vitaminlady posts hormones breast health

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WESTPORT, CT (Reuters Health) Nov 13 2000

 Postmenopausal use of estrogen therapy, particularly when it includes progestin, significantly increases the risk that a woman will develop breast cancer by age 70, according to researchers at Harvard University, Boston, Massachusetts. 

Prior studies of the effects of postmenopausal hormone use on breast cancer risk have been limited by the inability to completely control for other risk factors, particularly age at menopause, Dr. Graham A. Colditz and Dr. Bernard Rosner explain in the November issue of the American Journal of Epidemiology. 

In order to circumvent this issue, they developed a model that calculates the cumulative risk of breast cancer resulting from several risk factors, and applied it to data collected on 58,520 women enrolled in the Nurses Health Study for 14 years. 

The cumulative risk of breast cancer at age 70 was increased by 57% in women with a history of benign breast disease, the researchers found. 

In women who used unopposed postmenopausal estrogen from ages 50 to 60, the cumulative risk increased by 23% compared with women who had never used hormones. The risk was increased by 67% in those who used estrogen plus progestin. 

Alcohol use increased the cumulative by 7% in women who reported one alcoholic drink per day from age 18 years, compared with nondrinkers. 

Other well-known risk factors, such as a family history of breast cancer, age at menopause, age at menarche, height and parity, also affected the cumulative risk of breast cancer, according to the report. 

In general, the findings are "consistent with a broad range of epidemiologic studies," Dr. Colditz and Dr. Rosner say. However, "the observation regarding risk in women with benign breast disease was unexpected." They note that further studies are needed to identify the genetic and environmental factors that account for this association. 

The findings support a strong role for reproductive factors in the risk of postmenopausal breast cancer, the authors say. 

Am J Epidemiol 2000;152:950-964. 

As a side note, in December 2000 I came across this: Dec 15 - An advisory committee commissioned by the National Toxicology Program of the NIH to help compile the Tenth Report on Carcinogens has recommended that steroidal estrogens be listed as substances that are "known to be a cause of human cancers."

Early Menarche 

Children in developing countries may be reaching puberty early because of exposure to DDT, which has been banned for decades in Europe and the United States, Belgian researchers said last week.

Scientists at the University of Liege believe the chemical, which is still used in the developing world to fight mosquito-borne diseases such as malaria, may accelerate puberty in young girls.

In a study of 39 immigrant girls from countries that use DDT, which mimics the effects of estrogen, researchers found high levels of the DDT derivative DDE in girls who began to menstruate very early.

"A possible relationship with exposure to DDT is suggested," team leader Jean-Pierre Bourguignon said.

All of the girls, who came from 22 developing countries, began menarche before the age of 10 and began to develop breasts by the age of 8.

Researchers had suspected that undernourishment followed by rapid weight gain after immigration could have contributed precocious puberty, but Bourguignon and his team said the girls had a normal weight and height when they arrived in Belgium.

The researchers found that most of the girls had blood levels of DDE that were 10 times higher those in native children. DDE is usually undetectable in children born in Belgium.

"The prevalence of precocious puberty was found to be 80-fold higher in foreign children than in Belgian natives," Bourguignon said in the paper published in the journal Human Reproduction.

He called for further research to confirm the findings and to determine the mechanism through which the chemical could cause precocious puberty.