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Study shows increased risk of cancer for stressed
women
By Emma MasonEurekalert,
September 24, 2003
But
more research needs to be done
Stress
can increase a woman's chance of developing breast cancer, according to a
new, prospective study of Swedish women, ECCO12 – The European Cancer
Conference heard on Wednesday, September 24. However, the study's
lead author, Dr Östen Helgesson, warned that his findings should be
treated with caution as the design of the study meant that it was not
possible to assess how much stress was needed to increase the risk of
breast cancer. Furthermore, the questionnaire used in the study had not
been finally validated as an accurate way of recording stress and relating
it to the chances of developing breast cancer. Although the
association between stress and breast cancer has been investigated, there
have been few studies that have examined the link prospectively, and these
have produced contradictory findings. Dr Helgesson, a general practitioner
from Gothenburg, Sweden, and a doctoral student at the Sahlgrenska
Academy, believes his study is another stepping stone along the way to
discovering whether stress can be used as a predictor of subsequent breast
cancer. He said: "This
study is prospective and is based on information that is unbiased with
respect to knowledge of disease. Therefore it can be regarded as more
valid than results drawn from case-control studies. It showed a
statistically significant, positive relationship between stress and breast
cancer, and this association was independent of potential confounding
factors, such as alcohol, body mass index, education, maternal history of
breast cancer, smoking, age at which the women started their periods, age
at which they had their first baby, the interval between the two, and
their age at menopause." Dr Helgesson and his
colleagues from the Sahlgrenska Academy followed 1,462 Swedish women, aged
between 38 and 60, for 24 years. The women had a physical examination and
answered a simple questionnaire in 1968/91. They were asked by a physician
whether they had had a feeling of stress for a month or longer, including
tension, fear, anxiety, or sleep disturbances connected with conflicts in
the family or at work. There were six degrees of stress varying from
"no stress experience at all", up to "experienced mental
stress constantly during the last five years". The women had
follow-up examinations in 1974/5, 1980/81 and 1992/93, but they were not
asked about stress again, and therefore the study relates to stress
experienced over a particular five-year period as reported at one point in
time i.e. 1968/69. The researchers
found that women who said they had experienced stress during the five
years before the first examination had double the risk of developing
breast cancer during the following 24-year period, compared to women who
had reported no stress. Out of 1,350 women for whom there were complete
data, 24 who had experienced stress went on to develop breast cancer and
432 women who had experienced stress did not develop breast cancer.
Amongst the women who had not experienced stress, 23 developed breast
cancer and 871 did not.2 The mean average age
at which the women were diagnosed with breast cancer was 60.25 which is in
line with statistics from Sweden's National Board of Health and Welfare
that show the highest incidence of breast cancer occurs in the group of
women aged between 60 and 69 (23.6% of total breast cancer incidence as
measured in 1992), while other sources indicate a median age of 65 at
which breast cancer is diagnosed. Therefore, the study did not show that
women who suffered stress developed breast cancer at an earlier age than
other women. Dr Helgesson said:
"Although our study does show a significant association between
stress and breast cancer, I would emphasise that more research needs to be
carried out before it can be said that stress definitely increases a
woman's risk of breast cancer. Ours is one of only a very small number of
prospective studies, and although our findings are significant, more and
larger prospective studies need to be done. Our work takes us one step
forward to discovering whether stress really is a predictor of subsequent
breast cancer." Copyright
© 2002 Global Action on Aging |
