1. In this prospective cohort study, higher cardiorespiratory fitness (CRF) was associated with a substantially lower risk of breast cancer in postmenopausal women.
2. However, this protective effect of high CRF was only seen in those with overweight/obesity or a higher body fat percentage.
Evidence Rating Level: 2 (Good)
Several risk factors exist for developing breast cancer, especially in postmenopausal women. Cardiorespiratory fitness (CRF) represents a modifiable risk factor that may affect the risk of developing breast cancer. The evidence for CRF to reduce the incidence of breast cancer has not been well established. As a result, the objective of the present prospective study was to evaluate the association between CRF and invasive breast cancer in postmenopausal women.
The present study recruited 17,840 (median age= 60 years) cancer-free postmenopausal women who had a CRF assessment from the UK Biobank between 2006 and 2010. Participants were included if they had not had a menstrual period for >365 days, had a history of double oophorectomy, or had no other menstrual information available but were older than 55 years. Women were excluded if they had a personal history of cancer or mastectomy at baseline. Estimated CRF (eCRF) was assessed using a submaximal bicycle test and was classified as low (<20th percentile), moderate (20th to <80th percentile), and high (≥ 80th percentile). Statistical analyses were performed using regression models. The primary outcome was the time from baseline assessment to incident breast cancer diagnosis.
The results demonstrated that over a median follow-up of 11 years, 3% of women were diagnosed with invasive breast cancer. Patients with higher eCRF had a 24% lower risk of developing breast cancer than those with a low or moderate eCRF. However, it was found that this result was limited to those who were classified as having overweight/obesity. The study was limited by using a submaximal bicycle test to determine eCRF, rather than the gold standard: a maximal treadmill test with oxygen expiration capture. However, these results suggested that in certain populations, eCRF may decrease the incidence of breast cancer among postmenopausal women.
©2023 2 Minute Medicine, Inc. All rights reserved. No works may be reproduced without expressed written consent from 2 Minute Medicine, Inc. Inquire about licensing here. No article should be construed as medical advice and is not intended as such by the authors or by 2 Minute Medicine, Inc.