Caffeine is thought to be the most widely consumed drug in the world, its presence felt in foods and beverages such as coffee, tea, and chocolate and in many medications, too.  The drug is generally thought to increase the risk of developing breast cancer but an exhaustive 10-year study indicates most women can enjoy their caffeine with no fears of increased risk for breast cancer.

Ken Ishitani, MD, PhD, and his colleagues followed 38,432 women, age 45 years and older, for an average of ten years after their enrollment in the study between 1992 and 1995.  During the follow-up period of study, 1,188 women were diagnosed with invasive breast cancer.  Ishitani is affiliated with both the Brigham and Womens Hospital and Harvard Medical School in Boston and with the Tokyo Women’s Medical University in Japan.

Caffeine-related breast cancer concerns took root when an early study showed that women with non-cancerous (benign) breast disease found relief from painful symptoms when they eliminated caffeine from their diets.  Ishitani’s research showed no statistically significant association between caffeine in breast cancer for most women.  There are certain segments of the female population, however, who should remain cautious about the health effects of caffeine.

Women with benign breast disease who drank coffee were found, in Ishitani’s research, to be at slightly increased risk of breast cancer although the increase is said to be non-significant.  A significant association, however, was seen in women who drank four or more cups of coffee a day.

Women who have breast tumors that measure 2 centimeters or larger are likely to experience more rapid progression of disease when caffeine consumption is continued, as are women who have either estrogen receptor-negative or progesterone receptor-negative breast cancers.  With these types of cancer, the hormones estrogen and progesterone do not bind with the cancerous tumor.

Ishitani describes breast cancer development as a complex disease for which more research is needed for a better understanding of the disease process, including the influence caffeine may contribute to disease development and progression.

The latest issue of the medical journal, Archives of Internal Medicine, carries full details of the Ishitani study.

Source: JAMA