Elevated allostatic load (AL) has been associated with adverse socioenvironmental stressors and tumour characteristics that convey poor prognosis in patients with breast cancer. This study, recently published in JAMA, showed that high AL scores are linked to challenging life situations and are connected to higher mortality rates in breast cancer patients.
Allostatic load (AL) is a cumulative measure of physiologic damage due to cognitive-emotional responses and perceptions of socioenvironmental stressors, including factors such as low socioeconomic status. The AL score integrates primary (e.g., cortisol) and secondary outcomes (e.g., C-reactive protein) from the hypothalamic-pituitary-adrenal axis and sympathetic adrenal medullary pathway, along with tertiary outcomes (e.g., cancer). Emerging literature suggests that elevated AL scores are associated with exposure to adverse socioenvironmental stressors, increased risk of developing chronic diseases such as cancer, and worse all-cause mortality. This study aimed to analyse sociodemographic, clinical, and treatment differences between patients with high and low AL, and assess how AL is linked to all-cause mortality in breast cancer patients.
This cohort study used data from an institutional electronic medical record and cancer registry at the National Cancer Institute Comprehensive Cancer Center. The participants were patients diagnosed with stage I-III breast cancer between 2012 and 2020. The AL measure was derived from four physiologic systems, including cardiovascular (heart rate and blood pressure), metabolic (body mass index [BMI], alkaline phosphatase, blood glucose, and albumin), renal (creatinine, blood urea nitrogen), and immune (including white blood cell count). AL was calculated using the quartile method, the most common method of calculating AL in the literature, in which higher scores are indicative of worse physiologic dysregulation. AL was classified into high and low, with high AL defined as a total AL score greater than the median.
In total, 4,459 patients with breast cancer were included in this study. Black patients (adjusted relative ratio, aRR[95%CI]:1.11[1.04-1.18), those with single marital status (aRR[95%CI]:1.06[1.00-1.12]), and those with government-supplied insurance (Medicaid, aRR[95%CI]: 1.14[1.07-1.21]; Medicare aRR[95%CI]: 1.11[1.03-1.19]) exhibited higher adjusted mean AL scores compared to their white, married, or privately insured counterparts. After adjusting for sociodemographic, clinical, and treatment factors, high AL was associated with a 46% increase in mortality risk (HR[95%CI]: 1.46[1.11-1.93]) compared to low AL. Furthermore, when AL was examined as quartiles, those in the highest 2 quartiles (Q3: HR[95%CI]: 1.53[1.07-2.18] and Q4: HR[95%CI]: 1.79[1.16-2.75]) had significantly increased risks of mortality.
This study underscores the utility of routine clinical measurements, encompassing vital signs, anthropometric assessments, and laboratory analyses, in establishing a robust AL score. The study suggests that high AL scores are tied to challenging life situations and are connected to higher mortality rates in breast cancer patients.