Abstract
BACKGROUND: Breast cancer (BC) survivors are at an increased risk of long-term cardiovascular disease (CVD), often attributed to cancer treatment. However, cancer treatment may also negatively impact health-related quality of life (HRQoL), a risk factor of CVD in the general population. OBJECTIVE: We examined whether sleep disturbance, and physical or mental HRQoL were associated with CVD risk in BC survivors. METHODS: We conducted a longitudinal analysis in the Women's Health Initiative of postmenopausal women given a diagnosis of invasive BC during follow-up through 2010 with no history of CVD before BC. The primary outcome was incident CVD, defined as physician-adjudicated coronary heart disease or stroke, after BC. Physical and mental HRQoL, measured by the Short-Form 36 Physical and Mental Component Summary scores, and sleep disturbance, measured by the Women's Health Initiative Insomnia Rating Scale, were recorded post BC. Time-dependent Cox proportional hazards models were used starting at BC diagnosis until 2010 or censoring and adjusted for relevant confounders. RESULTS: In 2884 BC survivors, 157 developed CVD during a median follow-up of 9.5 years. After adjustment, higher Physical Component Summary scores were significantly associated with a lower risk of CVD (hazard ratio, 0.90 [95% confidence interval, 0.81-0.99]; per 5-point increment in Physical Component Summary). No associations with CVD were found for Mental Component Summary or Insomnia Rating Scale. CONCLUSION: In BC survivors, poor physical HRQoL is a significant predictor of CVD. IMPLICATIONS FOR PRACTICE: Our findings highlight the importance for nurses to assess and promote physical HRQoL as part of a holistic approach to mitigating the risk of CVD in BC survivors.