Table 2. Questionnaire and fingernail sampling response among children of the two major public schools of the town.

Test	Comment	Participation n (%)
Population:	total	432 (100.0)
	drop-outs1	14 (3.2)
	study population	418 (96.8)
Questionnaire:	handed-out	418 (100.0)
	returned	338 (80.9)
	at least partially completed	288 (68.9)
Fingernail sampling:		219 (52.4)

¹Children who dropped out at various points in time because of relocation or absence for other reasons than health.