Abstract B10: Fasting blood glucose and bone mineral density in Latina breast cancer survivors
Authors: Dieli-Conwright Christina , Avery Lindsey , Mortimer Joanne , Tripathy Debu , Spicer Darcy , Bernstein Leslie 
Published: October 2015

Background. Elevated fasting blood glucose (FBG) in Latina women has been identified as a risk factor for osteoporosis, independent of history of breast cancer. Elevated FBG, a sign of poor glycemic control among Latina women has been shown to increase bone resorption and subsequent bone loss over time. Treatment for breast cancer can also result in significant decreases in bone mineral density (BMD), which may be further exacerbated by the premature onset of menopause. Decreases in estrogen associated with the onset of menopause and hormonal therapy have been shown to accelerate bone loss in women.

Purpose. The purpose of the present investigation was: 1) to examine the association between FBG and lumbar spine and hip (regional) BMD in Latina breast cancer survivors (LBCS); and 2) to examine the influence of menopausal status on FBG and BMD in LBCS. We hypothesized that increased FBG would be correlated with decreased lumbar spine and hip BMD in LBCS. Additionally, it was hypothesized that postmenopausal status would further exaggerate the association between increased FBG and BMD in LBCS.

Methods. The present study included baseline data from 24 LBCS, recruited from Los Angeles County Hospital and Norris Comprehensive Cancer Center at USC as a part of a larger ongoing exercise trial. Participants included Stage I-III breast cancer patients who were sedentary and had received chemotherapy and/or radiation within 6 months prior to joining the study. Participants reported to the Women's Health and Exercise Laboratory at the USC for data collection. Participants were required to fast for 12 hours prior to the study visit and plasma FBG was measured using a venous sample from the antecubital vein. Participants completed a dual-energy x-ray absorptiometry (Lunar DEXA®GE Healthcare) scan to measure right (R) and left (L) hip (femur; F) BMD (RFBMD, LFBMD, respectively) and lumbar spine BMD (LSBMD). T scores were obtained via DEXA scan, which is the score of the site-specific BMD when compared to the young (30-year-old woman) normal reference mean. Pearson correlations were used to examine associations between FBG and T-scores of RF/LF/LS BMD in LBCS. Independent t-tests were used to compare mean FBG and BMD values between premenopausal and postmenopausal LBCS. Statistical significance was set at p&lt;0.05.

Results. Mean ages were 46.2±7.0 years in premenopausal (PRE) LBCS (n=10) and 56.9±7.5 years in postmenopausal (POST) LBCS (n=14). Mean FBG and T-scores of regional BMD (LSBMD, RFBMD, LFBMD) are listed in Table 1. Mean FBG was significantly greater in postmenopausal LBCS when compared to premenopausal women (p&lt;0.01). T-scores of LSBMD, RFBMD and LFBMD did not significantly differ in premenopausal and postmenopausal LBCS (p=0.58, p=0.97, p=0.54, respectively). Increased FBG was not associated with decreased LSBMD, RFBMD or LFBMD in premenopausal LBCS (p=0.38, r2=-0.31; p=0.99, r2=0.01; p=0.75, r2=0.12, respectively). Increased FBG was not associated with decreased LSBMD, RFBMD or LFBMD in postmenopausal LBCS (p=0.16, r2=0.40; p=0.80, r2=0.08; p=0.55, r2=0.17, respectively).

Conclusion. In this limited sample size, FBG was not shown to be a predictive factor for decreased BMD in either premenopausal or postmenopausal LBCS, despite elevated FBG in postmenopausal LBCS. Our results differed from our hypothesis which, may be due to FBG levels that were only slightly elevated in LBCS with relatively healthy BMD. However, future investigations are warranted to further investigate whether elevated FBG is a risk factor for osteoporosis in larger sample of LBCS over a longer follow-up period.

Table 1. Outcome Measures

PRE LBCS

FBG** 95.0±6.72 mg/dL*

LSBMD T-score# -0.32±0.73

RFBMD T-score# 0.33±0.34

LFBMD T-score# 0.14±0.35

POST LBCS

FBG** 107.8±22.0 mg/dL*

LSBMD T-score# -0.14±0.054

RFBMD T-score# 0.25±0.42

LFBMD T-score# 0.27±0.34

**Means are ± SD; #Means are ± SE. *Means are statistically significantly different (p&lt;0.05).

Citation Format: Christina Dieli-Conwright, Lindsey Avery, Joanne Mortimer, Debu Tripathy, Darcy Spicer, Leslie Bernstein. Fasting blood glucose and bone mineral density in Latina breast cancer survivors. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr B10.