LONDON (Reuters) - Women with high levels of stress in their everyday lives are at less risk than others of developing breast cancer for the first time, according to research in the British Medical Journal published on Friday.
Scientists from Denmark drew their conclusions after studying 6,689 women over a period of 18 years, and speculated that it may be because daily stress suppressed production of oestrogen, which is a risk factor in breast cancer.
"Prolonged-low key stress of everyday life results in a persistent activation of stress hormones which may impair oestrogen synthesis and may therefore be related to lower risk of breast cancer," they wrote.
However, they pointed out that this theory was untested and deserved greater investigation.
Not only did the researchers from the National Institute of Public Health in Copenhagen find a lower incidence of primary breast cancer among stressed women, they found that the higher the day-to-day stress levels the lower the risk.
However, they warned that stress was not a health cure, given that high levels had also been associated with increased risk of potential killers like heart disease.
They also noted that their findings were at odds with studies in Finland and Sweden -- the former found no link between daily stress and breast cancer while the latter found a direct association with higher risk.
They said that part of the reason for the apparent discrepancy might be that their study only looked at first-time incidence of breast cancer while the others looked at all cases.
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