Washington, Aug 18 - Family quarrels and a lack of free time can bring on headaches among children, says a new study.

Up to 30 percent of all kids worldwide complain of headaches arising at least once a week, say Jennifer Gassmann of the Cleveland Clinic, Ohio and her co-authors of the study.

This investigation was a component of a large-scale study entitled 'Children, Adolescents, and Headache', in which data was collected in four annual 'waves' from 2003 to 2006.

Out of a multitude of variables tested, study co-authors chose to look at the ones that concerned the children's family and leisure time.

Boys who experienced more than one family quarrel per week had a 1.8 time higher risk of

developing headaches.

The amount of free time available to them seemed to be even more important: boys who only sometimes had time to themselves had a 2.