Table 1.

Characterization of the cohort

	Participants		Blood donors not participatinga
	Women	Men	Women	Men
Numbers	70 657	67 834	186 893	146 411
Age (years)	36 (25–48)	39 (28–50)	33 (24–46)	39 (27–52)
Age strata (%)
18–25	26.9	18.2	31.0	20.4
26–35	22.3	24.7	24.0	23.0
36–45	21.2	22.6	18.3	18.6
46–55	18.7	20.7	15.8	19.0
56–70	10.8	13.8	10.8	18.9
Haemoglobin (mmol/L)	137.0 (130.5–141.8)	151.5 (146.6–157.9)	135.4 (128.9–141.8)	151.5 (145–157.9)
Full blood donationsb
Number of donors	68 235	64 578	184 675	143 527
Donations during the past year	2 (2–3)	2 (2–3)	2 (1–2)	2 (1–3)
Donations during the past 3 years	4 (3–6)	5 (3–8)	2 (1–4)	3 (1–6)
Donations during the past 5 years	6 (3–9)	7 (4–12)	3 (1–5)	4 (1–8)
Plasma donations
Number of donors	5003	6945	3614	4640
Donations during the past year	3 (2–4)	3 (2–5)	2 (1–3)	2 (1–3)
Donations during the past 3 years	3 (2–6)	4 (2–8)	2 (1–3)	2 (1–4)
Donations during the past 5 years	3 (2–6)	4 (2–8)	2 (1–3)	2 (1–4)
Current smoking status (%)	15.3	14.8	–	–
Weight (kg)	69 (62–78)	84 (77–93)	–	–
Height (cm)	169 (165–173)	182 (178–187)	–	–
BMI (kg/m2)	24 (21.9–27.0)	25.3 (23.4–27.8)	–	–
Short form 12c
Physical component score	57 (55–58)	57 (55–58)	–	–
Mental component score	55 (50–58)	56 (53–58)	–	–

Results are reported as medians (interquartile ranges), numbers, or percentages.

BMI, body mass index; Short form 12, The 12-Item Short Form Health Survey.

^aBlood donors not participating are defined as donors who had not yet received invitation and participant information. The number of blood donors who have declined to participate upon invitation is 4.0%.

^bFull blood donors/plasma donors are defined as donors with at least one full blood/plasma donation during the past year before inclusion (including the inclusion donation).

^cShort form 12: higher scores reflect higher self-reported health-related quality of life.