Study: Those with the slowest walking pace have double the risk for all cause mortality compared with cancer-free peers

A slow walking pace appears to be associated with an increased mortality risk in cancer survivors, according to a large cohort study published in Cancer Epidemiology, Biomarkers & Prevention. Compared with cancer-free peers, cancer survivors self-reported poorer ambulatory function up to five years after their treatment.

In a comparison of over 30,000 cancer survivors with over 200,000 cancer-free controls, cancer survivors had a 42% greater risk of walking at the slowest pace compared with non-cancer controls at an odds ratio (OR) of 1.42 (95% CI, 1.30-1.54), Elizabeth Salerno, PhD, MPH, Washington University in St. Louis School of Medicine, St. Louis, Missouri, and colleagues reported. Similarly, after adjusting for all possible confounders, cancer survivors had a 24% higher risk of being disabled from a mobility standpoint at an OR of 1.24 (95% CI, 1.17-1.31).

Compared with cancer survivors who walked the fastest, survivors who walked the slowest had double the risk for all-cause mortality at a Hazard Ratio (HR) of 2.22 (95% CI, 2.06-2.39), while mobility disability following a diagnosis of cancer was associated with an almost 2-fold increased risk of all-cause mortality at a HR of 1.80 (1.73-1.88). This pattern of association also persisted for cancer-specific mortality —HR 2.12 (1.83-2.45).

“Poor ambulatory function has been consistently associated with worsened survival in healthy older adults,” Salerno and colleagues pointed out. “Ambulatory function has often been referred to as the ’sixth vital sign’ given its validated and prognostic value for its functional perspective on health status.” While this association appears to also extend to cancer patients, the researchers pointed out that not many studies of ambulatory function vis-a-vis particular cancer types have been done, which they note is “an important consideration in directing more precise interventions to promote functional health and longevity during survivorship.”

The researchers sought to address the evidence gaps associated with ambulation and cancer survivorship over 15 different cancer types. They looked at:

  • “Whether a diagnosis of cancer is associated with lower ambulatory function.”
  • “The independent effects of these functional domains on mortality in cancer survivors specifically, as well as the joint effect of both a cancer diagnosis and poor ambulatory function.”

They hypothesized that not only would cancer survivors have an increased risk in decline of ambulatory function, but that it would “be associated with increased risk of all-cause and cancer-specific mortality in cancer survivors.”

Participants in the study were part of the NIH-American Association of Retired Persons (AARP) Diet and Health Study, a large, prospective trial involving over 500,000 AARP members between 50 and 71 years of age. At baseline, participants were just over 60 years of age, and over 56% of them reported that they were in very good health. Over two-thirds of cancer survivors had early stage I disease and close to 60% had undergone surgery as part of their treatment.

“At follow-up, participants self-reported their normal walking pace [’easy’ (<2mph); ’normal, average’ (2-2.9mph); ’brisk’ (3-3.9 mph) and ’very brisk, striding’ (≥ 4 mph); and ’unable to walk’]. Ambulatory function was evaluated in terms of walking pace and mobility disability,” the investigators explained.

Analyses confirmed that the association between cancer diagnosis and an increased risk of all-cause mortality persisted in nine different cancer types, they found.

More specifically, survivors who reported the slowest walking pace had an almost 2-fold increased risk of all-cause mortality at a HR in excess of 1.91 if they had a history of breast, colon, melanoma, non-Hodgkin lymphoma, oral, prostate, rectal, respiratory, or urinary cancer. “More robust associations were evident for mobility disability,” researchers added.

Both cancer survivors and the cancer-free controls with poorer ambulatory function had an increased risk of all-cause mortality, but this was more pronounced in the survivors. For example, compared with controls who had the fastest walking pace, cancer survivors with the slowest walking pace had an over 10-fold higher risk of all-cause mortality at a HR of 10.37 compared with a HR of 3.91 for controls with the slowest walking pace.

“[O]ur results… suggest that risks associated with lower ambulatory function may be two to three times stronger for early mortality in survivors compared with the general population,” Salerno and colleagues wrote. “Given that cancer survivors with poor ambulatory function had two to three times greater mortality risk than their cancer-free peers, public health efforts should focus on identifying and targeting survivors who are at-risk for poor functional health to ultimately improve survival.”

Among the study’s limitations are that the “analytic sample was comprised of less than the original NIH-AARP cohort, thus results may be more relevant to individuals who filled out the follow-up questionnaire,” and “limited treatment information available from cancer registries also made it difficult to understand the specific regimens that may be detrimental to ambulatory function,” they noted.

  1. Cancer survivors had poorer ambulatory function up to five years after their treatment than their cancer-free peers.

  2. All-cause mortality was significantly higher among cancer survivors with the slowest walking pace compared to survivors who walked the fastest.

Pam Harrison, Contributing Writer, BreakingMED™

Research was supported in part by the Intramural Research Program of the NIH.

The authors had no conflicts of interest to declare.

Cat ID: 118

Topic ID: 78,118,282,494,730,118,935,192,255,48,925