Table III.

Univariate and multivariate logistic regression analyses on return donors vs non-return donors.

Characteristic	Men		Women
	Unadjusted OR (95% CI)	Adjusted OR* (95% CI)	Unadjusted OR (95% CI)	Adjusted OR* (95% CI)
Age
18–29	1.0	1.0	1.0	1.0
30–49	1.81 (1.39–2.35)	1.64 (1.20–2.25)	1.36 (1.10–1.68)	1.36 (1.07–1.73)
≥50	2.60 (2.01–3.37)	1.85 (1.31–2.59)	2.63 (2.10–3.30)	2.09 (1.57–2.78)
Blood type
Not O-negative	1.00	1.0	1.0	1.0
O-negative	0.74 (0.59–0.93)	0.82 (0.64–1.05)	0.78 (0.62–0.98)	0.83 (0.65–1.07)
Return rate in previous 4 years
0%–25%	1.0	1.0	1.0	1.0
26%–50%	1.01 (0.68–1.49)	0.92 (0.62–1.39)	0.53 (0.37–0.74)	0.49 (0.34–0.70)
51%–75%	1.91 (1.31–2.79)	1.71 (1.15–2.54)	1.22 (0.89–1.69)	1.10 (0.78–1.54)
76%–100%	6.34 (4.34–9.26)	5.39 (3.63–8.01)	2.98 (2.16–4.09)	2.48 (1.78–3.47)
Lifetime donations
0–5	1.0	1.0	1.0	1.0
6–10	1.12 (0.79–1.59)	1.11 (0.76–1.62)	1.12 (0.87–1.44)	1.08 (0.82–1.42)
11–20	1.24 (0.91–1.68)	1.06 (0.75–1.51)	1.04 (0.82–1.31)	0.90 (0.69–1.19)
≥21	2.07 (1.64–2.63)	1.35 (0.98–1.85)	1.96 (1.59–2.41)	1.29 (0.98–1.68)
Deferral
No	1.0	1.0	1.0	1.0
Yes	0.84 (0.72–0.99)	0.73 (0.61–0.88)	0.76 (0.64–0.90)	0.78 (0.64–0.95)

^*Adjusted for all other variables included in the model.