Washington, Aug 18 (IANS):  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 2.1 time higher risk of developing headaches.

Parents' behaviour when their child complained of a headache also seemed to play a major role.

Their responses had a particularly strong effect on the frequency of symptoms in girls: reinforcing parental responses raised their risk of recurrent headaches by 25 percent.

The sexes also differed with respect to the frequency of headache. Twice as many girls as boys had their symptoms at least once a week.

The children's age, however, seemed to have no more than a minor effect on headache manifestations.

These findings appeared in the current issue of the Deutsches �rzteblatt International.