25-Hydroxy vitamin-D, obesity, and associated variables as predictors of breast cancer risk and tamoxifen benefit in NSABP-P1.

Abstract

Observational studies suggest that host factors are associated with breast cancer risk. The influence of obesity, vitamin-D status, insulin resistance, inflammation, and elevated adipocytokines in women at high risk of breast cancer is unknown. The NSABP-P1 trial population was used for a nested case-control study. Cases were drawn from those who developed invasive breast cancer and controls selected from unaffected participants (≤4 per case) matched for age, race, 5 year Gail score, and geographic location of clinical center as a surrogate for latitude. Fasting serum banked at trial enrolment was assayed for 25-hydroxy vitamin-D (25OHD), insulin, leptin (adipocytokine), and C-reactive protein (CRP, marker of inflammation). Logistic regression was used to test for associations between study variables and the risk of invasive breast cancer. Two hundred and thirty-one cases were matched with 856 controls. Mean age was 54, and 49% were premenopausal. There were negative correlations for 25OHD with body mass index (BMI), insulin, CRP, and leptin. BMI ≥ 25 kg/m(2) was associated with higher breast cancer risk (odds ratio [OR] 1.45, p = 0.02) and tamoxifen treatment was associated with lower risk (OR = 0.44, p < 0.001). Suboptimal 25OHD (<72 nmol/l) did not influence breast cancer risk (OR = 1.06, p = 0.76). When evaluated as continuous variables, 25OHD, insulin, CRP, and leptin levels were not associated with breast cancer risk (all p > 0.34). In this high risk population, higher BMI was associated with a greater breast cancer risk. Serum levels of 25OHD, insulin, CRP, and leptin were not independent predictors of either breast cancer risk or tamoxifen benefit.

• Authors: Eitan Amir, Reena S Cecchini, Patricia A Ganz, Joseph P Costantino, Samantha Beddows, Nicola Hood, Pamela J Goodwin
• Journal: Breast cancer research and treatment (Breast Cancer Res Treat) Vol. 133 Issue 3 Pg. 1077-88 (Jun 2012) ISSN: 1573-7217 [Electronic] Netherlands
• PMID: 22415479 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents, Hormonal
• Insulin
• Leptin
• Tamoxifen
• Vitamin D
• C-Reactive Protein
• 25-hydroxyvitamin D

Topics

• Adult
• Aged
• Antineoplastic Agents, Hormonal (therapeutic use)
• Body Mass Index
• Breast Neoplasms (blood, epidemiology, prevention & control)
• C-Reactive Protein (metabolism)
• Case-Control Studies
• Female
• Humans
• Insulin (blood)
• Leptin (blood)
• Middle Aged
• Obesity (complications)
• Odds Ratio
• Risk
• Tamoxifen (therapeutic use)
• Vitamin D (analogs & derivatives, blood)