In our study, participant schools were selected by educational authorities; the schoolchildren samples were selected from whole classes to be screened by their usual teacher (who received the training).
In a random sub-sample of some 200 schoolchildren, a sample of venous blood was taken to measure serum retinol, as an indicator of vitamin A status, and to measure blood lipids.
Two southern European samples of schoolchildren (a Spanish sample and an Italian sample) [2, 15] showed very low percentages of subjects assigned to grade 4 or 5 of the DHC (21.8% to 17.1% and 27.3%, respectively) when compared with the Albanian sample.
A total of 954 schoolchildren was sampled, obtaining an accuracy level of ±3%, 5% alpha error, an anticipated proportion of 50% (situation of maximum uncertainty), and loss rate of 6%.
The study also found that some Mexican erasers popular with schoolchildren and several samples of glazed clay pottery advertised as lead-free contained high levels of the heavy metal.
The sample of schoolchildren was selected in 2011, through a sampling process involving two random stages.
estimates based on a representative sample of schoolchildren with Japanese estimates based on an upper-income, heavily urban sample.
In study 1, a sample of schoolchildren (n = 62; M = 12.48 years; SD = 1.72) took part in a cold-pressor task.
This study was designed to (1) provide information on the prevalence of pediatric pain as well as other pain related characteristics in a sample of schoolchildren, and (2) study the suitability of a system to grade the severity of chronic pain problems among children.
Population: A group of children with migraine identified from 3 sources: (a) children with migraine who were identified through a random sample of schoolchildren, (b) children with migraine attending specialist clinics and (c) children with migraine who are members related to members of Migraine Action.
