1
|
Atkinson C, Ray RM, Li W, Lin MG, Gao DL, Shannon J, Stalsberg H, Porter PL, Frankenfeld CL, Wähälä K, Thomas DB, Lampe JW. Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China. Nutr Res 2016; 36:863-71. [PMID: 27440541 DOI: 10.1016/j.nutres.2016.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 01/12/2023]
Abstract
Equol (a bacterial metabolite of the soy isoflavone daidzein) is produced by 30% to 50% of humans and may be associated with health outcomes. We hypothesized that plasma equol would be inversely associated with risks of fibrocystic breast conditions (FBC) and breast cancer (BC). Plasma from women in a breast self-examination trial in Shanghai with BC (n=269) or FBC (n=443), and age-matched controls (n=1027) was analyzed for isoflavones. Equol was grouped into categories (<20, 20-<45, and ≥45nmol/L) and, among women with daidzein ≥20nmol/L, the log10 equol:daidzein ratio was grouped into tertiles. Where available, non-cancerous tissue (NCT) adjacent to the carcinomas from women with BC were classified as non-proliferative or proliferative (n=130 and 172, respectively). The lesions from women with FBC were similarly classified (n=99 and 92, respectively). Odds ratios (OR) and 95% confidence intervals (CI) were calculated across equol categories and tertiles of log10 equol:daidzein ratio. Equol categories were not associated with FBC or BC (P>.05). For log10 equol:daidzein, compared to controls there were positive associations in the mid tertile for proliferative FBC (OR 2.06, 95% CI 1.08-3.93), BC with proliferative NCT (OR 2.95, 95% CI 1.37-6.35), and all BC regardless of histology (OR 2.37, 95% CI 1.43-3.95). However, trends in ORs with increasing plasma equol values or equol:daidzein ratios were not observed (P>.05). The results of this study do not provide evidence that equol plays a role in the etiology of these breast conditions. However, further work is needed to confirm or refute this conclusion.
Collapse
Affiliation(s)
- Charlotte Atkinson
- Bristol Dental School, University of Bristol, Bristol, UK; NIHR Biomedical Research Unit in Nutrition, Diet, and Lifestyle, University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, UK.
| | - Roberta M Ray
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Wenjin Li
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Ming-Gang Lin
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Dao Li Gao
- Zhong Shan Hospital Cancer Center, Shanghai, China
| | | | | | - Peggy L Porter
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | | | - David B Thomas
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | |
Collapse
|