Objective:

To examine the independent associations of prolonged and interrupted sedentary behavior with cancer risk among UK Biobank participants.

Approach:

• Study Design: A prospective cohort study involving 91,292 participants without a history of cancer, using wrist-worn accelerometers to measure sedentary behavior and physical activity.
• Data Collection: Participants wore accelerometers for 7 days between 2013 and 2015, with follow-up for a median of 12.4 years using hospital admission and mortality records.
• Data Analysis: Multivariable Cox proportional hazards models were used, adjusting for various factors, and isotemporal substitution models estimated associations with replacing prolonged sedentary behavior.

Key Findings:

• Prolonged sedentary behavior was linked to higher risks of cancer mortality and incidence, including obesity-related and type 2 diabetes-related cancers.
• Interrupted sedentary behavior was associated with lower risks of cancer outcomes.
• Each additional hour of prolonged sedentary behavior increased cancer mortality and incidence risks.
• Replacing prolonged sedentary behavior with physical activity reduced cancer risks, especially with vigorous-intensity activity.

Interpretation:

Accumulating sedentary time in shorter, interrupted bouts is independently linked to a lower risk of cancer outcomes.

Limitations:

• The study cannot prove causality.
• Residual confounding and healthy volunteer bias may affect results.
• Measurement imprecision due to only 7 days of accelerometer wear.
• The accelerometer could not identify the context of sedentary activities.

Conclusion:

Replacing prolonged sedentary behavior with physical activity is associated with a lower risk of cancer death.

Sources:

• PLOS Medicine