Framingham risk score and its relationship with cardiorespiratory fitness and physical activity levels in older breast cancer survivors

Older breast cancer (BC) survivors are at increased risk of developing cardiovascular disease (CVD). The Framingham Risk Score (FRS) is a widely used tool for estimating 10-year risk of atherosclerotic CVD or myocardial infarction. Cardiorespiratory fitness, objectively measured as peak oxygen uptake (VO₂peak), is a strong predictor of all-cause and CVD mortality. Despite this, the relationship between VO₂peak, physical activity levels, and traditional risk factors used to guide long-term CVD risk in older BC survivors remains understudied.

This study aimed to examine whether cardiorespiratory fitness and physical activity levels are associated with 10-year FRS estimates in older, long-term BC survivors.

BC survivors (≥60 years) who were greater than one year post anthracycline or trastuzumab therapy and without established CVD were enrolled. Cardiorespiratory fitness was assessed using gas- exchange analysis during a graded maximal exercise test performed on a stationary cycle ergometer and weekly physical activity was assessed from a self-report questionnaire. FRS was determined from health history questionnaires (deriving age, smoking history and medication use), fasted blood draw (HDL- and total cholesterol) and resting blood pressure measurement (systolic blood pressure) in order to calculate 10-year risk scores. Pearsons or Spearmans correlation coefficients were used to examine associations between 10-year FRS and VO₂peak and self reported physical activity levels. Data are reported as mean ± SD or median (IQR), and statistical significance was set at α < 0.05.

Seventy-one participants were included in the analysis (mean age: 69 ± 5 years, BMI: 27.4 ± 5.4 kg/m2, time post treatment: 13.9 ± 6.1 years). Mean VO₂peak was 19.1 ± 4.5 mL/kg/min, and participants self-reported 210 (70-300) minutes of exercise per week. The median composite FRS score was 13.0 (9.3-16.0), corresponding to a 10-year FRS of 10.0 (5.6-15.9). No significant association was found between FRS and VO₂peak (ρ = -0.076, p = 0.529). In contrast, self-reported physical activity was significantly, albeit weakly, associated with 10-year FRS (ρ = −0.240, p = 0.047).

Despite its wide-spread clinical use, 10-year FRS score is not related to VO₂peak in older BC survivors, despite VO₂peak being a major predictor of all-cause and CVD mortality. Future risk stratification should consider adding physical activity and VO₂peak alongside FRS to improve CVD prediction in older long-term BC survivors.

Correlations between primary outcomes