Cosmetics Use and Mammographic Breast Density (MBD) in Iranian Women: A Cross-Sectional Study

Background: Since breast cancer is increasing worldwide and previous risk factors cannot justify such an increasing trend, investigating new environmental factors is necessary for each population. Mammographic breast density (MBD) is a strong risk factor for breast cancer as well as a biomarker for the effect of chemicals on breast tissue. Objective: Given limited data about the association between breast density and cosmetic products containing endocrine-disrupting chemicals (EDCs), the purpose of this study was to evaluate the effects of cosmetic products on MBD in Iranian women. Methods: In this cross-sectional study, women who attended two university hospitals for breast screening mammography and who had been living in the capital city of Iran for the last 3 years or more were recruited. We asked women to fill out a questionnaire containing two parts; the first part was about the women's characteristics and medical history and the second part consisted of cosmetic use. The frequency of cosmetic use was measured using the Likert scale in four scales. One expert radiologist in each center reported the MBD on a four-category scale. Results: The mean age of 813 participants was 50.16±7.65. Three hundred-seven (37.8%) women had low breast density and 506(62.2%) had high breast density. Based on our results, heavy use of moisturizers, sunscreen, nail polish, eye products, makeup products, and lipstick was associated with increased breast density. In multivariable analysis after adjusting for menopause, excessive use of nail polish, sunscreen, and moisturizing cream was associated with increased MBD. Conclusion: Our study shows a probability of an increased MBD with the excessive use of cosmetic products. Since a small increase in the risk of breast cancer may lead to a considerable public health impact, thus further studies are needed to find new prevention strategies.