Sedentary behaviour and physical activity are increasingly recognised as determinants of health across the life-span. Our (1,2) and other recent meta-analyses have identified linear and non-linear dose-response associations for sedentary time and physical activity with cardio-metabolic markers and chronic disease, including total and cause-specific mortality, incident cardio-vascular disease, cancer and diabetes. Such evidence forms the cornerstone of public health guideline development on sedentary and active behaviours.
However, the majority of this evidence is based on self-reported physical activity, which has important limitations. Objective measurements, by means of small, non-invasive, body-worn electronic devices, allow detailed and more valid assessment of the entire activity intensity spectrum (from sedentary time to high-intensity activity), both in terms of total time volume and accumulation patterns. This has been increasingly examined in recent years in prospective studies, which allows inference on temporal sequence. Cross-cohort analyses can explore differences between population subgroups (defined by ethnicity, BMI, etc.) and also enhance statistical power and heterogeneity of exposure distribution. Given the diversity of objective methods between different cohorts, harmonisation of the exposure data is vital. Our unit leads cross-cohort consortia focusing on harmonisation and pooling of objective sedentary and activity data from cohort studies with great geographic diversity.
This PhD project will examine dose-response associations of a diversity of sedentary and activity exposures with cardio-metabolic health markers, using cross-cohort harmonised objective exposure data. Given the diversity of data available, the exact project undertaken may be decided after discussions with the supervisory team. We are looking for a PhD student with a strong background in epidemiology or exercise science/physiology, and ideally knowledge in physical activity assessment and experience in statistical analyses of epidemiological datasets.
- Patterson R, McNamara E, Tainio M, de Sa TH, Smith AD, Sharp SJ, Edwards P, Woodcock J, Brage S, Wijndaele K: Sedentary behaviour and risk of all-cause, cardiovascular and cancer mortality, and incident type 2 diabetes: a systematic review and dose response meta-analysis. Eur J Epidemiol 2018
- Smith AD, Crippa A, Woodcock J, Brage S: Physical activity and incident type 2 diabetes mellitus: a systematic review and dose-response meta-analysis of prospective cohort studies. Diabetologia 59:2527-2545, 2016