Associations between Serum 25-Hydroxyvitamin D Levels and Health-Related Quality-of-Life Measures in Patients with Breast Cancer: A Longitudinal Study

Abstract

Background: Recent evidence suggests that vitamin D might lower breast cancer mortality. There is also growing interest in vitamin D's potential association with health-related quality-of-life (HRQoL). Associations between circulating 25-hydroxyvitamin D (25OHD) concentrations and HRQoL were examined prospectively among breast cancer survivors at the time of diagnosis and 1 year later.

Methods: 504 women with incident early-stage breast cancer at Roswell Park Comprehensive Cancer Center were included, and 372 patients provided assessments 1 year later. At each timepoint, participants provided blood samples and completed the SF-36 Health Survey, and surveys on perceived stress, depression, and fatigue. Season-adjusted serum 25OHD concentrations were analyzed in relation to HRQoL measures using multivariable logistic regression models.

Results: Approximately 32% of participants had deficient vitamin D levels at diagnosis, which decreased to 25% at 1 year. Concurrently, although SF-36 physical health summary scores were lower at 1 year, mental health summary scores improved, and levels of depression and perceived stress were lower. In comparison with women with sufficient 25OHD levels (>30 ng/mL) at diagnosis, those who were deficient (<20 ng/mL) had significantly worse HRQoL at diagnosis and 1 year later. Vitamin D deficiency 1 year post-diagnosis was also associated with worse HRQoL, particularly among breast cancer survivors who took vitamin D supplements.

Conclusions: Breast cancer survivors with vitamin D deficiency were more likely to report lower HRQoL than those with sufficient levels at the time of diagnosis and 1 year post-diagnosis.

Impact: Our results indicate a potential benefit of vitamin D supplementation for improving breast cancer survivorship.

Figure 1.. Associations between circulating 25OHD levels and quality-of-life at the time of breast cancer diagnosis.

Models reflect the dichotomized baseline quality-of-life outcome as a function of baseline vitamin D level in all study participants (N=504) and by vitamin D supplement use prior to diagnosis. ^aModels are adjusted for age (continuous), menopausal status (premenopausal, postmenopausal), race (white, Black), level of education attained (high school or less, some college, college graduate, advanced degree, missing), BMI at diagnosis (continuous, log-transformed), smoking status (current, former, never, missing), breast cancer stage (0, I, IA, ≥IIB) and estrogen receptor status (positive, negative, not determined). ^bFor models with poor fit (due to small sample sizes), absolute ridging and Newton-Raphson techniques were used to achieve model convergence.

Figure 2.. Associations between circulating 25OHD levels at diagnosis and quality-of-life 1-year post-diagnosis.

Models reflect the dichotomized 1-year quality-of-life outcome measures as a function of baseline vitamin D level in participants with data on change in vitamin D levels. ^aModels adjusted for age (continuous), menopausal status (pre- / post-), race (Caucasian, African American), education (High school and less, some college, college graduate (4 year), advanced degree, missing), BMI at 12 months post-diagnosis (continuous, log-transformed), smoking status (current, former, never, missing), breast cancer stage (stage 0, stage I, stage IIA, ≥ Stage IIB), ER status (positive, negative, not determined), and baseline quality-of-life measure (continuous).

Figure 3.. Associations between circulating 25OHD levels and quality-of-life 1-year post-diagnosis.

Models reflect the dichotomized 1-year quality-of-life outcome measures as a function of vitamin D levels at 1-year post diagnosis in participants with a change in vitamin D levels. ^aModels adjusted for age (continuous), menopausal status (pre- / post-), race (Caucasian, African American), education (High school and less, some college, college graduate (4 year), advanced degree, missing), BMI at 1 year post-diagnosis (continuous, log-transformed), smoking status (current, former, never, missing), stage (stage 0, stage I, stage IIA, > Stage IIB), ER status (positive, negative, not determined), and baseline quality-of-life measure (continuous).