Table 1

Description of the sample
		Invited	Participated frequency	Participated percent	χ²

Total		2712	1803	66.5
Gender	Men	560	368	65.7	0.2
	Women	2150	1433	66.7
Age	-29	152	87	57.2	18.1**
	30–39	570	350	61.4
	40–49	781	540	69.1
	50–59	826	573	69.4
	60-	381	251	65.9
Department	Health and Social	1184	773	65.3	24.7***
	Culture and Leisure	106	68	64.2
	Administration	78	69	88.5
	School and Kindergarten	1031	688	66.7
	Technical	301	193	64.1
Occupation groups	Low-skilled blue-collar workers	135	68	50.4	48.7***
	High-skilled blue-collar workers	77	43	55.8
	Low-skilled white-collar workers	1093	678	62.0
	High-skilled white-collar workers	1405	1012	72.0

Note: * p < 0.05, p < 0.01, * p < 0.001
Lau Journal of Occupational Medicine and Toxicology 2008 3:9 doi:10.1186/1745-6673-3-9