Allostatic Load/Chronic Stress and Cardiovascular Outcomes in Patients Diagnosed With Breast, Lung, or Colorectal Cancer

Background Cardiovascular disease and cancer share a common risk factor: chronic stress/allostatic load (AL). A 1‐point increase in AL is linked to up to a 30% higher risk of major cardiac events (MACE) in patients with prostate cancer. However, AL's role in MACE in breast cancer, lung cancer, or colorectal cancer remains unknown. Methods and Results Patients ≥18 years of age diagnosed with the mentioned 3 cancers of interest (2010–2019) and followed up at a large, hybrid academic‐community practice were included in this retrospective cohort study. AL was modeled as an ordinal measure (0–11). Adjusted Fine–Gray competing risks regressions estimated the impact of AL precancer diagnosis on 2‐year MACE (a composite of heart failure, ischemic stroke, acute coronary syndrome, and atrial fibrillation). The effect of AL changes over time on MACE was calculated via piecewise Cox regression (before, and 2 months, 6 months, and 1 year after cancer diagnosis). Among 16 467 patients, 50.5% had breast cancer, 27.9% had lung cancer, and 21.4% had colorectal cancer. A 1‐point elevation in AL before breast cancer diagnosis corresponded to a 10% heightened associated risk of MACE (adjusted hazard ratio, 1.10 [95% CI, 1.06–1.13]). Similar findings were noted in lung cancer (adjusted hazard ratio, 1.16 [95% CI, 1.12–1.20]) and colorectal cancer (adjusted hazard ratio, 1.13 [95% CI, 1.08–1.19]). When considering AL as a time‐varying exposure, the peak associated MACE risk occurred with a 1‐point AL rise between 6 and 12 months post‐ breast cancer, lung cancer, and colorectal cancer diagnosis. Conclusions AL warrants investigation as a potential marker in these patients to identify those at elevated cardiovascular risk and intervene accordingly.