Letters Section Editor: Jody W. Zylke, MD, Senior Editor.
Author Affiliations: NCH Healthcare Group, Naples, Florida (Dr Goldstein; firstname.lastname@example.org); and Medical Service, Comando Brigata Alpina “Julia,” Udine, Italy (Dr Mascitelli).
To the Editor: Dr Johnson and colleagues,1 using the SEER database, reported a statistically significant increase in the incidence of breast cancer with distant disease among women aged 25 to 39 years in the United States between 1976 and 2009. We suggest that folate supplementation might play a contributory role in this trend.
Studies have raised suspicion that folate supplementation might increase the incidence of subsequent breast cancer in women. For example, the large prospective Women's Health Study demonstrated that higher blood folate concentrations were associated with a relative risk of 1.99 for developing premenopausal invasive breast cancer (P = .04 for trend).2 Higher total folate intake, but not folate intake from food, was associated with invasive breast cancer (P = .03 for trend), suggesting that supplemental folate intake may be associated with the increased risk.
Goldstein MR, Mascitelli L. Incidence Rate of Breast Cancer in Young Women. JAMA. 2013;309(23):2433. doi:10.1001/jama.2013.6447