Neurobehavioral effects of transportation noise in primary schoolchildren: a cross-sectional study

Table 1 Characteristics of the children that completed the NES and whose parents returned their questionnaire (n = 485) and the schools they visit (n = 24).

	%	Mean +/- Std	Range
Age (yrs)		10.5 +/- 0.6	8.8 - 12.8
% girls	48.8
Socio-economic status
% employed^a)	91.9
% crowded^b)	32.9
% homeowners	81.4
Mother's education (index 0-1)^c)		0.5 +/- 0.3	0.0 - 1.0
% longstanding illness^d)	27.7
% ADHD	1.9
% dyslexia	3.5
% main language at home is Dutch	93.4
Parental support (scale 1-12)^e)		8.6 +/- 1.9	3 - 12
Glazing
% Single glazing at school	47.8
% Double glazing at school	49.5
% Triple glazing at school	2.7
% Double glazing at home	55.6
Noise exposure (L_{Aeq, 7-23 hr}) in dB(A)
Aircraft noise at school		48.6 +/- 7.1^f)	36.3 - 62.8
Aircraft noise at home		48.1 +/- 7.1^f)	34.5 - 63.4
Road traffic noise at school		48.7 +/- 8.6^f)	34.0 - 62.0
Road traffic noise at home		50.2 +/- 7.3^f)	28.0 - 67.0

a) measure of the highest employment status in the child's household. At least one of the parents has to do paid work for at least 19 hrs per week.; b) This is an objective measure of the number of people per room at home. If the number of people is smaller/equal to the number of rooms than the child's household is defined as crowded; c) Mother's education was measured using a ranked index of standard qualifications. A relative index was then calculated for this variable in order to make comparisons between different measures in each country. The index ranges from 0 to 1, with higher number indicating low educational attainment; d) based on parental reports of the child having either attention deficit hyperactivity disorder (ADHD), asthma/bronchitis, eczema, epilepsy, depression, diabetes or dyslexia; e) parental support for school work is assessed by a self-report scale in the children's questionnaire This ordinal scale (alpha = 0.65) was constructed by means of the following items: "If I have a problem at school my parents/carers are ready to help." "My parents/carers are willing to come to school and talk to teachers", and "My parents/carers encourage me to do well at school". Answers were indicated on a 4-point category scale ("Never, sometimes, often, always"). The score on each of the items was summed up (possible score 3-12); f) presented are the arithmetic mean and corresponding standard deviation; Abbreviations: Std = Standard Deviation.

ISSN: 1476-069X