(Agencies)
Updated: 2007-11-23 15:07

PARIS - Active parents can, by their example, encourage their children to be physically active, but the effect is less than widely thought, according to a study of more than 5,000 10- and 11-year-olds published Friday.

Its findings touch on strategies for reducing diseases such as obesity, cardiovascular conditions and diabetes that are growing at epidemic proportions due mainly to a couch-potato lifestyle.

A team of British and US researchers led by Calum Mattocks of the University of Bristol monitored 4,451 children for at least 10 hours a day over three days, tracking the intensity and frequency of their exercise with accelerometers attached to their ankles.

The children were also asked to record any time they swam or rode bicycles because the devices do not monitor these activities accurately.

The researchers then compared the results against statements provided by the parents on their level of physical activity in several categories.

These included maternal walking or swimming during pregnancy, parental exercise when the child was 21 months old, maternal smoking during pregnancy, and parental smoking at an early age.

Surprisingly, children of smoking parents tended to be slightly more active physically than kids whose parents were non-smokers.

"Few of the early life factors were associated with later physical activity in 10- to 11-year-olds, and for those that were, the association was modest," says the study, published in the British journal The Lancet.

But even the scarcity of links is important, the researchers said.

It can help health officials provide guidelines to parents which emphasise the factors - however few - that are known to work, they said.