Table 1

 Description of sample before and after smoke-free legislation in Scotland. Values are numbers (percentages) unless stated otherwise

Characteristic2006 (n=2532)2007 (n=2389)
Mean age (years)11.511.4
Boys1289 (50.9)1227 (51.4)
Family affluence scale*:(n=2445)(n=2258)
 Low803 (32.8)739 (32.7)
 Medium825 (33.7)763 (33.8)
 High817 (33.4)756 (33.5)
Cotinine confirmed smoking status†:
 Non-smokers2339 (92.3)2217 (92.8)
 Smokers46 (1.8)35 (1.5)
 Missing‡147 (5.8)137 (5.7)
Family structure (parent figures that sample lives with):
 Both parents1723 (68.0)1602 (67.1)
 Parent and step parent240 (9.5)229 (9.6)
 Single mother453 (17.9)432 (18.1)
 Single father45 (1.8)41 (1.7)
 Other§36 (1.4)35 (1.5)
 Unclassifiable17 (0.7)33 (1.4)
 Missing18 (0.7)17 (0.7)

*Pupils who reported living in both parent, step, or single parent families only.

†Non-smokers=self reported non-smokers with cotinine concentrations <15 ng/ml; smokers=cotinine concentrations >15 mg/ml regardless of self reported smoking status.

‡Pupils who did not answer the smoking question or have a cotinine concentration assigned to them by the laboratory.

§Pupils who reported to be living in a foster home or children's home or some other arrangement.