Table 1.

Characteristics of the population-based controls associated with each blood sample (N = 2223).

	N (%)	Time of sample collection
		Wave 1	Wave 2	Wave 3
		N (%)	N (%)	N (%)
Total	2223	414 (19)	889 (40)	920 (41)
Age
<20y	392 (18)	39 (10)	172 (44)	181 (46)
20–39y	658 (30)	137 (21)	248 (38)	273 (41)
40–59y	671 (30)	116 (17)	266 (40)	289 (43)
60y+	502 (23)	122 (24)	203 (40)	177 (35)
Sex
Men	1037 (47)	191 (18)	401 (39)	445 (43)
Women	1186 (53)	223 (19)	448 (41)	475 (40)
Region
Non-metropolitan region	714 (32)	95 (13)	284 (40)	335 (47)
Metropolitan region	1509 (68)	319 (21)	605 (40)	585 (39)