The benefits of exercise for overall health and disease prevention are well known. While research overwhelmingly points to physical activity as a protective factor against colorectal cancer, more research is necessary to delineate how the timing of physical activity during one’s life impacts the risk of developing colon cancer. In a recently published study, researchers examined the differences in colon cancer incidence in relation to levels of physical activity at different stages of life.
Researchers conducted a baseline survey in 1995 and 1996 of adult men and women to measure exposures to moderate-to-vigorous physical activity (MVPA) and several other lifestyle-related factors among nearly 300,000 adults (50-71 years). Study follow-ups ceased in 2011 or following any diagnosis of colon cancer or death.
In the primary exposure assessment, participants were asked to report and quantify MVPA they had participated in at various stages of their life: at ages 15-18, 19-29, 30-35, and in the previous decade. MVPA levels were measured by time:
- Rarely or none
- Less than 1 hour a week
- 1-3 hours a week
- 4-7 hours a week
- Greater than 7 hours per week
Pattern Recognition and Impact on Colon Cancer Risk
Researchers identified specific patterns of MVPA:
- Maintaining the same general level of physical activity throughout the life course (whether low, moderate, or high levels of MVPA)
- Raising levels of physical activity during the life course, either earlier or later in life (increasers)
- Reducing the amount of MVPA over time, either earlier or later in life (decreasers)
Several key findings emerged from these patterns:
- Participants who maintained high MVPA levels throughout their life had a 15% lower risk of colon cancer than those who maintained low MVPA levels throughout their life
- Participants who increased MVPA levels at a younger age had a 10% reduced risk of colon cancer, and participants who increased MVPA levels at an older age had an 8% reduced risk of colon cancer
- Decreasing MVPA levels during the life course resulted in a 12% higher risk of colon cancer incidence when compared with individuals who maintained low MVPA levels throughout their life
These findings suggest that individuals who consistently engage in MVPA throughout their life and those who increase MVPA levels during their life have a lower risk of being diagnosed with colon cancer. They provide hope to individuals who may begin their fitness journey later in life.
Emma Edwards is a Colorectal Cancer Prevention Intern with the Colon Cancer Foundation.