Determinants of physical activity in the UK Millennium Cohort Study


This project was carried out by the MRC Centre of Epidemiology for Child Health at University College London with funding from the Wellcome Trust and in collaboration with the Universities of Bath, Bristol and Cambridge and the Centre for Longitudinal Studies. The project ended in late 2011.


The prevalence of obesity in children has increased dramatically in recent years in most industrialised countries, with evidence of earlier age at onset.. In the UK, more than one quarter of 2-10 year old children are obese or overweight. The implications for children and their future health and well-being are immense but the reasons for the increase among pre-pubertal children remain unclear.  Information on tracking of activity and sedentary behaviours from childhood to adolescence is limited and mostly based on self report which can be difficult for children and their parents and may be misleading. There is some evidence to suggest that maintenance of physical activity may protect against abdominal fatness, especially in women, and that sedentary behaviours are very stable through childhood. This indicates that strategies to maintain healthy activity behaviours or to avoid or reverse unhealthy activity behaviours will need to target early childhood.

Further research is needed to understand how physically active and sedentary young children are, how this develops through childhood, and what promotes and impedes maintenance of a healthy level of physical activity throughout childhood and into adult life. The availability of objective accelerometer based measures of physical activity suitable for large scale studies in early childhood creates opportunities to address these questions but have not to date been widely used in large scale studies at this age

Research Questions

A range of questions were addressed, including:

1.     How many 7 year old children meet recommended levels of physical activity?

2.     Do children who engage in more physically active lifestyles at preschool age have higher levels of physical activity and lower levels of overweight and obesity at age 7?

3.     How is physical activity at age 7 socially and ethnically patterned?

Data Collection and Analysis

Parents/carers and children were invited to take part in the physical activity project at the seven year survey. Those who agreed to take part were contacted by the ICH physical activity team and sent an activity monitor for the cohort child to wear for up to 7 days.  Monitors were returned by post and analysed for duration and intensity of activity and the results will be linked to relevant variables in MCS in order to address the specified research questions.

At May 2010, 12,810 accelerometers had been sent to cohort children and 9,424 (74% of those sent) had been returned. Of these, 8,465 (66% of those sent) had been worn. Accelerometer data are being cleaned and processed at ICH and will be linked to the main MCS4 data to examine biases in consent and response.

Ethics Approval: Northern and Yorkshire REC 07/MRE03/32

Funding: The Wellcome Trust

Project Team:

Professor Carol Dezateux, Principal Investigator, Institute of Child Health, UCL

Dr Lucy Griffiths, Co-Investigator, Institute of Child Health, UCL