved her job as a GP, but it was highly demanding, especially when she started taking on extra managerial responsibilities.

She often found herself working in the evenings, which she had to juggle with running a home, raising two daughters and worrying about her two elderly parents. It all added up to a hectic lifestyle that will sound familiar to millions of British women.

‘It was pressurised and I can remember times when I felt exhausted, but it became second nature,’ says Jan, 59, from Leeds. ‘Certainly my husband Don was concerned, but I convinced him I was fine and it was what I wanted to do - and it was. I loved my job. There was no reason to worry about my health.’

Then, at the end of a holiday in October 2009, Jan noticed a lump in her breast. Concerned, she immediately went for tests - and her worst fears were realised.

‘I knew, just from the nature of the lump, that it could be cancer. But it's still a horrible shock when you hear those words,’ she recalls. ‘It's something that's on your “dread list” as a woman.’

Signed off work to begin surgery, chemotherapy and radiotherapy, she started to take stock.  ‘I started to worry about the stress of my job, and what role it might have played in me getting cancer,’ she says. ‘Breast cancer doesn't develop overnight and I'm not saying that was the cause of it, but in the two years prior to the diagnosis, I was under a lot of pressure.

‘I also wondered if putting myself back in that situation would affect my risk of recurrence.’

Anyone told they have a serious illness will instinctively look for a reason. Often there is none. But in the case of breast cancer, research is increasingly showing that one particular group is at more risk: professional women.

The latest findings, published in June in the journal Social Science & Medicine, are dramatic. Researchers analysed data from about 4,000 women over a 55-year period and found that women in professional jobs were nearly 70 per cent more likely to develop breast cancer than housewives or women in ‘lower-status occupations’.

'There's no doubt stress affects your immune system. I don't know what part it played in my illness, but this coloured my view in terms of coming back to work'

So why are high achieving women such a high risk group? Might 'having it all' also unfortunately include breast cancer? Putting off babies to forge a career may be one factor. Breast cancer is commonly driven by the hormone oestrogen, and it's known that having children, and breastfeeding before the age of 30, offer natural protection because they reduce the total number of menstrual cycles a woman has, lowering her oestrogen levels.

Some 49,564 women were diagnosed with breast cancer in the UK in 2010, up from 37,107 women in 1995. Experts suggest this rise is partly driven by the fact that women are delaying their families until later in life: nearly half of all births in England and Wales are now to women over 30, according to the Office of National Statistics.

And women in demanding careers are the group most likely of all to put off having children, or not have them at all. They also have smaller families. ‘There's no doubt professional women are more likely to get breast cancer,’ says Lester Barr, consultant breast surgeon at South Manchester University and Christie Hospitals, and chairman of the charity Genesis Breast Cancer Prevention.

‘There's definitely a link and it's probably a combination of factors. First, professional women tend to have fewer children, they have them later in life and they may breastfeed for less time, all of which are risk factors for breast cancer because of its relationship with the oestrogen cycle.’

Mr Barr adds that alcohol - which has also been linked to breast cancer - is another factor. Figures published last year showed professional middle-aged women were drinking more than teenagers for the first time, downing 9.1 units a week on average.

'Research found that the longer the woman held a job, the greater the risk of cancer, and that being in authority over others was a risk factor'

‘Women are drinking twice as much as they did and professional women tend to have a glass of wine every day to relax,’ he says. ‘Another drive may be more use of the contraceptive pill, and more use of HRT to avoid menopausal symptoms in a high-pressure job.’

Both the pill and HRT change oestrogen levels in women and so may encourage cancer to develop. A 2011 study estimated that just over three out of 100 breast cancers in women in the UK are linked to HRT use.

However, the latest study offered another explanation for professional women's susceptibility to breast cancer: stress. The researchers said that lifestyle and hormonal factors could not fully explain the increased incidence of tumours among this group, and believe the pressures of entering a male-dominated workplace could also have had a role.

‘Women who entered managerial occupations in the 1970s experienced prejudice and discrimination due to prevailing cultural attitudes that men made better leaders than women,’ said Dr Tetyana Pudrovska, who led the study.

‘Exercising job authority was particularly stressful for women... we believe women are still facing the same kind of stresses, and therefore the increased risk is likely to be there today.’

The research found that the longer the woman held a job, the greater the risk of cancer, and that being in authority over others was a risk factor. And this is just the latest evidence to suggest a relationship between stress and cancer.

In 2007, a study of 36,000 Swedish working women aged 30 to 50 found those who felt stressed at work were 30 per cent more likely to develop breast cancer than those who felt in control of things.

Experts have suggested that consistently high levels of the stress hormone cortisol may inhibit the immune system, allowing cancerous cells to flourish.

