Manufactured chemicals are found in many consumer products. Some of these chemicals, such as phthalates and parabens, act as xenoestrogens. Xenoestrogens are chemicals that mimic the effect of the natural hormone estrogen. Laboratory studies have shown xenoestrogens can cause pre-cancerous changes in normal human breast cells. It is not known whether they increase breast cancer risk in women.
The purpose of this study is to compare the effects of over-the-counter personal care products that contain xenoestrogens with personal care products that are xenoestrogen-free on premenopausal women’s normal breast cells. Participants will use paraben- and phthalate-free personal care products for one month to help researchers evaluate the impact of chemical exposure on breast cells. Clinical studies have shown that when study volunteers decrease their exposure to xenoestrogens, levels in blood or urine decrease as well. This study builds on an earlier study that recruited participants in 2017 through the Army of Women.
If you agree to be in this study you will be contacted by the research team and asked to provide a list of all personal care products you currently use. These products will be screened for chemical content to determine if you are eligible to participate in the study. If you are determined to be eligible and consent to participate in the study, you will be asked to go to the California Pacific Medical Center in San Francisco, CA, for two study visits over the course of 29 days. Each of these visits will take approximately one hour.
Study Visit 1 (Day 1):
You will be asked to complete a one-page survey about your health history.
• All of the volunteers will provide blood and urine samples, and have cells removed from one breast using Random Periareolar Fine Needle Aspiration (FNA). This is an outpatient procedure done in the study doctor’s office with local anesthesia applied to the breast. It usually takes about 20 minutes, including the time for the local anesthesia to take effect. The total volume of the fluid and cells taken from your breast will be two to four drops.
• Two-thirds of the volunteers will receive a supply of paraben- and phthalate-free personal care products on Day 1 of the study along with a log notebook to record use of these personal care products. These volunteers will be asked to discontinue use of their own products and use only the study-provided products for the next 28 days.
• One third of the volunteers (randomly selected control subjects) will be asked to continue to use their normal personal care products, and to record their use in a log notebook provided by the study.
In the days between Study Visits 1 and 2, you will keep a daily log of personal care product use. You will be contacted by the research team by telephone at least once a week to follow your progress.
Study Visit 2 (Day 29):
• You will be asked to go into the research clinic for a second fine needle aspiration on the opposite breast as described in Study Visit 1. You will also be asked to provide a urine sample and blood sample.
• You will be asked to complete a one-page survey about your health history.
• You will turn in your study log book of cosmetic product use.
• The control participants will receive the supply of paraben- and phthalate-free personal care products that the non-control participants received in Study Visit 1. Use of these products by control subjects is optional and will not be restricted or recorded.
Two days after your last study visit, you will be contacted by telephone for a final follow-up interview. Your individual test results will be reported to you with guidance on interpretation. You will also be informed if any of the personal care products you used before the study contain chemicals that may pose health risks.