Medicine & Science in Sports & Exercise:
A-35 Free Communication/Poster - Epidemiology - Disease Prevention/Treament - Youth: JUNE 1, 2011 7:30 AM - 12:30 PM: ROOM: Hall B
1University of Bristol, Bristol, United Kingdom. 2University of Glasgow, Glasgow, United Kingdom. 3University of Bath, Bath, United Kingdom. 4University of South Carolina, Columbia, SC.
(No relationships reported)
PURPOSE: The aim of this study was to investigate associations between objectively measured physical activity assessed at ages 12, 14 and 16 and CVD risk factors measured at age 16 in the Avon Longitudinal Study of Parents and Children (ALSPAC) a large population-based prospective study
METHODS: All children who attended research clinics at ages 12, 14 and 16 had measures of physical activity, fat mass, height and blood pressure. They were asked to wear a uni-axial accelerometer for seven days. Fat mass was measured using a DXA scanner. Height was measured with shoes and socks removed. Blood pressure was measured using an automated device. At the 16 year clinic participants were asked to fast overnight or for a minimum of 6 hours. Blood samples were immediately spun and frozen at -80oC. Samples were assayed for plasma lipids (total cholesterol, triglycerides and HDL) using a modification of the standard Lipid Research Clinics Protocol. Insulin was measured by an ELISA assay that does not cross-react with pro-insulin and plasma glucose was measured by automated assay.
RESULTS: A total of 4431 subjects provided physical activity and fat mass data at one or more time points. Blood samples at age 16 were provided by 3496 people. Higher levels of physical activity in childhood were associated with reduced fat mass in adolescence. Higher levels of physical activity were also associated with more favourable levels of insulin, LDL cholesterol, HDL cholesterol and triglycerides, with these associations being mediated largely by associations of physical activity with fat mass. For example, a 100 counts/min higher total activity level at age 12 was associated with a 2.3% (95% CI 3.6, 1.0) lower insulin level at age 16, with this association attenuating to -0.0% (95% CI -1.3, 1.3) after adjustment for 16 year fat mass.
CONCLUSIONS: Greater levels of objectively measured physical activity in childhood are prospectively associated with lower fat mass in adolescence and as a consequence reduced CVD risk profiles