Identifying health consequences of, and the social and environmental determinants for, physical activity and sedentary behaviour
Within an established program of observational-study research that uses large, multi-variable cross-sectional and prospective data sets, we conduct two main threads of investigation designed to inform population-based approaches to the primary prevention of cardiovascular disease and diabetes:
- What are the unique relationships of physical activity and sedentary behaviour with cardio-metabolic risk biomarkers and with morbidity and mortality outcomes?
- Identifying the environmental and social determinants of physical activity and sedentary behaviour — what needs to be changed in order to increase physical activity and reduce prolonged sitting time?
Data sets used for these studies include:
- AusDiab (the Australian Diabetes, Obesity and Lifestyle study), with data collected at three time points (AusDiab1 1999–2000; AusDiab2 2004–05; and AusDiab3 2011–12).
- NHANES (the National Health and Nutrition Examination Survey)
— a population-representative surveillance study of US civilians.
- PLACE (Physical Activity in Localities and Community Environments)
— a study with two observation points four years apart that includes objective measures of environmental attributes derived from Geographic Information Systems data sets.
- IPEN (International Physical Activity and the Environment Network study)
— a US National Cancer Institute funded study gathering accelerometer, survey and geographic information system data from 11 countries.
In identifying unique health consequences of physical activity and sedentary behaviour, in our work with AusDiab — for example, we are using device-derived measures to examine relationships with cardio-metabolic risk biomarkers of the patterns and accumulation of time spent sitting, standing, stepping and in light-intensity and moderate-to-vigorous intensity activity. AusDiab 3 is the first large population based study that has highly precise measures of sitting time (ActivPal inclinometer) together with an array of biological measures, including an oral glucose tolerance test. Compared to accelerometer-derived data, ActivPal data provide a much more precise indicator of sitting time, as it is able to measure posture and is thus an excellent tool to identify health consequences of too little physical activity and too much sitting.
In understanding the social and environmental determinants of physical activity and sedentary behaviour, we are working with data from AusDiab and the PLACE and IPEN studies to identify unique behavioural determinants with the potential to be addressed through large-scale policy initiatives to reduce chronic disease risk. For example, we have initially shown significant associations of objective and perceived indices of ‘neighbourhood walkability' with levels of physical activity and sedentary behaviour; ongoing studies are examining the influence of specific environmental attributes (including walking routes and local destinations).
The AusDiab project is generously supported by NHMRC