The major risk factors for breast cancer are if you have a positive family history (a mother or sister who had breast cancer before menopause) or if you have already had breast cancer, or if you are over 50.

Other minor risk factors, such as no children or late childbirth, early onset of periods, or late menopause etc. are not of great significance, since 75 percent of women who get breast cancer do not have these risk factors nor do they have a positive family history.

A detailed study of 2,000 women is going on in three major centers in the U.S. and may give more information about specific risk factors.

• THYROID FUNCTION AND IODINE: Rates of breast cancer are high in developed countries with the exception of Japan. Since breast cancer is known to be higher in countries where iodine content of soil and water is low, some believe the high level of iodine in seaweeds consumed by Japanese women may have a protective feature, but this has not yet been proven.

Breast cancer is often associated with low levels of thyroid hormones, or hypothyroidism. However, thyroid hormone blood levels may be normal, but functioning at suboptimal levels. Basal body temperature below 97.6F on a regular basis combined with symptoms of low metabolism may indicate the thyroid is not functioning well (see chart for information on how to take the basal body temperature correctly).

In his twenty years of research into fibrocystic breast disease, Dr. William Ghent, professor of surgery at Queen's University in Kingston, Ontario, has found that a special form of non-toxic diatomic iodine reduces the incidence of breast cancer in women who take this preparation on a regular basis. His results will be published in the Canadian Journal of Surgery in Oct/93 (see chapter on cystic breast disease).

• DIET AND BREAST CANCER: A diet high in animal fats and dairy products is associated with an elevated risk of breast cancer.

The countries with the highest breast cancer rates are those with the highest rate of fat consumption. A large scale study sponsored by The National Cancer Institute is studying 15,000 women on normal diets and 15,000 women on a 20 percent fat diet and will compare their rates of breast cancer. The results will be ready between 1995 and 97.

Many women's groups feel that although the low fat diet has not been conclusively proven, it makes sense to reduce fat for other health reasons as well.

The first National Conference on Diet and Breast Cancer called for government and industry to lower the fat content of food. The conference said that medical doctors are not trained in nutrition, and their attitude towards diet and breast cancer is often one of "passive neglect."

There is much you can do to improve your diet right now. The best cancer preventive diet is one that emphasizes fresh fruits and vegetables, whole grains and fish and poultry and avoids sugar, excess fat, dairy and red meat.

There is evidence to suggest that eating foods high in vitamins A, C, E, and selenium lowers cancer risk. As well, research indicates that taking extra betacarotene and vitamin-C help protect against cancer.

Women should limit alcohol consumption, since women who drink two glasses of alcohol a day have a higher rate of breast cancer than non-drinkers.

• ENVIRONMENT AND BREAST CANCER: As mentioned earlier, several studies have indicated that women with breast cancer tend to have higher levels of organochlorines in their breast tissues than women who do not have breast cancer.

Greenpeace has just published a report (Nov/92) entitled, Breast Cancer and the Environment: The Chlorine Connection.

Organochlorines are highly persistent and toxic substances, like DDT, PCP and dioxin plus literally thousands of other chemicals whose effects have not yet been studied. These chemicals are used to make PVC plastics, solvents, pesticides, refrigerants, and in the pulp and paper industry. These same chemicals persist in meat and dairy products. This may be the real reason that high fat diets lead to increased breast cancer risk.