GROWING EVIDENCE SHOWS CHRONIC STRESS—often fueled by systemic racism—negatively impacts a person’s health, putting them at increased risk for several diseases, including cancer. With that knowledge, researchers are designing interventions aimed at offsetting the ripple effects of that stress among those most at risk for cancer.

Two presentations during an April 16 session at the American Association for Cancer Research (AACR) Annual Meeting 2023 focused on how chronic stress influences breast cancer risk and outcomes for African American women. (The AACR publishes Cancer Today.)

Both studies used allostatic load to assess how chronic stress manifested itself in participants. “Allostatic load is a measure of chronic physiologic stress, or wear and tear on the body,” said epidemiologist Adana A.M. Llanos of the Columbia University Mailman School of Public Health in New York City. “It’s really a good measure of the body’s response to chronic, lifelong, accumulated exposures that are stressful.”

While a standardized measure for allostatic load is needed, the presenters said researchers have identified several common criteria—including blood pressure, body mass index, cholesterol, hypertension and obesity—that were used in these studies. These factors are weighed to assign patients a score of 0 to 8, with 8 representing the highest allostatic load.

For the past three decades, researchers have investigated the theory that “the health of African American and Black women begins to deteriorate in early adulthood as a physical consequence of chronic cumulative socioeconomic disadvantage,” Llanos said. She noted that accumulating evidence has found a high allostatic load puts Black people at increased risk for health issues like cardiovascular disease and cancer, as well as poorer outcomes from these conditions.

Llanos presented a study that involved 409 women ages 20 to 75 who identified as African American or Black and had breast cancer. Researchers determined their allostatic load one year before diagnosis based on their health records. They found those with elevated scores had increased risk of “more aggressive tumor features,” such as larger tumors or tumors with abnormal, quick-growing cells, Llanos said. “We are seeing a relationship between pre-diagnosis measures of allostatic load and breast cancer outcomes,” she said.

With increased recognition of the link between chronic stress and cancer, researchers are trying to leverage that knowledge to help those most at risk. Lucile L. Adams-Campbell, an epidemiologist and associate director for minority health and health disparities research at Georgetown University in Washington, D.C., presented her study assessing if physical activity can reduce allostatic load in African American women with high cancer risk.

The study involved 213 postmenopausal African American women ages 45 to 65 who were at increased risk for breast cancer and were unhealthy, as determined by waist circumference, blood pressure and glucose levels; 40% of the women also had a family history of breast cancer. Participants were randomly assigned to a supervised exercise program, a home-based exercise plan or no exercise routine, and everyone was asked not to change their diet. Their allostatic load scores were recorded at the study’s outset and across the next six months.

Participants in both exercise groups saw dips in their allostatic load scores, while the scores of those doing no exercise program stayed roughly the same. To the researchers’ surprise, however, the home-based exercise had a bigger impact on scores than the supervised program. “What we think is good might not be what other people think is good,” Adams-Campbell said, theorizing that the convenience of the at-home option proved more beneficial.

Additionally, the study found exercise impacted breast cancer risk among those with a family history of the disease, with their risk decreasing as their allostatic load dropped. This aligns with prior research finding high allostatic load exacerbates cancer risk factors, such as smoking and obesity, according to Adams-Campbell.

Adams-Campbell said the results highlight how targeting interventions to those at highest risk can yield the biggest impact. “We don’t want to exclude people, but we also need to recognize that the family history was the most important factor that really showed the significant differences between the groups,” she said.

Thomas Celona is an editor at Cancer Today.