(Editor's Note: Research pointers are new to this week's BMJ. The journal describes them as fascinating observations that don't have a direct clinical or public health message, but do make exciting science.)

This research pointer suggests that there is an important link between the risk of breast cancer and nutritional status, through its influence on concentrations of ovarian hormones (estrogen and progesterone) produced during the menstrual cycle.

These findings are consistent with the view that the level of breast cancer is much higher among women in industrialised countries (where food is virtually unlimited) than among women in countries with more traditional lifestyles.

Previously published data on hormones from saliva samples collected from women in Bolivia, the Democratic Republic of Congo, Nepal, Poland and the United States were used to investigate the relation between hormone concentrations and the level of breast cancer in each country.

The relationship of mean total energy intake in each country with hormone concentrations was also examined.

Higher concentrations of ovarian progesterone were strongly associated with an increasing level of breast cancer, confirming the expected relation between hormone concentration and risk of breast cancer in these populations.

High energy status in a population was also associated with high hormone concentrations. Conversely, poor energy status was associated with impaired ovarian function and, consequently, a lower hormone concentration in women.

These findings confirm the view that women from populations with a high risk of breast cancer are expected to have comparatively high concentrations of ovarian hormones, say the authors. Furthermore, since ovarian function responds to nutritional status, a woman's risk of breast cancer may be modified by eating less and exercising more, they conclude.

(Reference: Research pointer: Lifestyle, hormones, and risk of breast cancer BMJ Volume 322, pp 586-587.)

Related websites:

BMJ website

British Medical Association

[Contact: Grazyna Jasienska, Emma Wilkinson]

09-Mar-2001