Jan O'Mahony may never know if the strain of taking on too much did play a role in her illness, but after the shock of being diagnosed with early stage cancer, and the trauma of treatment and recovery, she decided to give up her job completely.

‘Thankfully, I got a good prognosis, and I wanted to put myself at the lowest possible risk of recurrence,’ she says. ‘There's no doubt stress affects your immune system. I don't know what part it played in my illness, but this coloured my view in terms of coming back to work. You only get one crack at life and I had to listen to what my heart was saying.’

She adds that now she has more free time she is able to lead a healthier lifestyle. It's well known that regular exercise, a balanced diet and keeping a healthy weight are all protective against cancer and its return.

'When the cancer came back, I wondered if continuing to work at such a fast pace was the reason why'

‘I've got a better balance in my life now,’ she says. ‘I think women, and particularly my generation, tend to just take things on without thinking about it. As I'd got older I'd found exercise harder and harder to fit in. Now I do Pilates and go to the gym every week and I've lost weight.’

About 55,000 people in the UK are diagnosed with breast cancer each year. Just over 80 per cent of cases occur in women aged over 50

So could too many deadlines contribute to a tumour? The theory that stress causes cancer is still controversial. Analysis of 12 trials in six countries, published in the British Medical Journal, found no link between work-related stress levels and cancer.

One problem is that stress is notoriously difficult to define. For this reason Dr Pudrovska's paper has been criticised by some experts.

‘What one person considers stressful might be enjoyable to another,’ says Dr Hannah Bridges, senior information officer at Breakthrough Breast Cancer. ‘The researchers didn't ask the women what their stress levels were.’

Whether high-achieving women are putting themselves under so much pressure it's making them ill may be open to debate. But it often takes something as serious as cancer to get us to reassess our priorities.


Taking omega-3 fish oil supplements may increase the risk of aggressive prostate cancer by 70%

Is the fish-oil religion dying at last?

A supplement taken by millions for its health benefits may trigger aggressive and lethal prostate cancer, research has shown.

Omega-3 fatty acids, derived from fish oils and lauded for their anti-inflammatory properties, were found to increase the risk of high-grade disease by 71 per cent.

Taking omega-3 was also associated with a 44 per cent greater chance of developing low-grade prostate cancer. Overall, the fatty acids raised the risk of all prostate cancers by 43 per cent.

High blood concentrations of all three omega-3 fatty acids commonly found in supplements, EPA, DPA and DHA, were linked to the findings.

Scientists conducting the study compared blood samples from 834 men diagnosed with prostate cancer, and 1,393 participants without the disease.

The results add to evidence published in 2011 by the same U.S. team which associated high blood levels of DHA with a doubling of the risk of high-grade prostate cancer.

Co-author Dr Thodore Brasky, from Ohio State University, said: ‘What's important is that we have been able to replicate our findings from 2011 and we have confirmed that marine omega-3 fatty acids play a role in prostate cancer occurrence.’

Writing in the online edition of the Journal of the National Cancer Institute, the scientists said the evidence suggested that the fatty acids played a role in prostate cancer development.

People tempted to up their intake of omega-3, particularly by means of supplements, ‘should consider its potential risks’.

Omega-3 fish oils are one of the most fashionable and popular supplements on the high street.

They are said to have a plethora of health benefits, including protection against heart attacks and strokes, staving off arthritis, boosting brain power, and preventing behavioural disorders in children.

Each year Britons reportedly spend around £116 million on fish oil supplements. Globally, omega-3 sales run into billions.

The new study involved men participating in the Selenium and Vitamin E Cancer Prevention Trial (Select), which investigated potential ways to reduce the risk of prostate cancer.

No benefit was seen from selenium and an increased number of prostate cancers occurred among men taking vitamin E.

Men with the highest blood levels of omega-3 fatty acids were significantly more likely to be diagnosed with prostate cancer than those with the lowest levels.

In terms of blood concentration, the difference between the two groups was somewhat greater than the effect of eating salmon twice a week, said lead scientist Dr Alan Kristal, from the Fred Hutchinson Cancer Research Center in Seattle.

‘We've shown once again that use of nutritional supplements may be harmful,’ he said.

Further research is needed to uncover the mechanisms that might cause omega-3 to drive prostate cancer, said the researchers.

One potentially harmful effect was the conversion of omega-3 fatty acids into compounds that can damage cells and DNA, they added.

Omega-3 was also thought to contribute to immunosuppression, the dampening down of the immune system.

It was not known to what extent omega-3 might affect the progress of prostate cancer in men who already had the disease.

‘It's important to note that these results do not address the question of whether omega-3s play a detrimental role in prostate cancer prognosis,’ said Dr Brasky.

Each year around 41,000 men in the UK are diagnosed with prostate cancer and 11,000 die from the disease.


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