Table 1.

Year of survey, age, number and attendance rate of eligible participants (the Tromsø Study)

Survey year	Men			Women
	age group, years	participants, n	Attendance rate, %	age group, years	participants, n	Attendance rate, %
1974	20–49	6,595	74.4	–	–	–
1979–80	20–54	8,477	73.8	20–49	8,143	81.8
1986–87	12–64	10,963	71.8	12–67	10,863	79.0
1994–95	25–97	12,865	69.6	25–97	14,293	74.9
2001–02	30–89	3,511	75.7	30–89	4,619	80.8
2007–08	30–87	6,054	62.9	30–87	6,930	68.4