Table 1. Baseline characteristics, by randomised arm and gender.

		Randomised arm (male)			Randomised arm (female)
		8-week (n = 7,417)	10-week (n = 7,413)	12-week (n = 7,411)	12-week (n = 7,549)	14-week (n = 7,545)	16-week (n = 7,528)
Mean (SD) age (years)		44.7 (14.1)	44.7 (14.2)	44.7 (14.2)	40.77 (14.0)	40.89 (13.9)	40.94 (14.0)
Blood type n (%)	High demand	996 (13.43)	933 (12.59)	965 (13.02)	1,130 (14.97)	1,062 (14.08)	1,002 (13.31)
	Standard demand	6,421 (86.57)	6,480 (87.41)	6,446 (86.98)	6,419 (85.03)	6,483 (85.92)	6,526 (86.69)
Ethnicity n (%)	White	6,751 (91.02)	6,752 (91.08)	6,745 (91.01)	6,984 (92.52)	6,992 (92.67)	6,949 (92.31)
	Black/mixed black	101 (1.36)	96 (1.30)	100 (1.35)	103 (1.36)	93 (1.23)	134 (1.78)
	Asian/mixed Asian	255 (3.44)	271 (3.66)	258 (3.48)	171 (2.27)	177 (2.35)	154 (2.05)
	Other or not stated	310 (4.18)	294 (3.97)	308 (4.16)	291 (3.85)	283 (3.75)	291 (3.87)
New donor n (%)	No	6,817 (91.91)	6,818 (91.97)	6,818 (92.00)	6,742 (89.31)	6,744 (89.38)	6,727 (89.36)
	Yes	600 (8.09)	595 (8.03)	593 (8.00)	807 (10.69)	801 (10.62)	801 (10.64)
Recruitment source n (%)	Centre	4,907 (66.16)	4,840 (65.29)	4,855 (65.51)	4,851 (64.26)	4,921 (65.22)	4,901 (65.10)
	Mobile	1,437 (19.37)	1,510 (20.37)	1,512 (20.40)	1,545 (20.47)	1,482 (19.64)	1,486 (19.74)
	No invite	1,073 (14.47)	1,063 (14.34)	1,044 (14.09)	1,153 (15.27)	1,142 (15.14)	1,141 (15.16)
Mean (SD) deferrals for low Hb in previous 2 years		0.04 (0.24)	0.04 (0.23)	0.04 (0.24)	0.12 (0.39)	0.12 (0.38)	0.12 (0.39)
Mean (SD) deferrals for other reasons in previous 2 years		0.32 (0.69)	0.32 (0.68)	0.32 (0.69)	0.36 (0.68)	0.34 (0.68)	0.34 (0.68)
Mean (SD) number of blood donation visits in previous 2 years		4.19 (2.40)	4.22 (2.42)	4.18 (2.40)	3.46 (1.91)	3.45 (1.89)	3.44 (1.93)
Mean (SD) SF-6D score at baseline		0.86 (0.08)	0.86 (0.08)	0.86 (0.09)	0.85 (0.09)	0.85 (0.09)	0.85 (0.09)