Amount and intensity of physical activity and risk of incident cancer in the UK Biobank

Abstract

ImportanceThe influence of total daily and light intensity activity on cancer risk remains unclear, as most existing knowledge is drawn from studies relying on self-reported leisure-time activities of moderate-vigorous intensity.ObjectiveTo investigate associations between total daily activity, including step counts, and activity intensity on incident cancer risk.Design, Setting, and ParticipantsProspective analysis of cancer-free UK Biobank participants who wore accelerometers for 7-days (between 2013-2015), followed for cancer incidence through national registries (mean follow-up 5.8 years (SD=1.3)).ExposuresTime-series machine learning models derived daily total activity (average acceleration), behaviour time, step counts, and peak 30-minute cadence from wrist-based accelerometer data.Main Outcomes and MeasuresA composite cancer outcome of 13 cancers previously associated with low physical activity (bladder, breast, colon, endometrial, oesophageal adenocarcinoma, gastric cardia, head and neck, kidney, liver, lung, myeloid leukaemia, myeloma, and rectum) based on previous studies of self-reported activity. Cox proportional hazards regression models estimated hazard ratios (HR) and 95% confidence intervals (CI), adjusted for age, sex, ethnicity, smoking, alcohol, education, Townsend Deprivation Index, and reproductive factors. Associations of reducing sedentary time in favour of increased light and moderate-vigorous activity were examined using compositional data analyses.ResultsAmong 86 556 participants (mean age 62.0 years (SD=7.9) at accelerometer assessment), 2 669 cancers occurred. Higher total physical activity was associated with a lower overall cancer risk (HR1SD=0.85, [95%CI 0.81-0.89]). On average, reallocating one hour/day from sedentary behaviour to moderate-vigorous physical activity was associated with a lower risk (HR=0.92, [0.89-0.95]), as was reallocating one hour/day to light-intensity physical activity (HR=0.94, [0.92-0.96]). Compared to individuals taking 5 000 daily steps, those who took 9 000 steps had an 18% lower risk of physical-activity-related cancer (HR=0.82, [0.74-0.90]). We found no significant association with peak 30-minute cadence after adjusting for total steps.Conclusion and RelevanceHigher total daily physical activity and less sedentary time, in favour of both light and moderate-vigorous intensity activity, were associated with a lower risk of certain cancers. For less active adults, increasing step counts by 4 000 daily steps may be a practical public health intervention for lowering the risk of some cancers.KEY POINTSQuestionWhat insights can we gain about the relationships between total daily activity, step counts, and activity intensity on cancer risk using accelerometer data?FindingsIn an analysis of 86 556 individuals from the UK Biobank who provided a week of accelerometer-based activity data, higher levels of total physical activity, reducing sedentary time in favour of light or moderate-vigorous intensity activities, and higher daily step counts were associated with a lower risk of certain cancers.MeaningFor less active adults, increasing activity time and accumulating more daily steps may be practical interventions for lowering the risk of some cancers.

Physical activity, metabolites, and breast cancer associations

“…Accelerometers, devices that capture movement, movement intensity, and activity type (e.g., stepping), are commonly used in large-scale epidemiological studies. Higher accelerometer-measured activity is consistently associated with lower breast cancer risk [13]. The range of metabolites investigated in studies exploring the relationships between accelerometer-measured activity and the metabolome is also limited.…”

“…The most extensive study to date analyzed 328 metabolites, highlighting associations with BCAA pathways and carbohydrate metabolism [10]. No study has investigated the relationship between step counts and metabolites, despite increasing recognition of step count as an important indicator of total activity relevant to cancer [13,14].…”