Factors Associated with Mammography Screening Choices by Women Aged 40-49 at Average Risk.

The U.S. Preventive Services Task Force (USPSTF) does not recommend routine mammogram screening for women aged 40-49 years at average risk for breast cancer. We aimed to assess the extent to which women were following guideline recommendations and to examine whether guideline awareness and other individual-level factors were associated with adherence. We surveyed a nationally representative panel of 383 U.S. women aged 40-49 years at low risk for hereditary breast cancer in October 2019. Only 29% of women reported not having initiated screening mammography. Most women (80%) were unaware of the USPSTF screening guideline related to age of initiation and frequency of mammography. Being aware of the recommendation to initiate screening at age 50 increased the odds of not initiating screening (odds ratio [OR] = 6.70,  < 0.001), whereas being older than 45 years (OR = 0.22,  < 0.001) and having a primary care doctor decreased the odds of not initiating screening (OR = 0.25,  < 0.001). Mammogram screening in excess of USPSTF recommendations is prevalent among U.S. women aged 40-49 years. Efforts are needed to increase women's awareness of the rationale for guidelines and the opportunities to discuss with providers whether delaying mammograms is appropriate.