A measure of environmental stress had a significant association with mortality risk in patients with breast cancer, a large retrospective cohort study showed.

Patients with a high allostatic load (AL) had almost a 50% higher all-cause mortality risk versus patients with a low AL. Stratification of AL scores showed that patients in the highest (fourth) quartile had almost an 80% greater risk than those in the lowest (first) quartile. Patients in the third quartile had a 56% greater relative risk as compared with the first quartile.

“There was a significant dose-dependent association between increased AL and a higher risk of all-cause mortality,” reported Samilia Obeng-Gyasi, MD, MPH, of the Ohio State University in Columbus, and co-authors in JAMA Network Open. “Furthermore, AL remained significantly associated with higher all-cause mortality after adjusting for the Charlson Comorbidity Index.”

“These findings suggest increased AL is reflective of socioeconomic marginalization and associated with all-cause mortality in patients with breast cancer,” they concluded.

The results added to a growing body of evidence that external stressors may adversely affect outcomes in cancer and other diseases.