Results of a recent study find no link between the use of antihist Study: Antihistamines Do Not Increase Breast Cancer Risk (dateline December 8, 2003) | Breast Health News | Imaginis - The Women's Health & Wellness Resource Network

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Study: Antihistamines Do Not Increase Breast Cancer Risk (dateline December 8, 2003)

Results of a recent study find no link between the use of antihistamines and an increased risk of breast cancer. Some animal experts had found that antihistamines and antidepressants promoted the growth of tumors in mice, leading some to speculate that these medications may increase breast cancer risk in humans. However, a study of over 6,000 women found no elevated breast cancer risk among women with a history of antihistamine use, regardless of age or duration of use.

According to Dr. Victoria Nadalin of the Division of Preventive Oncology at Cancer Care Ontario, in Toronto, Ontario, and colleagues, antihistamines share similarities to DPPE, a tamoxifen derivative which has been shown to promote tumor growth, and to antidepressants. Therefore, the researchers felt it was necessary to study whether antihistamines, which are often taken over-the-counter to alleviate ailments including colds and allergies, may increase the risk of breast cancer.

Dr. Nadalin and her colleagues used data from the Ontario Cancer Registry to identify 3,133 women who had been diagnosed with breast cancer between 1996 and 1998. They compared these women with another group of 3,062 women who had never had breast cancer. Participants were mailed questionnaires that included questions about their use of antihistamines (including type and duration).

After analyzing their data, the researchers found that antihistamine users were at no increased risk for breast cancer. Furthermore, age, menopausal status, and duration of antihistamine use did not influence breast cancer risk. Therefore, Dr. Nadalin and her team conclude that women who use antihistamines have no greater risk of breast cancer than women who do not use this type of medication.

While antihistamines do not appear to increase breast cancer risk, researchers have identified several factors that can lead to a higher risk of breast cancer. These factors include:

  • Advancing age
  • Family history of breast cancer
  • Personal history of biopsy revealing pre-cancerous conditions, such as lobular carcinoma in situ (LCIS) 
  • Genetic mutations of the BRCA1 or BRCA2 genes 
  • Early onset of menstruation (before age 12)
  • Late menopause (after age 50)
  • Not having children, or having children after age 30
  • Long-term use of hormone replacement therapy (HRT)

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