A study by Salerno et al published in Cancer Epidemiology, Biomarkers & Prevention investigating the association of a cancer diagnosis and poor ambulatory function of survivors and subsequent mortality has found that cancer survivors with poor ambulatory function had a two to three times greater mortality risk than their cancer-free counterparts. Widespread public health efforts should focus on identifying and targeting cancer survivors who are at risk for poor functional health to improve survival, reported the study authors.
Ambulatory function, as indicated by walking pace and major mobility disability, is critical for independence into old age. Studies show that poor ambulatory function has been consistently linked with worsened survival in healthy older adults.
Study Methodology
The researchers analyzed data from the NIH-American Association of Retired Persons (AARP) Diet and Health Study, which included over 500,000 AARP members between the ages of 50 and 71 who responded to a baseline questionnaire assessing diet, medical history, and demographics between 1995 and 1996. Between 2004 and 2006, surviving members of the cohort were sent a follow-up questionnaire that assessed health status, lifestyle behaviors, body size, and ambulatory function, among other factors. Ambulatory function was determined by self-reported walking pace and mobility disability.
After excluding individuals for reporting inaccuracies and incomplete questionnaires, the final number of participants included 30,403 cancer survivors and 202,732 individuals who had never been diagnosed with cancer. The median age of the participants was 61.8 years; most identified as White (92.4%), male (56.7%), and being in very good health (56.4%).
The researchers used multinomial logistic regression to quantify the association between cancer and ambulatory function. They then explored the independent effects of walking pace and mobility disability in cancer survivors and the joint effects of both a cancer diagnosis and poor ambulatory function on mortality using Cox proportional hazards models. The models explored specific associations across 15 cancer types.
Findings
KEY POINTS
- Cancer survivors with poor ambulatory function had a two to three times greater mortality risk than their cancer-free counterparts.
- Lower ambulatory function was associated with several cancer types, especially respiratory or oral cancers.
- Efforts to improve ambulatory function during survivorship—including physical activity, which has been shown to increase gait speed—may be beneficial for survivors, especially older cancer survivors.
The researchers found that the cancer survivors had 42% greater odds of walking at the slowest pace [odds ratio [OR] = 1.42, confidence interval [CI] = 1.30–1.54) and 24% greater odds of mobility disability (OR = 1.24, CI = 1.17–1.31), compared with cancer-free participants, adjusting for baseline demographics, health indicators, and cancer type. Survivors reporting the slowest pace were at greater risk than those who walked the fastest: all-cause mortality (hazard ratio [HR] = 2.22, CI = 2.06–2.39) and cancer mortality (HR = 2.12, CI = 1.83–2.45).
Similar trends emerged for mobility disability (HRs > 1.64). Lower ambulatory function was associated with several cancer types, and the strongest associations were observed for survivors of respiratory or oral cancers. All-cause mortality associations were significant for more than nine cancer types.
“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,” concluded the study authors.
Translational Relevance
The results from this study show the role of a cancer diagnosis on patients’ ambulatory function and the implications of poor function on survival.
Elizabeth Salerno, PhD, MPH
“Our findings suggest that functional health may be adversely affected by a broad range of cancer diagnoses and may be an important determinant for survival,” said Elizabeth Salerno, PhD, MPH, Assistant Professor of Surgery at Washington School of Medicine in St. Louis and lead author of the study, in a statement. “There is still much to be learned about these complex relationships, but our results highlight the potential importance of monitoring, and even targeting, ambulatory function after cancer for survival benefits, particularly in older cancer survivors.”
Disclosure: Funding for this study was provided by National Cancer Institute. For full disclosures of the study authors, visit cebp.aacrjournals.org.
