Table 2.

Number of participants by gender, age, and socio-economic status.

Variable		N	% valid
Gender	Male	1,034	44.8
	Female	1,276	55.2
	Missing#	1
Age	17–19 years	69	3.0
	20–29 years	240	10.5
	30–39 years	293	12.8
	40–49 years	420	18.4
	50–59 years	344	15.1
	60–69 years	440	19.3
	70–79 years	322	14.1
	80 years and more	155	6.8
	Missing	28
Socio-economic status	Low	318	14.6
	Middle	1,145	52.5
	High	717	32.9
	Missing	131

^#In one case during the study (between study part I and II) a sex change occurred.